#!/usr/bin/perl

use strict;
use warnings;

#    Copyright 2012 Grant Street Group, All Rights Reserved.
#
#    This program is free software: you can redistribute it and/or modify
#    it under the terms of the GNU Affero General Public License as
#    published by the Free Software Foundation, either version 3 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 Affero General Public License for more details.
#
#    You should have received a copy of the GNU Affero General Public License
#    along with this program.  If not, see <http://www.gnu.org/licenses/>.

# PODNAME: gitc-promoted
# ABSTRACT: Return a list of promoted changesets
our $VERSION = '0.60'; # VERSION

use App::Gitc::Util qw(
    changesets_promoted_between
    git
    project_name
    sort_changesets_by_name
);
use Date::PeriodParser ();
use Getopt::Long qw( :config pass_through );
use POSIX qw( strftime );
use Time::Local qw( timegm timelocal );
use List::MoreUtils qw( first_index );

# process command line arguments
our ($period, $bare) = ('sometime');
GetOptions(
    'period|p=s' => \$period,
    'bare|b'     => \$bare,
);
our $target = shift or die "You must specify a promotion target\n";

# parse and verify the period
our ( $start, $end ) = parse_period($period);
die "I don't understand the period '$period'\n" if $start < 0;

my ( $start_stamp, $end_stamp ) = period( local => '%FT%T' );
my @additions = changesets_promoted_between({
    project => scalar project_name(),
    target  => $target,
    start   => $start_stamp,
    end     => $end_stamp,
});

# display the output
my $between = english_date_range( $start, $end );
if ($bare) {
    print join "\n", @additions;
}
else {
    print "# Changesets promoted to $target $between\n";
    print "promoted:\n";
    print "    - $_\n" for @additions;
}

############################## helper subs #########################

sub parse_period {
    my $period = shift;
    $period = q{} if not defined $period; # /me glances wistfully at v5.10

    # a single release branch name (which, conveniently, is a timestamp)
    if ( my $end_time = parse_promotion_tag_time($period) ) {
        our $target;
        my @tags = git "tag -l $target/*";
        my $index = first_index { $_ eq "$target/$period" } @tags;
        die "Can't find the tag $target/$period\n" if $index < 0;
        my $start_time = $index == 0
                       ? 0
                       : parse_promotion_tag_time( $tags[ $index - 1 ] );
        return ( $start_time + 1, $end_time );
    }

    my $mdy = qr{ \d{1,2} / \d{1,2} / (?: \d{2} | \d{4} ) }xms;
    if ( $period =~ m{\A ($mdy) \s* - \s* ($mdy)\z}xms ) {
        my ($start_m, $start_d, $start_y) = split /\//, $1;
        my ($end_m, $end_d, $end_y) = split /\//, $2;
        my $start = timelocal( 0,   0,  0, $start_d, --$start_m, $start_y );
        my $end   = timelocal( 59, 59, 23,   $end_d,   --$end_m,   $end_y );
        return ($start, $end);
    }

    return Date::PeriodParser::parse_period($period);
}

sub parse_promotion_tag_time {
    my ($tag) = @_;
    return if not $tag;
    if ( $tag =~ m{(\d{4}-\d{2}-\d{2}T\d{2}_\d{2}_\d{2})\z} ) {
        my $stamp = $1;
        my ($y,$m,$d,$H,$M,$S) = split /[-T_Z]/, $stamp;
        $m--;  # number of months since January
        my $time = timegm( $S, $M, $H, $d, $m, $y );
        return $time;
    }

    return;
}

sub period {
    my ( $zone_name, $format ) = @_;
    our ( $start, $end );
    die "You must specify a time zone.  Either 'gm' or 'local'\n"
        if not $zone_name;

    my $zone = $zone_name eq 'local'
             ? sub { localtime(shift) }
             : sub { gmtime(shift)    };
    return map { strftime($format, $zone->($_)) } $start, $end;
}

sub english_date_range {
    my ( $start, $end ) = period( local => '%m/%d/%Y' );

    # same dates, so include the times
    if ( $start eq $end ) {
        my ( $start_time, $end_time ) = period( local => '%T' );
        $start .= ' ' . $start_time;
        $end   .= ' ' . $end_time;
    }

    return "between $start and $end";
}

__END__

=pod

=head1 NAME

gitc-promoted - Return a list of promoted changesets

=head1 VERSION

version 0.60

=head1 AUTHOR

Grant Street Group <developers@grantstreet.com>

=head1 COPYRIGHT AND LICENSE

This software is Copyright (c) 2013 by Grant Street Group.

This is free software, licensed under:

  The GNU Affero General Public License, Version 3, November 2007

=cut
