#!/usr/bin/env bash
# 1st argument is video/audio source mkv
# 2nd argument is ass source mkv
# 3rd argument is output file
# 4th argument is timeshift (in milliseconds)
# When it's done, check that the number of fonts attached == largest attachment #
# Ignore Error: An attachment with the ID x was not found.

ffmpeg -i "$2" -vn -an -c:s copy temp-subtitle.ass
mkvextract attachments "$2" `seq 1 100`
fontsuffixes="ttf ttc otc otf TTF TTC OTF OTC pfa pfb PFA PFB"
array_count=0
for font in $fontsuffixes 
    do
    for f in *.$font
    do 
        [ -e "$f" ] || continue
        myarray+=(--attachment-mime-type application/x-truetype-font --attach-file "$f")
        ((array_count++))
    done
done
echo "Number of fonts attached: $fontcount"
mkvmerge -o temp-preshift.mkv "$1" temp-subtitle.ass "${myarray[@]}"
fontcount=0
for font in $fontsuffixes 
    do
    for f in *.$font
    do 
        [ -e "$f" ] || continue
        echo "Attached font $f"
        fontcount=$((fontcount+1))
        rm "$f"
    done
done
echo "Number of fonts attached: $fontcount"

#The shift assumes that the track 2 is the subtitle track. Otherwise, change the value below
subtrack=2
mkvmerge -o "$3" -y $subtrack:$4 temp-preshift.mkv
rm temp-preshift.mkv
rm temp-subtitle.ass