# Movable Type (r) Open Source (C) 2001-2008 Six Apart, Ltd.
# This program is distributed under the terms of the
# GNU General Public License, version 2.
#
# $Id: Local.pm 4196 2009-09-04 07:46:50Z takayama $

# Storing revision histories locally in the databse

package MT::Revisable::Local;

use strict;
use base 'MT::ErrorHandler';

sub revision_pkg {
    my $driver = shift;
    my ($class) = @_;
    my $props = $class->properties;

    return $props->{revision_pkg} if $props->{revision_pkg};

    my $rev = ref $class || $class;
    $rev .= '::Revision';
    
    return $props->{revision_pkg} = $rev;
}

sub revision_props {
    my $driver = shift;
    my ($class) = @_;
    my $obj_ds = $class->datasource;
    my $obj_id = $obj_ds . '_id';
    return {
        key         => $class->datasource,
        column_defs => {
            id          => 'integer not null auto_increment',
            label       => 'string(255)',
            description => 'string(255)',
            $obj_id     => 'integer not null',
            $obj_ds     => 'blob not null',
            rev_number  => 'integer not null',
            changed     => 'string(255) not null'
        },
        indexes => {
            $obj_id => 1
        },
        defaults => {
            rev_number => 0
        },
        audit => 1,
        primary_key => 'id',
        datasource  => $class->datasource . '_rev'
    };
}

sub init_revisioning {
    my $driver = shift;
    my ($class) = @_;
    my $datasource = $class->datasource;
    
    my $subclass = $class->revision_pkg;
    return unless $subclass;
    
    my $rev_props = $class->revision_props;
    
    no strict 'refs'; ## no critic
    return if defined ${"${subclass}::VERSION"};
    
    ## Try to use this subclass first to see if it exists
    my $subclass_file = $subclass . '.pm';
    $subclass_file =~ s{::}{/}g;
    eval "# line " . __LINE__ . " " . __FILE__ . "\nno warnings 'all';require '$subclass_file';$subclass->import();";
    if ($@) {
        ## Die if we get an unexpected error
        die $@ unless $@ =~ /Can't locate /;
    } else {
        ## This class exists.  We don't need to do anything.
        return 1;
    }

    my $base_class = 'MT::Object';

    my $subclass_src = "
        # line " . __LINE__ . " " . __FILE__ . "
        package $subclass;
        our \$VERSION = 1.0;
        use base qw($base_class);
        
        1;
    ";

    ## no critic ProhibitStringyEval 
    eval $subclass_src or print STDERR "Could not create package $subclass!\n";

    $subclass->install_properties($rev_props);    
}

sub save_revision {
    my $driver = shift;
    my ($obj, $description) = @_;    
    my $datasource = $obj->datasource;    
    my $obj_id = $datasource . '_id';
    my $packed_obj = $obj->pack_revision(); 
    my $changed_cols = $obj->{changed_revisioned_cols};
    my $current_revision = $obj->current_revision;

    require MT::Serialize;
    my $rev_class = MT->model($datasource . ':revision');
    my $revision = $rev_class->new;
    $revision->set_values({
        $obj_id     => $obj->id,
        $datasource => MT::Serialize->serialize(\$packed_obj),
        changed     => join ',', @$changed_cols,
    });
    $revision->rev_number(++$current_revision);
    $revision->description($description)
        if defined($description);
    $revision->save or return;
    
    return $current_revision;
}

sub object_from_revision {
    my $driver = shift;
    my ($obj, $rev) = @_;
    my $datasource = $obj->datasource;

    my $rev_obj = $obj->clone;
    my $serialized_obj = $rev->$datasource;
    require MT::Serialize;
    my $packed_obj = MT::Serialize->unserialize($serialized_obj);
    $rev_obj->unpack_revision($$packed_obj);
    
    # Here we cheat since audit columns aren't revisioned
    $rev_obj->modified_by($rev->created_by);
    $rev_obj->modified_on($rev->modified_on);    
    
    my @changed = split ',', $rev->changed;
    
    return [ $rev_obj, \@changed, $rev->rev_number];
}

sub load_revision {
    my $driver = shift;
    my ($obj, $terms, $args) = @_;
    my $datasource = $obj->datasource;    
    my $rev_class = MT->model($datasource . ':revision');

    # Only specified a rev_number
    if(defined $terms && ref $terms ne 'HASH') { 
        $terms = { rev_number => $_[0] };         
    }    
    $terms->{$datasource . '_id'} ||= $obj->id;    
    
    if ( wantarray ) {
        my @rev = map { $obj->object_from_revision($_); }
            $rev_class->load( $terms, $args );
        unless (@rev) {
            return $obj->error( $rev_class->errstr );
        }
        return @rev;
    }
    else {
        my $rev = $rev_class->load( $terms, $args )
            or return $obj->error( $rev_class->errstr );
        my $array = $obj->object_from_revision($rev);
        return $array;
    }    
}

sub handle_max_revisions {
    my $driver = shift;
    my ( $obj, $max ) = @_;
    return unless $max;

    my $datasource = $obj->datasource;    
    my $rev_class = MT->model($datasource . ':revision');
    my $terms = { $datasource . '_id' => $obj->id };    
    my $count = $rev_class->count( $terms );
    if ( $max <= $count ) {
        my $rev_iter = $rev_class->load_iter(
            $terms,
            { sort => 'created_on', direction => 'ascend', limit => $count - $max + 1 }
        );
        while ( my $rev = $rev_iter->() ) {
            $rev->remove;
        }
        return $max - 1;
    }
    return $count;
}

sub remove_revisions {
    my $driver = shift;
    my ( $obj ) = @_;

    my $rpkg = $obj->revision_pkg or return;
    my $key = $obj->datasource . '_id';
    $rpkg->remove({ $key => $obj->id });
}

1;
