#!/usr/bin/perl
	
	use strict;
	use warnings;
	use Time::Piece;
	
	if ( ! defined $ARGV[0] || ! defined $ARGV[1] ) {
		print "Need to pass args\n";
		exit 1;
	}
	
	my $ffmpegBin = `which ffmpeg`;
	chomp $ffmpegBin;
	
	if ( ! -e $ffmpegBin ) {
		print "You need ffmpeg installed to use this\n";
		exit 1;
	}
	
	my $track_list_path = shift(@ARGV);
	my $full_file_path = shift(@ARGV);
	
	my $track_list_file = `cat $track_list_path`;
	chomp $track_list_file;
	
	# Key is track name - val is array ref containing start time and end time
	my %track_times;
	my %track_names;
	
	sub prepend_zeros($) {
	
		my $time = shift;
		if ( $time =~ m/^[0-9]{1,2}\:[0-9]{2}$/ ) {
			if ( length $time == 4 ) {
				$time = "00:0" . $time;
			} elsif ( length $time == 5 ) {
				$time = "00:" . $time;
			} elsif ( length $time == 7 ) {
				$time = "0" . $time;
			} elsif ( length $time == 8 ) {
				# Don't need to do anything
			} else {
				print "Couldn't prepend zero's for $time\n";
				my $len = length $time;
				print "length of $time is $len\n";
				exit 1;
			}
	
		}
	
		return $time;
	
	}
	
	sub remove_spaces($) {
	
		my $track_name = shift;
		if ( $track_name =~ m/\s/ ) {
			$track_name =~ s/\s/_/g;
			return $track_name;
		}
	
		return $track_name;
	
	}
	
	sub get_end_time($$) {
	
		my $start_time = shift;
		my $next_start_time = shift;
		my $end_time;
		if ( $next_start_time =~ m/^(.*)\:([0-9]{2})$/ ) {
			my $end_time_val = $2 - 1;
			if ( $end_time_val < 0 ) { $end_time_val = 0; }
			if ( length $end_time_val == 1 ) { $end_time_val = "0" . $end_time_val; }
			$end_time = $1 . ":" . $end_time_val;
			$end_time = prepend_zeros($end_time);
			return $end_time;
		} else {
			print "get_end_time couldn't match regex on $next_start_time - exiting\n";
			exit 1;
		}
	
	}
	
	sub get_track_length() {
	
		my $ffmpegCmd = "$ffmpegBin -i '$full_file_path' 2>&1";
		my $ffmpegOutput = `$ffmpegCmd`;
		chomp $ffmpegOutput;
		if ( ! defined $ffmpegOutput || $ffmpegOutput eq "" ) {
			print "Something went wrong with calling $ffmpegCmd\n";
			exit 1;
		}
	
		my $duration;
		foreach my $line ( split("\n", $ffmpegOutput) ) {
			if ( $line =~ m/Duration:\ (.*)\.[0-9]{2},/ ) {
				$duration = $1;
				return $duration;
			}
		}
	
		print "Couldnt get duration of $full_file_path from $ffmpegCmd\n";
		exit 1;
	}
	
	sub convert_to_mp3() {
	
		my $filename;
		if ( $full_file_path =~ m/^.*\/(.*)\.(mp4)$/ ) {
			$filename = $1 . ".mp3";
		} else {
			print "Couldn't parse relative filename out of $full_file_path\n";
			exit 1;
		}
	
		#my $ffmpegCmd = "ffmpeg -i '$full_file_path' -vn acodec libmp3lame -ac 2 -ab 160k -ar 48000 '$filename'";
		my $ffmpegCmd = "ffmpeg -i '$full_file_path' -vn -acodec libmp3lame -ac 2 -qscale:a 4 -ar 48000 '$filename' > /dev/null 2>&1";
	
		print "Converting $full_file_path to mp3...\n";
		system("$ffmpegCmd") == 0 or die "Failed to convert $full_file_path to an mp3 with $ffmpegCmd\n";
	
		return $filename;
	
	}
	
	sub run_split($$$$$) {
	
		# ffmpeg -i Ryo\ Fukui\ -\ Scenery\ 1976\ \(FULL\ ALBUM\)-Hrr3dp7zRQY.mp4 -acodec copy -ss 00:00:00 -to 00:04:15 shibz.mp4
		my $mp3_file = shift;
		my $track_number = shift;
		my $track_name = shift;
		my $start_time = shift;
		my $end_time = shift;
		# Optionally covert to different codec?
		my $filename = "$track_number" . "-" . "$track_name" . ".mp3";
		my $ffmpegCmd = "$ffmpegBin -i '$mp3_file' -acodec copy -ss $start_time -to $end_time '$filename' > /dev/null 2>&1";
		system("$ffmpegCmd") == 0 or die "Failed to run $ffmpegCmd\n";
	
	}
	
	foreach my $line ( split("\n",$track_list_file) ) {
		#if ( $line =~ m/^([0-9]{1,2})\.\ (.*)\ ([0-9]{1,2}:[0-9]{2})$/ ) {
		if ( $line =~ m/^([0-9]{1,2})\.\ (.*)\ (.*)$/ ) {
			my @times;
			# Start time
			my $start_time = prepend_zeros($3);
			push(@times, $start_time);
			$track_times{$1} = \@times;
			my $track_name = remove_spaces($2);
			$track_names{$1} = $track_name;
		} else { 
			print "$line doesn't match regex, exiting\n";
			exit 1;
		}
	}
	
	foreach my $track_number ( sort keys %track_times ) {
	
		my $next_track_val = $track_number + 1;
		my $next_start_time;
		my $end_time;
		if ( defined $track_times{$next_track_val} ) {
			$next_start_time = $track_times{$next_track_val}[0];
			$end_time = get_end_time($track_times{$track_number}[0],$next_start_time);
		} else {
			$end_time = get_track_length;
		}
		
		push(@{$track_times{$track_number}}, $end_time);
	
	}
	
	my $mp3_file = convert_to_mp3();
	
	foreach my $track_number ( sort keys %track_times ) {
	
		print "Splitting $track_number - $track_names{$track_number} - $track_times{$track_number}[0] - $track_times{$track_number}[1]\n";
		run_split($mp3_file,$track_number,$track_names{$track_number},$track_times{$track_number}[0],$track_times{$track_number}[1]);
	
	}