#!/usr/local/bin/perl -w
use strict ; $0 =~ s/.*\/// ; # -*- perl -*-

# A Perl script to export the music of an iTunes playlist as files, e. g. to
# copy the music files of your favourite playlist to an USB stick. First export
# the playlist from iTunes as a text file, then call
#
#    export-playlist-music playlist-file target-directory 
#
# Tested on the Macintosh only; assumes CR line endings in the playlist file. 
# Preserves the Artist/Album directory structure. Does not copy files that are
# already present with the correct size.
#
# Version 1 [ni 2010-01-27].
#
# Copyright (c) 2009, 2010
# Juergen Nickelsen <ni@w21.org>. All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.


my $filename_field = "Location";        # file name column title

die("usage: $0 playlist to-location\n") unless @ARGV == 2;
my ($playlist, $target_dir) = @ARGV;

create_dir($target_dir);
$/ = "\r";                              # traditional Macintosh text file
open(PL, $playlist) or die("$0: cannot open $playlist\n");

# column titles are in the first line
my $first_line = <PL>;
chomp($first_line);
my @column_titles = split(/\t/, $first_line);

#print(join(":", @column_titles), "\n");
while (<PL>) {
        chomp();

        # I could just use the last field for the file name, but I want to have
        # this code more generic so I can reuse it for other playlist handling
        # code. Runtime is insignificant compared with copying the file anyway.
        my @fields = split(/\t/);
        my %data = ();
        for (my $i = 0; $i < @fields; $i++) {
                $data{$column_titles[$i]} = $fields[$i] || "";
        }

        # file name is missing in some lines, dunno why; perhaps vanished files
        unless ($data{$filename_field}) {
                warn("$playlist:$.: $filename_field undefined\n");
                next;
        }
        copy_file($data{$filename_field}, $target_dir);
}

# create a directory if it does not yet exist, die on fail
sub create_dir {
        my ($dir) = @_;
        unless (-d $dir) {
                mkdir($dir) or die("$0: cannot create $dir ($!)\n");
        }
}

sub filesize {
        my ($fname) = @_;
        my ($dev, $ino, $mode, $nlink, $uid, $gid, $rdev, $size,
            $atime, $mtime, $ctime, $blksize, $blocks) = stat($fname)
              or warn("$0: stat $fname: $!\n");
        #print("size is $size\n");
        return $size;
}

sub copy_file {
        my ($fname, $to_dir) = @_;
        my $ufname = $fname;            # the Unix filename
        $ufname =~ tr{:/}{/:};
        $ufname =~ s{^[^/]*}{};

        my @path = split(/:/, $fname);
        my $artist = $path[-3];         # this is always this way, right?
        my $album = $path[-2];
        my $title = $path[-1];
        my $tfname = "$to_dir/$artist/$album/$title";  # the target file name

        if (-f $tfname && (filesize($tfname) == filesize($ufname))) {
                print("skip $ufname\n");
                return;
        }
        print("$tfname\n");
        create_dir("$to_dir/$artist");
        create_dir("$to_dir/$artist/$album");
        local $/;
        unless (open(IN, $ufname)) {
                warn("$0: cannot open $ufname ($!)\n");
                return;
        }
        unless (open(OUT, ">$tfname")) {
                 warn("$0: cannot write to $tfname ($!)\n");
                 close(IN);
                 return;
        }
        unless (print OUT (<IN>)) {
                warn("$0: error writing to $tfname ($!)\n");
        }
        close(IN);
        close(OUT) or warn("$0: error closing $tfname ($!)\n");
}

#EOF