#!/bin/sh
set -eu

EXT="flac" # default

errecho() { echo "$*" >&2 ; }
die() { errecho "$*" && exit 1 ; }
clean() {
	trap 'exit' INT HUP QUIT EXIT
	[ -f "${DEFAULT_PICTURE:-}" ] && rm -f "$DEFAULT_PICTURE"
	[ -f "${COVER_PICTURE:-}" ] && rm -f "$COVER_PICTURE"
	[ -f "${JSON:-}" ] && rm -f "$JSON"
}

# wrapper to grab a specific tag from flac/opus/mp3
grab_tag() {
	case ${1##*.} in
		flac) metaflac --show-tag="$2" -- "$1" | cut -d '=' -f 2- ;;
		opus) opusinfo -- "$1" | awk -v RS='\n' -v FS='=' -v OFS='' "/^\\t$2=/"'{$1=""; print $0}' ;;
		mp3)
			case "$2" in
				ARTIST) id3 -q '%_a' -- "$1" ;;
				ALBUM) id3 -q '%_A' -- "$1" ;;
				TRACKNUMBER) id3 -q '%_###T' -- "$1" ;;
				TITLE) id3 -q '%_t' -- "$1" ;;
				ALBUMARTIST) id3 -2 -q "%|%{TPE2}||%{TXXX:ALBUM ARTIST}|?" -- "$1" ;;
				*) printf 'unknown tag used for mp3' ;;
			esac
			;;
		*) die 'unknown filetype'
	esac
}

# grab track info, make tracknumber 3-padded just in case for long albums
# (no album has > 999 tracks. I think.)
grab_info() {
	set +e
	DURATION="$(ffprobe -v quiet -of csv=p=0 -show_entries format=duration "$1")"
	ARTIST="$(grab_tag "$1" ARTIST)"
	ALBUM="$(grab_tag "$1" ALBUM)"
	TITLE="$(grab_tag "$1" TITLE)"
	ALBUMARTIST="$(grab_tag "$1" ALBUMARTIST)"
	TRACKNUMBER="$(printf '%03g' "$(grab_tag "$1" TRACKNUMBER)")"
	set -e
}

convert_vid() {
	ffmpeg -nostdin ${VERBOSE--loglevel error} -y -loop 1 -framerate 4 -f image2 -i "$1" -i "$2" \
		-t "$DURATION" \
		-pix_fmt yuv420p \
		${acopy:--c:a libopus -b:a 256k} \
		-r 4 \
		-b:v 500k \
		-c:v libvpx \
		-deadline realtime \
		"$3"
	errecho "Successfully converted $2"
}

# extracts cover from $1 to $2
# returns 0 if $2 (output) exists, 1 if not
extract_cover() {
	set +e
	{
		case ${1##*.} in
			flac) metaflac --export-picture-to="$2" -- "$1" ;;
			opus) opustags --output-cover "$2" -- "$1" ;;
			mp3) ffmpeg -nostdin -i "$1" -map "0:v:0" -c:v copy "$2" ;;
			*) die 'unknown filetype' ;;
		esac
	} >/dev/null 2>&1
	set -e
	# resize within the bounds of 1280x720
	# if it's square then make it 722x720 so youtube doesn't make it a short
	[ -f "$2" ] && vipsthumbnail -o "$2" -s '722x720' -c "$2" || true
}

# sets COVER_PIC for use in convert_vid
set_cover() {
	COVER_PICTURE="$(mktemp -u -t XXXXXX.png)"
	extract_cover "$1" "$COVER_PICTURE"
	if [ -f "$COVER_PICTURE" ]; then
		:
	elif [ -f "track$TRACKNUMBER.png" ]; then
		cp "track$TRACKNUMBER.png" "$COVER_PICTURE"
	else
		cp "$DEFAULT_PICTURE" "$COVER_PICTURE"
	fi
}

# SCRIPT START #

trap 'clean' INT HUP QUIT EXIT

SONG="" BANDCAMP="" NO_CONVERT=""
OUTDIR="/tmp/albumsetup/${PWD##*/}"
while getopts :vnd:e:p:s:b: OPT; do
	case "$OPT" in
		v) VERBOSE="" ;; # can use ${var-rep} for this
		d) cd "$OPTARG" && OUTDIR="${OUTDIR%/*}/${PWD##*/}" ;;
		e) EXT="$OPTARG" ;;
		p) tmpcover="$OPTARG" ;;
		s) SONG="$OPTARG" && OUTDIR="${OUTDIR%/*}" ;; # individual song
		b) BANDCAMP="$OPTARG" ;; # bandcamp link to extract data
		n) NO_CONVERT=1 ;; # don't convert, just get metadata.txt (only affects default albumsetup)
		*) die "albumsetup: invalid option: -$OPTARG" ;;
	esac
done
shift "$((OPTIND - 1))"

[ ! -f "$tmpcover" ] && die "Default cover not specified! (-p IMG)"

mkdir -p "$OUTDIR"

# default cover image, fallback if tracks don't have embedded art
DEFAULT_PICTURE="$(mktemp -u -t XXXXXX.png)"
vipsthumbnail -o "$DEFAULT_PICTURE" -s '722x720' -c "$tmpcover"

# copy audio codec if opus since output codec is opus
[ "$EXT" = "opus" ] && acopy="-c:a copy"

# INDIVIDUAL SONG #
if [ -n "$SONG" ]; then
	grab_info "$SONG"
	set_cover "$SONG"

	# lots of %%/* as to not accidentally create directories
	convert_vid "$COVER_PICTURE" "$SONG" "$OUTDIR/SONG ${ARTIST%%/*} - ${TITLE%%/*}.webm"

# INDIVIDUAL TRACKS FOR FULL ALBUM + COMPLETE VID #
else
	# make a sorted list of the files by tracknumber first
	# so that we don't have to do it individually for everything later
	for f in ./*."$EXT"; do
		grab_info "$f"
		printf '%s\t%s\n' "$TRACKNUMBER" "$f"
	done | sort | cut -f 2- > "$OUTDIR/tmp_sorted_list"

	total_time=0 # this var helps for more precise timestamps
	while read -r f; do
		grab_info "$f"
		set_cover "$f"
		output_file="$OUTDIR/$TRACKNUMBER ${ARTIST%%/*} - ${TITLE%%/*}.webm"

		# STUFF FOR INDIVIDUAL VID #
		errecho "Converting $f"
		[ -z "$NO_CONVERT" ] && convert_vid "$COVER_PICTURE" "$f" "$output_file"
		rm -f "$COVER_PICTURE"

		# metadata print to send to metadata.txt
		printf '%s - %s - %s\n' "${ARTIST:-unknown artist}" "${ALBUM:-unknown album}" "${TITLE:-unknown title}" \
			>> "$OUTDIR/metadata.txt"

		# build ffmpeg concat metadata
		# make safe filename for ffmpeg concat; replace all ' with '\''
		sf="$(printf '%s' "$output_file" | sed "s/'/'\\\\''/g")"

		# tracklist
		printf '%02d:%02d:%02d - %s\n' \
			"$((${total_time%%.*} / 3600))" "$((${total_time%%.*} % 3600 / 60))" "$((${total_time%%.*} % 60))" \
			"$ARTIST - $TITLE" >> "$OUTDIR/metadata_fullvid.txt"
		total_time="$(printf '%s\n' "$total_time + $DURATION" | bc)"

		printf "file '%s'\n" "$sf" >> "$OUTDIR/ffmpeg_tracklist.txt"
	done < "$OUTDIR/tmp_sorted_list"

	[ ! -f "$OUTDIR/metadata.txt" ] && die "No files found!"

	if [ -z "$NO_CONVERT" ]; then
		errecho "Building full video..."
		ffmpeg -nostdin -safe 0 -f concat -i "$OUTDIR/ffmpeg_tracklist.txt" -c copy "$OUTDIR/${ALBUMARTIST%%/*} - ${ALBUM%%/*}.webm"
	fi
	rm "$OUTDIR/ffmpeg_tracklist.txt"

	# Bandcamp check and info retrieval
	if [ -n "$BANDCAMP" ]; then
		JSON="$(mktemp -t "ALBUMSETUP_JSON.XXXX")"
		curl -L -s -o - "$BANDCAMP" | pup 'script[type="application/ld+json"]' 'text{}' > "$JSON"
		albumartist="$(jq -r '.byArtist.name' < "$JSON")"
		date="$(jq -r '.datePublished' < "$JSON")"
		date="$(date -d "$date" -u +'%Y-%m-%d')"
		desc="$(jq -r 'if (.description) then .description | gsub("[\\r]"; "") else empty end' <"$JSON")"
		creds="$(jq -r 'if (.creditText) then .creditText | gsub("[\\r]"; "") else empty end' <"$JSON")"
		{
			printf '%s - %s\n\n' "$albumartist" "$ALBUM"
			cat "$OUTDIR/metadata.txt"
			printf '\nReleased %s\nDOWNLOAD: %s\n\n' "$date" "$BANDCAMP"
			[ -n "$desc" ] || [ -n "$creds" ] && printf '%s\n' 'Release notes:'
			printf '%s\n\n%s' "$desc" "$creds" | sed -e 's/</‹/g'
		} > "$OUTDIR/metadata2.txt"
		mv "$OUTDIR/metadata2.txt" "$OUTDIR/metadata.txt"
		rm -f "$JSON"
	fi

	rm -f "$DEFAULT_PICTURE"
fi