#!/bin/bash

SCRIPTPATH="$( cd "$(dirname "${BASH_SOURCE[0]}")" ; pwd -P )"
SELF=$SCRIPTPATH/$(basename $0)
LOG=/var/log/ripit.log

function usage() {
    cat <<EOF
ripit, semi-automated dvd ripping
usage: $0 master </path/to/storage>
       $0 event <device> <path/to/storage>
       $0 slave <device> <path/to/storage>
EOF
}

if [[ $# < 2 ]] ; then
    usage
    exit 1
fi

if [[ $1 == "master" ]] ; then
    # mode: master

    STORAGE=$2
    RULES=/etc/udev/rules.d/99-ripit.rules

    # add udev rule which calls slave on disk insertion
    cat > $RULES <<EOF
ACTION=="change", KERNEL=="sr[0-9]*", ENV{ID_CDROM_DVD}=="1", ENV{ID_CDROM_MEDIA_STATE}=="complete", RUN+="$SELF event \$kernel '$STORAGE'"
EOF
    udevadm control --reload-rules

    echo "udev rule installed, waiting for disk insertion"

    # tail slave log
    touch $LOG
    tail -n 0 -f $LOG

    echo "removing udev rule"
    rm -rf $RULES
    udevadm control --reload-rules

elif [[ $1 == "event" ]] ; then
    # mode: event

    exec >> $LOG
    exec 2>&1

    echo "$@"
    # re-invoke self detached to avoid blocking udevd
    echo "$SELF" slave "${@:2}" | batch

elif [[ $1 == "slave" ]] ; then

    # mode: slave

    exec >> $LOG
    exec 2>&1

    dev=/dev/$2

    echo "insertion event: $dev"

    # grab volume label
    TITLE=$(blkid -o value -s LABEL $dev)

    # TODO convert "UPPER_SNAKE_CASE" to "Title Space Case"
    # TODO grab title from DVD content rather than volume label?

    dst=$3/$TITLE.mp4
    if [ -f $dst ] ; then
        echo "$dst already exists"
    else
        echo "ripping: $dst"
        # TODO: avoid calling handbrake as root?
        # TODO: refine transcoding options
        HandBrakeCLI -i $dev \
            --main-feature \
            --audio-lang-list eng,fra \
            --subtitle-lang-list eng,fra \
            -f av_mp4 \
            -o $dst

        # TODO: remove output on failure
        # TODO: chown/chmod output
    fi

    eject $dev
else
    usage
fi