#!/bin/sh

# this scripts makes tagging flac files quick and easy!

die() { printf "\nusage: tagit [OPTION] files\n
options:
 -a: artist
 -A: album artist
 -t: song title
 -T: album title
 -n: track number
 -N: auto number tracks
 -d: release date
 -D: disc number
 -g: genre
 -c: content group
 -o: organisation
 -s: show all tags
 -S: scan replay gain
 -r: apply replay gain
 -e: embed cover art
 -R: remove excess tags\n" && exit
}

while getopts "a:A:t:T:n:d:D:g:c:o:e:NsSrRh" o; do case "${o}" in
	a) artist="${OPTARG}";;
	A) aartist="${OPTARG}";;
	t) title="${OPTARG}";;
	T) album="${OPTARG}";;
	n) tnum="${OPTARG}";;
	N) anum="true";;
	d) date="${OPTARG}";;
	D) dnum="${OPTARG}";;
	g) genre="${OPTARG}";;
	c) content="${OPTARG}";;
	o) org="${OPTARG}";;
	s) show="true";;
	S) scan="true";;
	r) rgain="true";;
	e) cover="${OPTARG}";;
	R) remove="true";;
	h|*) die;;
esac done

shift $((OPTIND - 1))

if [ -n "$anum" ]; then
	[ -z "$(find "$PWD" -type f -name '*.flac' )" ] && echo "no flac files found to number!" && exit
	echo "auto numbering tracks..."
	i=1
	find "$PWD" -type f -name '*.flac' | sort -n | while read -r f; do
		metaflac --preserve-modtime --remove-tag=TRACKNUMBER --set-tag=TRACKNUMBER="$i" "$f"
		i=$((i+1))
	done
	[ -z "$1" ] && exit
fi

[ -z "$1" ] && echo "no input files specified!" && die

for f in "$@"; do [ ! -f "$f" ] && echo "invalid file: $f" && die; done

[ "${1##*.}" != "flac" ] && echo "only flac files can be specified!" && die

[ -n "$show" ] && metaflac --show-all-tags "$@" && exit
[ -n "$scan" ] && metaflac --scan-replay-gain "$@" && exit

if [ -n "$cover" ]; then
	[ ! -f "$cover" ] && echo "invalid file: $cover" && die
	metaflac --preserve-modtime --remove --block-type=PICTURE,PADDING --dont-use-padding "$@"
	metaflac --preserve-modtime --import-picture-from="$cover" "$@"
fi

tag="metaflac --preserve-modtime"

[ -n "$artist" ] && tag="${tag} --remove-tag=ARTIST --set-tag=ARTIST=\"$artist\""
[ -n "$aartist" ] && tag="${tag} --remove-tag=ALBUMARTIST --set-tag=ALBUMARTIST=\"$aartist\""
[ -n "$title" ] && tag="${tag} --remove-tag=TITLE --set-tag=TITLE=\"$title\""
[ -n "$album" ] && tag="${tag} --remove-tag=ALBUM --set-tag=ALBUM=\"$album\""
[ -n "$tnum" ] && tag="${tag} --remove-tag=TRACKNUMBER --set-tag=TRACKNUMBER=\"$tnum\""
[ -n "$dnum" ] && tag="${tag} --remove-tag=DISCNUMBER --set-tag=DISCNUMBER=\"$dnum\""
[ -n "$date" ] && tag="${tag} --remove-tag=DATE --set-tag=DATE=\"$date\""
[ -n "$genre" ] && tag="${tag} --remove-tag=GENRE --set-tag=GENRE=\"$genre\""
[ -n "$content" ] && tag="${tag} --remove-tag=CONTENTGROUP --set-tag=CONTENTGROUP=\"$content\""
[ -n "$org" ] && tag="${tag} --remove-tag=ORGANIZATION --set-tag=ORGANIZATION=\"$org\""
[ -n "$rgain" ] && tag="${tag} --add-replay-gain"
[ -n "$remove" ] && tag="${tag} --remove-all-tags-except=ALBUM=ARTIST=TITLE=CONTENTGROUP=GENRE=ALBUMARTIST=ENCODER=DISCNUMBER=REPLAYGAIN_TRACK_GAIN=REPLAYGAIN_TRACK_PEAK=REPLAYGAIN_ALBUM_GAIN=REPLAYGAIN_ALBUM_PEAK=DATE=ORGANIZATION=TRACKNUMBER"

for i in "$@"; do tag="${tag} \"$i\""; done

echo "applying tags..." && eval $tag && echo "done!"