#!/bin/bash
# iterates files in current directory
# if the file has track metadata found using ffprobe:
# its name will be configured to reflect its corresponding track number

# TODO protect files from being overwritten
# when implementing mv, be sure to include -n 

# TODO create failsafe in the case of multiple tracks sharing the same track number

let MAX_TRACK=0
let GREATEST_TEN=1000 # i seriously doubt an album will exceed this number of tracks
			# bump up this number if somehow that's the case
echo ""
echo "Prefix Files By Track v0.1"
echo "--------------------------------"
echo "AUTHOR: Packrat"
echo "COMPANY: GMR Toolz & Software"
echo "UNLICENSED"
echo "" 
echo '+----------------------------------+
|        ###   #    #  ####        |
|       #   #  ##  ##  #   #       |
|       #      # ## #  ####        |
|       #  ##  #    #  # #         |
|       #   #  #    #  #  #        |
|        ####  #    #  #   #       |
+----------------------------------+'
echo ""
echo "IN USING THIS SCRIPT, YOU ARE WAIVING PACKRAT OF ALL LIABILITY FOR ANY DAMAGES CAUSED BY HIS SUBPAR PROGRAMMING"
echo "YOU'VE BEEN WARNED"
echo "" 

echo 'Continue?'
read -p 'y/n : '


declare -A TRACKS
declare -A ORIGINAL_NAMES
ALBUM=""
ARTIST=""

sample_file() {
	echo ?
	if [ $# -gt 0 ]; then
		TRACK="$(ffmpeg -i "$1" 2>&1>/dev/null | grep -iwe 'TRACK' -iwe 'ALBUM' -iwe 'ARTIST')"
		ALBUM=$(echo "$TRACK" | grep -iw "ALBUM" | sed -E 's/^[^:]*://')
		ARTIST=$(echo "$TRACK" | grep -iw "ARTIST" | sed -E 's/^[^:]*://')

	fi
}

collect_track_metadata() {
	for FILE in *; do
		TRACK="$(ffmpeg -i "$FILE" 2>&1>/dev/null | grep -iwe 'TRACK' -iwe 'ALBUM' -iwe 'ARTIST')"
		echo $TRACK?
		A=$(echo "$TRACK" | grep -iw "ARTIST" | sed -E 's/^[^:]*://')
		if [ "$A" != "$ARTIST" ]; then
			echo "Artist isn't a match, giving up"
			echo "$A!"
			echo "$Artist!"
			continue
		fi
		A=$(echo "$TRACK" | grep -iw "ALBUM" | sed -E 's/^[^:]*://')
		if [ "$A" != "$ALBUM" ]; then
			echo "Album isn't a match, giving up"
			echo "$A!"
			echo "$Album!"
			continue
		fi
		# check that grep found an instance of "track". returns non-zero exit if it did not
		if [ $? -gt 0 ]; then
			continue
		fi
		# remove whitespace, ensure its interpreted as a base10 integer
		let TRACK=10#$(echo "$TRACK" | grep -iw "track" |  sed -E 's/^[^:]*://' | sed -E 's/\ //g')
		if [ $TRACK -gt $MAX_TRACK ]; then
			let MAX_TRACK=$TRACK
		fi
		ORIGINAL_NAMES[$TRACK]="$FILE"
		FILE=$(echo $FILE | sed -E 's/\ /_/g')
		TRACKS["$FILE"]=$TRACK
	done
}

prefix_filenames_with_max_track_number() {
	for file in ${!TRACKS[@]}; do
		while true; do
			let A=$MAX_TRACK/$GREATEST_TEN
			if [ $A -ge 1 ]; then
				break
			fi
			let GREATEST_TEN=$GREATEST_TEN/10
			if [ $GREATEST_TEN -le 1 ]; then
				break
			fi
		done

	done
	# hold the new tracks in a new array ordered from lowest to highest
	declare -a NEW_TRACKS
	# rename the files
	for FILE in ${!TRACKS[@]}; do
		TRACK=${TRACKS["$FILE"]}
		INDEX=$TRACK
		I=0
		while true; do
			let B=10**$I
			let A=$TRACK*$B
			let A=$A/$GREATEST_TEN
			if [ $A -lt 1 ]; then
				let I=$I+1
				continue
			fi
			break
		done
		for ((x=0; x < $I; x++)); do
			TRACK="0$TRACK"
		done
		NEW_TRACKS[$INDEX]="$TRACK.${ORIGINAL_NAMES[$INDEX]}"
	done
	echo ""
	for NEW_TRACK_NAME in "${NEW_TRACKS[@]}"; do
		echo "$NEW_TRACK_NAME"
	done

	echo "Commit?"
	read -p "y/n : "
	if [ $REPLY == "y" ]; then
		echo "DOIN IT"
	fi
	for INDEX in ${!NEW_TRACKS[@]}; do
		cp "${ORIGINAL_NAMES[$INDEX]}" "${NEW_TRACKS[$INDEX]}"
	done

}

sample_file $1
collect_track_metadata
prefix_filenames_with_max_track_number

echo ${!ORIGINAL_NAMES[@]}
for i in ${!ORIGINAL_NAMES[@]}; do
	echo $i
	echo "${ORIGINAL_NAMES[$i]}"
done