# CDDB::Fake.pm -- CDDB File Faker
# RCS Info        : $Id: CDDB-Fake.pm,v 1.5 2004/08/13 13:38:04 jv Exp $
# Author          : Johan Vromans
# Created On      : Tue Mar 25 22:38:32 2003
# Last Modified By: Johan Vromans
# Last Modified On: Fri Aug 13 15:28:55 2004
# Update Count    : 139
# Status          : Unknown, Use with caution!

=head1 NAME

CDDB::Fake - Fake CDDB entries if you have none

=head1 SYNOPSIS

    use CDDB::Fake;
    my $cddb = CDDB::Fake->new("music/Egg/Egg/.nocddb");
    print "Artist: ", $cddb->artist, "\n";
    foreach my $track ( $cddb->tracks ) {
        print "Track ", $track->number, ": ", $track->title, "\n";
    }

=head1 DESCRIPTION

Sometimes there's no CDDB file available for a piece of music. For
example, when you created a collection of tracks from other albums. In
this case, a text file containing the name of the artist / album,
followed by a mere list of the track titles can be used as a
fall-back.

CDDB::Fake implements a part of the CDDB::File API based on manually
crafted fall-back files.

I've adopted the convention to name files with CDDB data C<.cddb>, and
the fake data C<.nocddb>.

For example, you can cut the results of a search at Gracenote
(cddb.com) and paste it into the file .nocddb. For example:

    Birelli Lagrene / Standards

       1. C'est Si Bon
       2. Softly, As in a Morning Sunrise
       3. Days of Wine and Roses
      ...
      12. Nuages

The track titles may be optionally followed by trailing TABs (not
spaces) and a MM:SS time indicator (which may have a leading space if
it's M:SS).

Extra track information can be passed on lines that follow the track
title. These lines must start with whitespace, and may not begin with
a number. Anything that follows the list of tracks is considered extra disc information. For example:

    Birelli Lagrene / Standards

       1. C'est Si Bon
          Original version
       2. Softly, As in a Morning Sunrise
          Live recording.
          Probably incomplete.
       3. Days of Wine and Roses
      ...
      12. Nuages

    This album was recorded in the Olympia Studios in Paris.

Multiple lines of additional info are concatenated with newlines
inbetween. However, if one of the lines contains C<\n> (that's
backslash-n), all lines are conctenated using a single whitespace, and
the C<\n>'s are turned into real newlines.

A tool is included to generate a fake file from the names of the files
in the directory.

B<WARNING:> CDDB::Fake implements only a part of the CDDB::File API.

=cut

package CDDB::Fake;

$VERSION = "2.00";

use strict;
use warnings;
use Carp;

=head1 METHODS

=over 4

=item new I<file>

The new() package method takes the name of a file, and parses it. A
CDDB::Fake object is then created from the file data.

=cut

sub new {
    my ($pkg, $file) = @_;

    my $self = {
		_title => "",
		_artist => "",
		_extd => "",
	       };

    my $fh;
    if ( ref($file) ) {
	# For testing.
	$fh = $file;
    }
    else {
	open($fh, $file) or croak("$file: $!\n");
    }
    my $off = 150;
    my $state = 0;
    my $va = 0;
    my $to;
    while ( <$fh> ) {
	next unless /\S/;
	s/[\r\n]+$//;

	# State 0: Looking for artist/title.
	if ( $state == 0 ) {
	    if ( /^\s*(.+)\s+\/\s+(.*)/ ) {
		$self->{_artist} = _deblank($1);
		$self->{_title} = _deblank($2);
	    }
	    else {
		# Eponymous.
		$self->{_artist} = $self->{_title}  = _deblank($_);
	    }
	    $va = lc($self->{_artist}) eq "various";
	    $state++;
	    next;
	}

	# State 1: Processing tracks.
	if ( $state == 1 ) {
	    if ( /^\s*(\d+)\.?\s+(.*)/ ) {
		my $tn = 0 + $1;
		my $tt = $2;
		my $tl;
		if ( $tt =~ /^(.*?)\t+ ?(\d+):(\d\d)\s*$/ ) {
		    $tt = _deblank($1);
		    $tl = 60 * $2 + $3;
		    $self->{_length} += $tl;
		}
		else {
		    $tt = _deblank($tt);
		}
		my $art = $self->{_artist};
		if ( $va ) {
		    if ( $tt =~ /^(.+?):\s+(.*)/ ) {
			$art = _deblank($1);
			$tt  = _deblank($2);
		    }
		    elsif ( $tt =~ /^(.+?)\s+\/\s+(.*)/ ) {
			$art = _deblank($1);
			$tt  = _deblank($2);
		    }
		}
		push(@{$self->{_tracks}},
		     $to = CDDB::Fake::Track->new($art, $tn, $tt,
						  $tl, $off, ""));
		$off += 75 * $tl if $tl;
		next;
	    }
	    elsif ( defined($to) && /^\s+(.+)/ ) {
		$to->_extd_append($1);
		next;
	    }
	    else {
		$state++;
	    }
	}

	# State 2: Remainder (ext info).
	if ( $state == 2 ) {
	    $self->{_extd} = $_ . "\n";
	    $state++;
	    next;
	}

	# State 3: Rest of ext info.
	$self->{_extd} .= $_ . "\n";

    }

    $self->{_extd} = _newlines($self->{_extd});

    bless $self, $pkg;
}

sub _deblank {
    my $t = shift;
    for ( $t ) {
	s/^\s+//;
	s/\s+$//;
	s/\s+/ /g;
	return $_;
    }
}

sub _newlines {
    my $t = shift;
    for ( $t ) {
	return $_ unless /\\n/;
	s/\s\n\s/ /g;
	s/\\n/\n/g;
	return $_;
    }
}

=item artist

Returns the name of the artist.

=cut

sub artist {
    my ($self) = @_;
    $self->{_artist};
}

=item title

Returns the name of the album.

=cut

sub title {
    my ($self) = @_;
    $self->{_title};
}

=item track_count

Returns the number of tracks.

=cut

sub track_count {
    my ($self) = @_;
    scalar(@{$self->{_tracks}});
}

=item tracks

Returns a list of track objects.

=cut

sub tracks {
    my ($self) = @_;
    @{$self->{_tracks}};
}

=item id

=item all_ids

Returns the (fake) id for this disc.

=cut

sub id { "00000000" }

sub all_ids { ("00000000") }

=item year

=item genre

=item submitted_by

=item processed_by

These methods return empty strings since the information is not
available in CDDB::Fake files.

=cut

sub year         { "" }
sub genre        { "" }
sub submitted_by { "" }
sub processed_by { "" }
sub revision     { 1  }

=item length

This method will return the accumulated length of all the tracks,
provided this information is present in the fake file.

=cut

sub length {
    my ($self) = @_;
    $self->{_length} || 0;
}

=item extd

Returns the extended disc information, that is everything that follows
the list of tracks in the fake file.

=cut

sub extd  {
    my ($self) = @_;
    $self->{_extd} || "";
}

=item as_cddb

Returns the data in the format of a CDDB entry.

=cut

sub as_cddb {
    my ($self) = @_;

    my $ret = "";

    # Writing CDDB data requires some line breaking and such.
    my $out = sub {
	my ($tag, $desc) = @_;
	$desc =~ s/\n/\\n/g;
	$desc =~ s/\\n$//;
	$tag .= "=";
	$desc = $tag . $desc;
	for ( ;; ) {
	    my $t = substr($desc,0,70,$tag);
	    $ret .= $t . "\n";
	    last if $desc eq $tag;
	}
    };

    my @tracks = $self->tracks;

    # Header.
    $ret = "# xmcd 2.0 CD database file\n" .
      "# Copyright (C) 1996,2004 Johan Vromans\n" .
	"#\n";

    if ( $self->length ) {
	$ret .= "# Track frame offsets:\n";
	foreach ( @tracks ) {
	    $ret .= "#\t" . $_->offset . "\n";
	}
	$ret .= "#\n" .
	  "# Disc length: " . $self->length . " seconds\n" .
	    "#\n";
    }

    $out->("DISCID", $self->id);
    $out->("DTITLE", $self->artist . " / " . $self->title);

    my $i;
    for ( $i=0; $i < @tracks; $i++ ) {
	$out->("TTITLE$i", $tracks[$i]->title)
	  if defined $tracks[$i];
    }

    $out->("EXTD", $self->extd);

    for ( $i=0; $i < @tracks; $i++ ) {
	$out->("EXTT$i", $tracks[$i]->extd);
    }
    $out->("PLAYORDER", "");
    $ret;
}

=back

=cut

package CDDB::Fake::Track;

sub new {
    my ($pkg, $disc, $num, $tt, $len, $off, $extd) = @_;
    bless [ $disc, $num, $tt, $len, $off, $extd ], $pkg;
}

=pod

Track objects provide the following methods:

=over 4

=item artist

The artist, usually the same as the artist of the disc.

=cut

sub artist { shift->[0] || ""}

=item number

The track number, starting with 1.

=cut

sub number { shift->[1] || 0 }

=item title

The track title.

=cut

sub title  { shift->[2] || ""}

=item length

The track length (in seconds).

This will be zero unless a track length was specified in the fake info.

=cut

sub length { shift->[3] || 0}

=item offset

The track offset.

This will be bogus unless track offsets could be estimated using the
length information.

=cut

sub offset { shift->[4] || 0 }

=item extd

This extended track info, if present.

=cut

sub extd {
    CDDB::Fake::_newlines(shift->[5] || "");
}

sub _extd_append {
    my ($self, $text) = @_;
    if ( defined($self->[5]) && CORE::length($self->[5]) > 0 ) {
	$self->[5] .= " " . $text;
    }
    else {
	$self->[5] = $text;
    }
}

=head1 EXAMPLES

It is often handy to generalize the handling of real and fake files:

    use CDDB::File;	# the real one
    use CDDB::Fake;	# the fake one
    use Carp;

    # Return a CDDB::File object if a .cddb file is present, otherwise
    # return a CDDB::Fake onkect from a .nocddb file, if present.

    sub cddb_info($) {
	my $df = shift;
	croak("cddb_info(dir)\n") unless -d $df;
	return CDDB::File->new("$df/.cddb")   if -s "$df/.cddb";
	return CDDB::Fake->new("$df/.nocddb") if -s "$df/.nocddb";
	undef;
    }

=head1 SEE ALSO

L<CDDB::File>.

=head1 AUTHOR

Johan Vromans <jvromans@squirrel.nl>

=head1 COPYRIGHT

This programs is Copyright 2003,2004, Squirrel Consultancy.

This program is free software; you can redistribute it and/or modify
it under the terms of the Perl Artistic License or the GNU General
Public License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.

=cut

1;