#!/usr/bin/env perl

##  Soul Singin'
##  01 July 2012
##  
##  completely rewritten M3U playlist generator
##  http://www.perlmonks.org/?node_id=132478

##  preliminaries
use strict ;
use warnings ; 
no warnings qw( uninitialized numeric void ) ;
use MP3::Info ;

## arguments
( my $inpath = $ARGV[0] ) =~ s/\/$// ; 
my $otfile = $ARGV[1] ;

## die if the arguments are empty
if ( $inpath eq "" || $otfile eq "" ) {
    die "mk-m3u.pl <source dir> <output file>\n" ; 
}

## die if cannot find source path
if ( ! -e $inpath ) {
    die $inpath . " does not exist.\n" ;
}

## should we overwrite existing files?
if ( -e $otfile ) {
    print $otfile . " already exists.\n" ;
    print 'Should I overwrite it? (Type "yes" to overwrite). ' ;
    my $response = <STDIN> ; 
    
    if ( $response !~ /yes/i ) {
	die 'You did not type "yes", so I will not overwrite ' . $otfile . ".\n" ; 
    }
}

## get the MP3 files that we want to add to our playlist
my @infiles = sort( grep { -f $_ && ($_ =~ /\.mp3$/i) } glob "$inpath/*" ) ;

## prepare our new M3U playlist
open( OTFILE, ">$otfile" ) || die "could not overwrite $otfile : $!";
print OTFILE "#EXTM3U\n";

foreach my $infile (@infiles) {

    ## get info from the files
    my $mtag = get_mp3tag( $infile) ;
    my $info = get_mp3info($infile) ;

    my $artist = $mtag->{ARTIST} ; 
    my $stitle = $mtag->{TITLE} ; 

    ## create title-author pair
    my $pair ;

    if ( $stitle ne "" ) {
	$pair .= $stitle ; 
    }

    if ( $artist ne "" && $stitle ne "" ) {
	$pair .= " (by " . $artist . ")" ; 
    } elsif ( $artist ne "" ) {
	$pair .= $artist ;  
    }

    if ( $pair !~ /[A-Za-z0-9]/ ) {
	$pair = $infile ;  
    }

    ## prepare output line
    my $otline = "#EXTINF:" . int ($info->{SECS}) . "," . $pair ; 
    
    ## send output to our new M3U playlist
    print OTFILE $otline . "\n" ; 
    print OTFILE $infile . "\n" ;
    
}

##  close the M3U playlist
close OTFILE;