#!/bin/bash
#
# m4a to wav
# for music from iPod
# http://www.linuxquestions.org/questions/showthread.php?t=170553

# This software is licensed under the GNU General Public License
# For the full text of the GNU GPL, see:
#
# http://www.gnu.org/copyleft/gpl.html
#
# No guarantees of any kind are associated with use of this software.

#requirements: faad, lame
LOGFILE="mp4tomp3conversion.txt"
count=0

help_convert()
{
	echo
	echo "This software is licensed under the GNU General Public License"
	echo "For the full text of the GNU GPL, see:"
	echo "http://www.gnu.org/copyleft/gpl.html"
	echo "No guarantees of any kind are associated with use of this software."
	echo "requirements: faad, lame"
	echo
	echo "Usage: $0 [-h] [-r] [-d path]"
	echo "Options: "
	echo "-h displays this help"
	echo "-r recursively scans directories"
	echo "-d specifies a path other the current path"
	exit 1
}

# handle options passed in by the user
recursive=0
directory=`pwd`
while getopts "hrd:" opt
do 
	case $opt in
		h) help_convert;;
		r) recursive=1;;
		d) directory="$OPTARG";;
		*) help_convert;;
	esac
done
# This nifty IFS line is from:
# http://www.issociate.de/board/post/420747/files_and_directories_with_spaces_in_bash_script.html
IFS=$'\n'
echo `date` >> $LOGFILE
# if not recursive, then limit the find to the directory itself.
if [ $recursive == 1 ]; then
	total_files=`find ${directory} -iname '*.m4a' -print`
	echo `find ${directory} -iname '*.m4a' -print | wc -l `" mp4 files to begin with" >> $LOGFILE
else
	total_files=`find ${directory} -maxdepth 1 -iname '*.m4a' -print`
	echo `find ${directory} -maxdepth 1 -iname '*.m4a' -print | wc -l `" mp4 files to begin with" >> $LOGFILE
fi 

for i in $total_files
	do
		x=`echo "$i"|sed -e 's/\.m4a/\.wav/'`
		y=`echo "$i"|sed -e 's/\.m4a/\.mp3/'`
		echo "X: $x"
		echo "Y: $y"
		# if the directory name doesn't start with a / then prepend the path
		# to the directory name.
		if [[ "$directory" =~ ^[^/] ]]
		then 
			x=`pwd`/`echo ${x}|sed -e 's/^\.\///'`
			y=`pwd`/`echo $y|sed -e 's/^\.\///'`
			orig=`pwd`/`echo ${i}|sed -e 's/^\.\///'`
		else
			orig=$i
		fi
		faad ${orig}
		echo "X: $x"
		echo "Y: $y"

		faad -i ${orig} 2>.trackinfo.txt
		sed -i '23s/unknown: /title: /' .trackinfo.txt
		sed -i '24s/unknown: /artist: /' .trackinfo.txt

		year=`grep 'date: ' .trackinfo.txt|sed -e 's/date: //'`

		sed -i 's/unknown: iTunes/iTunes: iTunes/' .trackinfo.txt

		genrecount=`grep -c 'genre: ' .trackinfo.txt`
		unknowncount=`grep -c 'unknown: ' .trackinfo.txt`

		if [ "$genrecount" -eq 1 ] && [ "$unknowncount" -eq 2 ]; then
			sed -i '25s/unknown: /composer: /' .trackinfo.txt
			sed -i '26s/unknown: /album: /' .trackinfo.txt
			genre=`grep 'genre: ' .trackinfo.txt|sed -e 's/genre: //'`
		fi

		if [ "$genrecount" -eq 1 ] && [ "$unknowncount" -eq 1 ]; then
			sed -i '25s/unknown: /album: /' .trackinfo.txt
			genre=`grep 'genre: ' .trackinfo.txt|sed -e 's/genre: //'`
		fi

		if [ "$genrecount" -eq 0 ] && [ "$unknowncount" -eq 3 ]; then
			sed -i '25s/unknown: /composer: /' .trackinfo.txt
			sed -i '26s/unknown: /album: /' .trackinfo.txt
			sed -i '27s/unknown: /genre: /' .trackinfo.txt
			genre='other'
		fi

		if [ "$genrecount" -eq 0 ] && [ "$unknowncount" -eq 2 ]; then
			sed -i '25s/unknown: /album: /' .trackinfo.txt
			sed -i '26s/unknown: /genre: /' .trackinfo.txt
			genre='other'
		fi
	
		title=`grep 'title: ' .trackinfo.txt|sed -e 's/title: //'`
		artist=`grep 'artist: ' .trackinfo.txt|sed -e 's/artist: //'`
		album=`grep 'album: ' .trackinfo.txt|sed -e 's/album: //'`
		track=`grep 'track: ' .trackinfo.txt|sed -e 's/track: //'`

		lame --alt-preset 192 --id3v2-only --tt "$title" --ta "$artist" --tl "$album" --tg "$genre" --tn "$track" --ty "$year" "$x" "$y"
		rm .trackinfo.txt
		rm "$x"
# if you want to rename the files, then here's the place.
		#mv "$y" "$artist - $title.mp3"
		rm ${orig}
		((count++))
		echo "$orig converted" >> $LOGFILE
done
echo "$count mp4 files converted to mp3" >> $LOGFILE