#!/bin/sh

usage(){
	fmt <<EOF
DESCRIPTION
	Adapted from ogg-cover-art by acabal: https://github.com/acabal/scripts/blob/master/ogg-cover-art

USAGE
	ogg-cover-art [COVER-FILENAME] META-FILENAME
		convert normal image into ogg supported metadata
EOF
	exit
}
die(){ printf "Error: ${1}\n" 1>&2; exit 1; }
require(){ command -v $1 > /dev/null 2>&1 || { suggestion=""; if [ ! -z "$2" ]; then suggestion=" $2"; fi; die "$1 is not installed.${suggestion}"; } }
if [ $# -eq 1 ]; then if [ "$1" = "--help" -o "$1" = "-h" ]; then usage; fi fi
#End boilerplate

#require "opuscomment.pl" "Try: apt-get install opus-tools"

if [ $# -eq 0 ]; then
	usage
fi

imagePath=""

if [ $# -eq 1 ]; then
	imagePath="$1"
fi

if [ ! -f "${imagePath}" ]; then
	die "Couldn't find cover image."
fi

imageMimeType=$(file -b --mime-type "${imagePath}")

if [ "${imageMimeType}" != "image/jpeg" -a "${imageMimeType}" != "image/png" ]; then
	die "Cover image isn't a jpg or png image."
fi

#Insert cover image from file

#metadata_block_picture format
#See: https://xiph.org/flac/format.html#metadata_block_picture
imageWithHeader="$(mktemp -t "tmp.XXXXXXXXXX")"
description=""

#Reset cache file
echo -n "" > "${imageWithHeader}"

#Picture type <32>
printf "0: %.8x" 3 | xxd -r -g0 >> "${imageWithHeader}"

#Mime type length <32>
printf "0: %.8x" $(echo -n "${imageMimeType}" | wc -c) | xxd -r -g0 >> "${imageWithHeader}"

#Mime type (n * 8)
echo -n "${imageMimeType}" >> "${imageWithHeader}"

#Description length <32>
printf "0: %.8x" $(echo -n "${description}" | wc -c) | xxd -r -g0 >> "${imageWithHeader}"

#Description (n * 8)
echo -n "${description}" >> "${imageWithHeader}"

#Picture with <32>
printf "0: %.8x" 0 | xxd -r -g0  >> "${imageWithHeader}"

#Picture height <32>
printf "0: %.8x" 0 | xxd -r -g0 >> "${imageWithHeader}"

#Picture color depth <32>
printf "0: %.8x" 0 | xxd -r -g0 >> "${imageWithHeader}"

#Picture color count <32>
printf "0: %.8x" 0 | xxd -r -g0 >> "${imageWithHeader}"

#Image file size <32>
printf "0: %.8x" $(wc -c "${imagePath}" | cut --delimiter=' ' --fields=1) | xxd -r -g0 >> "${imageWithHeader}"

#Image file
cat "${imagePath}" >> "${imageWithHeader}"

echo "metadata_block_picture=$(base64 --wrap=0 < "${imageWithHeader}")"

#Delete temp files
rm "${imageWithHeader}"