package Gitalist::Git::Object::Commit;
use MooseX::Declare;

class Gitalist::Git::Object::Commit
    extends Gitalist::Git::Object
    with Gitalist::Git::Object::HasTree {
        use MooseX::Types::Moose qw/Str Int Bool Maybe ArrayRef/;
        use MooseX::Types::Common::String qw/NonEmptySimpleStr/;
        use List::MoreUtils qw/any zip/;
        our $SHA1RE = qr/[0-9a-fA-F]{40}/;

        has '+type' => ( default => 'commit' );
        has '+_gpp_obj' => ( handles => [ 'comment',
                                          'tree_sha1',
                                          'committer',
                                          'committed_time',
                                          'author',
                                          'authored_time',
                                          'parents',
                                          'parent_sha1',
                                          'parent_sha1s',
                                      ],
                         );

        method patch ( Maybe[NonEmptySimpleStr] $parent? ) {
            my @args = qw/format-patch --encoding=utf8 --stdout -1/;
            my $refspec = $self->sha1;
            if (defined $parent) {
                push @args, '-n';
                $refspec = $parent . '..' . $self->sha1;
            }
            push @args, '--root', $refspec;
            my $out = $self->_run_cmd( @args );
            return $out;
        }

        method diff ( Maybe[Bool] :$patch?,
                       Maybe[NonEmptySimpleStr] :$parent?,
                       Maybe[NonEmptySimpleStr] :$file?
                   ) {
            $parent = $parent
                ? $parent
                    : $self->parents <= 1
                        ? $self->parent_sha1
                            : '-c';
            my @etc = (
                ( $file  ? ('--', $file) : () ),
            );

            my @out = $self->_raw_diff(
                ( $patch ? '--patch-with-raw' : () ),
                ( $parent ? $parent : () ),
                $self->sha1, @etc,
            );

            # XXX Yes, there is much wrongness having _parse_diff_tree be destructive.
            my @difftree = $self->_parse_diff_tree(\@out);

            return \@difftree
                unless $patch;

            # The blank line between the tree and the patch.
            shift @out;

            # XXX And no I'm not happy about having diff return tree + patch.
            return \@difftree, [$self->_parse_diff(@out)];
        }

        ## Private methods
        # gitweb uses the following sort of command for diffing merges:
        # /home/dbrook/apps/bin/git --git-dir=/home/dbrook/dev/app/.git diff-tree -r -M --no-commit-id --patch-with-raw --full-index --cc 316cf158df3f6207afbae7270bcc5ba0 --
        # and for regular diffs
        # /home/dbrook/apps/bin/git --git-dir=/home/dbrook/dev/app/.git diff-tree -r -M --no-commit-id --patch-with-raw --full-index 2e3454ca0749641b42f063730b0090e1 316cf158df3f6207afbae7270bcc5ba0 --
        method _raw_diff (@args) {
            return $self->_run_cmd_list(
                qw(diff-tree -r -M --no-commit-id --full-index),
                @args
            );
        }

        method _parse_diff_tree ($diff) {
            my @keys = qw(modesrc modedst sha1src sha1dst status src dst);
            my @ret;
            while (@$diff and $diff->[0] =~ /^:\d+/) {
                my $line = shift @$diff;
                # see. man git-diff-tree for more info
                # mode src, mode dst, sha1 src, sha1 dst, status, src[, dst]
                my @vals = $line =~ /^:(\d+) (\d+) ($SHA1RE) ($SHA1RE) ([ACDMRTUX]\d*)\t([^\t]+)(?:\t([^\n]+))?$/;
                my %line = zip @keys, @vals;
                # Some convenience keys
                $line{file}   = $line{src};
                $line{sha1}   = $line{sha1dst};
                $line{is_new} = $line{sha1src} =~ /^0+$/
                    if $line{sha1src};
                @line{qw/status sim/} = $line{status} =~ /(R)(\d+)/
                    if $line{status} =~ /^R/;
                push @ret, \%line;
            }

            return @ret;
        }

        method _parse_diff (@diff) {
            my @ret;
            for (@diff) {
                # This regex is a little pathological.
                if (m{^diff --git (a/(.*?)) (b/\2)}) {
                    push @ret, {
                        head => $_,
                        a    => $1,
                        b    => $3,
                        file => $2,
                        diff => '',
                    };
                    next;
                }

                if (/^index (\w+)\.\.(\w+) (\d+)$/) {
                    @{$ret[-1]}{qw(index src dst mode)} = ($_, $1, $2, $3);
                    next
                }

                # XXX Somewhat hacky. Ahem.
                $ret[@ret ? -1 : 0]{diff} .= "$_\n";
            }

            return @ret;
        }

    }
