timediff

#!/usr/bin/perl -w

# Read the whole time log
my %timelog;
open TIMELOG, "< .timelog";
while (<TIMELOG>) {
	next unless /(.*?):(.*?) (.*?) (.*?) (.*?)/;
	$timelog{$1}{$2} = $3 + $4;
}
close TIMELOG;

# Use git rev-parse to analyse the command line
sub rev_parse ($) {
	my ($rev, $plus) = ($_[0] =~ /^(.*?)(\+?)$/);
	$rev = `git rev-parse --short $rev`;
	$rev or die "Usage: ./timediff [<before-rev> [<after-rev>]]";
	chomp $rev;
	return $rev . $plus;
}

# Obtain the revisions of interest
my $pending = `git status --porcelain --untracked=no` ? 1 : 0;
my $bspec = defined($ARGV[0]) ? $ARGV[0] : $pending ? "HEAD"  : "HEAD^";
my $aspec = defined($ARGV[1]) ? $ARGV[1] : $pending ? "HEAD+" : "HEAD";

# Print the differences
my $bef = rev_parse($bspec);
my $aft = rev_parse($aspec);
my $total = 0;
print STDERR "Showing differences between $bef..$aft\n";
foreach (sort keys(%{$timelog{$bef}})) {
	next unless exists $timelog{$aft}{$_};
	my $diff = $timelog{$aft}{$_} - $timelog{$bef}{$_};
	printf "%s: %+.2f\n", $_, $diff;
	$total += $diff;
}
printf "total: %+.2f\n", $total;