#!/bin/sh
set -euf

dirminsize () {
	cleanup() {
		trap 'exit' INT HUP QUIT TERM EXIT
		rm -f "$tmpjxl7" "$tmpjxl8" "$tmpjxl9" "$tmpwebp"
		kill 0
	}
	tmpwebp=$(mktemp -u -t webp2jxl_XXXX.webp)
	tmpjxl7=$(mktemp -u -t webp2jxl_XXXX.jxl)
	tmpjxl8=$(mktemp -u -t webp2jxl_XXXX.jxl)
	tmpjxl9=$(mktemp -u -t webp2jxl_XXXX.jxl)

	trap 'cleanup' INT HUP QUIT TERM EXIT

	ext="webp,png,jxl" depth="-maxdepth 1"
	while getopts ":e:r" OPT; do
		case "$OPT" in
			e) ext="$OPTARG" ;;
			r) depth="" ;;
			*) exit 1 ;;
		esac
	done
	shift $((OPTIND - 1))

	exts=$(awk -F ',' -v OFS=' -o ' '{ for(i=1; i<=NF; i++) $i="-iname *." $i; print}' <<-EOF
			$ext
		EOF
	)

	while IFS= read -r f; do
		[ -z "$f" ] && continue
		echo "$f"
		vips webpsave "$f" "$tmpwebp" --min-size --lossless &
		vips jxlsave "$f" "$tmpjxl7" --lossless --effort 7 &
		vips jxlsave "$f" "$tmpjxl8" --lossless --effort 8 &
		vips jxlsave "$f" "$tmpjxl9" --lossless --effort 9 &
		wait
		read -r _ outfile <<-EOF
			$(wc -c "$f" "$tmpwebp" "$tmpjxl7" "$tmpjxl8" "$tmpjxl9" | sort -n)
		EOF
		mv "$outfile" "${f%.*}.${outfile##*.}" || continue
		[ "${outfile##*.}" != "${f##*.}" ] && rm "$f" # remove if there are 2
	done <<-EOF
		$(set -f; find "${1:-.}" -type f $depth $exts)
	EOF
}

jxld2q() {
	for n; do
		case "$n" in
			*.*) i=d; d="$n" ;;
			*) i=q; q="$n" ;;
		esac
		[ "$i" = q ] && d="$(printf '0.1 + (100 - %s) *  0.09\n' "$q" | bc)"
		[ "$i" = d ] && q="$(printf '100 - ((%s - 0.1) / 0.09)\n' "$d" | bc)"
		echo "distance = $d | quality = $q"
	done
}

cmd=$1; shift
case "$cmd" in
	dirminsize) dirminsize "$@" ;;
	jxld2q) jxld2q "$@" ;;
	help|-h) cat >&2 <<-EOF
		available commands:
		* dirminsize - tries to losslessly squeeze out as much size as possible from every file
		  in the directory by converting to webp/jxl with various efforts
		  options: -r (recursive) -e <ext1,ext2,...>
		* jxld2q $@ - convert to/from jxl distance/quality for each arg
	EOF
	;;
	*) errecho "wrong command. use help or -h for help" ;;
esac