#!/bin/bash -e

# TODO doc
# 
# Reencodes DVD structures to mkv using a local scratchdir
#
# All audio streams and subtitles are copied
# Video is reencoded with x264 -profile slow -crf 22

# TODO: 
# - multiple video streams
# - refining encoding process
# - try to find subtitle language

# in case one wants to use avconv....
FFMPEG=ffmpeg

function usage {
	echo "Usage: $0 Moviefolder"
	exit 1
}
[ "$#" == "1" ] || usage

export TMP_VID_DIR=/mnt/tmp
VIDEO_DIR=$(readlink -f "$1")

function is_dvd {
	if [ -d "$VIDEO_DIR/VIDEO_TS" ]; then
		return 0
	else
		return 1
	fi
}

# 
function print {
	echo $@ > /dev/null
}

function finish {
	print "exit code $? [$@]"
	[ -f "$TMPVOB" ] && rm "$TMPVOB"
	print .
}

trap finish EXIT

function _process_dvd {
	echo "Working on VIDEO_DIR $VIDEO_DIR"
	echo "Folder recognized as $DIRNAME"
	is_dvd || return 2

	pushd "$VIDEO_DIR/VIDEO_TS/"
		local d_path="$TMP_VID_DIR/$1"
		mkdir -p "$d_path"
		[ -L "$d_path/src" ] || ln -s "$VIDEO_DIR" "$d_path/src"
		local vobs=$(ls *.VOB | sort)
		TMPVOB="$d_path/movie.vob"
		local destfile="$d_path/movie.mkv"
		cat $vobs > "$TMPVOB"
		
                $FFMPEG \
			-analyzeduration 2G -probesize 2G \
			-i "$d_path/movie.vob" \
			-map 0 -dn \
			-c:v libx264 -preset slow -crf 22 \
			-c:a copy \
			-c:s copy \
			"$destfile" || rm "$destfile"
		mv "$destfile" "$VIDEO_DIR"
        popd
}

if [ ! -d "$VIDEO_DIR" ] || ! is_dvd ; then
	# "no (dvd) directory given"
	exit 1
fi

DIRNAME="$(basename "$VIDEO_DIR")"

[ ! -f "$VIDEO_DIR/movie.mkv" ] && is_dvd && _process_dvd "$DIRNAME"