#!/bin/bash -e

if [ -z "$1" -o -z "$2" ]; then
    echo "Usage: $0 videodir chapterdir destdir"
    exit 1
fi

videodir="$(cd "$1" && pwd)"
chapterdir="$(cd "$2" && pwd)"
destdir="$(cd "$3" && pwd)"

cd "$videodir"
find . -type f | while read infile; do
    if [ ! -r "$infile" ]; then
        echo "Missing file $infile"
        exit 1
    fi

    outfile="${destdir}/${infile}"
    if [ -e "$outfile" ]; then
        echo "Skipping $infile, it already exists in destination directory!"
        continue
    fi

    chapterfile="${chapterdir}/${infile}.chapters"
    if [ ! -e "$chapterfile" ]; then
        echo "Skipping $infile, no chapters!"
        continue
    fi

    mkvmerge \
        -o "$outfile" \
        --chapters "${chapterfile}" \
        --no-chapters \
        "$infile"
done