read log-like commit specs

[git-chart] / git-chart

#!/usr/bin/perl

use strict;
use warnings;
use POSIX qw(ceil);
use Getopt::Long;
use Date::Parse;

sub usage() {
        print "Usage: git chart\n";
}

sub gather_data($) {
        my $options = shift;
        my %perday;

        print "Gathering data ...\n";

        my $groups = 0;
        my $commits = 0;
        open my $fd, '-|', qw(git log --date=short), '--pretty=%ad,%s', @{$options->{cmdline}};
        die "failed to get revs" unless $fd;
        while (<$fd>) {
                chomp;
                $commits += 1;
                my ($date, $sub) = split ',', $_, 2;
                if (exists $perday{$date}) {
                        $perday{$date} += 1;
                } else {
                        $perday{$date} = 1;
                        $groups += 1;
                }
        }
        close $fd;

        print "...done, $commits commits in $groups days. Grouping\n";

        my $step=$options->{step}*24*3600; # days to seconds

        my @keys = sort keys %perday;
        my $from = $keys[0];
        my $to = $keys[@keys-1];

        my %dataset ;
        my $first;
        my $next;
        my $val = 0;
        my $max = 0;
        while (my $key = shift @keys) {
                my $day = str2time($key);
                unless ($first) {
                        $first = $day;
                        $next = $first + $step;
                }
                if ($day < $next) {
                        $val += $perday{$key};
                } else {
                        # TODO what do we put as key?
                        $dataset{$first} = $val;
                        $max = $val if $max < $val;
                        while ($day >= $next) {
                                $first = $next;
                                $next = $first + $step;
                                $dataset{$first} = 0 unless $day < $next;
                        }
                        $val = $perday{$key};
                }
        }
        $dataset{$first} = $val;
        $max = $val if $max < $val;

        $options->{max} = $max;
        return \%dataset;
}

# functions to plot the datasets.
# each function can be called with either one or two parameters.
# when called with two parameters, the first is assumed to be the dataset, and the second the options
# (array and hash ref respectively).
# when called with a single parameter, it is assumed to be an options hash ref, and the dataset is 
# created by calling gather_data with the passed options.

# google chart API
# TODO needs a lot of customization
sub google_chart($;$) {
        my $dataset = shift;
        my $options = shift;
        if (! defined $options) {
                $options = $dataset;
                $dataset = gather_data($options);
        }

        my $height=$options->{chart_height};
        my $max = $options->{max};

        my @keys = sort keys %$dataset;
        my $from = $keys[0];
        my $to = $keys[@keys-1];

        my @data;
        while (my $key = shift @keys) {
                push @data, $dataset->{$key};
        }

        my $width=ceil(4*$height/3);

        my $url="https://chart.googleapis.com/chart?chs=${width}x${height}&cht=bvg&chd=t:%s&chds=0,$max&chbh=a&chxt=y&chxr=0,0,$max";

        my $launch = sprintf $url, join(",",@data);
        print $launch, "\n";
        # `git web--browse "$launch"`
}

# gnuplot
sub gnuplot_chart($;$) {
        my $dataset = shift;
        my $options = shift;
        if (! defined $options) {
                $options = $dataset;
                $dataset = gather_data($options);
        }

        my @keys = sort keys %$dataset;
        my $from = $keys[0];
        my $to = $keys[@keys-1];
        my $data = '';
        while (my $key = shift @keys) {
                $data .= "$key $dataset->{$key}\n";
        }
        my $max = $options->{max};

        # TODO allow customization
        # in particular, detect (lack of) display and set term to dumb accordingly
        my $termcmd = $options->{gnuplot_term};

        my $plotsetup = $options->{gnuplot_setup};
        $plotsetup .= "\nset yrange [0:$max]\n";
        $plotsetup .= "set xrange ['$from':'$to']\n";
        my $plotstyle = $options->{gnuplot_style};
        my $plotoptions = $options->{gnuplot_plotwith};

        open my $gp, "|gnuplot -persist";

        my $gp_script = <<GPCMD
$termcmd
set xdata time
set timefmt "%s"
set format x "%b\\n%Y"
$plotsetup
$plotstyle
plot "-" using 1:2 $plotoptions
$data
GPCMD
        ;

        print STDOUT $gp_script;
        print $gp $gp_script;
        close $gp;
}

# some defaults
my %options = (
        step => 1,
        cmdline => [],
        # charting/plotting options
        plotter => \&gnuplot_chart,
        chart_height => 144,
        gnuplot_term => '',
        gnuplot_setup => "set nokey",
        gnuplot_style => 'set style data histeps',
        gnuplot_plotwith => '',
);

my %steps = (
        daily => 1,
        weekly => 7,
        monthly => 30,
);

sub parse_step(@) {
        my $key = shift;
        my $step = shift;
        if (exists $steps{$key}) {
                $options{step} = $steps{$key};
                return;
        }
        die "this can't happen ($key)" unless $key eq 'step';

        if ($step =~/^\d+$/) {
                $options{step} = 0 + $step;
                return
        } else {
                if (exists $steps{$step}) {
                        $options{step} = $steps{$step};
                        return;
                }
                die "unknown step $step";
        }
}

# read our options first
Getopt::Long::Configure('pass_through');
GetOptions(
        'daily' => \&parse_step,
        'weekly' => \&parse_step,
        'monthly' => \&parse_step,
        'step=s' => sub { parse_step(@_) },
        google => sub { $options{plotter} = \&google_chart },
        gnuplot => sub { $options{plotter} = \&gnuplot_chart },
);

# if anything was left, check for log options
if (@ARGV) {
        $options{cmdline} = \@ARGV;
}

die "step must be strictly positive!" unless $options{step} > 0;

$options{plotter}->(\%options);