Refuse to open a directory in the status and stage view

[tig] / tig.c

/* Copyright (c) 2006-2008 Jonas Fonseca <fonseca@diku.dk>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#ifndef TIG_VERSION
#define TIG_VERSION "unknown-version"
#endif

#ifndef DEBUG
#define NDEBUG
#endif

#include <assert.h>
#include <errno.h>
#include <ctype.h>
#include <signal.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <time.h>

#include <regex.h>

#include <locale.h>
#include <langinfo.h>
#include <iconv.h>

/* ncurses(3): Must be defined to have extended wide-character functions. */
#define _XOPEN_SOURCE_EXTENDED

#ifdef HAVE_NCURSESW_NCURSES_H
#include <ncursesw/ncurses.h>
#else
#ifdef HAVE_NCURSES_NCURSES_H
#include <ncurses/ncurses.h>
#else
#include <ncurses.h>
#endif
#endif

#if __GNUC__ >= 3
#define __NORETURN __attribute__((__noreturn__))
#else
#define __NORETURN
#endif

static void __NORETURN die(const char *err, ...);
static void warn(const char *msg, ...);
static void report(const char *msg, ...);
static int read_properties(FILE *pipe, const char *separators, int (*read)(char *, size_t, char *, size_t));
static void set_nonblocking_input(bool loading);
static size_t utf8_length(const char *string, int *width, size_t max_width, int *trimmed, bool reserve);
static bool prompt_yesno(const char *prompt);
static int load_refs(void);

#define ABS(x)          ((x) >= 0  ? (x) : -(x))
#define MIN(x, y)       ((x) < (y) ? (x) :  (y))

#define ARRAY_SIZE(x)   (sizeof(x) / sizeof(x[0]))
#define STRING_SIZE(x)  (sizeof(x) - 1)

#define SIZEOF_STR      1024    /* Default string size. */
#define SIZEOF_REF      256     /* Size of symbolic or SHA1 ID. */
#define SIZEOF_REV      41      /* Holds a SHA-1 and an ending NUL. */
#define SIZEOF_ARG      32      /* Default argument array size. */

/* Revision graph */

#define REVGRAPH_INIT   'I'
#define REVGRAPH_MERGE  'M'
#define REVGRAPH_BRANCH '+'
#define REVGRAPH_COMMIT '*'
#define REVGRAPH_BOUND  '^'

#define SIZEOF_REVGRAPH 19      /* Size of revision ancestry graphics. */

/* This color name can be used to refer to the default term colors. */
#define COLOR_DEFAULT   (-1)

#define ICONV_NONE      ((iconv_t) -1)
#ifndef ICONV_CONST
#define ICONV_CONST     /* nothing */
#endif

/* The format and size of the date column in the main view. */
#define DATE_FORMAT     "%Y-%m-%d %H:%M"
#define DATE_COLS       STRING_SIZE("2006-04-29 14:21 ")

#define AUTHOR_COLS     20
#define ID_COLS         8

/* The default interval between line numbers. */
#define NUMBER_INTERVAL 5

#define TAB_SIZE        8

#define SCALE_SPLIT_VIEW(height)        ((height) * 2 / 3)

#define NULL_ID         "0000000000000000000000000000000000000000"

#ifndef GIT_CONFIG
#define GIT_CONFIG "config"
#endif

#define TIG_LS_REMOTE \
        "git ls-remote . 2>/dev/null"

#define TIG_DIFF_CMD \
        "git show --pretty=fuller --no-color --root --patch-with-stat --find-copies-harder -C %s 2>/dev/null"

#define TIG_LOG_CMD     \
        "git log --no-color --cc --stat -n100 %s 2>/dev/null"

#define TIG_MAIN_BASE \
        "git log --no-color --pretty=raw --parents --topo-order"

#define TIG_MAIN_CMD \
        TIG_MAIN_BASE " %s 2>/dev/null"

#define TIG_TREE_CMD    \
        "git ls-tree %s %s"

#define TIG_BLOB_CMD    \
        "git cat-file blob %s"

/* XXX: Needs to be defined to the empty string. */
#define TIG_HELP_CMD    ""
#define TIG_PAGER_CMD   ""
#define TIG_STATUS_CMD  ""
#define TIG_STAGE_CMD   ""
#define TIG_BLAME_CMD   ""

/* Some ascii-shorthands fitted into the ncurses namespace. */
#define KEY_TAB         '\t'
#define KEY_RETURN      '\r'
#define KEY_ESC         27


struct ref {
        char *name;             /* Ref name; tag or head names are shortened. */
        char id[SIZEOF_REV];    /* Commit SHA1 ID */
        unsigned int head:1;    /* Is it the current HEAD? */
        unsigned int tag:1;     /* Is it a tag? */
        unsigned int ltag:1;    /* If so, is the tag local? */
        unsigned int remote:1;  /* Is it a remote ref? */
        unsigned int tracked:1; /* Is it the remote for the current HEAD? */
        unsigned int next:1;    /* For ref lists: are there more refs? */
};

static struct ref **get_refs(const char *id);

struct int_map {
        const char *name;
        int namelen;
        int value;
};

static int
set_from_int_map(struct int_map *map, size_t map_size,
                 int *value, const char *name, int namelen)
{

        int i;

        for (i = 0; i < map_size; i++)
                if (namelen == map[i].namelen &&
                    !strncasecmp(name, map[i].name, namelen)) {
                        *value = map[i].value;
                        return OK;
                }

        return ERR;
}


/*
 * String helpers
 */

static inline void
string_ncopy_do(char *dst, size_t dstlen, const char *src, size_t srclen)
{
        if (srclen > dstlen - 1)
                srclen = dstlen - 1;

        strncpy(dst, src, srclen);
        dst[srclen] = 0;
}

/* Shorthands for safely copying into a fixed buffer. */

#define string_copy(dst, src) \
        string_ncopy_do(dst, sizeof(dst), src, sizeof(src))

#define string_ncopy(dst, src, srclen) \
        string_ncopy_do(dst, sizeof(dst), src, srclen)

#define string_copy_rev(dst, src) \
        string_ncopy_do(dst, SIZEOF_REV, src, SIZEOF_REV - 1)

#define string_add(dst, from, src) \
        string_ncopy_do(dst + (from), sizeof(dst) - (from), src, sizeof(src))

static char *
chomp_string(char *name)
{
        int namelen;

        while (isspace(*name))
                name++;

        namelen = strlen(name) - 1;
        while (namelen > 0 && isspace(name[namelen]))
                name[namelen--] = 0;

        return name;
}

static bool
string_nformat(char *buf, size_t bufsize, size_t *bufpos, const char *fmt, ...)
{
        va_list args;
        size_t pos = bufpos ? *bufpos : 0;

        va_start(args, fmt);
        pos += vsnprintf(buf + pos, bufsize - pos, fmt, args);
        va_end(args);

        if (bufpos)
                *bufpos = pos;

        return pos >= bufsize ? FALSE : TRUE;
}

#define string_format(buf, fmt, args...) \
        string_nformat(buf, sizeof(buf), NULL, fmt, args)

#define string_format_from(buf, from, fmt, args...) \
        string_nformat(buf, sizeof(buf), from, fmt, args)

static int
string_enum_compare(const char *str1, const char *str2, int len)
{
        size_t i;

#define string_enum_sep(x) ((x) == '-' || (x) == '_' || (x) == '.')

        /* Diff-Header == DIFF_HEADER */
        for (i = 0; i < len; i++) {
                if (toupper(str1[i]) == toupper(str2[i]))
                        continue;

                if (string_enum_sep(str1[i]) &&
                    string_enum_sep(str2[i]))
                        continue;

                return str1[i] - str2[i];
        }

        return 0;
}

#define prefixcmp(str1, str2) \
        strncmp(str1, str2, STRING_SIZE(str2))

static inline int
suffixcmp(const char *str, int slen, const char *suffix)
{
        size_t len = slen >= 0 ? slen : strlen(str);
        size_t suffixlen = strlen(suffix);

        return suffixlen < len ? strcmp(str + len - suffixlen, suffix) : -1;
}

/* Shell quoting
 *
 * NOTE: The following is a slightly modified copy of the git project's shell
 * quoting routines found in the quote.c file.
 *
 * Help to copy the thing properly quoted for the shell safety.  any single
 * quote is replaced with '\'', any exclamation point is replaced with '\!',
 * and the whole thing is enclosed in a
 *
 * E.g.
 *  original     sq_quote     result
 *  name     ==> name      ==> 'name'
 *  a b      ==> a b       ==> 'a b'
 *  a'b      ==> a'\''b    ==> 'a'\''b'
 *  a!b      ==> a'\!'b    ==> 'a'\!'b'
 */

static size_t
sq_quote(char buf[SIZEOF_STR], size_t bufsize, const char *src)
{
        char c;

#define BUFPUT(x) do { if (bufsize < SIZEOF_STR) buf[bufsize++] = (x); } while (0)

        BUFPUT('\'');
        while ((c = *src++)) {
                if (c == '\'' || c == '!') {
                        BUFPUT('\'');
                        BUFPUT('\\');
                        BUFPUT(c);
                        BUFPUT('\'');
                } else {
                        BUFPUT(c);
                }
        }
        BUFPUT('\'');

        if (bufsize < SIZEOF_STR)
                buf[bufsize] = 0;

        return bufsize;
}


/*
 * User requests
 */

#define REQ_INFO \
        /* XXX: Keep the view request first and in sync with views[]. */ \
        REQ_GROUP("View switching") \
        REQ_(VIEW_MAIN,         "Show main view"), \
        REQ_(VIEW_DIFF,         "Show diff view"), \
        REQ_(VIEW_LOG,          "Show log view"), \
        REQ_(VIEW_TREE,         "Show tree view"), \
        REQ_(VIEW_BLOB,         "Show blob view"), \
        REQ_(VIEW_BLAME,        "Show blame view"), \
        REQ_(VIEW_HELP,         "Show help page"), \
        REQ_(VIEW_PAGER,        "Show pager view"), \
        REQ_(VIEW_STATUS,       "Show status view"), \
        REQ_(VIEW_STAGE,        "Show stage view"), \
        \
        REQ_GROUP("View manipulation") \
        REQ_(ENTER,             "Enter current line and scroll"), \
        REQ_(NEXT,              "Move to next"), \
        REQ_(PREVIOUS,          "Move to previous"), \
        REQ_(VIEW_NEXT,         "Move focus to next view"), \
        REQ_(REFRESH,           "Reload and refresh"), \
        REQ_(MAXIMIZE,          "Maximize the current view"), \
        REQ_(VIEW_CLOSE,        "Close the current view"), \
        REQ_(QUIT,              "Close all views and quit"), \
        \
        REQ_GROUP("View specific requests") \
        REQ_(STATUS_UPDATE,     "Update file status"), \
        REQ_(STATUS_REVERT,     "Revert file changes"), \
        REQ_(STATUS_MERGE,      "Merge file using external tool"), \
        REQ_(STAGE_NEXT,        "Find next chunk to stage"), \
        REQ_(TREE_PARENT,       "Switch to parent directory in tree view"), \
        \
        REQ_GROUP("Cursor navigation") \
        REQ_(MOVE_UP,           "Move cursor one line up"), \
        REQ_(MOVE_DOWN,         "Move cursor one line down"), \
        REQ_(MOVE_PAGE_DOWN,    "Move cursor one page down"), \
        REQ_(MOVE_PAGE_UP,      "Move cursor one page up"), \
        REQ_(MOVE_FIRST_LINE,   "Move cursor to first line"), \
        REQ_(MOVE_LAST_LINE,    "Move cursor to last line"), \
        \
        REQ_GROUP("Scrolling") \
        REQ_(SCROLL_LINE_UP,    "Scroll one line up"), \
        REQ_(SCROLL_LINE_DOWN,  "Scroll one line down"), \
        REQ_(SCROLL_PAGE_UP,    "Scroll one page up"), \
        REQ_(SCROLL_PAGE_DOWN,  "Scroll one page down"), \
        \
        REQ_GROUP("Searching") \
        REQ_(SEARCH,            "Search the view"), \
        REQ_(SEARCH_BACK,       "Search backwards in the view"), \
        REQ_(FIND_NEXT,         "Find next search match"), \
        REQ_(FIND_PREV,         "Find previous search match"), \
        \
        REQ_GROUP("Option manipulation") \
        REQ_(TOGGLE_LINENO,     "Toggle line numbers"), \
        REQ_(TOGGLE_DATE,       "Toggle date display"), \
        REQ_(TOGGLE_AUTHOR,     "Toggle author display"), \
        REQ_(TOGGLE_REV_GRAPH,  "Toggle revision graph visualization"), \
        REQ_(TOGGLE_REFS,       "Toggle reference display (tags/branches)"), \
        \
        REQ_GROUP("Misc") \
        REQ_(PROMPT,            "Bring up the prompt"), \
        REQ_(SCREEN_REDRAW,     "Redraw the screen"), \
        REQ_(SCREEN_RESIZE,     "Resize the screen"), \
        REQ_(SHOW_VERSION,      "Show version information"), \
        REQ_(STOP_LOADING,      "Stop all loading views"), \
        REQ_(EDIT,              "Open in editor"), \
        REQ_(NONE,              "Do nothing")


/* User action requests. */
enum request {
#define REQ_GROUP(help)
#define REQ_(req, help) REQ_##req

        /* Offset all requests to avoid conflicts with ncurses getch values. */
        REQ_OFFSET = KEY_MAX + 1,
        REQ_INFO

#undef  REQ_GROUP
#undef  REQ_
};

struct request_info {
        enum request request;
        const char *name;
        int namelen;
        const char *help;
};

static struct request_info req_info[] = {
#define REQ_GROUP(help) { 0, NULL, 0, (help) },
#define REQ_(req, help) { REQ_##req, (#req), STRING_SIZE(#req), (help) }
        REQ_INFO
#undef  REQ_GROUP
#undef  REQ_
};

static enum request
get_request(const char *name)
{
        int namelen = strlen(name);
        int i;

        for (i = 0; i < ARRAY_SIZE(req_info); i++)
                if (req_info[i].namelen == namelen &&
                    !string_enum_compare(req_info[i].name, name, namelen))
                        return req_info[i].request;

        return REQ_NONE;
}


/*
 * Options
 */

static const char usage[] =
"tig " TIG_VERSION " (" __DATE__ ")\n"
"\n"
"Usage: tig        [options] [revs] [--] [paths]\n"
"   or: tig show   [options] [revs] [--] [paths]\n"
"   or: tig blame  [rev] path\n"
"   or: tig status\n"
"   or: tig <      [git command output]\n"
"\n"
"Options:\n"
"  -v, --version   Show version and exit\n"
"  -h, --help      Show help message and exit";

/* Option and state variables. */
static bool opt_date                    = TRUE;
static bool opt_author                  = TRUE;
static bool opt_line_number             = FALSE;
static bool opt_line_graphics           = TRUE;
static bool opt_rev_graph               = FALSE;
static bool opt_show_refs               = TRUE;
static int opt_num_interval             = NUMBER_INTERVAL;
static int opt_tab_size                 = TAB_SIZE;
static int opt_author_cols              = AUTHOR_COLS-1;
static char opt_cmd[SIZEOF_STR]         = "";
static char opt_path[SIZEOF_STR]        = "";
static char opt_file[SIZEOF_STR]        = "";
static char opt_ref[SIZEOF_REF]         = "";
static char opt_head[SIZEOF_REF]        = "";
static char opt_remote[SIZEOF_REF]      = "";
static bool opt_no_head                 = TRUE;
static FILE *opt_pipe                   = NULL;
static char opt_encoding[20]            = "UTF-8";
static bool opt_utf8                    = TRUE;
static char opt_codeset[20]             = "UTF-8";
static iconv_t opt_iconv                = ICONV_NONE;
static char opt_search[SIZEOF_STR]      = "";
static char opt_cdup[SIZEOF_STR]        = "";
static char opt_git_dir[SIZEOF_STR]     = "";
static signed char opt_is_inside_work_tree      = -1; /* set to TRUE or FALSE */
static char opt_editor[SIZEOF_STR]      = "";
static FILE *opt_tty                    = NULL;

static enum request
parse_options(int argc, const char *argv[])
{
        enum request request = REQ_VIEW_MAIN;
        size_t buf_size;
        const char *subcommand;
        bool seen_dashdash = FALSE;
        int i;

        if (!isatty(STDIN_FILENO)) {
                opt_pipe = stdin;
                return REQ_VIEW_PAGER;
        }

        if (argc <= 1)
                return REQ_VIEW_MAIN;

        subcommand = argv[1];
        if (!strcmp(subcommand, "status") || !strcmp(subcommand, "-S")) {
                if (!strcmp(subcommand, "-S"))
                        warn("`-S' has been deprecated; use `tig status' instead");
                if (argc > 2)
                        warn("ignoring arguments after `%s'", subcommand);
                return REQ_VIEW_STATUS;

        } else if (!strcmp(subcommand, "blame")) {
                if (argc <= 2 || argc > 4)
                        die("invalid number of options to blame\n\n%s", usage);

                i = 2;
                if (argc == 4) {
                        string_ncopy(opt_ref, argv[i], strlen(argv[i]));
                        i++;
                }

                string_ncopy(opt_file, argv[i], strlen(argv[i]));
                return REQ_VIEW_BLAME;

        } else if (!strcmp(subcommand, "show")) {
                request = REQ_VIEW_DIFF;

        } else if (!strcmp(subcommand, "log") || !strcmp(subcommand, "diff")) {
                request = subcommand[0] == 'l' ? REQ_VIEW_LOG : REQ_VIEW_DIFF;
                warn("`tig %s' has been deprecated", subcommand);

        } else {
                subcommand = NULL;
        }

        if (!subcommand)
                /* XXX: This is vulnerable to the user overriding
                 * options required for the main view parser. */
                string_copy(opt_cmd, TIG_MAIN_BASE);
        else
                string_format(opt_cmd, "git %s", subcommand);

        buf_size = strlen(opt_cmd);

        for (i = 1 + !!subcommand; i < argc; i++) {
                const char *opt = argv[i];

                if (seen_dashdash || !strcmp(opt, "--")) {
                        seen_dashdash = TRUE;

                } else if (!strcmp(opt, "-v") || !strcmp(opt, "--version")) {
                        printf("tig version %s\n", TIG_VERSION);
                        return REQ_NONE;

                } else if (!strcmp(opt, "-h") || !strcmp(opt, "--help")) {
                        printf("%s\n", usage);
                        return REQ_NONE;
                }

                opt_cmd[buf_size++] = ' ';
                buf_size = sq_quote(opt_cmd, buf_size, opt);
                if (buf_size >= sizeof(opt_cmd))
                        die("command too long");
        }

        opt_cmd[buf_size] = 0;

        return request;
}


/*
 * Line-oriented content detection.
 */

#define LINE_INFO \
LINE(DIFF_HEADER,  "diff --git ",       COLOR_YELLOW,   COLOR_DEFAULT,  0), \
LINE(DIFF_CHUNK,   "@@",                COLOR_MAGENTA,  COLOR_DEFAULT,  0), \
LINE(DIFF_ADD,     "+",                 COLOR_GREEN,    COLOR_DEFAULT,  0), \
LINE(DIFF_DEL,     "-",                 COLOR_RED,      COLOR_DEFAULT,  0), \
LINE(DIFF_INDEX,        "index ",         COLOR_BLUE,   COLOR_DEFAULT,  0), \
LINE(DIFF_OLDMODE,      "old file mode ", COLOR_YELLOW, COLOR_DEFAULT,  0), \
LINE(DIFF_NEWMODE,      "new file mode ", COLOR_YELLOW, COLOR_DEFAULT,  0), \
LINE(DIFF_COPY_FROM,    "copy from",      COLOR_YELLOW, COLOR_DEFAULT,  0), \
LINE(DIFF_COPY_TO,      "copy to",        COLOR_YELLOW, COLOR_DEFAULT,  0), \
LINE(DIFF_RENAME_FROM,  "rename from",    COLOR_YELLOW, COLOR_DEFAULT,  0), \
LINE(DIFF_RENAME_TO,    "rename to",      COLOR_YELLOW, COLOR_DEFAULT,  0), \
LINE(DIFF_SIMILARITY,   "similarity ",    COLOR_YELLOW, COLOR_DEFAULT,  0), \
LINE(DIFF_DISSIMILARITY,"dissimilarity ", COLOR_YELLOW, COLOR_DEFAULT,  0), \
LINE(DIFF_TREE,         "diff-tree ",     COLOR_BLUE,   COLOR_DEFAULT,  0), \
LINE(PP_AUTHOR,    "Author: ",          COLOR_CYAN,     COLOR_DEFAULT,  0), \
LINE(PP_COMMIT,    "Commit: ",          COLOR_MAGENTA,  COLOR_DEFAULT,  0), \
LINE(PP_MERGE,     "Merge: ",           COLOR_BLUE,     COLOR_DEFAULT,  0), \
LINE(PP_DATE,      "Date:   ",          COLOR_YELLOW,   COLOR_DEFAULT,  0), \
LINE(PP_ADATE,     "AuthorDate: ",      COLOR_YELLOW,   COLOR_DEFAULT,  0), \
LINE(PP_CDATE,     "CommitDate: ",      COLOR_YELLOW,   COLOR_DEFAULT,  0), \
LINE(PP_REFS,      "Refs: ",            COLOR_RED,      COLOR_DEFAULT,  0), \
LINE(COMMIT,       "commit ",           COLOR_GREEN,    COLOR_DEFAULT,  0), \
LINE(PARENT,       "parent ",           COLOR_BLUE,     COLOR_DEFAULT,  0), \
LINE(TREE,         "tree ",             COLOR_BLUE,     COLOR_DEFAULT,  0), \
LINE(AUTHOR,       "author ",           COLOR_CYAN,     COLOR_DEFAULT,  0), \
LINE(COMMITTER,    "committer ",        COLOR_MAGENTA,  COLOR_DEFAULT,  0), \
LINE(SIGNOFF,      "    Signed-off-by", COLOR_YELLOW,   COLOR_DEFAULT,  0), \
LINE(ACKED,        "    Acked-by",      COLOR_YELLOW,   COLOR_DEFAULT,  0), \
LINE(DEFAULT,      "",                  COLOR_DEFAULT,  COLOR_DEFAULT,  A_NORMAL), \
LINE(CURSOR,       "",                  COLOR_WHITE,    COLOR_GREEN,    A_BOLD), \
LINE(STATUS,       "",                  COLOR_GREEN,    COLOR_DEFAULT,  0), \
LINE(DELIMITER,    "",                  COLOR_MAGENTA,  COLOR_DEFAULT,  0), \
LINE(DATE,         "",                  COLOR_BLUE,     COLOR_DEFAULT,  0), \
LINE(LINE_NUMBER,  "",                  COLOR_CYAN,     COLOR_DEFAULT,  0), \
LINE(TITLE_BLUR,   "",                  COLOR_WHITE,    COLOR_BLUE,     0), \
LINE(TITLE_FOCUS,  "",                  COLOR_WHITE,    COLOR_BLUE,     A_BOLD), \
LINE(MAIN_AUTHOR,  "",                  COLOR_GREEN,    COLOR_DEFAULT,  0), \
LINE(MAIN_COMMIT,  "",                  COLOR_DEFAULT,  COLOR_DEFAULT,  0), \
LINE(MAIN_TAG,     "",                  COLOR_MAGENTA,  COLOR_DEFAULT,  A_BOLD), \
LINE(MAIN_LOCAL_TAG,"",                 COLOR_MAGENTA,  COLOR_DEFAULT,  0), \
LINE(MAIN_REMOTE,  "",                  COLOR_YELLOW,   COLOR_DEFAULT,  0), \
LINE(MAIN_TRACKED, "",                  COLOR_YELLOW,   COLOR_DEFAULT,  A_BOLD), \
LINE(MAIN_REF,     "",                  COLOR_CYAN,     COLOR_DEFAULT,  0), \
LINE(MAIN_HEAD,    "",                  COLOR_CYAN,     COLOR_DEFAULT,  A_BOLD), \
LINE(MAIN_REVGRAPH,"",                  COLOR_MAGENTA,  COLOR_DEFAULT,  0), \
LINE(TREE_DIR,     "",                  COLOR_DEFAULT,  COLOR_DEFAULT,  A_NORMAL), \
LINE(TREE_FILE,    "",                  COLOR_DEFAULT,  COLOR_DEFAULT,  A_NORMAL), \
LINE(STAT_HEAD,    "",                  COLOR_YELLOW,   COLOR_DEFAULT,  0), \
LINE(STAT_SECTION, "",                  COLOR_CYAN,     COLOR_DEFAULT,  0), \
LINE(STAT_NONE,    "",                  COLOR_DEFAULT,  COLOR_DEFAULT,  0), \
LINE(STAT_STAGED,  "",                  COLOR_MAGENTA,  COLOR_DEFAULT,  0), \
LINE(STAT_UNSTAGED,"",                  COLOR_MAGENTA,  COLOR_DEFAULT,  0), \
LINE(STAT_UNTRACKED,"",                 COLOR_MAGENTA,  COLOR_DEFAULT,  0), \
LINE(BLAME_ID,     "",                  COLOR_MAGENTA,  COLOR_DEFAULT,  0)

enum line_type {
#define LINE(type, line, fg, bg, attr) \
        LINE_##type
        LINE_INFO,
        LINE_NONE
#undef  LINE
};

struct line_info {
        const char *name;       /* Option name. */
        int namelen;            /* Size of option name. */
        const char *line;       /* The start of line to match. */
        int linelen;            /* Size of string to match. */
        int fg, bg, attr;       /* Color and text attributes for the lines. */
};

static struct line_info line_info[] = {
#define LINE(type, line, fg, bg, attr) \
        { #type, STRING_SIZE(#type), (line), STRING_SIZE(line), (fg), (bg), (attr) }
        LINE_INFO
#undef  LINE
};

static enum line_type
get_line_type(const char *line)
{
        int linelen = strlen(line);
        enum line_type type;

        for (type = 0; type < ARRAY_SIZE(line_info); type++)
                /* Case insensitive search matches Signed-off-by lines better. */
                if (linelen >= line_info[type].linelen &&
                    !strncasecmp(line_info[type].line, line, line_info[type].linelen))
                        return type;

        return LINE_DEFAULT;
}

static inline int
get_line_attr(enum line_type type)
{
        assert(type < ARRAY_SIZE(line_info));
        return COLOR_PAIR(type) | line_info[type].attr;
}

static struct line_info *
get_line_info(const char *name)
{
        size_t namelen = strlen(name);
        enum line_type type;

        for (type = 0; type < ARRAY_SIZE(line_info); type++)
                if (namelen == line_info[type].namelen &&
                    !string_enum_compare(line_info[type].name, name, namelen))
                        return &line_info[type];

        return NULL;
}

static void
init_colors(void)
{
        int default_bg = line_info[LINE_DEFAULT].bg;
        int default_fg = line_info[LINE_DEFAULT].fg;
        enum line_type type;

        start_color();

        if (assume_default_colors(default_fg, default_bg) == ERR) {
                default_bg = COLOR_BLACK;
                default_fg = COLOR_WHITE;
        }

        for (type = 0; type < ARRAY_SIZE(line_info); type++) {
                struct line_info *info = &line_info[type];
                int bg = info->bg == COLOR_DEFAULT ? default_bg : info->bg;
                int fg = info->fg == COLOR_DEFAULT ? default_fg : info->fg;

                init_pair(type, fg, bg);
        }
}

struct line {
        enum line_type type;

        /* State flags */
        unsigned int selected:1;
        unsigned int dirty:1;

        void *data;             /* User data */
};


/*
 * Keys
 */

struct keybinding {
        int alias;
        enum request request;
        struct keybinding *next;
};

static struct keybinding default_keybindings[] = {
        /* View switching */
        { 'm',          REQ_VIEW_MAIN },
        { 'd',          REQ_VIEW_DIFF },
        { 'l',          REQ_VIEW_LOG },
        { 't',          REQ_VIEW_TREE },
        { 'f',          REQ_VIEW_BLOB },
        { 'B',          REQ_VIEW_BLAME },
        { 'p',          REQ_VIEW_PAGER },
        { 'h',          REQ_VIEW_HELP },
        { 'S',          REQ_VIEW_STATUS },
        { 'c',          REQ_VIEW_STAGE },

        /* View manipulation */
        { 'q',          REQ_VIEW_CLOSE },
        { KEY_TAB,      REQ_VIEW_NEXT },
        { KEY_RETURN,   REQ_ENTER },
        { KEY_UP,       REQ_PREVIOUS },
        { KEY_DOWN,     REQ_NEXT },
        { 'R',          REQ_REFRESH },
        { KEY_F(5),     REQ_REFRESH },
        { 'O',          REQ_MAXIMIZE },

        /* Cursor navigation */
        { 'k',          REQ_MOVE_UP },
        { 'j',          REQ_MOVE_DOWN },
        { KEY_HOME,     REQ_MOVE_FIRST_LINE },
        { KEY_END,      REQ_MOVE_LAST_LINE },
        { KEY_NPAGE,    REQ_MOVE_PAGE_DOWN },
        { ' ',          REQ_MOVE_PAGE_DOWN },
        { KEY_PPAGE,    REQ_MOVE_PAGE_UP },
        { 'b',          REQ_MOVE_PAGE_UP },
        { '-',          REQ_MOVE_PAGE_UP },

        /* Scrolling */
        { KEY_IC,       REQ_SCROLL_LINE_UP },
        { KEY_DC,       REQ_SCROLL_LINE_DOWN },
        { 'w',          REQ_SCROLL_PAGE_UP },
        { 's',          REQ_SCROLL_PAGE_DOWN },

        /* Searching */
        { '/',          REQ_SEARCH },
        { '?',          REQ_SEARCH_BACK },
        { 'n',          REQ_FIND_NEXT },
        { 'N',          REQ_FIND_PREV },

        /* Misc */
        { 'Q',          REQ_QUIT },
        { 'z',          REQ_STOP_LOADING },
        { 'v',          REQ_SHOW_VERSION },
        { 'r',          REQ_SCREEN_REDRAW },
        { '.',          REQ_TOGGLE_LINENO },
        { 'D',          REQ_TOGGLE_DATE },
        { 'A',          REQ_TOGGLE_AUTHOR },
        { 'g',          REQ_TOGGLE_REV_GRAPH },
        { 'F',          REQ_TOGGLE_REFS },
        { ':',          REQ_PROMPT },
        { 'u',          REQ_STATUS_UPDATE },
        { '!',          REQ_STATUS_REVERT },
        { 'M',          REQ_STATUS_MERGE },
        { '@',          REQ_STAGE_NEXT },
        { ',',          REQ_TREE_PARENT },
        { 'e',          REQ_EDIT },

        /* Using the ncurses SIGWINCH handler. */
        { KEY_RESIZE,   REQ_SCREEN_RESIZE },
};

#define KEYMAP_INFO \
        KEYMAP_(GENERIC), \
        KEYMAP_(MAIN), \
        KEYMAP_(DIFF), \
        KEYMAP_(LOG), \
        KEYMAP_(TREE), \
        KEYMAP_(BLOB), \
        KEYMAP_(BLAME), \
        KEYMAP_(PAGER), \
        KEYMAP_(HELP), \
        KEYMAP_(STATUS), \
        KEYMAP_(STAGE)

enum keymap {
#define KEYMAP_(name) KEYMAP_##name
        KEYMAP_INFO
#undef  KEYMAP_
};

static struct int_map keymap_table[] = {
#define KEYMAP_(name) { #name, STRING_SIZE(#name), KEYMAP_##name }
        KEYMAP_INFO
#undef  KEYMAP_
};

#define set_keymap(map, name) \
        set_from_int_map(keymap_table, ARRAY_SIZE(keymap_table), map, name, strlen(name))

static struct keybinding *keybindings[ARRAY_SIZE(keymap_table)];

static void
add_keybinding(enum keymap keymap, enum request request, int key)
{
        struct keybinding *keybinding;

        keybinding = calloc(1, sizeof(*keybinding));
        if (!keybinding)
                die("Failed to allocate keybinding");

        keybinding->alias = key;
        keybinding->request = request;
        keybinding->next = keybindings[keymap];
        keybindings[keymap] = keybinding;
}

/* Looks for a key binding first in the given map, then in the generic map, and
 * lastly in the default keybindings. */
static enum request
get_keybinding(enum keymap keymap, int key)
{
        struct keybinding *kbd;
        int i;

        for (kbd = keybindings[keymap]; kbd; kbd = kbd->next)
                if (kbd->alias == key)
                        return kbd->request;

        for (kbd = keybindings[KEYMAP_GENERIC]; kbd; kbd = kbd->next)
                if (kbd->alias == key)
                        return kbd->request;

        for (i = 0; i < ARRAY_SIZE(default_keybindings); i++)
                if (default_keybindings[i].alias == key)
                        return default_keybindings[i].request;

        return (enum request) key;
}


struct key {
        const char *name;
        int value;
};

static struct key key_table[] = {
        { "Enter",      KEY_RETURN },
        { "Space",      ' ' },
        { "Backspace",  KEY_BACKSPACE },
        { "Tab",        KEY_TAB },
        { "Escape",     KEY_ESC },
        { "Left",       KEY_LEFT },
        { "Right",      KEY_RIGHT },
        { "Up",         KEY_UP },
        { "Down",       KEY_DOWN },
        { "Insert",     KEY_IC },
        { "Delete",     KEY_DC },
        { "Hash",       '#' },
        { "Home",       KEY_HOME },
        { "End",        KEY_END },
        { "PageUp",     KEY_PPAGE },
        { "PageDown",   KEY_NPAGE },
        { "F1",         KEY_F(1) },
        { "F2",         KEY_F(2) },
        { "F3",         KEY_F(3) },
        { "F4",         KEY_F(4) },
        { "F5",         KEY_F(5) },
        { "F6",         KEY_F(6) },
        { "F7",         KEY_F(7) },
        { "F8",         KEY_F(8) },
        { "F9",         KEY_F(9) },
        { "F10",        KEY_F(10) },
        { "F11",        KEY_F(11) },
        { "F12",        KEY_F(12) },
};

static int
get_key_value(const char *name)
{
        int i;

        for (i = 0; i < ARRAY_SIZE(key_table); i++)
                if (!strcasecmp(key_table[i].name, name))
                        return key_table[i].value;

        if (strlen(name) == 1 && isprint(*name))
                return (int) *name;

        return ERR;
}

static const char *
get_key_name(int key_value)
{
        static char key_char[] = "'X'";
        const char *seq = NULL;
        int key;

        for (key = 0; key < ARRAY_SIZE(key_table); key++)
                if (key_table[key].value == key_value)
                        seq = key_table[key].name;

        if (seq == NULL &&
            key_value < 127 &&
            isprint(key_value)) {
                key_char[1] = (char) key_value;
                seq = key_char;
        }

        return seq ? seq : "(no key)";
}

static const char *
get_key(enum request request)
{
        static char buf[BUFSIZ];
        size_t pos = 0;
        char *sep = "";
        int i;

        buf[pos] = 0;

        for (i = 0; i < ARRAY_SIZE(default_keybindings); i++) {
                struct keybinding *keybinding = &default_keybindings[i];

                if (keybinding->request != request)
                        continue;

                if (!string_format_from(buf, &pos, "%s%s", sep,
                                        get_key_name(keybinding->alias)))
                        return "Too many keybindings!";
                sep = ", ";
        }

        return buf;
}

struct run_request {
        enum keymap keymap;
        int key;
        char cmd[SIZEOF_STR];
};

static struct run_request *run_request;
static size_t run_requests;

static enum request
add_run_request(enum keymap keymap, int key, int argc, const char **argv)
{
        struct run_request *req;
        char cmd[SIZEOF_STR];
        size_t bufpos;

        for (bufpos = 0; argc > 0; argc--, argv++)
                if (!string_format_from(cmd, &bufpos, "%s ", *argv))
                        return REQ_NONE;

        req = realloc(run_request, (run_requests + 1) * sizeof(*run_request));
        if (!req)
                return REQ_NONE;

        run_request = req;
        req = &run_request[run_requests++];
        string_copy(req->cmd, cmd);
        req->keymap = keymap;
        req->key = key;

        return REQ_NONE + run_requests;
}

static struct run_request *
get_run_request(enum request request)
{
        if (request <= REQ_NONE)
                return NULL;
        return &run_request[request - REQ_NONE - 1];
}

static void
add_builtin_run_requests(void)
{
        struct {
                enum keymap keymap;
                int key;
                const char *argv[1];
        } reqs[] = {
                { KEYMAP_MAIN,    'C', { "git cherry-pick %(commit)" } },
                { KEYMAP_GENERIC, 'G', { "git gc" } },
        };
        int i;

        for (i = 0; i < ARRAY_SIZE(reqs); i++) {
                enum request req;

                req = add_run_request(reqs[i].keymap, reqs[i].key, 1, reqs[i].argv);
                if (req != REQ_NONE)
                        add_keybinding(reqs[i].keymap, req, reqs[i].key);
        }
}

/*
 * User config file handling.
 */

static struct int_map color_map[] = {
#define COLOR_MAP(name) { #name, STRING_SIZE(#name), COLOR_##name }
        COLOR_MAP(DEFAULT),
        COLOR_MAP(BLACK),
        COLOR_MAP(BLUE),
        COLOR_MAP(CYAN),
        COLOR_MAP(GREEN),
        COLOR_MAP(MAGENTA),
        COLOR_MAP(RED),
        COLOR_MAP(WHITE),
        COLOR_MAP(YELLOW),
};

#define set_color(color, name) \
        set_from_int_map(color_map, ARRAY_SIZE(color_map), color, name, strlen(name))

static struct int_map attr_map[] = {
#define ATTR_MAP(name) { #name, STRING_SIZE(#name), A_##name }
        ATTR_MAP(NORMAL),
        ATTR_MAP(BLINK),
        ATTR_MAP(BOLD),
        ATTR_MAP(DIM),
        ATTR_MAP(REVERSE),
        ATTR_MAP(STANDOUT),
        ATTR_MAP(UNDERLINE),
};

#define set_attribute(attr, name) \
        set_from_int_map(attr_map, ARRAY_SIZE(attr_map), attr, name, strlen(name))

static int   config_lineno;
static bool  config_errors;
static const char *config_msg;

/* Wants: object fgcolor bgcolor [attr] */
static int
option_color_command(int argc, const char *argv[])
{
        struct line_info *info;

        if (argc != 3 && argc != 4) {
                config_msg = "Wrong number of arguments given to color command";
                return ERR;
        }

        info = get_line_info(argv[0]);
        if (!info) {
                if (!string_enum_compare(argv[0], "main-delim", strlen("main-delim"))) {
                        info = get_line_info("delimiter");

                } else if (!string_enum_compare(argv[0], "main-date", strlen("main-date"))) {
                        info = get_line_info("date");

                } else {
                        config_msg = "Unknown color name";
                        return ERR;
                }
        }

        if (set_color(&info->fg, argv[1]) == ERR ||
            set_color(&info->bg, argv[2]) == ERR) {
                config_msg = "Unknown color";
                return ERR;
        }

        if (argc == 4 && set_attribute(&info->attr, argv[3]) == ERR) {
                config_msg = "Unknown attribute";
                return ERR;
        }

        return OK;
}

static bool parse_bool(const char *s)
{
        return (!strcmp(s, "1") || !strcmp(s, "true") ||
                !strcmp(s, "yes")) ? TRUE : FALSE;
}

static int
parse_int(const char *s, int default_value, int min, int max)
{
        int value = atoi(s);

        return (value < min || value > max) ? default_value : value;
}

/* Wants: name = value */
static int
option_set_command(int argc, const char *argv[])
{
        if (argc != 3) {
                config_msg = "Wrong number of arguments given to set command";
                return ERR;
        }

        if (strcmp(argv[1], "=")) {
                config_msg = "No value assigned";
                return ERR;
        }

        if (!strcmp(argv[0], "show-author")) {
                opt_author = parse_bool(argv[2]);
                return OK;
        }

        if (!strcmp(argv[0], "show-date")) {
                opt_date = parse_bool(argv[2]);
                return OK;
        }

        if (!strcmp(argv[0], "show-rev-graph")) {
                opt_rev_graph = parse_bool(argv[2]);
                return OK;
        }

        if (!strcmp(argv[0], "show-refs")) {
                opt_show_refs = parse_bool(argv[2]);
                return OK;
        }

        if (!strcmp(argv[0], "show-line-numbers")) {
                opt_line_number = parse_bool(argv[2]);
                return OK;
        }

        if (!strcmp(argv[0], "line-graphics")) {
                opt_line_graphics = parse_bool(argv[2]);
                return OK;
        }

        if (!strcmp(argv[0], "line-number-interval")) {
                opt_num_interval = parse_int(argv[2], opt_num_interval, 1, 1024);
                return OK;
        }

        if (!strcmp(argv[0], "author-width")) {
                opt_author_cols = parse_int(argv[2], opt_author_cols, 0, 1024);
                return OK;
        }

        if (!strcmp(argv[0], "tab-size")) {
                opt_tab_size = parse_int(argv[2], opt_tab_size, 1, 1024);
                return OK;
        }

        if (!strcmp(argv[0], "commit-encoding")) {
                const char *arg = argv[2];
                int arglen = strlen(arg);

                switch (arg[0]) {
                case '"':
                case '\'':
                        if (arglen == 1 || arg[arglen - 1] != arg[0]) {
                                config_msg = "Unmatched quotation";
                                return ERR;
                        }
                        arg += 1; arglen -= 2;
                default:
                        string_ncopy(opt_encoding, arg, strlen(arg));
                        return OK;
                }
        }

        config_msg = "Unknown variable name";
        return ERR;
}

/* Wants: mode request key */
static int
option_bind_command(int argc, const char *argv[])
{
        enum request request;
        int keymap;
        int key;

        if (argc < 3) {
                config_msg = "Wrong number of arguments given to bind command";
                return ERR;
        }

        if (set_keymap(&keymap, argv[0]) == ERR) {
                config_msg = "Unknown key map";
                return ERR;
        }

        key = get_key_value(argv[1]);
        if (key == ERR) {
                config_msg = "Unknown key";
                return ERR;
        }

        request = get_request(argv[2]);
        if (request == REQ_NONE) {
                const char *obsolete[] = { "cherry-pick" };
                size_t namelen = strlen(argv[2]);
                int i;

                for (i = 0; i < ARRAY_SIZE(obsolete); i++) {
                        if (namelen == strlen(obsolete[i]) &&
                            !string_enum_compare(obsolete[i], argv[2], namelen)) {
                                config_msg = "Obsolete request name";
                                return ERR;
                        }
                }
        }
        if (request == REQ_NONE && *argv[2]++ == '!')
                request = add_run_request(keymap, key, argc - 2, argv + 2);
        if (request == REQ_NONE) {
                config_msg = "Unknown request name";
                return ERR;
        }

        add_keybinding(keymap, request, key);

        return OK;
}

static int
set_option(const char *opt, char *value)
{
        const char *argv[SIZEOF_ARG];
        int valuelen;
        int argc = 0;

        /* Tokenize */
        while (argc < ARRAY_SIZE(argv) && (valuelen = strcspn(value, " \t"))) {
                argv[argc++] = value;
                value += valuelen;

                /* Nothing more to tokenize or last available token. */
                if (!*value || argc >= ARRAY_SIZE(argv))
                        break;

                *value++ = 0;
                while (isspace(*value))
                        value++;
        }

        if (!strcmp(opt, "color"))
                return option_color_command(argc, argv);

        if (!strcmp(opt, "set"))
                return option_set_command(argc, argv);

        if (!strcmp(opt, "bind"))
                return option_bind_command(argc, argv);

        config_msg = "Unknown option command";
        return ERR;
}

static int
read_option(char *opt, size_t optlen, char *value, size_t valuelen)
{
        int status = OK;

        config_lineno++;
        config_msg = "Internal error";

        /* Check for comment markers, since read_properties() will
         * only ensure opt and value are split at first " \t". */
        optlen = strcspn(opt, "#");
        if (optlen == 0)
                return OK;

        if (opt[optlen] != 0) {
                config_msg = "No option value";
                status = ERR;

        }  else {
                /* Look for comment endings in the value. */
                size_t len = strcspn(value, "#");

                if (len < valuelen) {
                        valuelen = len;
                        value[valuelen] = 0;
                }

                status = set_option(opt, value);
        }

        if (status == ERR) {
                fprintf(stderr, "Error on line %d, near '%.*s': %s\n",
                        config_lineno, (int) optlen, opt, config_msg);
                config_errors = TRUE;
        }

        /* Always keep going if errors are encountered. */
        return OK;
}

static void
load_option_file(const char *path)
{
        FILE *file;

        /* It's ok that the file doesn't exist. */
        file = fopen(path, "r");
        if (!file)
                return;

        config_lineno = 0;
        config_errors = FALSE;

        if (read_properties(file, " \t", read_option) == ERR ||
            config_errors == TRUE)
                fprintf(stderr, "Errors while loading %s.\n", path);
}

static int
load_options(void)
{
        const char *home = getenv("HOME");
        const char *tigrc_user = getenv("TIGRC_USER");
        const char *tigrc_system = getenv("TIGRC_SYSTEM");
        char buf[SIZEOF_STR];

        add_builtin_run_requests();

        if (!tigrc_system) {
                if (!string_format(buf, "%s/tigrc", SYSCONFDIR))
                        return ERR;
                tigrc_system = buf;
        }
        load_option_file(tigrc_system);

        if (!tigrc_user) {
                if (!home || !string_format(buf, "%s/.tigrc", home))
                        return ERR;
                tigrc_user = buf;
        }
        load_option_file(tigrc_user);

        return OK;
}


/*
 * The viewer
 */

struct view;
struct view_ops;

/* The display array of active views and the index of the current view. */
static struct view *display[2];
static unsigned int current_view;

/* Reading from the prompt? */
static bool input_mode = FALSE;

#define foreach_displayed_view(view, i) \
        for (i = 0; i < ARRAY_SIZE(display) && (view = display[i]); i++)

#define displayed_views()       (display[1] != NULL ? 2 : 1)

/* Current head and commit ID */
static char ref_blob[SIZEOF_REF]        = "";
static char ref_commit[SIZEOF_REF]      = "HEAD";
static char ref_head[SIZEOF_REF]        = "HEAD";

struct view {
        const char *name;       /* View name */
        const char *cmd_fmt;    /* Default command line format */
        const char *cmd_env;    /* Command line set via environment */
        const char *id;         /* Points to either of ref_{head,commit,blob} */

        struct view_ops *ops;   /* View operations */

        enum keymap keymap;     /* What keymap does this view have */
        bool git_dir;           /* Whether the view requires a git directory. */

        char cmd[SIZEOF_STR];   /* Command buffer */
        char ref[SIZEOF_REF];   /* Hovered commit reference */
        char vid[SIZEOF_REF];   /* View ID. Set to id member when updating. */

        int height, width;      /* The width and height of the main window */
        WINDOW *win;            /* The main window */
        WINDOW *title;          /* The title window living below the main window */

        /* Navigation */
        unsigned long offset;   /* Offset of the window top */
        unsigned long lineno;   /* Current line number */

        /* Searching */
        char grep[SIZEOF_STR];  /* Search string */
        regex_t *regex;         /* Pre-compiled regex */

        /* If non-NULL, points to the view that opened this view. If this view
         * is closed tig will switch back to the parent view. */
        struct view *parent;

        /* Buffering */
        size_t lines;           /* Total number of lines */
        struct line *line;      /* Line index */
        size_t line_alloc;      /* Total number of allocated lines */
        size_t line_size;       /* Total number of used lines */
        unsigned int digits;    /* Number of digits in the lines member. */

        /* Drawing */
        struct line *curline;   /* Line currently being drawn. */
        enum line_type curtype; /* Attribute currently used for drawing. */
        unsigned long col;      /* Column when drawing. */

        /* Loading */
        FILE *pipe;
        time_t start_time;
};

struct view_ops {
        /* What type of content being displayed. Used in the title bar. */
        const char *type;
        /* Open and reads in all view content. */
        bool (*open)(struct view *view);
        /* Read one line; updates view->line. */
        bool (*read)(struct view *view, char *data);
        /* Draw one line; @lineno must be < view->height. */
        bool (*draw)(struct view *view, struct line *line, unsigned int lineno);
        /* Depending on view handle a special requests. */
        enum request (*request)(struct view *view, enum request request, struct line *line);
        /* Search for regex in a line. */
        bool (*grep)(struct view *view, struct line *line);
        /* Select line */
        void (*select)(struct view *view, struct line *line);
};

static struct view_ops blame_ops;
static struct view_ops blob_ops;
static struct view_ops help_ops;
static struct view_ops log_ops;
static struct view_ops main_ops;
static struct view_ops pager_ops;
static struct view_ops stage_ops;
static struct view_ops status_ops;
static struct view_ops tree_ops;

#define VIEW_STR(name, cmd, env, ref, ops, map, git) \
        { name, cmd, #env, ref, ops, map, git }

#define VIEW_(id, name, ops, git, ref) \
        VIEW_STR(name, TIG_##id##_CMD,  TIG_##id##_CMD, ref, ops, KEYMAP_##id, git)


static struct view views[] = {
        VIEW_(MAIN,   "main",   &main_ops,   TRUE,  ref_head),
        VIEW_(DIFF,   "diff",   &pager_ops,  TRUE,  ref_commit),
        VIEW_(LOG,    "log",    &log_ops,    TRUE,  ref_head),
        VIEW_(TREE,   "tree",   &tree_ops,   TRUE,  ref_commit),
        VIEW_(BLOB,   "blob",   &blob_ops,   TRUE,  ref_blob),
        VIEW_(BLAME,  "blame",  &blame_ops,  TRUE,  ref_commit),
        VIEW_(HELP,   "help",   &help_ops,   FALSE, ""),
        VIEW_(PAGER,  "pager",  &pager_ops,  FALSE, "stdin"),
        VIEW_(STATUS, "status", &status_ops, TRUE,  ""),
        VIEW_(STAGE,  "stage",  &stage_ops,  TRUE,  ""),
};

#define VIEW(req)       (&views[(req) - REQ_OFFSET - 1])
#define VIEW_REQ(view)  ((view) - views + REQ_OFFSET + 1)

#define foreach_view(view, i) \
        for (i = 0; i < ARRAY_SIZE(views) && (view = &views[i]); i++)

#define view_is_displayed(view) \
        (view == display[0] || view == display[1])


enum line_graphic {
        LINE_GRAPHIC_VLINE
};

static int line_graphics[] = {
        /* LINE_GRAPHIC_VLINE: */ '|'
};

static inline void
set_view_attr(struct view *view, enum line_type type)
{
        if (!view->curline->selected && view->curtype != type) {
                wattrset(view->win, get_line_attr(type));
                wchgat(view->win, -1, 0, type, NULL);
                view->curtype = type;
        }
}

static int
draw_chars(struct view *view, enum line_type type, const char *string,
           int max_len, bool use_tilde)
{
        int len = 0;
        int col = 0;
        int trimmed = FALSE;

        if (max_len <= 0)
                return 0;

        if (opt_utf8) {
                len = utf8_length(string, &col, max_len, &trimmed, use_tilde);
        } else {
                col = len = strlen(string);
                if (len > max_len) {
                        if (use_tilde) {
                                max_len -= 1;
                        }
                        col = len = max_len;
                        trimmed = TRUE;
                }
        }

        set_view_attr(view, type);
        waddnstr(view->win, string, len);
        if (trimmed && use_tilde) {
                set_view_attr(view, LINE_DELIMITER);
                waddch(view->win, '~');
                col++;
        }

        return col;
}

static int
draw_space(struct view *view, enum line_type type, int max, int spaces)
{
        static char space[] = "                    ";
        int col = 0;

        spaces = MIN(max, spaces);

        while (spaces > 0) {
                int len = MIN(spaces, sizeof(space) - 1);

                col += draw_chars(view, type, space, spaces, FALSE);
                spaces -= len;
        }

        return col;
}

static bool
draw_lineno(struct view *view, unsigned int lineno)
{
        char number[10];
        int digits3 = view->digits < 3 ? 3 : view->digits;
        int max_number = MIN(digits3, STRING_SIZE(number));
        int max = view->width - view->col;
        int col;

        if (max < max_number)
                max_number = max;

        lineno += view->offset + 1;
        if (lineno == 1 || (lineno % opt_num_interval) == 0) {
                static char fmt[] = "%1ld";

                if (view->digits <= 9)
                        fmt[1] = '0' + digits3;

                if (!string_format(number, fmt, lineno))
                        number[0] = 0;
                col = draw_chars(view, LINE_LINE_NUMBER, number, max_number, TRUE);
        } else {
                col = draw_space(view, LINE_LINE_NUMBER, max_number, max_number);
        }

        if (col < max) {
                set_view_attr(view, LINE_DEFAULT);
                waddch(view->win, line_graphics[LINE_GRAPHIC_VLINE]);
                col++;
        }

        if (col < max)
                col += draw_space(view, LINE_DEFAULT, max - col, 1);
        view->col += col;

        return view->width - view->col <= 0;
}

static bool
draw_text(struct view *view, enum line_type type, const char *string, bool trim)
{
        view->col += draw_chars(view, type, string, view->width - view->col, trim);
        return view->width - view->col <= 0;
}

static bool
draw_graphic(struct view *view, enum line_type type, chtype graphic[], size_t size)
{
        int max = view->width - view->col;
        int i;

        if (max < size)
                size = max;

        set_view_attr(view, type);
        /* Using waddch() instead of waddnstr() ensures that
         * they'll be rendered correctly for the cursor line. */
        for (i = 0; i < size; i++)
                waddch(view->win, graphic[i]);

        view->col += size;
        if (size < max) {
                waddch(view->win, ' ');
                view->col++;
        }

        return view->width - view->col <= 0;
}

static bool
draw_field(struct view *view, enum line_type type, const char *text, int len, bool trim)
{
        int max = MIN(view->width - view->col, len);
        int col;

        if (text)
                col = draw_chars(view, type, text, max - 1, trim);
        else
                col = draw_space(view, type, max - 1, max - 1);

        view->col += col + draw_space(view, LINE_DEFAULT, max - col, max - col);
        return view->width - view->col <= 0;
}

static bool
draw_date(struct view *view, struct tm *time)
{
        char buf[DATE_COLS];
        char *date;
        int timelen = 0;

        if (time)
                timelen = strftime(buf, sizeof(buf), DATE_FORMAT, time);
        date = timelen ? buf : NULL;

        return draw_field(view, LINE_DATE, date, DATE_COLS, FALSE);
}

static bool
draw_view_line(struct view *view, unsigned int lineno)
{
        struct line *line;
        bool selected = (view->offset + lineno == view->lineno);
        bool draw_ok;

        assert(view_is_displayed(view));

        if (view->offset + lineno >= view->lines)
                return FALSE;

        line = &view->line[view->offset + lineno];

        wmove(view->win, lineno, 0);
        view->col = 0;
        view->curline = line;
        view->curtype = LINE_NONE;
        line->selected = FALSE;

        if (selected) {
                set_view_attr(view, LINE_CURSOR);
                line->selected = TRUE;
                view->ops->select(view, line);
        } else if (line->selected) {
                wclrtoeol(view->win);
        }

        scrollok(view->win, FALSE);
        draw_ok = view->ops->draw(view, line, lineno);
        scrollok(view->win, TRUE);

        return draw_ok;
}

static void
redraw_view_dirty(struct view *view)
{
        bool dirty = FALSE;
        int lineno;

        for (lineno = 0; lineno < view->height; lineno++) {
                struct line *line = &view->line[view->offset + lineno];

                if (!line->dirty)
                        continue;
                line->dirty = 0;
                dirty = TRUE;
                if (!draw_view_line(view, lineno))
                        break;
        }

        if (!dirty)
                return;
        redrawwin(view->win);
        if (input_mode)
                wnoutrefresh(view->win);
        else
                wrefresh(view->win);
}

static void
redraw_view_from(struct view *view, int lineno)
{
        assert(0 <= lineno && lineno < view->height);

        for (; lineno < view->height; lineno++) {
                if (!draw_view_line(view, lineno))
                        break;
        }

        redrawwin(view->win);
        if (input_mode)
                wnoutrefresh(view->win);
        else
                wrefresh(view->win);
}

static void
redraw_view(struct view *view)
{
        wclear(view->win);
        redraw_view_from(view, 0);
}


static void
update_view_title(struct view *view)
{
        char buf[SIZEOF_STR];
        char state[SIZEOF_STR];
        size_t bufpos = 0, statelen = 0;

        assert(view_is_displayed(view));

        if (view != VIEW(REQ_VIEW_STATUS) && (view->lines || view->pipe)) {
                unsigned int view_lines = view->offset + view->height;
                unsigned int lines = view->lines
                                   ? MIN(view_lines, view->lines) * 100 / view->lines
                                   : 0;

                string_format_from(state, &statelen, "- %s %d of %d (%d%%)",
                                   view->ops->type,
                                   view->lineno + 1,
                                   view->lines,
                                   lines);

                if (view->pipe) {
                        time_t secs = time(NULL) - view->start_time;

                        /* Three git seconds are a long time ... */
                        if (secs > 2)
                                string_format_from(state, &statelen, " %lds", secs);
                }
        }

        string_format_from(buf, &bufpos, "[%s]", view->name);
        if (*view->ref && bufpos < view->width) {
                size_t refsize = strlen(view->ref);
                size_t minsize = bufpos + 1 + /* abbrev= */ 7 + 1 + statelen;

                if (minsize < view->width)
                        refsize = view->width - minsize + 7;
                string_format_from(buf, &bufpos, " %.*s", (int) refsize, view->ref);
        }

        if (statelen && bufpos < view->width) {
                string_format_from(buf, &bufpos, " %s", state);
        }

        if (view == display[current_view])
                wbkgdset(view->title, get_line_attr(LINE_TITLE_FOCUS));
        else
                wbkgdset(view->title, get_line_attr(LINE_TITLE_BLUR));

        mvwaddnstr(view->title, 0, 0, buf, bufpos);
        wclrtoeol(view->title);
        wmove(view->title, 0, view->width - 1);

        if (input_mode)
                wnoutrefresh(view->title);
        else
                wrefresh(view->title);
}

static void
resize_display(void)
{
        int offset, i;
        struct view *base = display[0];
        struct view *view = display[1] ? display[1] : display[0];

        /* Setup window dimensions */

        getmaxyx(stdscr, base->height, base->width);

        /* Make room for the status window. */
        base->height -= 1;

        if (view != base) {
                /* Horizontal split. */
                view->width   = base->width;
                view->height  = SCALE_SPLIT_VIEW(base->height);
                base->height -= view->height;

                /* Make room for the title bar. */
                view->height -= 1;
        }

        /* Make room for the title bar. */
        base->height -= 1;

        offset = 0;

        foreach_displayed_view (view, i) {
                if (!view->win) {
                        view->win = newwin(view->height, 0, offset, 0);
                        if (!view->win)
                                die("Failed to create %s view", view->name);

                        scrollok(view->win, TRUE);

                        view->title = newwin(1, 0, offset + view->height, 0);
                        if (!view->title)
                                die("Failed to create title window");

                } else {
                        wresize(view->win, view->height, view->width);
                        mvwin(view->win,   offset, 0);
                        mvwin(view->title, offset + view->height, 0);
                }

                offset += view->height + 1;
        }
}

static void
redraw_display(void)
{
        struct view *view;
        int i;

        foreach_displayed_view (view, i) {
                redraw_view(view);
                update_view_title(view);
        }
}

static void
update_display_cursor(struct view *view)
{
        /* Move the cursor to the right-most column of the cursor line.
         *
         * XXX: This could turn out to be a bit expensive, but it ensures that
         * the cursor does not jump around. */
        if (view->lines) {
                wmove(view->win, view->lineno - view->offset, view->width - 1);
                wrefresh(view->win);
        }
}

/*
 * Navigation
 */

/* Scrolling backend */
static void
do_scroll_view(struct view *view, int lines)
{
        bool redraw_current_line = FALSE;

        /* The rendering expects the new offset. */
        view->offset += lines;

        assert(0 <= view->offset && view->offset < view->lines);
        assert(lines);

        /* Move current line into the view. */
        if (view->lineno < view->offset) {
                view->lineno = view->offset;
                redraw_current_line = TRUE;
        } else if (view->lineno >= view->offset + view->height) {
                view->lineno = view->offset + view->height - 1;
                redraw_current_line = TRUE;
        }

        assert(view->offset <= view->lineno && view->lineno < view->lines);

        /* Redraw the whole screen if scrolling is pointless. */
        if (view->height < ABS(lines)) {
                redraw_view(view);

        } else {
                int line = lines > 0 ? view->height - lines : 0;
                int end = line + ABS(lines);

                wscrl(view->win, lines);

                for (; line < end; line++) {
                        if (!draw_view_line(view, line))
                                break;
                }

                if (redraw_current_line)
                        draw_view_line(view, view->lineno - view->offset);
        }

        redrawwin(view->win);
        wrefresh(view->win);
        report("");
}

/* Scroll frontend */
static void
scroll_view(struct view *view, enum request request)
{
        int lines = 1;

        assert(view_is_displayed(view));

        switch (request) {
        case REQ_SCROLL_PAGE_DOWN:
                lines = view->height;
        case REQ_SCROLL_LINE_DOWN:
                if (view->offset + lines > view->lines)
                        lines = view->lines - view->offset;

                if (lines == 0 || view->offset + view->height >= view->lines) {
                        report("Cannot scroll beyond the last line");
                        return;
                }
                break;

        case REQ_SCROLL_PAGE_UP:
                lines = view->height;
        case REQ_SCROLL_LINE_UP:
                if (lines > view->offset)
                        lines = view->offset;

                if (lines == 0) {
                        report("Cannot scroll beyond the first line");
                        return;
                }

                lines = -lines;
                break;

        default:
                die("request %d not handled in switch", request);
        }

        do_scroll_view(view, lines);
}

/* Cursor moving */
static void
move_view(struct view *view, enum request request)
{
        int scroll_steps = 0;
        int steps;

        switch (request) {
        case REQ_MOVE_FIRST_LINE:
                steps = -view->lineno;
                break;

        case REQ_MOVE_LAST_LINE:
                steps = view->lines - view->lineno - 1;
                break;

        case REQ_MOVE_PAGE_UP:
                steps = view->height > view->lineno
                      ? -view->lineno : -view->height;
                break;

        case REQ_MOVE_PAGE_DOWN:
                steps = view->lineno + view->height >= view->lines
                      ? view->lines - view->lineno - 1 : view->height;
                break;

        case REQ_MOVE_UP:
                steps = -1;
                break;

        case REQ_MOVE_DOWN:
                steps = 1;
                break;

        default:
                die("request %d not handled in switch", request);
        }

        if (steps <= 0 && view->lineno == 0) {
                report("Cannot move beyond the first line");
                return;

        } else if (steps >= 0 && view->lineno + 1 >= view->lines) {
                report("Cannot move beyond the last line");
                return;
        }

        /* Move the current line */
        view->lineno += steps;
        assert(0 <= view->lineno && view->lineno < view->lines);

        /* Check whether the view needs to be scrolled */
        if (view->lineno < view->offset ||
            view->lineno >= view->offset + view->height) {
                scroll_steps = steps;
                if (steps < 0 && -steps > view->offset) {
                        scroll_steps = -view->offset;

                } else if (steps > 0) {
                        if (view->lineno == view->lines - 1 &&
                            view->lines > view->height) {
                                scroll_steps = view->lines - view->offset - 1;
                                if (scroll_steps >= view->height)
                                        scroll_steps -= view->height - 1;
                        }
                }
        }

        if (!view_is_displayed(view)) {
                view->offset += scroll_steps;
                assert(0 <= view->offset && view->offset < view->lines);
                view->ops->select(view, &view->line[view->lineno]);
                return;
        }

        /* Repaint the old "current" line if we be scrolling */
        if (ABS(steps) < view->height)
                draw_view_line(view, view->lineno - steps - view->offset);

        if (scroll_steps) {
                do_scroll_view(view, scroll_steps);
                return;
        }

        /* Draw the current line */
        draw_view_line(view, view->lineno - view->offset);

        redrawwin(view->win);
        wrefresh(view->win);
        report("");
}


/*
 * Searching
 */

static void search_view(struct view *view, enum request request);

static bool
find_next_line(struct view *view, unsigned long lineno, struct line *line)
{
        assert(view_is_displayed(view));

        if (!view->ops->grep(view, line))
                return FALSE;

        if (lineno - view->offset >= view->height) {
                view->offset = lineno;
                view->lineno = lineno;
                redraw_view(view);

        } else {
                unsigned long old_lineno = view->lineno - view->offset;

                view->lineno = lineno;
                draw_view_line(view, old_lineno);

                draw_view_line(view, view->lineno - view->offset);
                redrawwin(view->win);
                wrefresh(view->win);
        }

        report("Line %ld matches '%s'", lineno + 1, view->grep);
        return TRUE;
}

static void
find_next(struct view *view, enum request request)
{
        unsigned long lineno = view->lineno;
        int direction;

        if (!*view->grep) {
                if (!*opt_search)
                        report("No previous search");
                else
                        search_view(view, request);
                return;
        }

        switch (request) {
        case REQ_SEARCH:
        case REQ_FIND_NEXT:
                direction = 1;
                break;

        case REQ_SEARCH_BACK:
        case REQ_FIND_PREV:
                direction = -1;
                break;

        default:
                return;
        }

        if (request == REQ_FIND_NEXT || request == REQ_FIND_PREV)
                lineno += direction;

        /* Note, lineno is unsigned long so will wrap around in which case it
         * will become bigger than view->lines. */
        for (; lineno < view->lines; lineno += direction) {
                struct line *line = &view->line[lineno];

                if (find_next_line(view, lineno, line))
                        return;
        }

        report("No match found for '%s'", view->grep);
}

static void
search_view(struct view *view, enum request request)
{
        int regex_err;

        if (view->regex) {
                regfree(view->regex);
                *view->grep = 0;
        } else {
                view->regex = calloc(1, sizeof(*view->regex));
                if (!view->regex)
                        return;
        }

        regex_err = regcomp(view->regex, opt_search, REG_EXTENDED);
        if (regex_err != 0) {
                char buf[SIZEOF_STR] = "unknown error";

                regerror(regex_err, view->regex, buf, sizeof(buf));
                report("Search failed: %s", buf);
                return;
        }

        string_copy(view->grep, opt_search);

        find_next(view, request);
}

/*
 * Incremental updating
 */

static void
reset_view(struct view *view)
{
        int i;

        for (i = 0; i < view->lines; i++)
                free(view->line[i].data);
        free(view->line);

        view->line = NULL;
        view->offset = 0;
        view->lines  = 0;
        view->lineno = 0;
        view->line_size = 0;
        view->line_alloc = 0;
        view->vid[0] = 0;
}

static void
end_update(struct view *view, bool force)
{
        if (!view->pipe)
                return;
        while (!view->ops->read(view, NULL))
                if (!force)
                        return;
        set_nonblocking_input(FALSE);
        if (view->pipe == stdin)
                fclose(view->pipe);
        else
                pclose(view->pipe);
        view->pipe = NULL;
}

static bool
begin_update(struct view *view, bool refresh)
{
        if (opt_cmd[0]) {
                string_copy(view->cmd, opt_cmd);
                opt_cmd[0] = 0;
                /* When running random commands, initially show the
                 * command in the title. However, it maybe later be
                 * overwritten if a commit line is selected. */
                if (view == VIEW(REQ_VIEW_PAGER))
                        string_copy(view->ref, view->cmd);
                else
                        view->ref[0] = 0;

        } else if (view == VIEW(REQ_VIEW_TREE)) {
                const char *format = view->cmd_env ? view->cmd_env : view->cmd_fmt;
                char path[SIZEOF_STR];

                if (strcmp(view->vid, view->id))
                        opt_path[0] = path[0] = 0;
                else if (sq_quote(path, 0, opt_path) >= sizeof(path))
                        return FALSE;

                if (!string_format(view->cmd, format, view->id, path))
                        return FALSE;

        } else if (!refresh) {
                const char *format = view->cmd_env ? view->cmd_env : view->cmd_fmt;
                const char *id = view->id;

                if (!string_format(view->cmd, format, id, id, id, id, id))
                        return FALSE;

                /* Put the current ref_* value to the view title ref
                 * member. This is needed by the blob view. Most other
                 * views sets it automatically after loading because the
                 * first line is a commit line. */
                string_copy_rev(view->ref, view->id);
        }

        /* Special case for the pager view. */
        if (opt_pipe) {
                view->pipe = opt_pipe;
                opt_pipe = NULL;
        } else {
                view->pipe = popen(view->cmd, "r");
        }

        if (!view->pipe)
                return FALSE;

        set_nonblocking_input(TRUE);
        reset_view(view);
        string_copy_rev(view->vid, view->id);

        view->start_time = time(NULL);

        return TRUE;
}

#define ITEM_CHUNK_SIZE 256
static void *
realloc_items(void *mem, size_t *size, size_t new_size, size_t item_size)
{
        size_t num_chunks = *size / ITEM_CHUNK_SIZE;
        size_t num_chunks_new = (new_size + ITEM_CHUNK_SIZE - 1) / ITEM_CHUNK_SIZE;

        if (mem == NULL || num_chunks != num_chunks_new) {
                *size = num_chunks_new * ITEM_CHUNK_SIZE;
                mem = realloc(mem, *size * item_size);
        }

        return mem;
}

static struct line *
realloc_lines(struct view *view, size_t line_size)
{
        size_t alloc = view->line_alloc;
        struct line *tmp = realloc_items(view->line, &alloc, line_size,
                                         sizeof(*view->line));

        if (!tmp)
                return NULL;

        view->line = tmp;
        view->line_alloc = alloc;
        view->line_size = line_size;
        return view->line;
}

static bool
update_view(struct view *view)
{
        char in_buffer[BUFSIZ];
        char out_buffer[BUFSIZ * 2];
        char *line;
        /* The number of lines to read. If too low it will cause too much
         * redrawing (and possible flickering), if too high responsiveness
         * will suffer. */
        unsigned long lines = view->height;
        int redraw_from = -1;

        if (!view->pipe)
                return TRUE;

        /* Only redraw if lines are visible. */
        if (view->offset + view->height >= view->lines)
                redraw_from = view->lines - view->offset;

        /* FIXME: This is probably not perfect for backgrounded views. */
        if (!realloc_lines(view, view->lines + lines))
                goto alloc_error;

        while ((line = fgets(in_buffer, sizeof(in_buffer), view->pipe))) {
                size_t linelen = strlen(line);

                if (linelen)
                        line[linelen - 1] = 0;

                if (opt_iconv != ICONV_NONE) {
                        ICONV_CONST char *inbuf = line;
                        size_t inlen = linelen;

                        char *outbuf = out_buffer;
                        size_t outlen = sizeof(out_buffer);

                        size_t ret;

                        ret = iconv(opt_iconv, &inbuf, &inlen, &outbuf, &outlen);
                        if (ret != (size_t) -1) {
                                line = out_buffer;
                                linelen = strlen(out_buffer);
                        }
                }

                if (!view->ops->read(view, line))
                        goto alloc_error;

                if (lines-- == 1)
                        break;
        }

        {
                int digits;

                lines = view->lines;
                for (digits = 0; lines; digits++)
                        lines /= 10;

                /* Keep the displayed view in sync with line number scaling. */
                if (digits != view->digits) {
                        view->digits = digits;
                        redraw_from = 0;
                }
        }

        if (ferror(view->pipe) && errno != 0) {
                report("Failed to read: %s", strerror(errno));
                end_update(view, TRUE);

        } else if (feof(view->pipe)) {
                report("");
                end_update(view, FALSE);
        }

        if (view == VIEW(REQ_VIEW_TREE)) {
                /* Clear the view and redraw everything since the tree sorting
                 * might have rearranged things. */
                redraw_view(view);

        } else if (redraw_from >= 0) {
                /* If this is an incremental update, redraw the previous line
                 * since for commits some members could have changed when
                 * loading the main view. */
                if (redraw_from > 0)
                        redraw_from--;

                /* Since revision graph visualization requires knowledge
                 * about the parent commit, it causes a further one-off
                 * needed to be redrawn for incremental updates. */
                if (redraw_from > 0 && opt_rev_graph)
                        redraw_from--;

                /* Incrementally draw avoids flickering. */
                redraw_view_from(view, redraw_from);
        }

        if (view == VIEW(REQ_VIEW_BLAME))
                redraw_view_dirty(view);

        /* Update the title _after_ the redraw so that if the redraw picks up a
         * commit reference in view->ref it'll be available here. */
        update_view_title(view);
        return TRUE;

alloc_error:
        report("Allocation failure");
        end_update(view, TRUE);
        return FALSE;
}

static struct line *
add_line_data(struct view *view, void *data, enum line_type type)
{
        struct line *line = &view->line[view->lines++];

        memset(line, 0, sizeof(*line));
        line->type = type;
        line->data = data;

        return line;
}

static struct line *
add_line_text(struct view *view, const char *text, enum line_type type)
{
        char *data = text ? strdup(text) : NULL;

        return data ? add_line_data(view, data, type) : NULL;
}


/*
 * View opening
 */

enum open_flags {
        OPEN_DEFAULT = 0,       /* Use default view switching. */
        OPEN_SPLIT = 1,         /* Split current view. */
        OPEN_BACKGROUNDED = 2,  /* Backgrounded. */
        OPEN_RELOAD = 4,        /* Reload view even if it is the current. */
        OPEN_NOMAXIMIZE = 8,    /* Do not maximize the current view. */
        OPEN_REFRESH = 16,      /* Refresh view using previous command. */
};

static void
open_view(struct view *prev, enum request request, enum open_flags flags)
{
        bool backgrounded = !!(flags & OPEN_BACKGROUNDED);
        bool split = !!(flags & OPEN_SPLIT);
        bool reload = !!(flags & (OPEN_RELOAD | OPEN_REFRESH));
        bool nomaximize = !!(flags & (OPEN_NOMAXIMIZE | OPEN_REFRESH));
        struct view *view = VIEW(request);
        int nviews = displayed_views();
        struct view *base_view = display[0];

        if (view == prev && nviews == 1 && !reload) {
                report("Already in %s view", view->name);
                return;
        }

        if (view->git_dir && !opt_git_dir[0]) {
                report("The %s view is disabled in pager view", view->name);
                return;
        }

        if (split) {
                display[1] = view;
                if (!backgrounded)
                        current_view = 1;
        } else if (!nomaximize) {
                /* Maximize the current view. */
                memset(display, 0, sizeof(display));
                current_view = 0;
                display[current_view] = view;
        }

        /* Resize the view when switching between split- and full-screen,
         * or when switching between two different full-screen views. */
        if (nviews != displayed_views() ||
            (nviews == 1 && base_view != display[0]))
                resize_display();

        if (view->pipe)
                end_update(view, TRUE);

        if (view->ops->open) {
                if (!view->ops->open(view)) {
                        report("Failed to load %s view", view->name);
                        return;
                }

        } else if ((reload || strcmp(view->vid, view->id)) &&
                   !begin_update(view, flags & OPEN_REFRESH)) {
                report("Failed to load %s view", view->name);
                return;
        }

        if (split && prev->lineno - prev->offset >= prev->height) {
                /* Take the title line into account. */
                int lines = prev->lineno - prev->offset - prev->height + 1;

                /* Scroll the view that was split if the current line is
                 * outside the new limited view. */
                do_scroll_view(prev, lines);
        }

        if (prev && view != prev) {
                if (split && !backgrounded) {
                        /* "Blur" the previous view. */
                        update_view_title(prev);
                }

                view->parent = prev;
        }

        if (view->pipe && view->lines == 0) {
                /* Clear the old view and let the incremental updating refill
                 * the screen. */
                werase(view->win);
                report("");
        } else if (view_is_displayed(view)) {
                redraw_view(view);
                report("");
        }

        /* If the view is backgrounded the above calls to report()
         * won't redraw the view title. */
        if (backgrounded)
                update_view_title(view);
}

static bool
run_confirm(const char *cmd, const char *prompt)
{
        bool confirmation = prompt_yesno(prompt);

        if (confirmation)
                system(cmd);

        return confirmation;
}

static void
open_external_viewer(const char *cmd)
{
        def_prog_mode();           /* save current tty modes */
        endwin();                  /* restore original tty modes */
        system(cmd);
        fprintf(stderr, "Press Enter to continue");
        getc(opt_tty);
        reset_prog_mode();
        redraw_display();
}

static void
open_mergetool(const char *file)
{
        char cmd[SIZEOF_STR];
        char file_sq[SIZEOF_STR];

        if (sq_quote(file_sq, 0, file) < sizeof(file_sq) &&
            string_format(cmd, "git mergetool %s", file_sq)) {
                open_external_viewer(cmd);
        }
}

static void
open_editor(bool from_root, const char *file)
{
        char cmd[SIZEOF_STR];
        char file_sq[SIZEOF_STR];
        const char *editor;
        char *prefix = from_root ? opt_cdup : "";

        editor = getenv("GIT_EDITOR");
        if (!editor && *opt_editor)
                editor = opt_editor;
        if (!editor)
                editor = getenv("VISUAL");
        if (!editor)
                editor = getenv("EDITOR");
        if (!editor)
                editor = "vi";

        if (sq_quote(file_sq, 0, file) < sizeof(file_sq) &&
            string_format(cmd, "%s %s%s", editor, prefix, file_sq)) {
                open_external_viewer(cmd);
        }
}

static void
open_run_request(enum request request)
{
        struct run_request *req = get_run_request(request);
        char buf[SIZEOF_STR * 2];
        size_t bufpos;
        char *cmd;

        if (!req) {
                report("Unknown run request");
                return;
        }

        bufpos = 0;
        cmd = req->cmd;

        while (cmd) {
                char *next = strstr(cmd, "%(");
                int len = next - cmd;
                char *value;

                if (!next) {
                        len = strlen(cmd);
                        value = "";

                } else if (!strncmp(next, "%(head)", 7)) {
                        value = ref_head;

                } else if (!strncmp(next, "%(commit)", 9)) {
                        value = ref_commit;

                } else if (!strncmp(next, "%(blob)", 7)) {
                        value = ref_blob;

                } else {
                        report("Unknown replacement in run request: `%s`", req->cmd);
                        return;
                }

                if (!string_format_from(buf, &bufpos, "%.*s%s", len, cmd, value))
                        return;

                if (next)
                        next = strchr(next, ')') + 1;
                cmd = next;
        }

        open_external_viewer(buf);
}

/*
 * User request switch noodle
 */

static int
view_driver(struct view *view, enum request request)
{
        int i;

        if (request == REQ_NONE) {
                doupdate();
                return TRUE;
        }

        if (request > REQ_NONE) {
                open_run_request(request);
                /* FIXME: When all views can refresh always do this. */
                if (view == VIEW(REQ_VIEW_STATUS) ||
                    view == VIEW(REQ_VIEW_MAIN) ||
                    view == VIEW(REQ_VIEW_LOG) ||
                    view == VIEW(REQ_VIEW_STAGE))
                        request = REQ_REFRESH;
                else
                        return TRUE;
        }

        if (view && view->lines) {
                request = view->ops->request(view, request, &view->line[view->lineno]);
                if (request == REQ_NONE)
                        return TRUE;
        }

        switch (request) {
        case REQ_MOVE_UP:
        case REQ_MOVE_DOWN:
        case REQ_MOVE_PAGE_UP:
        case REQ_MOVE_PAGE_DOWN:
        case REQ_MOVE_FIRST_LINE:
        case REQ_MOVE_LAST_LINE:
                move_view(view, request);
                break;

        case REQ_SCROLL_LINE_DOWN:
        case REQ_SCROLL_LINE_UP:
        case REQ_SCROLL_PAGE_DOWN:
        case REQ_SCROLL_PAGE_UP:
                scroll_view(view, request);
                break;

        case REQ_VIEW_BLAME:
                if (!opt_file[0]) {
                        report("No file chosen, press %s to open tree view",
                               get_key(REQ_VIEW_TREE));
                        break;
                }
                open_view(view, request, OPEN_DEFAULT);
                break;

        case REQ_VIEW_BLOB:
                if (!ref_blob[0]) {
                        report("No file chosen, press %s to open tree view",
                               get_key(REQ_VIEW_TREE));
                        break;
                }
                open_view(view, request, OPEN_DEFAULT);
                break;

        case REQ_VIEW_PAGER:
                if (!opt_pipe && !VIEW(REQ_VIEW_PAGER)->lines) {
                        report("No pager content, press %s to run command from prompt",
                               get_key(REQ_PROMPT));
                        break;
                }
                open_view(view, request, OPEN_DEFAULT);
                break;

        case REQ_VIEW_STAGE:
                if (!VIEW(REQ_VIEW_STAGE)->lines) {
                        report("No stage content, press %s to open the status view and choose file",
                               get_key(REQ_VIEW_STATUS));
                        break;
                }
                open_view(view, request, OPEN_DEFAULT);
                break;

        case REQ_VIEW_STATUS:
                if (opt_is_inside_work_tree == FALSE) {
                        report("The status view requires a working tree");
                        break;
                }
                open_view(view, request, OPEN_DEFAULT);
                break;

        case REQ_VIEW_MAIN:
        case REQ_VIEW_DIFF:
        case REQ_VIEW_LOG:
        case REQ_VIEW_TREE:
        case REQ_VIEW_HELP:
                open_view(view, request, OPEN_DEFAULT);
                break;

        case REQ_NEXT:
        case REQ_PREVIOUS:
                request = request == REQ_NEXT ? REQ_MOVE_DOWN : REQ_MOVE_UP;

                if ((view == VIEW(REQ_VIEW_DIFF) &&
                     view->parent == VIEW(REQ_VIEW_MAIN)) ||
                   (view == VIEW(REQ_VIEW_DIFF) &&
                     view->parent == VIEW(REQ_VIEW_BLAME)) ||
                   (view == VIEW(REQ_VIEW_STAGE) &&
                     view->parent == VIEW(REQ_VIEW_STATUS)) ||
                   (view == VIEW(REQ_VIEW_BLOB) &&
                     view->parent == VIEW(REQ_VIEW_TREE))) {
                        int line;

                        view = view->parent;
                        line = view->lineno;
                        move_view(view, request);
                        if (view_is_displayed(view))
                                update_view_title(view);
                        if (line != view->lineno)
                                view->ops->request(view, REQ_ENTER,
                                                   &view->line[view->lineno]);

                } else {
                        move_view(view, request);
                }
                break;

        case REQ_VIEW_NEXT:
        {
                int nviews = displayed_views();
                int next_view = (current_view + 1) % nviews;

                if (next_view == current_view) {
                        report("Only one view is displayed");
                        break;
                }

                current_view = next_view;
                /* Blur out the title of the previous view. */
                update_view_title(view);
                report("");
                break;
        }
        case REQ_REFRESH:
                report("Refreshing is not yet supported for the %s view", view->name);
                break;

        case REQ_MAXIMIZE:
                if (displayed_views() == 2)
                        open_view(view, VIEW_REQ(view), OPEN_DEFAULT);
                break;

        case REQ_TOGGLE_LINENO:
                opt_line_number = !opt_line_number;
                redraw_display();
                break;

        case REQ_TOGGLE_DATE:
                opt_date = !opt_date;
                redraw_display();
                break;

        case REQ_TOGGLE_AUTHOR:
                opt_author = !opt_author;
                redraw_display();
                break;

        case REQ_TOGGLE_REV_GRAPH:
                opt_rev_graph = !opt_rev_graph;
                redraw_display();
                break;

        case REQ_TOGGLE_REFS:
                opt_show_refs = !opt_show_refs;
                redraw_display();
                break;

        case REQ_SEARCH:
        case REQ_SEARCH_BACK:
                search_view(view, request);
                break;

        case REQ_FIND_NEXT:
        case REQ_FIND_PREV:
                find_next(view, request);
                break;

        case REQ_STOP_LOADING:
                for (i = 0; i < ARRAY_SIZE(views); i++) {
                        view = &views[i];
                        if (view->pipe)
                                report("Stopped loading the %s view", view->name),
                        end_update(view, TRUE);
                }
                break;

        case REQ_SHOW_VERSION:
                report("tig-%s (built %s)", TIG_VERSION, __DATE__);
                return TRUE;

        case REQ_SCREEN_RESIZE:
                resize_display();
                /* Fall-through */
        case REQ_SCREEN_REDRAW:
                redraw_display();
                break;

        case REQ_EDIT:
                report("Nothing to edit");
                break;

        case REQ_ENTER:
                report("Nothing to enter");
                break;

        case REQ_VIEW_CLOSE:
                /* XXX: Mark closed views by letting view->parent point to the
                 * view itself. Parents to closed view should never be
                 * followed. */
                if (view->parent &&
                    view->parent->parent != view->parent) {
                        memset(display, 0, sizeof(display));
                        current_view = 0;
                        display[current_view] = view->parent;
                        view->parent = view;
                        resize_display();
                        redraw_display();
                        report("");
                        break;
                }
                /* Fall-through */
        case REQ_QUIT:
                return FALSE;

        default:
                report("Unknown key, press 'h' for help");
                return TRUE;
        }

        return TRUE;
}


/*
 * Pager backend
 */

static bool
pager_draw(struct view *view, struct line *line, unsigned int lineno)
{
        char *text = line->data;

        if (opt_line_number && draw_lineno(view, lineno))
                return TRUE;

        draw_text(view, line->type, text, TRUE);
        return TRUE;
}

static bool
add_describe_ref(char *buf, size_t *bufpos, const char *commit_id, const char *sep)
{
        char refbuf[SIZEOF_STR];
        char *ref = NULL;
        FILE *pipe;

        if (!string_format(refbuf, "git describe %s 2>/dev/null", commit_id))
                return TRUE;

        pipe = popen(refbuf, "r");
        if (!pipe)
                return TRUE;

        if ((ref = fgets(refbuf, sizeof(refbuf), pipe)))
                ref = chomp_string(ref);
        pclose(pipe);

        if (!ref || !*ref)
                return TRUE;

        /* This is the only fatal call, since it can "corrupt" the buffer. */
        if (!string_nformat(buf, SIZEOF_STR, bufpos, "%s%s", sep, ref))
                return FALSE;

        return TRUE;
}

static void
add_pager_refs(struct view *view, struct line *line)
{
        char buf[SIZEOF_STR];
        char *commit_id = (char *)line->data + STRING_SIZE("commit ");
        struct ref **refs;
        size_t bufpos = 0, refpos = 0;
        const char *sep = "Refs: ";
        bool is_tag = FALSE;

        assert(line->type == LINE_COMMIT);

        refs = get_refs(commit_id);
        if (!refs) {
                if (view == VIEW(REQ_VIEW_DIFF))
                        goto try_add_describe_ref;
                return;
        }

        do {
                struct ref *ref = refs[refpos];
                const char *fmt = ref->tag    ? "%s[%s]" :
                                  ref->remote ? "%s<%s>" : "%s%s";

                if (!string_format_from(buf, &bufpos, fmt, sep, ref->name))
                        return;
                sep = ", ";
                if (ref->tag)
                        is_tag = TRUE;
        } while (refs[refpos++]->next);

        if (!is_tag && view == VIEW(REQ_VIEW_DIFF)) {
try_add_describe_ref:
                /* Add <tag>-g<commit_id> "fake" reference. */
                if (!add_describe_ref(buf, &bufpos, commit_id, sep))
                        return;
        }

        if (bufpos == 0)
                return;

        if (!realloc_lines(view, view->line_size + 1))
                return;

        add_line_text(view, buf, LINE_PP_REFS);
}

static bool
pager_read(struct view *view, char *data)
{
        struct line *line;

        if (!data)
                return TRUE;

        line = add_line_text(view, data, get_line_type(data));
        if (!line)
                return FALSE;

        if (line->type == LINE_COMMIT &&
            (view == VIEW(REQ_VIEW_DIFF) ||
             view == VIEW(REQ_VIEW_LOG)))
                add_pager_refs(view, line);

        return TRUE;
}

static enum request
pager_request(struct view *view, enum request request, struct line *line)
{
        int split = 0;

        if (request != REQ_ENTER)
                return request;

        if (line->type == LINE_COMMIT &&
           (view == VIEW(REQ_VIEW_LOG) ||
            view == VIEW(REQ_VIEW_PAGER))) {
                open_view(view, REQ_VIEW_DIFF, OPEN_SPLIT);
                split = 1;
        }

        /* Always scroll the view even if it was split. That way
         * you can use Enter to scroll through the log view and
         * split open each commit diff. */
        scroll_view(view, REQ_SCROLL_LINE_DOWN);

        /* FIXME: A minor workaround. Scrolling the view will call report("")
         * but if we are scrolling a non-current view this won't properly
         * update the view title. */
        if (split)
                update_view_title(view);

        return REQ_NONE;
}

static bool
pager_grep(struct view *view, struct line *line)
{
        regmatch_t pmatch;
        char *text = line->data;

        if (!*text)
                return FALSE;

        if (regexec(view->regex, text, 1, &pmatch, 0) == REG_NOMATCH)
                return FALSE;

        return TRUE;
}

static void
pager_select(struct view *view, struct line *line)
{
        if (line->type == LINE_COMMIT) {
                char *text = (char *)line->data + STRING_SIZE("commit ");

                if (view != VIEW(REQ_VIEW_PAGER))
                        string_copy_rev(view->ref, text);
                string_copy_rev(ref_commit, text);
        }
}

static struct view_ops pager_ops = {
        "line",
        NULL,
        pager_read,
        pager_draw,
        pager_request,
        pager_grep,
        pager_select,
};

static enum request
log_request(struct view *view, enum request request, struct line *line)
{
        switch (request) {
        case REQ_REFRESH:
                load_refs();
                open_view(view, REQ_VIEW_LOG, OPEN_REFRESH);
                return REQ_NONE;
        default:
                return pager_request(view, request, line);
        }
}

static struct view_ops log_ops = {
        "line",
        NULL,
        pager_read,
        pager_draw,
        log_request,
        pager_grep,
        pager_select,
};


/*
 * Help backend
 */

static bool
help_open(struct view *view)
{
        char buf[BUFSIZ];
        int lines = ARRAY_SIZE(req_info) + 2;
        int i;

        if (view->lines > 0)
                return TRUE;

        for (i = 0; i < ARRAY_SIZE(req_info); i++)
                if (!req_info[i].request)
                        lines++;

        lines += run_requests + 1;

        view->line = calloc(lines, sizeof(*view->line));
        if (!view->line)
                return FALSE;

        add_line_text(view, "Quick reference for tig keybindings:", LINE_DEFAULT);

        for (i = 0; i < ARRAY_SIZE(req_info); i++) {
                const char *key;

                if (req_info[i].request == REQ_NONE)
                        continue;

                if (!req_info[i].request) {
                        add_line_text(view, "", LINE_DEFAULT);
                        add_line_text(view, req_info[i].help, LINE_DEFAULT);
                        continue;
                }

                key = get_key(req_info[i].request);
                if (!*key)
                        key = "(no key defined)";

                if (!string_format(buf, "    %-25s %s", key, req_info[i].help))
                        continue;

                add_line_text(view, buf, LINE_DEFAULT);
        }

        if (run_requests) {
                add_line_text(view, "", LINE_DEFAULT);
                add_line_text(view, "External commands:", LINE_DEFAULT);
        }

        for (i = 0; i < run_requests; i++) {
                struct run_request *req = get_run_request(REQ_NONE + i + 1);
                const char *key;

                if (!req)
                        continue;

                key = get_key_name(req->key);
                if (!*key)
                        key = "(no key defined)";

                if (!string_format(buf, "    %-10s %-14s `%s`",
                                   keymap_table[req->keymap].name,
                                   key, req->cmd))
                        continue;

                add_line_text(view, buf, LINE_DEFAULT);
        }

        return TRUE;
}

static struct view_ops help_ops = {
        "line",
        help_open,
        NULL,
        pager_draw,
        pager_request,
        pager_grep,
        pager_select,
};


/*
 * Tree backend
 */

struct tree_stack_entry {
        struct tree_stack_entry *prev;  /* Entry below this in the stack */
        unsigned long lineno;           /* Line number to restore */
        char *name;                     /* Position of name in opt_path */
};

/* The top of the path stack. */
static struct tree_stack_entry *tree_stack = NULL;
unsigned long tree_lineno = 0;

static void
pop_tree_stack_entry(void)
{
        struct tree_stack_entry *entry = tree_stack;

        tree_lineno = entry->lineno;
        entry->name[0] = 0;
        tree_stack = entry->prev;
        free(entry);
}

static void
push_tree_stack_entry(const char *name, unsigned long lineno)
{
        struct tree_stack_entry *entry = calloc(1, sizeof(*entry));
        size_t pathlen = strlen(opt_path);

        if (!entry)
                return;

        entry->prev = tree_stack;
        entry->name = opt_path + pathlen;
        tree_stack = entry;

        if (!string_format_from(opt_path, &pathlen, "%s/", name)) {
                pop_tree_stack_entry();
                return;
        }

        /* Move the current line to the first tree entry. */
        tree_lineno = 1;
        entry->lineno = lineno;
}

/* Parse output from git-ls-tree(1):
 *
 * 100644 blob fb0e31ea6cc679b7379631188190e975f5789c26 Makefile
 * 100644 blob 5304ca4260aaddaee6498f9630e7d471b8591ea6 README
 * 100644 blob f931e1d229c3e185caad4449bf5b66ed72462657 tig.c
 * 100644 blob ed09fe897f3c7c9af90bcf80cae92558ea88ae38 web.conf
 */

#define SIZEOF_TREE_ATTR \
        STRING_SIZE("100644 blob ed09fe897f3c7c9af90bcf80cae92558ea88ae38\t")

#define TREE_UP_FORMAT "040000 tree %s\t.."

static int
tree_compare_entry(enum line_type type1, const char *name1,
                   enum line_type type2, const char *name2)
{
        if (type1 != type2) {
                if (type1 == LINE_TREE_DIR)
                        return -1;
                return 1;
        }

        return strcmp(name1, name2);
}

static const char *
tree_path(struct line *line)
{
        const char *path = line->data;

        return path + SIZEOF_TREE_ATTR;
}

static bool
tree_read(struct view *view, char *text)
{
        size_t textlen = text ? strlen(text) : 0;
        char buf[SIZEOF_STR];
        unsigned long pos;
        enum line_type type;
        bool first_read = view->lines == 0;

        if (!text)
                return TRUE;
        if (textlen <= SIZEOF_TREE_ATTR)
                return FALSE;

        type = text[STRING_SIZE("100644 ")] == 't'
             ? LINE_TREE_DIR : LINE_TREE_FILE;

        if (first_read) {
                /* Add path info line */
                if (!string_format(buf, "Directory path /%s", opt_path) ||
                    !realloc_lines(view, view->line_size + 1) ||
                    !add_line_text(view, buf, LINE_DEFAULT))
                        return FALSE;

                /* Insert "link" to parent directory. */
                if (*opt_path) {
                        if (!string_format(buf, TREE_UP_FORMAT, view->ref) ||
                            !realloc_lines(view, view->line_size + 1) ||
                            !add_line_text(view, buf, LINE_TREE_DIR))
                                return FALSE;
                }
        }

        /* Strip the path part ... */
        if (*opt_path) {
                size_t pathlen = textlen - SIZEOF_TREE_ATTR;
                size_t striplen = strlen(opt_path);
                char *path = text + SIZEOF_TREE_ATTR;

                if (pathlen > striplen)
                        memmove(path, path + striplen,
                                pathlen - striplen + 1);
        }

        /* Skip "Directory ..." and ".." line. */
        for (pos = 1 + !!*opt_path; pos < view->lines; pos++) {
                struct line *line = &view->line[pos];
                const char *path1 = tree_path(line);
                char *path2 = text + SIZEOF_TREE_ATTR;
                int cmp = tree_compare_entry(line->type, path1, type, path2);

                if (cmp <= 0)
                        continue;

                text = strdup(text);
                if (!text)
                        return FALSE;

                if (view->lines > pos)
                        memmove(&view->line[pos + 1], &view->line[pos],
                                (view->lines - pos) * sizeof(*line));

                line = &view->line[pos];
                line->data = text;
                line->type = type;
                view->lines++;
                return TRUE;
        }

        if (!add_line_text(view, text, type))
                return FALSE;

        if (tree_lineno > view->lineno) {
                view->lineno = tree_lineno;
                tree_lineno = 0;
        }

        return TRUE;
}

static enum request
tree_request(struct view *view, enum request request, struct line *line)
{
        enum open_flags flags;

        if (request == REQ_VIEW_BLAME) {
                const char *filename = tree_path(line);

                if (line->type == LINE_TREE_DIR) {
                        report("Cannot show blame for directory %s", opt_path);
                        return REQ_NONE;
                }

                string_copy(opt_ref, view->vid);
                string_format(opt_file, "%s%s", opt_path, filename);
                return request;
        }
        if (request == REQ_TREE_PARENT) {
                if (*opt_path) {
                        /* fake 'cd  ..' */
                        request = REQ_ENTER;
                        line = &view->line[1];
                } else {
                        /* quit view if at top of tree */
                        return REQ_VIEW_CLOSE;
                }
        }
        if (request != REQ_ENTER)
                return request;

        /* Cleanup the stack if the tree view is at a different tree. */
        while (!*opt_path && tree_stack)
                pop_tree_stack_entry();

        switch (line->type) {
        case LINE_TREE_DIR:
                /* Depending on whether it is a subdir or parent (updir?) link
                 * mangle the path buffer. */
                if (line == &view->line[1] && *opt_path) {
                        pop_tree_stack_entry();

                } else {
                        const char *basename = tree_path(line);

                        push_tree_stack_entry(basename, view->lineno);
                }

                /* Trees and subtrees share the same ID, so they are not not
                 * unique like blobs. */
                flags = OPEN_RELOAD;
                request = REQ_VIEW_TREE;
                break;

        case LINE_TREE_FILE:
                flags = display[0] == view ? OPEN_SPLIT : OPEN_DEFAULT;
                request = REQ_VIEW_BLOB;
                break;

        default:
                return TRUE;
        }

        open_view(view, request, flags);
        if (request == REQ_VIEW_TREE) {
                view->lineno = tree_lineno;
        }

        return REQ_NONE;
}

static void
tree_select(struct view *view, struct line *line)
{
        char *text = (char *)line->data + STRING_SIZE("100644 blob ");

        if (line->type == LINE_TREE_FILE) {
                string_copy_rev(ref_blob, text);

        } else if (line->type != LINE_TREE_DIR) {
                return;
        }

        string_copy_rev(view->ref, text);
}

static struct view_ops tree_ops = {
        "file",
        NULL,
        tree_read,
        pager_draw,
        tree_request,
        pager_grep,
        tree_select,
};

static bool
blob_read(struct view *view, char *line)
{
        if (!line)
                return TRUE;
        return add_line_text(view, line, LINE_DEFAULT) != NULL;
}

static struct view_ops blob_ops = {
        "line",
        NULL,
        blob_read,
        pager_draw,
        pager_request,
        pager_grep,
        pager_select,
};

/*
 * Blame backend
 *
 * Loading the blame view is a two phase job:
 *
 *  1. File content is read either using opt_file from the
 *     filesystem or using git-cat-file.
 *  2. Then blame information is incrementally added by
 *     reading output from git-blame.
 */

struct blame_commit {
        char id[SIZEOF_REV];            /* SHA1 ID. */
        char title[128];                /* First line of the commit message. */
        char author[75];                /* Author of the commit. */
        struct tm time;                 /* Date from the author ident. */
        char filename[128];             /* Name of file. */
};

struct blame {
        struct blame_commit *commit;
        unsigned int header:1;
        char text[1];
};

#define BLAME_CAT_FILE_CMD "git cat-file blob %s:%s"
#define BLAME_INCREMENTAL_CMD "git blame --incremental %s -- %s"

static bool
blame_open(struct view *view)
{
        char path[SIZEOF_STR];
        char ref[SIZEOF_STR] = "";

        if (sq_quote(path, 0, opt_file) >= sizeof(path))
                return FALSE;

        if (*opt_ref && sq_quote(ref, 0, opt_ref) >= sizeof(ref))
                return FALSE;

        if (*opt_ref) {
                if (!string_format(view->cmd, BLAME_CAT_FILE_CMD, ref, path))
                        return FALSE;
        } else {
                view->pipe = fopen(opt_file, "r");
                if (!view->pipe &&
                    !string_format(view->cmd, BLAME_CAT_FILE_CMD, "HEAD", path))
                        return FALSE;
        }

        if (!view->pipe)
                view->pipe = popen(view->cmd, "r");
        if (!view->pipe)
                return FALSE;

        if (!string_format(view->cmd, BLAME_INCREMENTAL_CMD, ref, path))
                return FALSE;

        reset_view(view);
        string_format(view->ref, "%s ...", opt_file);
        string_copy_rev(view->vid, opt_file);
        set_nonblocking_input(TRUE);
        view->start_time = time(NULL);

        return TRUE;
}

static struct blame_commit *
get_blame_commit(struct view *view, const char *id)
{
        size_t i;

        for (i = 0; i < view->lines; i++) {
                struct blame *blame = view->line[i].data;

                if (!blame->commit)
                        continue;

                if (!strncmp(blame->commit->id, id, SIZEOF_REV - 1))
                        return blame->commit;
        }

        {
                struct blame_commit *commit = calloc(1, sizeof(*commit));

                if (commit)
                        string_ncopy(commit->id, id, SIZEOF_REV);
                return commit;
        }
}

static bool
parse_number(const char **posref, size_t *number, size_t min, size_t max)
{
        const char *pos = *posref;

        *posref = NULL;
        pos = strchr(pos + 1, ' ');
        if (!pos || !isdigit(pos[1]))
                return FALSE;
        *number = atoi(pos + 1);
        if (*number < min || *number > max)
                return FALSE;

        *posref = pos;
        return TRUE;
}

static struct blame_commit *
parse_blame_commit(struct view *view, const char *text, int *blamed)
{
        struct blame_commit *commit;
        struct blame *blame;
        const char *pos = text + SIZEOF_REV - 1;
        size_t lineno;
        size_t group;

        if (strlen(text) <= SIZEOF_REV || *pos != ' ')
                return NULL;

        if (!parse_number(&pos, &lineno, 1, view->lines) ||
            !parse_number(&pos, &group, 1, view->lines - lineno + 1))
                return NULL;

        commit = get_blame_commit(view, text);
        if (!commit)
                return NULL;

        *blamed += group;
        while (group--) {
                struct line *line = &view->line[lineno + group - 1];

                blame = line->data;
                blame->commit = commit;
                blame->header = !group;
                line->dirty = 1;
        }

        return commit;
}

static bool
blame_read_file(struct view *view, const char *line)
{
        if (!line) {
                FILE *pipe = NULL;

                if (view->lines > 0)
                        pipe = popen(view->cmd, "r");
                else if (!view->parent)
                        die("No blame exist for %s", view->vid);
                view->cmd[0] = 0;
                if (!pipe) {
                        report("Failed to load blame data");
                        return TRUE;
                }

                fclose(view->pipe);
                view->pipe = pipe;
                return FALSE;

        } else {
                size_t linelen = strlen(line);
                struct blame *blame = malloc(sizeof(*blame) + linelen);

                blame->commit = NULL;
                strncpy(blame->text, line, linelen);
                blame->text[linelen] = 0;
                return add_line_data(view, blame, LINE_BLAME_ID) != NULL;
        }
}

static bool
match_blame_header(const char *name, char **line)
{
        size_t namelen = strlen(name);
        bool matched = !strncmp(name, *line, namelen);

        if (matched)
                *line += namelen;

        return matched;
}

static bool
blame_read(struct view *view, char *line)
{
        static struct blame_commit *commit = NULL;
        static int blamed = 0;
        static time_t author_time;

        if (*view->cmd)
                return blame_read_file(view, line);

        if (!line) {
                /* Reset all! */
                commit = NULL;
                blamed = 0;
                string_format(view->ref, "%s", view->vid);
                if (view_is_displayed(view)) {
                        update_view_title(view);
                        redraw_view_from(view, 0);
                }
                return TRUE;
        }

        if (!commit) {
                commit = parse_blame_commit(view, line, &blamed);
                string_format(view->ref, "%s %2d%%", view->vid,
                              blamed * 100 / view->lines);

        } else if (match_blame_header("author ", &line)) {
                string_ncopy(commit->author, line, strlen(line));

        } else if (match_blame_header("author-time ", &line)) {
                author_time = (time_t) atol(line);

        } else if (match_blame_header("author-tz ", &line)) {
                long tz;

                tz  = ('0' - line[1]) * 60 * 60 * 10;
                tz += ('0' - line[2]) * 60 * 60;
                tz += ('0' - line[3]) * 60;
                tz += ('0' - line[4]) * 60;

                if (line[0] == '-')
                        tz = -tz;

                author_time -= tz;
                gmtime_r(&author_time, &commit->time);

        } else if (match_blame_header("summary ", &line)) {
                string_ncopy(commit->title, line, strlen(line));

        } else if (match_blame_header("filename ", &line)) {
                string_ncopy(commit->filename, line, strlen(line));
                commit = NULL;
        }

        return TRUE;
}

static bool
blame_draw(struct view *view, struct line *line, unsigned int lineno)
{
        struct blame *blame = line->data;
        struct tm *time = NULL;
        const char *id = NULL, *author = NULL;

        if (blame->commit && *blame->commit->filename) {
                id = blame->commit->id;
                author = blame->commit->author;
                time = &blame->commit->time;
        }

        if (opt_date && draw_date(view, time))
                return TRUE;

        if (opt_author &&
            draw_field(view, LINE_MAIN_AUTHOR, author, opt_author_cols, TRUE))
                return TRUE;

        if (draw_field(view, LINE_BLAME_ID, id, ID_COLS, FALSE))
                return TRUE;

        if (draw_lineno(view, lineno))
                return TRUE;

        draw_text(view, LINE_DEFAULT, blame->text, TRUE);
        return TRUE;
}

static enum request
blame_request(struct view *view, enum request request, struct line *line)
{
        enum open_flags flags = display[0] == view ? OPEN_SPLIT : OPEN_DEFAULT;
        struct blame *blame = line->data;

        switch (request) {
        case REQ_ENTER:
                if (!blame->commit) {
                        report("No commit loaded yet");
                        break;
                }

                if (!strcmp(blame->commit->id, NULL_ID)) {
                        char path[SIZEOF_STR];

                        if (sq_quote(path, 0, view->vid) >= sizeof(path))
                                break;
                        string_format(opt_cmd, "git diff-index --root --patch-with-stat -C -M --cached HEAD -- %s 2>/dev/null", path);
                }

                open_view(view, REQ_VIEW_DIFF, flags);
                break;

        default:
                return request;
        }

        return REQ_NONE;
}

static bool
blame_grep(struct view *view, struct line *line)
{
        struct blame *blame = line->data;
        struct blame_commit *commit = blame->commit;
        regmatch_t pmatch;

#define MATCH(text, on)                                                 \
        (on && *text && regexec(view->regex, text, 1, &pmatch, 0) != REG_NOMATCH)

        if (commit) {
                char buf[DATE_COLS + 1];

                if (MATCH(commit->title, 1) ||
                    MATCH(commit->author, opt_author) ||
                    MATCH(commit->id, opt_date))
                        return TRUE;

                if (strftime(buf, sizeof(buf), DATE_FORMAT, &commit->time) &&
                    MATCH(buf, 1))
                        return TRUE;
        }

        return MATCH(blame->text, 1);

#undef MATCH
}

static void
blame_select(struct view *view, struct line *line)
{
        struct blame *blame = line->data;
        struct blame_commit *commit = blame->commit;

        if (!commit)
                return;

        if (!strcmp(commit->id, NULL_ID))
                string_ncopy(ref_commit, "HEAD", 4);
        else
                string_copy_rev(ref_commit, commit->id);
}

static struct view_ops blame_ops = {
        "line",
        blame_open,
        blame_read,
        blame_draw,
        blame_request,
        blame_grep,
        blame_select,
};

/*
 * Status backend
 */

struct status {
        char status;
        struct {
                mode_t mode;
                char rev[SIZEOF_REV];
                char name[SIZEOF_STR];
        } old;
        struct {
                mode_t mode;
                char rev[SIZEOF_REV];
                char name[SIZEOF_STR];
        } new;
};

static char status_onbranch[SIZEOF_STR];
static struct status stage_status;
static enum line_type stage_line_type;
static size_t stage_chunks;
static int *stage_chunk;

/* This should work even for the "On branch" line. */
static inline bool
status_has_none(struct view *view, struct line *line)
{
        return line < view->line + view->lines && !line[1].data;
}

/* Get fields from the diff line:
 * :100644 100644 06a5d6ae9eca55be2e0e585a152e6b1336f2b20e 0000000000000000000000000000000000000000 M
 */
static inline bool
status_get_diff(struct status *file, const char *buf, size_t bufsize)
{
        const char *old_mode = buf +  1;
        const char *new_mode = buf +  8;
        const char *old_rev  = buf + 15;
        const char *new_rev  = buf + 56;
        const char *status   = buf + 97;

        if (bufsize < 99 ||
            old_mode[-1] != ':' ||
            new_mode[-1] != ' ' ||
            old_rev[-1]  != ' ' ||
            new_rev[-1]  != ' ' ||
            status[-1]   != ' ')
                return FALSE;

        file->status = *status;

        string_copy_rev(file->old.rev, old_rev);
        string_copy_rev(file->new.rev, new_rev);

        file->old.mode = strtoul(old_mode, NULL, 8);
        file->new.mode = strtoul(new_mode, NULL, 8);

        file->old.name[0] = file->new.name[0] = 0;

        return TRUE;
}

static bool
status_run(struct view *view, const char cmd[], char status, enum line_type type)
{
        struct status *file = NULL;
        struct status *unmerged = NULL;
        char buf[SIZEOF_STR * 4];
        size_t bufsize = 0;
        FILE *pipe;

        pipe = popen(cmd, "r");
        if (!pipe)
                return FALSE;

        add_line_data(view, NULL, type);

        while (!feof(pipe) && !ferror(pipe)) {
                char *sep;
                size_t readsize;

                readsize = fread(buf + bufsize, 1, sizeof(buf) - bufsize, pipe);
                if (!readsize)
                        break;
                bufsize += readsize;

                /* Process while we have NUL chars. */
                while ((sep = memchr(buf, 0, bufsize))) {
                        size_t sepsize = sep - buf + 1;

                        if (!file) {
                                if (!realloc_lines(view, view->line_size + 1))
                                        goto error_out;

                                file = calloc(1, sizeof(*file));
                                if (!file)
                                        goto error_out;

                                add_line_data(view, file, type);
                        }

                        /* Parse diff info part. */
                        if (status) {
                                file->status = status;
                                if (status == 'A')
                                        string_copy(file->old.rev, NULL_ID);

                        } else if (!file->status) {
                                if (!status_get_diff(file, buf, sepsize))
                                        goto error_out;

                                bufsize -= sepsize;
                                memmove(buf, sep + 1, bufsize);

                                sep = memchr(buf, 0, bufsize);
                                if (!sep)
                                        break;
                                sepsize = sep - buf + 1;

                                /* Collapse all 'M'odified entries that
                                 * follow a associated 'U'nmerged entry.
                                 */
                                if (file->status == 'U') {
                                        unmerged = file;

                                } else if (unmerged) {
                                        int collapse = !strcmp(buf, unmerged->new.name);

                                        unmerged = NULL;
                                        if (collapse) {
                                                free(file);
                                                view->lines--;
                                                continue;
                                        }
                                }
                        }

                        /* Grab the old name for rename/copy. */
                        if (!*file->old.name &&
                            (file->status == 'R' || file->status == 'C')) {
                                sepsize = sep - buf + 1;
                                string_ncopy(file->old.name, buf, sepsize);
                                bufsize -= sepsize;
                                memmove(buf, sep + 1, bufsize);

                                sep = memchr(buf, 0, bufsize);
                                if (!sep)
                                        break;
                                sepsize = sep - buf + 1;
                        }

                        /* git-ls-files just delivers a NUL separated
                         * list of file names similar to the second half
                         * of the git-diff-* output. */
                        string_ncopy(file->new.name, buf, sepsize);
                        if (!*file->old.name)
                                string_copy(file->old.name, file->new.name);
                        bufsize -= sepsize;
                        memmove(buf, sep + 1, bufsize);
                        file = NULL;
                }
        }

        if (ferror(pipe)) {
error_out:
                pclose(pipe);
                return FALSE;
        }

        if (!view->line[view->lines - 1].data)
                add_line_data(view, NULL, LINE_STAT_NONE);

        pclose(pipe);
        return TRUE;
}

/* Don't show unmerged entries in the staged section. */
#define STATUS_DIFF_INDEX_CMD "git diff-index -z --diff-filter=ACDMRTXB --cached -M HEAD"
#define STATUS_DIFF_FILES_CMD "git diff-files -z"
#define STATUS_LIST_OTHER_CMD \
        "git ls-files -z --others --exclude-standard"
#define STATUS_LIST_NO_HEAD_CMD \
        "git ls-files -z --cached --exclude-standard"

#define STATUS_DIFF_INDEX_SHOW_CMD \
        "git diff-index --root --patch-with-stat -C -M --cached HEAD -- %s %s 2>/dev/null"

#define STATUS_DIFF_FILES_SHOW_CMD \
        "git diff-files --root --patch-with-stat -C -M -- %s %s 2>/dev/null"

#define STATUS_DIFF_NO_HEAD_SHOW_CMD \
        "git diff --no-color --patch-with-stat /dev/null %s 2>/dev/null"

/* First parse staged info using git-diff-index(1), then parse unstaged
 * info using git-diff-files(1), and finally untracked files using
 * git-ls-files(1). */
static bool
status_open(struct view *view)
{
        unsigned long prev_lineno = view->lineno;

        reset_view(view);

        if (!realloc_lines(view, view->line_size + 7))
                return FALSE;

        add_line_data(view, NULL, LINE_STAT_HEAD);
        if (opt_no_head)
                string_copy(status_onbranch, "Initial commit");
        else if (!*opt_head)
                string_copy(status_onbranch, "Not currently on any branch");
        else if (!string_format(status_onbranch, "On branch %s", opt_head))
                return FALSE;

        system("git update-index -q --refresh >/dev/null 2>/dev/null");

        if (opt_no_head) {
                if (!status_run(view, STATUS_LIST_NO_HEAD_CMD, 'A', LINE_STAT_STAGED))
                        return FALSE;
        } else if (!status_run(view, STATUS_DIFF_INDEX_CMD, 0, LINE_STAT_STAGED)) {
                return FALSE;
        }

        if (!status_run(view, STATUS_DIFF_FILES_CMD, 0, LINE_STAT_UNSTAGED) ||
            !status_run(view, STATUS_LIST_OTHER_CMD, '?', LINE_STAT_UNTRACKED))
                return FALSE;

        /* If all went well restore the previous line number to stay in
         * the context or select a line with something that can be
         * updated. */
        if (prev_lineno >= view->lines)
                prev_lineno = view->lines - 1;
        while (prev_lineno < view->lines && !view->line[prev_lineno].data)
                prev_lineno++;
        while (prev_lineno > 0 && !view->line[prev_lineno].data)
                prev_lineno--;

        /* If the above fails, always skip the "On branch" line. */
        if (prev_lineno < view->lines)
                view->lineno = prev_lineno;
        else
                view->lineno = 1;

        if (view->lineno < view->offset)
                view->offset = view->lineno;
        else if (view->offset + view->height <= view->lineno)
                view->offset = view->lineno - view->height + 1;

        return TRUE;
}

static bool
status_draw(struct view *view, struct line *line, unsigned int lineno)
{
        struct status *status = line->data;
        enum line_type type;
        const char *text;

        if (!status) {
                switch (line->type) {
                case LINE_STAT_STAGED:
                        type = LINE_STAT_SECTION;
                        text = "Changes to be committed:";
                        break;

                case LINE_STAT_UNSTAGED:
                        type = LINE_STAT_SECTION;
                        text = "Changed but not updated:";
                        break;

                case LINE_STAT_UNTRACKED:
                        type = LINE_STAT_SECTION;
                        text = "Untracked files:";
                        break;

                case LINE_STAT_NONE:
                        type = LINE_DEFAULT;
                        text = "    (no files)";
                        break;

                case LINE_STAT_HEAD:
                        type = LINE_STAT_HEAD;
                        text = status_onbranch;
                        break;

                default:
                        return FALSE;
                }
        } else {
                static char buf[] = { '?', ' ', ' ', ' ', 0 };

                buf[0] = status->status;
                if (draw_text(view, line->type, buf, TRUE))
                        return TRUE;
                type = LINE_DEFAULT;
                text = status->new.name;
        }

        draw_text(view, type, text, TRUE);
        return TRUE;
}

static enum request
status_enter(struct view *view, struct line *line)
{
        struct status *status = line->data;
        char oldpath[SIZEOF_STR] = "";
        char newpath[SIZEOF_STR] = "";
        const char *info;
        size_t cmdsize = 0;
        enum open_flags split;

        if (line->type == LINE_STAT_NONE ||
            (!status && line[1].type == LINE_STAT_NONE)) {
                report("No file to diff");
                return REQ_NONE;
        }

        if (status) {
                if (sq_quote(oldpath, 0, status->old.name) >= sizeof(oldpath))
                        return REQ_QUIT;
                /* Diffs for unmerged entries are empty when pasing the
                 * new path, so leave it empty. */
                if (status->status != 'U' &&
                    sq_quote(newpath, 0, status->new.name) >= sizeof(newpath))
                        return REQ_QUIT;
        }

        if (opt_cdup[0] &&
            line->type != LINE_STAT_UNTRACKED &&
            !string_format_from(opt_cmd, &cmdsize, "cd %s;", opt_cdup))
                return REQ_QUIT;

        switch (line->type) {
        case LINE_STAT_STAGED:
                if (opt_no_head) {
                        if (!string_format_from(opt_cmd, &cmdsize,
                                                STATUS_DIFF_NO_HEAD_SHOW_CMD,
                                                newpath))
                                return REQ_QUIT;
                } else {
                        if (!string_format_from(opt_cmd, &cmdsize,
                                                STATUS_DIFF_INDEX_SHOW_CMD,
                                                oldpath, newpath))
                                return REQ_QUIT;
                }

                if (status)
                        info = "Staged changes to %s";
                else
                        info = "Staged changes";
                break;

        case LINE_STAT_UNSTAGED:
                if (!string_format_from(opt_cmd, &cmdsize,
                                        STATUS_DIFF_FILES_SHOW_CMD, oldpath, newpath))
                        return REQ_QUIT;
                if (status)
                        info = "Unstaged changes to %s";
                else
                        info = "Unstaged changes";
                break;

        case LINE_STAT_UNTRACKED:
                if (opt_pipe)
                        return REQ_QUIT;

                if (!status) {
                        report("No file to show");
                        return REQ_NONE;
                }

                if (!suffixcmp(status->new.name, -1, "/")) {
                        report("Cannot display a directory");
                        return REQ_NONE;
                }

                opt_pipe = fopen(status->new.name, "r");
                info = "Untracked file %s";
                break;

        case LINE_STAT_HEAD:
                return REQ_NONE;

        default:
                die("line type %d not handled in switch", line->type);
        }

        split = view_is_displayed(view) ? OPEN_SPLIT : 0;
        open_view(view, REQ_VIEW_STAGE, OPEN_RELOAD | split);
        if (view_is_displayed(VIEW(REQ_VIEW_STAGE))) {
                if (status) {
                        stage_status = *status;
                } else {
                        memset(&stage_status, 0, sizeof(stage_status));
                }

                stage_line_type = line->type;
                stage_chunks = 0;
                string_format(VIEW(REQ_VIEW_STAGE)->ref, info, stage_status.new.name);
        }

        return REQ_NONE;
}

static bool
status_exists(struct status *status, enum line_type type)
{
        struct view *view = VIEW(REQ_VIEW_STATUS);
        struct line *line;

        for (line = view->line; line < view->line + view->lines; line++) {
                struct status *pos = line->data;

                if (line->type == type && pos &&
                    !strcmp(status->new.name, pos->new.name))
                        return TRUE;
        }

        return FALSE;
}


static FILE *
status_update_prepare(enum line_type type)
{
        char cmd[SIZEOF_STR];
        size_t cmdsize = 0;

        if (opt_cdup[0] &&
            type != LINE_STAT_UNTRACKED &&
            !string_format_from(cmd, &cmdsize, "cd %s;", opt_cdup))
                return NULL;

        switch (type) {
        case LINE_STAT_STAGED:
                string_add(cmd, cmdsize, "git update-index -z --index-info");
                break;

        case LINE_STAT_UNSTAGED:
        case LINE_STAT_UNTRACKED:
                string_add(cmd, cmdsize, "git update-index -z --add --remove --stdin");
                break;

        default:
                die("line type %d not handled in switch", type);
        }

        return popen(cmd, "w");
}

static bool
status_update_write(FILE *pipe, struct status *status, enum line_type type)
{
        char buf[SIZEOF_STR];
        size_t bufsize = 0;
        size_t written = 0;

        switch (type) {
        case LINE_STAT_STAGED:
                if (!string_format_from(buf, &bufsize, "%06o %s\t%s%c",
                                        status->old.mode,
                                        status->old.rev,
                                        status->old.name, 0))
                        return FALSE;
                break;

        case LINE_STAT_UNSTAGED:
        case LINE_STAT_UNTRACKED:
                if (!string_format_from(buf, &bufsize, "%s%c", status->new.name, 0))
                        return FALSE;
                break;

        default:
                die("line type %d not handled in switch", type);
        }

        while (!ferror(pipe) && written < bufsize) {
                written += fwrite(buf + written, 1, bufsize - written, pipe);
        }

        return written == bufsize;
}

static bool
status_update_file(struct status *status, enum line_type type)
{
        FILE *pipe = status_update_prepare(type);
        bool result;

        if (!pipe)
                return FALSE;

        result = status_update_write(pipe, status, type);
        pclose(pipe);
        return result;
}

static bool
status_update_files(struct view *view, struct line *line)
{
        FILE *pipe = status_update_prepare(line->type);
        bool result = TRUE;
        struct line *pos = view->line + view->lines;
        int files = 0;
        int file, done;

        if (!pipe)
                return FALSE;

        for (pos = line; pos < view->line + view->lines && pos->data; pos++)
                files++;

        for (file = 0, done = 0; result && file < files; line++, file++) {
                int almost_done = file * 100 / files;

                if (almost_done > done) {
                        done = almost_done;
                        string_format(view->ref, "updating file %u of %u (%d%% done)",
                                      file, files, done);
                        update_view_title(view);
                }
                result = status_update_write(pipe, line->data, line->type);
        }

        pclose(pipe);
        return result;
}

static bool
status_update(struct view *view)
{
        struct line *line = &view->line[view->lineno];

        assert(view->lines);

        if (!line->data) {
                /* This should work even for the "On branch" line. */
                if (line < view->line + view->lines && !line[1].data) {
                        report("Nothing to update");
                        return FALSE;
                }

                if (!status_update_files(view, line + 1)) {
                        report("Failed to update file status");
                        return FALSE;
                }

        } else if (!status_update_file(line->data, line->type)) {
                report("Failed to update file status");
                return FALSE;
        }

        return TRUE;
}

static bool
status_revert(struct status *status, enum line_type type, bool has_none)
{
        if (!status || type != LINE_STAT_UNSTAGED) {
                if (type == LINE_STAT_STAGED) {
                        report("Cannot revert changes to staged files");
                } else if (type == LINE_STAT_UNTRACKED) {
                        report("Cannot revert changes to untracked files");
                } else if (has_none) {
                        report("Nothing to revert");
                } else {
                        report("Cannot revert changes to multiple files");
                }
                return FALSE;

        } else {
                char cmd[SIZEOF_STR];
                char file_sq[SIZEOF_STR];

                if (sq_quote(file_sq, 0, status->old.name) >= sizeof(file_sq) ||
                    !string_format(cmd, "git checkout -- %s%s", opt_cdup, file_sq))
                        return FALSE;

                return run_confirm(cmd, "Are you sure you want to overwrite any changes?");
        }
}

static enum request
status_request(struct view *view, enum request request, struct line *line)
{
        struct status *status = line->data;

        switch (request) {
        case REQ_STATUS_UPDATE:
                if (!status_update(view))
                        return REQ_NONE;
                break;

        case REQ_STATUS_REVERT:
                if (!status_revert(status, line->type, status_has_none(view, line)))
                        return REQ_NONE;
                break;

        case REQ_STATUS_MERGE:
                if (!status || status->status != 'U') {
                        report("Merging only possible for files with unmerged status ('U').");
                        return REQ_NONE;
                }
                open_mergetool(status->new.name);
                break;

        case REQ_EDIT:
                if (!status)
                        return request;

                open_editor(status->status != '?', status->new.name);
                break;

        case REQ_VIEW_BLAME:
                if (status) {
                        string_copy(opt_file, status->new.name);
                        opt_ref[0] = 0;
                }
                return request;

        case REQ_ENTER:
                /* After returning the status view has been split to
                 * show the stage view. No further reloading is
                 * necessary. */
                status_enter(view, line);
                return REQ_NONE;

        case REQ_REFRESH:
                /* Simply reload the view. */
                break;

        default:
                return request;
        }

        open_view(view, REQ_VIEW_STATUS, OPEN_RELOAD);

        return REQ_NONE;
}

static void
status_select(struct view *view, struct line *line)
{
        struct status *status = line->data;
        char file[SIZEOF_STR] = "all files";
        const char *text;
        const char *key;

        if (status && !string_format(file, "'%s'", status->new.name))
                return;

        if (!status && line[1].type == LINE_STAT_NONE)
                line++;

        switch (line->type) {
        case LINE_STAT_STAGED:
                text = "Press %s to unstage %s for commit";
                break;

        case LINE_STAT_UNSTAGED:
                text = "Press %s to stage %s for commit";
                break;

        case LINE_STAT_UNTRACKED:
                text = "Press %s to stage %s for addition";
                break;

        case LINE_STAT_HEAD:
        case LINE_STAT_NONE:
                text = "Nothing to update";
                break;

        default:
                die("line type %d not handled in switch", line->type);
        }

        if (status && status->status == 'U') {
                text = "Press %s to resolve conflict in %s";
                key = get_key(REQ_STATUS_MERGE);

        } else {
                key = get_key(REQ_STATUS_UPDATE);
        }

        string_format(view->ref, text, key, file);
}

static bool
status_grep(struct view *view, struct line *line)
{
        struct status *status = line->data;
        enum { S_STATUS, S_NAME, S_END } state;
        char buf[2] = "?";
        regmatch_t pmatch;

        if (!status)
                return FALSE;

        for (state = S_STATUS; state < S_END; state++) {
                const char *text;

                switch (state) {
                case S_NAME:    text = status->new.name;        break;
                case S_STATUS:
                        buf[0] = status->status;
                        text = buf;
                        break;

                default:
                        return FALSE;
                }

                if (regexec(view->regex, text, 1, &pmatch, 0) != REG_NOMATCH)
                        return TRUE;
        }

        return FALSE;
}

static struct view_ops status_ops = {
        "file",
        status_open,
        NULL,
        status_draw,
        status_request,
        status_grep,
        status_select,
};


static bool
stage_diff_line(FILE *pipe, struct line *line)
{
        const char *buf = line->data;
        size_t bufsize = strlen(buf);
        size_t written = 0;

        while (!ferror(pipe) && written < bufsize) {
                written += fwrite(buf + written, 1, bufsize - written, pipe);
        }

        fputc('\n', pipe);

        return written == bufsize;
}

static bool
stage_diff_write(FILE *pipe, struct line *line, struct line *end)
{
        while (line < end) {
                if (!stage_diff_line(pipe, line++))
                        return FALSE;
                if (line->type == LINE_DIFF_CHUNK ||
                    line->type == LINE_DIFF_HEADER)
                        break;
        }

        return TRUE;
}

static struct line *
stage_diff_find(struct view *view, struct line *line, enum line_type type)
{
        for (; view->line < line; line--)
                if (line->type == type)
                        return line;

        return NULL;
}

static bool
stage_apply_chunk(struct view *view, struct line *chunk, bool revert)
{
        char cmd[SIZEOF_STR];
        size_t cmdsize = 0;
        struct line *diff_hdr;
        FILE *pipe;

        diff_hdr = stage_diff_find(view, chunk, LINE_DIFF_HEADER);
        if (!diff_hdr)
                return FALSE;

        if (opt_cdup[0] &&
            !string_format_from(cmd, &cmdsize, "cd %s;", opt_cdup))
                return FALSE;

        if (!string_format_from(cmd, &cmdsize,
                                "git apply --whitespace=nowarn %s %s - && "
                                "git update-index -q --unmerged --refresh 2>/dev/null",
                                revert ? "" : "--cached",
                                revert || stage_line_type == LINE_STAT_STAGED ? "-R" : ""))
                return FALSE;

        pipe = popen(cmd, "w");
        if (!pipe)
                return FALSE;

        if (!stage_diff_write(pipe, diff_hdr, chunk) ||
            !stage_diff_write(pipe, chunk, view->line + view->lines))
                chunk = NULL;

        pclose(pipe);

        return chunk ? TRUE : FALSE;
}

static bool
stage_update(struct view *view, struct line *line)
{
        struct line *chunk = NULL;

        if (!opt_no_head && stage_line_type != LINE_STAT_UNTRACKED)
                chunk = stage_diff_find(view, line, LINE_DIFF_CHUNK);

        if (chunk) {
                if (!stage_apply_chunk(view, chunk, FALSE)) {
                        report("Failed to apply chunk");
                        return FALSE;
                }

        } else if (!stage_status.status) {
                view = VIEW(REQ_VIEW_STATUS);

                for (line = view->line; line < view->line + view->lines; line++)
                        if (line->type == stage_line_type)
                                break;

                if (!status_update_files(view, line + 1)) {
                        report("Failed to update files");
                        return FALSE;
                }

        } else if (!status_update_file(&stage_status, stage_line_type)) {
                report("Failed to update file");
                return FALSE;
        }

        return TRUE;
}

static bool
stage_revert(struct view *view, struct line *line)
{
        struct line *chunk = NULL;

        if (!opt_no_head && stage_line_type == LINE_STAT_UNSTAGED)
                chunk = stage_diff_find(view, line, LINE_DIFF_CHUNK);

        if (chunk) {
                if (!prompt_yesno("Are you sure you want to revert changes?"))
                        return FALSE;

                if (!stage_apply_chunk(view, chunk, TRUE)) {
                        report("Failed to revert chunk");
                        return FALSE;
                }
                return TRUE;

        } else {
                return status_revert(stage_status.status ? &stage_status : NULL,
                                     stage_line_type, FALSE);
        }
}


static void
stage_next(struct view *view, struct line *line)
{
        int i;

        if (!stage_chunks) {
                static size_t alloc = 0;
                int *tmp;

                for (line = view->line; line < view->line + view->lines; line++) {
                        if (line->type != LINE_DIFF_CHUNK)
                                continue;

                        tmp = realloc_items(stage_chunk, &alloc,
                                            stage_chunks, sizeof(*tmp));
                        if (!tmp) {
                                report("Allocation failure");
                                return;
                        }

                        stage_chunk = tmp;
                        stage_chunk[stage_chunks++] = line - view->line;
                }
        }

        for (i = 0; i < stage_chunks; i++) {
                if (stage_chunk[i] > view->lineno) {
                        do_scroll_view(view, stage_chunk[i] - view->lineno);
                        report("Chunk %d of %d", i + 1, stage_chunks);
                        return;
                }
        }

        report("No next chunk found");
}

static enum request
stage_request(struct view *view, enum request request, struct line *line)
{
        switch (request) {
        case REQ_STATUS_UPDATE:
                if (!stage_update(view, line))
                        return REQ_NONE;
                break;

        case REQ_STATUS_REVERT:
                if (!stage_revert(view, line))
                        return REQ_NONE;
                break;

        case REQ_STAGE_NEXT:
                if (stage_line_type == LINE_STAT_UNTRACKED) {
                        report("File is untracked; press %s to add",
                               get_key(REQ_STATUS_UPDATE));
                        return REQ_NONE;
                }
                stage_next(view, line);
                return REQ_NONE;

        case REQ_EDIT:
                if (!stage_status.new.name[0])
                        return request;

                open_editor(stage_status.status != '?', stage_status.new.name);
                break;

        case REQ_REFRESH:
                /* Reload everything ... */
                break;

        case REQ_VIEW_BLAME:
                if (stage_status.new.name[0]) {
                        string_copy(opt_file, stage_status.new.name);
                        opt_ref[0] = 0;
                }
                return request;

        case REQ_ENTER:
                return pager_request(view, request, line);

        default:
                return request;
        }

        open_view(view, REQ_VIEW_STATUS, OPEN_RELOAD | OPEN_NOMAXIMIZE);

        /* Check whether the staged entry still exists, and close the
         * stage view if it doesn't. */
        if (!status_exists(&stage_status, stage_line_type))
                return REQ_VIEW_CLOSE;

        if (stage_line_type == LINE_STAT_UNTRACKED) {
                if (!suffixcmp(stage_status.new.name, -1, "/")) {
                        report("Cannot display a directory");
                        return REQ_NONE;
                }

                opt_pipe = fopen(stage_status.new.name, "r");
        }
        open_view(view, REQ_VIEW_STAGE, OPEN_REFRESH);

        return REQ_NONE;
}

static struct view_ops stage_ops = {
        "line",
        NULL,
        pager_read,
        pager_draw,
        stage_request,
        pager_grep,
        pager_select,
};


/*
 * Revision graph
 */

struct commit {
        char id[SIZEOF_REV];            /* SHA1 ID. */
        char title[128];                /* First line of the commit message. */
        char author[75];                /* Author of the commit. */
        struct tm time;                 /* Date from the author ident. */
        struct ref **refs;              /* Repository references. */
        chtype graph[SIZEOF_REVGRAPH];  /* Ancestry chain graphics. */
        size_t graph_size;              /* The width of the graph array. */
        bool has_parents;               /* Rewritten --parents seen. */
};

/* Size of rev graph with no  "padding" columns */
#define SIZEOF_REVITEMS (SIZEOF_REVGRAPH - (SIZEOF_REVGRAPH / 2))

struct rev_graph {
        struct rev_graph *prev, *next, *parents;
        char rev[SIZEOF_REVITEMS][SIZEOF_REV];
        size_t size;
        struct commit *commit;
        size_t pos;
        unsigned int boundary:1;
};

/* Parents of the commit being visualized. */
static struct rev_graph graph_parents[4];

/* The current stack of revisions on the graph. */
static struct rev_graph graph_stacks[4] = {
        { &graph_stacks[3], &graph_stacks[1], &graph_parents[0] },
        { &graph_stacks[0], &graph_stacks[2], &graph_parents[1] },
        { &graph_stacks[1], &graph_stacks[3], &graph_parents[2] },
        { &graph_stacks[2], &graph_stacks[0], &graph_parents[3] },
};

static inline bool
graph_parent_is_merge(struct rev_graph *graph)
{
        return graph->parents->size > 1;
}

static inline void
append_to_rev_graph(struct rev_graph *graph, chtype symbol)
{
        struct commit *commit = graph->commit;

        if (commit->graph_size < ARRAY_SIZE(commit->graph) - 1)
                commit->graph[commit->graph_size++] = symbol;
}

static void
clear_rev_graph(struct rev_graph *graph)
{
        graph->boundary = 0;
        graph->size = graph->pos = 0;
        graph->commit = NULL;
        memset(graph->parents, 0, sizeof(*graph->parents));
}

static void
done_rev_graph(struct rev_graph *graph)
{
        if (graph_parent_is_merge(graph) &&
            graph->pos < graph->size - 1 &&
            graph->next->size == graph->size + graph->parents->size - 1) {
                size_t i = graph->pos + graph->parents->size - 1;

                graph->commit->graph_size = i * 2;
                while (i < graph->next->size - 1) {
                        append_to_rev_graph(graph, ' ');
                        append_to_rev_graph(graph, '\\');
                        i++;
                }
        }

        clear_rev_graph(graph);
}

static void
push_rev_graph(struct rev_graph *graph, const char *parent)
{
        int i;

        /* "Collapse" duplicate parents lines.
         *
         * FIXME: This needs to also update update the drawn graph but
         * for now it just serves as a method for pruning graph lines. */
        for (i = 0; i < graph->size; i++)
                if (!strncmp(graph->rev[i], parent, SIZEOF_REV))
                        return;

        if (graph->size < SIZEOF_REVITEMS) {
                string_copy_rev(graph->rev[graph->size++], parent);
        }
}

static chtype
get_rev_graph_symbol(struct rev_graph *graph)
{
        chtype symbol;

        if (graph->boundary)
                symbol = REVGRAPH_BOUND;
        else if (graph->parents->size == 0)
                symbol = REVGRAPH_INIT;
        else if (graph_parent_is_merge(graph))
                symbol = REVGRAPH_MERGE;
        else if (graph->pos >= graph->size)
                symbol = REVGRAPH_BRANCH;
        else
                symbol = REVGRAPH_COMMIT;

        return symbol;
}

static void
draw_rev_graph(struct rev_graph *graph)
{
        struct rev_filler {
                chtype separator, line;
        };
        enum { DEFAULT, RSHARP, RDIAG, LDIAG };
        static struct rev_filler fillers[] = {
                { ' ',  '|' },
                { '`',  '.' },
                { '\'', ' ' },
                { '/',  ' ' },
        };
        chtype symbol = get_rev_graph_symbol(graph);
        struct rev_filler *filler;
        size_t i;

        if (opt_line_graphics)
                fillers[DEFAULT].line = line_graphics[LINE_GRAPHIC_VLINE];

        filler = &fillers[DEFAULT];

        for (i = 0; i < graph->pos; i++) {
                append_to_rev_graph(graph, filler->line);
                if (graph_parent_is_merge(graph->prev) &&
                    graph->prev->pos == i)
                        filler = &fillers[RSHARP];

                append_to_rev_graph(graph, filler->separator);
        }

        /* Place the symbol for this revision. */
        append_to_rev_graph(graph, symbol);

        if (graph->prev->size > graph->size)
                filler = &fillers[RDIAG];
        else
                filler = &fillers[DEFAULT];

        i++;

        for (; i < graph->size; i++) {
                append_to_rev_graph(graph, filler->separator);
                append_to_rev_graph(graph, filler->line);
                if (graph_parent_is_merge(graph->prev) &&
                    i < graph->prev->pos + graph->parents->size)
                        filler = &fillers[RSHARP];
                if (graph->prev->size > graph->size)
                        filler = &fillers[LDIAG];
        }

        if (graph->prev->size > graph->size) {
                append_to_rev_graph(graph, filler->separator);
                if (filler->line != ' ')
                        append_to_rev_graph(graph, filler->line);
        }
}

/* Prepare the next rev graph */
static void
prepare_rev_graph(struct rev_graph *graph)
{
        size_t i;

        /* First, traverse all lines of revisions up to the active one. */
        for (graph->pos = 0; graph->pos < graph->size; graph->pos++) {
                if (!strcmp(graph->rev[graph->pos], graph->commit->id))
                        break;

                push_rev_graph(graph->next, graph->rev[graph->pos]);
        }

        /* Interleave the new revision parent(s). */
        for (i = 0; !graph->boundary && i < graph->parents->size; i++)
                push_rev_graph(graph->next, graph->parents->rev[i]);

        /* Lastly, put any remaining revisions. */
        for (i = graph->pos + 1; i < graph->size; i++)
                push_rev_graph(graph->next, graph->rev[i]);
}

static void
update_rev_graph(struct rev_graph *graph)
{
        /* If this is the finalizing update ... */
        if (graph->commit)
                prepare_rev_graph(graph);

        /* Graph visualization needs a one rev look-ahead,
         * so the first update doesn't visualize anything. */
        if (!graph->prev->commit)
                return;

        draw_rev_graph(graph->prev);
        done_rev_graph(graph->prev->prev);
}


/*
 * Main view backend
 */

static bool
main_draw(struct view *view, struct line *line, unsigned int lineno)
{
        struct commit *commit = line->data;

        if (!*commit->author)
                return FALSE;

        if (opt_date && draw_date(view, &commit->time))
                return TRUE;

        if (opt_author &&
            draw_field(view, LINE_MAIN_AUTHOR, commit->author, opt_author_cols, TRUE))
                return TRUE;

        if (opt_rev_graph && commit->graph_size &&
            draw_graphic(view, LINE_MAIN_REVGRAPH, commit->graph, commit->graph_size))
                return TRUE;

        if (opt_show_refs && commit->refs) {
                size_t i = 0;

                do {
                        enum line_type type;

                        if (commit->refs[i]->head)
                                type = LINE_MAIN_HEAD;
                        else if (commit->refs[i]->ltag)
                                type = LINE_MAIN_LOCAL_TAG;
                        else if (commit->refs[i]->tag)
                                type = LINE_MAIN_TAG;
                        else if (commit->refs[i]->tracked)
                                type = LINE_MAIN_TRACKED;
                        else if (commit->refs[i]->remote)
                                type = LINE_MAIN_REMOTE;
                        else
                                type = LINE_MAIN_REF;

                        if (draw_text(view, type, "[", TRUE) ||
                            draw_text(view, type, commit->refs[i]->name, TRUE) ||
                            draw_text(view, type, "]", TRUE))
                                return TRUE;

                        if (draw_text(view, LINE_DEFAULT, " ", TRUE))
                                return TRUE;
                } while (commit->refs[i++]->next);
        }

        draw_text(view, LINE_DEFAULT, commit->title, TRUE);
        return TRUE;
}

/* Reads git log --pretty=raw output and parses it into the commit struct. */
static bool
main_read(struct view *view, char *line)
{
        static struct rev_graph *graph = graph_stacks;
        enum line_type type;
        struct commit *commit;

        if (!line) {
                int i;

                if (!view->lines && !view->parent)
                        die("No revisions match the given arguments.");
                if (view->lines > 0) {
                        commit = view->line[view->lines - 1].data;
                        if (!*commit->author) {
                                view->lines--;
                                free(commit);
                                graph->commit = NULL;
                        }
                }
                update_rev_graph(graph);

                for (i = 0; i < ARRAY_SIZE(graph_stacks); i++)
                        clear_rev_graph(&graph_stacks[i]);
                return TRUE;
        }

        type = get_line_type(line);
        if (type == LINE_COMMIT) {
                commit = calloc(1, sizeof(struct commit));
                if (!commit)
                        return FALSE;

                line += STRING_SIZE("commit ");
                if (*line == '-') {
                        graph->boundary = 1;
                        line++;
                }

                string_copy_rev(commit->id, line);
                commit->refs = get_refs(commit->id);
                graph->commit = commit;
                add_line_data(view, commit, LINE_MAIN_COMMIT);

                while ((line = strchr(line, ' '))) {
                        line++;
                        push_rev_graph(graph->parents, line);
                        commit->has_parents = TRUE;
                }
                return TRUE;
        }

        if (!view->lines)
                return TRUE;
        commit = view->line[view->lines - 1].data;

        switch (type) {
        case LINE_PARENT:
                if (commit->has_parents)
                        break;
                push_rev_graph(graph->parents, line + STRING_SIZE("parent "));
                break;

        case LINE_AUTHOR:
        {
                /* Parse author lines where the name may be empty:
                 *      author  <email@address.tld> 1138474660 +0100
                 */
                char *ident = line + STRING_SIZE("author ");
                char *nameend = strchr(ident, '<');
                char *emailend = strchr(ident, '>');

                if (!nameend || !emailend)
                        break;

                update_rev_graph(graph);
                graph = graph->next;

                *nameend = *emailend = 0;
                ident = chomp_string(ident);
                if (!*ident) {
                        ident = chomp_string(nameend + 1);
                        if (!*ident)
                                ident = "Unknown";
                }

                string_ncopy(commit->author, ident, strlen(ident));

                /* Parse epoch and timezone */
                if (emailend[1] == ' ') {
                        char *secs = emailend + 2;
                        char *zone = strchr(secs, ' ');
                        time_t time = (time_t) atol(secs);

                        if (zone && strlen(zone) == STRING_SIZE(" +0700")) {
                                long tz;

                                zone++;
                                tz  = ('0' - zone[1]) * 60 * 60 * 10;
                                tz += ('0' - zone[2]) * 60 * 60;
                                tz += ('0' - zone[3]) * 60;
                                tz += ('0' - zone[4]) * 60;

                                if (zone[0] == '-')
                                        tz = -tz;

                                time -= tz;
                        }

                        gmtime_r(&time, &commit->time);
                }
                break;
        }
        default:
                /* Fill in the commit title if it has not already been set. */
                if (commit->title[0])
                        break;

                /* Require titles to start with a non-space character at the
                 * offset used by git log. */
                if (strncmp(line, "    ", 4))
                        break;
                line += 4;
                /* Well, if the title starts with a whitespace character,
                 * try to be forgiving.  Otherwise we end up with no title. */
                while (isspace(*line))
                        line++;
                if (*line == '\0')
                        break;
                /* FIXME: More graceful handling of titles; append "..." to
                 * shortened titles, etc. */

                string_ncopy(commit->title, line, strlen(line));
        }

        return TRUE;
}

static enum request
main_request(struct view *view, enum request request, struct line *line)
{
        enum open_flags flags = display[0] == view ? OPEN_SPLIT : OPEN_DEFAULT;

        switch (request) {
        case REQ_ENTER:
                open_view(view, REQ_VIEW_DIFF, flags);
                break;
        case REQ_REFRESH:
                load_refs();
                open_view(view, REQ_VIEW_MAIN, OPEN_REFRESH);
                break;
        default:
                return request;
        }

        return REQ_NONE;
}

static bool
grep_refs(struct ref **refs, regex_t *regex)
{
        regmatch_t pmatch;
        size_t i = 0;

        if (!refs)
                return FALSE;
        do {
                if (regexec(regex, refs[i]->name, 1, &pmatch, 0) != REG_NOMATCH)
                        return TRUE;
        } while (refs[i++]->next);

        return FALSE;
}

static bool
main_grep(struct view *view, struct line *line)
{
        struct commit *commit = line->data;
        enum { S_TITLE, S_AUTHOR, S_DATE, S_REFS, S_END } state;
        char buf[DATE_COLS + 1];
        regmatch_t pmatch;

        for (state = S_TITLE; state < S_END; state++) {
                char *text;

                switch (state) {
                case S_TITLE:   text = commit->title;   break;
                case S_AUTHOR:
                        if (!opt_author)
                                continue;
                        text = commit->author;
                        break;
                case S_DATE:
                        if (!opt_date)
                                continue;
                        if (!strftime(buf, sizeof(buf), DATE_FORMAT, &commit->time))
                                continue;
                        text = buf;
                        break;
                case S_REFS:
                        if (!opt_show_refs)
                                continue;
                        if (grep_refs(commit->refs, view->regex) == TRUE)
                                return TRUE;
                        continue;
                default:
                        return FALSE;
                }

                if (regexec(view->regex, text, 1, &pmatch, 0) != REG_NOMATCH)
                        return TRUE;
        }

        return FALSE;
}

static void
main_select(struct view *view, struct line *line)
{
        struct commit *commit = line->data;

        string_copy_rev(view->ref, commit->id);
        string_copy_rev(ref_commit, view->ref);
}

static struct view_ops main_ops = {
        "commit",
        NULL,
        main_read,
        main_draw,
        main_request,
        main_grep,
        main_select,
};


/*
 * Unicode / UTF-8 handling
 *
 * NOTE: Much of the following code for dealing with unicode is derived from
 * ELinks' UTF-8 code developed by Scrool <scroolik@gmail.com>. Origin file is
 * src/intl/charset.c from the utf8 branch commit elinks-0.11.0-g31f2c28.
 */

/* I've (over)annotated a lot of code snippets because I am not entirely
 * confident that the approach taken by this small UTF-8 interface is correct.
 * --jonas */

static inline int
unicode_width(unsigned long c)
{
        if (c >= 0x1100 &&
           (c <= 0x115f                         /* Hangul Jamo */
            || c == 0x2329
            || c == 0x232a
            || (c >= 0x2e80  && c <= 0xa4cf && c != 0x303f)
                                                /* CJK ... Yi */
            || (c >= 0xac00  && c <= 0xd7a3)    /* Hangul Syllables */
            || (c >= 0xf900  && c <= 0xfaff)    /* CJK Compatibility Ideographs */
            || (c >= 0xfe30  && c <= 0xfe6f)    /* CJK Compatibility Forms */
            || (c >= 0xff00  && c <= 0xff60)    /* Fullwidth Forms */
            || (c >= 0xffe0  && c <= 0xffe6)
            || (c >= 0x20000 && c <= 0x2fffd)
            || (c >= 0x30000 && c <= 0x3fffd)))
                return 2;

        if (c == '\t')
                return opt_tab_size;

        return 1;
}

/* Number of bytes used for encoding a UTF-8 character indexed by first byte.
 * Illegal bytes are set one. */
static const unsigned char utf8_bytes[256] = {
        1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1,
        1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1,
        1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1,
        1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1,
        1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1,
        1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1,
        2,2,2,2,2,2,2,2, 2,2,2,2,2,2,2,2, 2,2,2,2,2,2,2,2, 2,2,2,2,2,2,2,2,
        3,3,3,3,3,3,3,3, 3,3,3,3,3,3,3,3, 4,4,4,4,4,4,4,4, 5,5,5,5,6,6,1,1,
};

/* Decode UTF-8 multi-byte representation into a unicode character. */
static inline unsigned long
utf8_to_unicode(const char *string, size_t length)
{
        unsigned long unicode;

        switch (length) {
        case 1:
                unicode  =   string[0];
                break;
        case 2:
                unicode  =  (string[0] & 0x1f) << 6;
                unicode +=  (string[1] & 0x3f);
                break;
        case 3:
                unicode  =  (string[0] & 0x0f) << 12;
                unicode += ((string[1] & 0x3f) << 6);
                unicode +=  (string[2] & 0x3f);
                break;
        case 4:
                unicode  =  (string[0] & 0x0f) << 18;
                unicode += ((string[1] & 0x3f) << 12);
                unicode += ((string[2] & 0x3f) << 6);
                unicode +=  (string[3] & 0x3f);
                break;
        case 5:
                unicode  =  (string[0] & 0x0f) << 24;
                unicode += ((string[1] & 0x3f) << 18);
                unicode += ((string[2] & 0x3f) << 12);
                unicode += ((string[3] & 0x3f) << 6);
                unicode +=  (string[4] & 0x3f);
                break;
        case 6:
                unicode  =  (string[0] & 0x01) << 30;
                unicode += ((string[1] & 0x3f) << 24);
                unicode += ((string[2] & 0x3f) << 18);
                unicode += ((string[3] & 0x3f) << 12);
                unicode += ((string[4] & 0x3f) << 6);
                unicode +=  (string[5] & 0x3f);
                break;
        default:
                die("Invalid unicode length");
        }

        /* Invalid characters could return the special 0xfffd value but NUL
         * should be just as good. */
        return unicode > 0xffff ? 0 : unicode;
}

/* Calculates how much of string can be shown within the given maximum width
 * and sets trimmed parameter to non-zero value if all of string could not be
 * shown. If the reserve flag is TRUE, it will reserve at least one
 * trailing character, which can be useful when drawing a delimiter.
 *
 * Returns the number of bytes to output from string to satisfy max_width. */
static size_t
utf8_length(const char *string, int *width, size_t max_width, int *trimmed, bool reserve)
{
        const char *start = string;
        const char *end = strchr(string, '\0');
        unsigned char last_bytes = 0;
        size_t last_ucwidth = 0;

        *width = 0;
        *trimmed = 0;

        while (string < end) {
                int c = *(unsigned char *) string;
                unsigned char bytes = utf8_bytes[c];
                size_t ucwidth;
                unsigned long unicode;

                if (string + bytes > end)
                        break;

                /* Change representation to figure out whether
                 * it is a single- or double-width character. */

                unicode = utf8_to_unicode(string, bytes);
                /* FIXME: Graceful handling of invalid unicode character. */
                if (!unicode)
                        break;

                ucwidth = unicode_width(unicode);
                *width  += ucwidth;
                if (*width > max_width) {
                        *trimmed = 1;
                        *width -= ucwidth;
                        if (reserve && *width == max_width) {
                                string -= last_bytes;
                                *width -= last_ucwidth;
                        }
                        break;
                }

                string  += bytes;
                last_bytes = bytes;
                last_ucwidth = ucwidth;
        }

        return string - start;
}


/*
 * Status management
 */

/* Whether or not the curses interface has been initialized. */
static bool cursed = FALSE;

/* The status window is used for polling keystrokes. */
static WINDOW *status_win;

static bool status_empty = TRUE;

/* Update status and title window. */
static void
report(const char *msg, ...)
{
        struct view *view = display[current_view];

        if (input_mode)
                return;

        if (!view) {
                char buf[SIZEOF_STR];
                va_list args;

                va_start(args, msg);
                if (vsnprintf(buf, sizeof(buf), msg, args) >= sizeof(buf)) {
                        buf[sizeof(buf) - 1] = 0;
                        buf[sizeof(buf) - 2] = '.';
                        buf[sizeof(buf) - 3] = '.';
                        buf[sizeof(buf) - 4] = '.';
                }
                va_end(args);
                die("%s", buf);
        }

        if (!status_empty || *msg) {
                va_list args;

                va_start(args, msg);

                wmove(status_win, 0, 0);
                if (*msg) {
                        vwprintw(status_win, msg, args);
                        status_empty = FALSE;
                } else {
                        status_empty = TRUE;
                }
                wclrtoeol(status_win);
                wrefresh(status_win);

                va_end(args);
        }

        update_view_title(view);
        update_display_cursor(view);
}

/* Controls when nodelay should be in effect when polling user input. */
static void
set_nonblocking_input(bool loading)
{
        static unsigned int loading_views;

        if ((loading == FALSE && loading_views-- == 1) ||
            (loading == TRUE  && loading_views++ == 0))
                nodelay(status_win, loading);
}

static void
init_display(void)
{
        int x, y;

        /* Initialize the curses library */
        if (isatty(STDIN_FILENO)) {
                cursed = !!initscr();
                opt_tty = stdin;
        } else {
                /* Leave stdin and stdout alone when acting as a pager. */
                opt_tty = fopen("/dev/tty", "r+");
                if (!opt_tty)
                        die("Failed to open /dev/tty");
                cursed = !!newterm(NULL, opt_tty, opt_tty);
        }

        if (!cursed)
                die("Failed to initialize curses");

        nonl();         /* Tell curses not to do NL->CR/NL on output */
        cbreak();       /* Take input chars one at a time, no wait for \n */
        noecho();       /* Don't echo input */
        leaveok(stdscr, TRUE);

        if (has_colors())
                init_colors();

        getmaxyx(stdscr, y, x);
        status_win = newwin(1, 0, y - 1, 0);
        if (!status_win)
                die("Failed to create status window");

        /* Enable keyboard mapping */
        keypad(status_win, TRUE);
        wbkgdset(status_win, get_line_attr(LINE_STATUS));

        TABSIZE = opt_tab_size;
        if (opt_line_graphics) {
                line_graphics[LINE_GRAPHIC_VLINE] = ACS_VLINE;
        }
}

static bool
prompt_yesno(const char *prompt)
{
        enum { WAIT, STOP, CANCEL  } status = WAIT;
        bool answer = FALSE;

        while (status == WAIT) {
                struct view *view;
                int i, key;

                input_mode = TRUE;

                foreach_view (view, i)
                        update_view(view);

                input_mode = FALSE;

                mvwprintw(status_win, 0, 0, "%s [Yy]/[Nn]", prompt);
                wclrtoeol(status_win);

                /* Refresh, accept single keystroke of input */
                key = wgetch(status_win);
                switch (key) {
                case ERR:
                        break;

                case 'y':
                case 'Y':
                        answer = TRUE;
                        status = STOP;
                        break;

                case KEY_ESC:
                case KEY_RETURN:
                case KEY_ENTER:
                case KEY_BACKSPACE:
                case 'n':
                case 'N':
                case '\n':
                default:
                        answer = FALSE;
                        status = CANCEL;
                }
        }

        /* Clear the status window */
        status_empty = FALSE;
        report("");

        return answer;
}

static char *
read_prompt(const char *prompt)
{
        enum { READING, STOP, CANCEL } status = READING;
        static char buf[sizeof(opt_cmd) - STRING_SIZE("git \0")];
        int pos = 0;

        while (status == READING) {
                struct view *view;
                int i, key;

                input_mode = TRUE;

                foreach_view (view, i)
                        update_view(view);

                input_mode = FALSE;

                mvwprintw(status_win, 0, 0, "%s%.*s", prompt, pos, buf);
                wclrtoeol(status_win);

                /* Refresh, accept single keystroke of input */
                key = wgetch(status_win);
                switch (key) {
                case KEY_RETURN:
                case KEY_ENTER:
                case '\n':
                        status = pos ? STOP : CANCEL;
                        break;

                case KEY_BACKSPACE:
                        if (pos > 0)
                                pos--;
                        else
                                status = CANCEL;
                        break;

                case KEY_ESC:
                        status = CANCEL;
                        break;

                case ERR:
                        break;

                default:
                        if (pos >= sizeof(buf)) {
                                report("Input string too long");
                                return NULL;
                        }

                        if (isprint(key))
                                buf[pos++] = (char) key;
                }
        }

        /* Clear the status window */
        status_empty = FALSE;
        report("");

        if (status == CANCEL)
                return NULL;

        buf[pos++] = 0;

        return buf;
}

/*
 * Repository references
 */

static struct ref *refs = NULL;
static size_t refs_alloc = 0;
static size_t refs_size = 0;

/* Id <-> ref store */
static struct ref ***id_refs = NULL;
static size_t id_refs_alloc = 0;
static size_t id_refs_size = 0;

static int
compare_refs(const void *ref1_, const void *ref2_)
{
        const struct ref *ref1 = *(const struct ref **)ref1_;
        const struct ref *ref2 = *(const struct ref **)ref2_;

        if (ref1->tag != ref2->tag)
                return ref2->tag - ref1->tag;
        if (ref1->ltag != ref2->ltag)
                return ref2->ltag - ref2->ltag;
        if (ref1->head != ref2->head)
                return ref2->head - ref1->head;
        if (ref1->tracked != ref2->tracked)
                return ref2->tracked - ref1->tracked;
        if (ref1->remote != ref2->remote)
                return ref2->remote - ref1->remote;
        return strcmp(ref1->name, ref2->name);
}

static struct ref **
get_refs(const char *id)
{
        struct ref ***tmp_id_refs;
        struct ref **ref_list = NULL;
        size_t ref_list_alloc = 0;
        size_t ref_list_size = 0;
        size_t i;

        for (i = 0; i < id_refs_size; i++)
                if (!strcmp(id, id_refs[i][0]->id))
                        return id_refs[i];

        tmp_id_refs = realloc_items(id_refs, &id_refs_alloc, id_refs_size + 1,
                                    sizeof(*id_refs));
        if (!tmp_id_refs)
                return NULL;

        id_refs = tmp_id_refs;

        for (i = 0; i < refs_size; i++) {
                struct ref **tmp;

                if (strcmp(id, refs[i].id))
                        continue;

                tmp = realloc_items(ref_list, &ref_list_alloc,
                                    ref_list_size + 1, sizeof(*ref_list));
                if (!tmp) {
                        if (ref_list)
                                free(ref_list);
                        return NULL;
                }

                ref_list = tmp;
                ref_list[ref_list_size] = &refs[i];
                /* XXX: The properties of the commit chains ensures that we can
                 * safely modify the shared ref. The repo references will
                 * always be similar for the same id. */
                ref_list[ref_list_size]->next = 1;

                ref_list_size++;
        }

        if (ref_list) {
                qsort(ref_list, ref_list_size, sizeof(*ref_list), compare_refs);
                ref_list[ref_list_size - 1]->next = 0;
                id_refs[id_refs_size++] = ref_list;
        }

        return ref_list;
}

static int
read_ref(char *id, size_t idlen, char *name, size_t namelen)
{
        struct ref *ref;
        bool tag = FALSE;
        bool ltag = FALSE;
        bool remote = FALSE;
        bool tracked = FALSE;
        bool check_replace = FALSE;
        bool head = FALSE;

        if (!prefixcmp(name, "refs/tags/")) {
                if (!suffixcmp(name, namelen, "^{}")) {
                        namelen -= 3;
                        name[namelen] = 0;
                        if (refs_size > 0 && refs[refs_size - 1].ltag == TRUE)
                                check_replace = TRUE;
                } else {
                        ltag = TRUE;
                }

                tag = TRUE;
                namelen -= STRING_SIZE("refs/tags/");
                name    += STRING_SIZE("refs/tags/");

        } else if (!prefixcmp(name, "refs/remotes/")) {
                remote = TRUE;
                namelen -= STRING_SIZE("refs/remotes/");
                name    += STRING_SIZE("refs/remotes/");
                tracked  = !strcmp(opt_remote, name);

        } else if (!prefixcmp(name, "refs/heads/")) {
                namelen -= STRING_SIZE("refs/heads/");
                name    += STRING_SIZE("refs/heads/");
                head     = !strncmp(opt_head, name, namelen);

        } else if (!strcmp(name, "HEAD")) {
                opt_no_head = FALSE;
                return OK;
        }

        if (check_replace && !strcmp(name, refs[refs_size - 1].name)) {
                /* it's an annotated tag, replace the previous sha1 with the
                 * resolved commit id; relies on the fact git-ls-remote lists
                 * the commit id of an annotated tag right before the commit id
                 * it points to. */
                refs[refs_size - 1].ltag = ltag;
                string_copy_rev(refs[refs_size - 1].id, id);

                return OK;
        }
        refs = realloc_items(refs, &refs_alloc, refs_size + 1, sizeof(*refs));
        if (!refs)
                return ERR;

        ref = &refs[refs_size++];
        ref->name = malloc(namelen + 1);
        if (!ref->name)
                return ERR;

        strncpy(ref->name, name, namelen);
        ref->name[namelen] = 0;
        ref->head = head;
        ref->tag = tag;
        ref->ltag = ltag;
        ref->remote = remote;
        ref->tracked = tracked;
        string_copy_rev(ref->id, id);

        return OK;
}

static int
load_refs(void)
{
        const char *cmd_env = getenv("TIG_LS_REMOTE");
        const char *cmd = cmd_env && *cmd_env ? cmd_env : TIG_LS_REMOTE;

        if (!*opt_git_dir)
                return OK;

        while (refs_size > 0)
                free(refs[--refs_size].name);
        while (id_refs_size > 0)
                free(id_refs[--id_refs_size]);

        return read_properties(popen(cmd, "r"), "\t", read_ref);
}

static int
read_repo_config_option(char *name, size_t namelen, char *value, size_t valuelen)
{
        if (!strcmp(name, "i18n.commitencoding"))
                string_ncopy(opt_encoding, value, valuelen);

        if (!strcmp(name, "core.editor"))
                string_ncopy(opt_editor, value, valuelen);

        /* branch.<head>.remote */
        if (*opt_head &&
            !strncmp(name, "branch.", 7) &&
            !strncmp(name + 7, opt_head, strlen(opt_head)) &&
            !strcmp(name + 7 + strlen(opt_head), ".remote"))
                string_ncopy(opt_remote, value, valuelen);

        if (*opt_head && *opt_remote &&
            !strncmp(name, "branch.", 7) &&
            !strncmp(name + 7, opt_head, strlen(opt_head)) &&
            !strcmp(name + 7 + strlen(opt_head), ".merge")) {
                size_t from = strlen(opt_remote);

                if (!prefixcmp(value, "refs/heads/")) {
                        value += STRING_SIZE("refs/heads/");
                        valuelen -= STRING_SIZE("refs/heads/");
                }

                if (!string_format_from(opt_remote, &from, "/%s", value))
                        opt_remote[0] = 0;
        }

        return OK;
}

static int
load_git_config(void)
{
        return read_properties(popen("git " GIT_CONFIG " --list", "r"),
                               "=", read_repo_config_option);
}

static int
read_repo_info(char *name, size_t namelen, char *value, size_t valuelen)
{
        if (!opt_git_dir[0]) {
                string_ncopy(opt_git_dir, name, namelen);

        } else if (opt_is_inside_work_tree == -1) {
                /* This can be 3 different values depending on the
                 * version of git being used. If git-rev-parse does not
                 * understand --is-inside-work-tree it will simply echo
                 * the option else either "true" or "false" is printed.
                 * Default to true for the unknown case. */
                opt_is_inside_work_tree = strcmp(name, "false") ? TRUE : FALSE;

        } else if (opt_cdup[0] == ' ') {
                string_ncopy(opt_cdup, name, namelen);
        } else {
                if (!prefixcmp(name, "refs/heads/")) {
                        namelen -= STRING_SIZE("refs/heads/");
                        name    += STRING_SIZE("refs/heads/");
                        string_ncopy(opt_head, name, namelen);
                }
        }

        return OK;
}

static int
load_repo_info(void)
{
        int result;
        FILE *pipe = popen("(git rev-parse --git-dir --is-inside-work-tree "
                           " --show-cdup; git symbolic-ref HEAD) 2>/dev/null", "r");

        /* XXX: The line outputted by "--show-cdup" can be empty so
         * initialize it to something invalid to make it possible to
         * detect whether it has been set or not. */
        opt_cdup[0] = ' ';

        result = read_properties(pipe, "=", read_repo_info);
        if (opt_cdup[0] == ' ')
                opt_cdup[0] = 0;

        return result;
}

static int
read_properties(FILE *pipe, const char *separators,
                int (*read_property)(char *, size_t, char *, size_t))
{
        char buffer[BUFSIZ];
        char *name;
        int state = OK;

        if (!pipe)
                return ERR;

        while (state == OK && (name = fgets(buffer, sizeof(buffer), pipe))) {
                char *value;
                size_t namelen;
                size_t valuelen;

                name = chomp_string(name);
                namelen = strcspn(name, separators);

                if (name[namelen]) {
                        name[namelen] = 0;
                        value = chomp_string(name + namelen + 1);
                        valuelen = strlen(value);

                } else {
                        value = "";
                        valuelen = 0;
                }

                state = read_property(name, namelen, value, valuelen);
        }

        if (state != ERR && ferror(pipe))
                state = ERR;

        pclose(pipe);

        return state;
}


/*
 * Main
 */

static void __NORETURN
quit(int sig)
{
        /* XXX: Restore tty modes and let the OS cleanup the rest! */
        if (cursed)
                endwin();
        exit(0);
}

static void __NORETURN
die(const char *err, ...)
{
        va_list args;

        endwin();

        va_start(args, err);
        fputs("tig: ", stderr);
        vfprintf(stderr, err, args);
        fputs("\n", stderr);
        va_end(args);

        exit(1);
}

static void
warn(const char *msg, ...)
{
        va_list args;

        va_start(args, msg);
        fputs("tig warning: ", stderr);
        vfprintf(stderr, msg, args);
        fputs("\n", stderr);
        va_end(args);
}

int
main(int argc, const char *argv[])
{
        struct view *view;
        enum request request;
        size_t i;

        signal(SIGINT, quit);

        if (setlocale(LC_ALL, "")) {
                char *codeset = nl_langinfo(CODESET);

                string_ncopy(opt_codeset, codeset, strlen(codeset));
        }

        if (load_repo_info() == ERR)
                die("Failed to load repo info.");

        if (load_options() == ERR)
                die("Failed to load user config.");

        if (load_git_config() == ERR)
                die("Failed to load repo config.");

        request = parse_options(argc, argv);
        if (request == REQ_NONE)
                return 0;

        /* Require a git repository unless when running in pager mode. */
        if (!opt_git_dir[0] && request != REQ_VIEW_PAGER)
                die("Not a git repository");

        if (*opt_encoding && strcasecmp(opt_encoding, "UTF-8"))
                opt_utf8 = FALSE;

        if (*opt_codeset && strcmp(opt_codeset, opt_encoding)) {
                opt_iconv = iconv_open(opt_codeset, opt_encoding);
                if (opt_iconv == ICONV_NONE)
                        die("Failed to initialize character set conversion");
        }

        if (load_refs() == ERR)
                die("Failed to load refs.");

        foreach_view (view, i)
                view->cmd_env = getenv(view->cmd_env);

        init_display();

        while (view_driver(display[current_view], request)) {
                int key;
                int i;

                foreach_view (view, i)
                        update_view(view);
                view = display[current_view];

                /* Refresh, accept single keystroke of input */
                key = wgetch(status_win);

                /* wgetch() with nodelay() enabled returns ERR when there's no
                 * input. */
                if (key == ERR) {
                        request = REQ_NONE;
                        continue;
                }

                request = get_keybinding(view->keymap, key);

                /* Some low-level request handling. This keeps access to
                 * status_win restricted. */
                switch (request) {
                case REQ_PROMPT:
                {
                        char *cmd = read_prompt(":");

                        if (cmd && string_format(opt_cmd, "git %s", cmd)) {
                                if (strncmp(cmd, "show", 4) && isspace(cmd[4])) {
                                        request = REQ_VIEW_DIFF;
                                } else {
                                        request = REQ_VIEW_PAGER;
                                }

                                /* Always reload^Wrerun commands from the prompt. */
                                open_view(view, request, OPEN_RELOAD);
                        }

                        request = REQ_NONE;
                        break;
                }
                case REQ_SEARCH:
                case REQ_SEARCH_BACK:
                {
                        const char *prompt = request == REQ_SEARCH ? "/" : "?";
                        char *search = read_prompt(prompt);

                        if (search)
                                string_ncopy(opt_search, search, strlen(search));
                        else
                                request = REQ_NONE;
                        break;
                }
                case REQ_SCREEN_RESIZE:
                {
                        int height, width;

                        getmaxyx(stdscr, height, width);

                        /* Resize the status view and let the view driver take
                         * care of resizing the displayed views. */
                        wresize(status_win, 1, width);
                        mvwin(status_win, height - 1, 0);
                        wrefresh(status_win);
                        break;
                }
                default:
                        break;
                }
        }

        quit(0);

        return 0;
}