package Config::Model::Backend::Dpkg::Patch;

use 5.10.1 ;
use Mouse;

extends 'Config::Model::Backend::Any';

with 'Config::Model::Backend::DpkgSyntax';

use Carp;
use Config::Model::Exception;
use Log::Log4perl qw(get_logger :levels);
use IO::File;

my $logger = get_logger("Backend::Dpkg::Patch");

my $patch_name_for_test = 'some-patch';

sub suffix { return ''; }

sub skip_open { 1;}

sub read {
    my $self = shift;
    my %args = @_;

    # args is:
    # object     => $obj,         # Config::Model::Node object
    # root       => './my_test',  # fake root directory, userd for tests
    # config_dir => /etc/foo',    # absolute path
    # file       => 'foo.conf',   # file name
    # file_path  => './my_test/etc/foo/foo.conf'
    # io_handle  => $io           # IO::File object
    # check      => yes|no|skip

    # io_handle is not defined as no file is specified in model

    my $patch_dir = $args{root} . $args{config_dir};
    my $check     = $args{check};
    my $node      = $args{object};

    # the default value is used for tests
    my $patch_name = $node->index_value || $patch_name_for_test;

    my $patch_file = "$patch_dir$patch_name";
    $logger->info("Parsing patch $patch_file");
    my $patch_io = IO::File->new($patch_file)
      || Config::Model::Exception::Syntax->throw(
        message => "cannot read patch $patch_file" );

    my ( $header, $diff ) = ( [],[] );
    my $target = $header;
    foreach my $l ( $patch_io->getlines ) {
        if ( $l =~ /^---/ ) {
            # beginning of quilt style patch
            $target = $diff;
        }
        elsif ( $l =~ /^===/ ) {
            # beginning of git diff style patch
            push @$diff, pop @$header if $target eq $header;    # get back the Index: line
            $target = $diff;
        }
        push @$target, $l;
    }
    chomp @$header;

    my $c = [] ;
    $logger->trace("header: @$header") ;
    my @stuff ;
    my $store_stuff = sub { push @stuff, shift ;} ;
    
    if (@$header) {
        $c = eval { $self->parse_dpkg_lines( $header, $check, 0, $store_stuff ); };
        my $e;
        if ( $e = Exception::Class->caught('Config::Model::Exception::Syntax') )
        {

            # FIXME: this is naughty. Should file a bug to add info in rethrow
            $e->{parsed_file} = $patch_file unless $e->parsed_file;
            $e->rethrow;
        }
        elsif ( $e = Exception::Class->caught() ) {
            ref $e ? $e->rethrow : die $e;
        }

        Config::Model::Exception::Syntax->throw(
            message => "More than 2 sections in $patch_name header" )
          if @$c > 4; # $c contains [ line_nb, section_ref ]
    }

    while (@$c) {
        my ( $section_line, $section ) = splice @$c, 0, 2;
        foreach ( my $i = 0 ; $i < $#$section ; $i += 2 ) {
            my $key = $section->[$i];
            my ( $v, $l, $a, @comments ) = @{ $section->[ $i + 1 ] };
            if ( my $found = $node->find_element( $key, case => 'any' ) ) {
                my @elt = ($found);
                $v .= join( "\n", @stuff ) if $found eq 'Subject';
                my @v = ( $found eq 'Description' ) ? ( split /\n/, $v, 2 ) : ($v);
                unshift @elt, 'Synopsis' if $found eq 'Description';
                foreach (@elt) {
                    my $sub_v = shift @v;
                    next unless defined $sub_v;
                    $logger->debug("storing $_  value: $sub_v");
                    $node->fetch_element($_)->store( value => $sub_v, check => $check );
                }
            }
        }
    }
    $node->fetch_element('diff')->store(join('',@$diff));

    return 1;
}

sub write {
    my $self = shift;
    my %args = @_;

    # args is:
    # object     => $obj,         # Config::Model::Node object
    # root       => './my_test',  # fake root directory, userd for tests
    # config_dir => /etc/foo',    # absolute path
    # file       => 'foo.conf',   # file name
    # file_path  => './my_test/etc/foo/foo.conf'
    # io_handle  => $io           # IO::File object

    # io_handle is not defined as no file is specified in model

    my $patch_dir = $args{root} . $args{config_dir};
    my $check     = $args{check};
    my $node      = $args{object};

    my $patch_name = $node->index_value || $patch_name_for_test;

    my $patch_file = "$patch_dir/$patch_name";
    $logger->info("Writing patch $patch_file");
    my $io = IO::File->new($patch_file,'w')
      || Config::Model::Exception::Syntax->throw(
        message => "cannot write patch $patch_file" );

    foreach my $elt ( $node -> get_element_name ) {
        my $elt_obj = $node->fetch_element($elt) ;
        my $type = $node->element_type($elt) ;

        my @v = $type eq 'list' ? $elt_obj->fetch_all_values
              : $type eq 'leaf' ? ($elt_obj->fetch)
              : ();

        foreach my $v (@v) {
            # say "write $elt -> $v" ;
            next unless defined $v and $v;
        
            if ($elt eq 'Synopsis') {
                my $long_description = $node->fetch_element_value('Description') ;
                $v .= "\n" . $long_description if $long_description ;
                $io->print("Description:");
                $self->write_dpkg_text($io,$v) ;
            }
            elsif ($elt eq 'Description') { } # done in Synopsis
            elsif ($elt eq 'diff' ) {
                $io->print($node->fetch_element_value('diff')) ;
            }
            else {
                $io->print("$elt:");
                $self->write_dpkg_text($io,$v) ;
            }
        }
    }

    return 1;
}

1;

__END__

=head1 NAME

Config::Model::Backend::Dpkg::Patch - Read and write Debian Dpkg Patch information

=head1 SYNOPSIS

No synopsis. This class is dedicated to configuration class C<Dpkg::Patch>

=head1 DESCRIPTION

This module is used directly by L<Config::Model> to read or write the
content of Debian C<Patch> file.

All C<Patch> files keyword are read in a case-insensitive manner.

=head1 CONSTRUCTOR

=head2 new ( node => $node_obj, name => 'Dpkg::Patch' ) ;

Inherited from L<Config::Model::Backend::Any>. The constructor will be
called by L<Config::Model::AutoRead>.

=head2 read ( io_handle => ... )

Of all parameters passed to this read call-back, only C<io_handle> is
used. This parameter must be L<IO::File> object already opened for
read. 

It can also be undef. In this case, C<read()> will return 0.

When a file is read,  C<read()> will return 1.

=head2 write ( io_handle => ... )

Of all parameters passed to this write call-back, only C<io_handle> is
used. This parameter must be L<IO::File> object already opened for
write. 

C<write()> will return 1.

=head1 AUTHOR

Dominique Dumont, (ddumont at cpan dot org)

=head1 SEE ALSO

L<Config::Model>, 
L<Config::Model::AutoRead>, 
L<Config::Model::Backend::Any>, 

=cut