#!/bin/sh
set -euf

errecho() { echo "$*" >&2 ; }

vmaf() {
	while getopts :s:t:T: OPT; do
		case "$OPT" in
			s) start="$OPTARG" ;;
			t) time="$OPTARG" ;;
			T) to="$OPTARG" ;;
			*) : ;
		esac
	done
	shift $((OPTIND - 1))

	exec ffmpeg ${start:+-ss "$start"} ${to:+-to "$to"} \
		-i "$1" -i "$2" ${time:+-t "$time"} \
		-lavfi "[0:v] setpts=PTS-STARTPTS [ref]; \
				[1:v] setpts=PTS-STARTPTS [dis]; \
				[dis][ref] libvmaf=log_fmt=xml:log_path=/dev/stdout:n_threads=$(nproc)" \
		-f null - \
}

moovcheck() {
	ffprobe -v trace -i "$1" 2>&1 | grep -F -e "type:'mdat'" -e "type:'moov'"
}

cmd=$1; shift
case "$cmd" in
	vmaf) vmaf "$@" ;;
	moovcheck) moovcheck "$@" ;;
	help|-h) cat >&2 <<-EOF
		available commands:
		* vmaf $1 $2 - get vmaf of $1 (ref) to $2 (distorted)
		  options: -s <start> -t <time> -T <to>
		* moovcheck $1 - check if moov is before mdat in $1
	EOF
	;;
	*) errecho "wrong command. use help or -h for help" ;;
esac