# Convert between different formats.
# By default tries to convert all files.
# Usage: transcode <FORMAT> [FILES]
function transcode() {
	local IFS=$'\n'
	local targets=("${@:2}")
	local format="${1}"
	local total=${#targets[@]}
	local count=0
	local failed=0
	local skipped=0

	# Report no format.
	if [[ "${format}" = "" ]]; then
		echo -e "${color_bred}No format specified.${color_default}"
		help transcode
		return 2
	fi

	# All files by default.
	if [[ "${targets}" = "" ]]; then
		targets=($(ls --classify | grep -v /$))
		total=${#targets[@]}
	fi

	# Process.
	for target in "${targets[@]}"; do
		# Increment counter.
		((count++))

		# Define context names and status.
		local from="${target##*.}"
		local to="${format}"
		local output="${target##*/}"
		output="${output%.*}.${to}"
		local status="[${count}/${total}] ${target} -> ${output}"

		# Show status.
		echo -e "${status}"

		# Skip if file exists.
		[[ -f "${output}" ]] && { ((skipped++)); continue; }

		# Support multiple inputs.
		[[ "${to}" = "mp3" ]] && from=""
		[[ "${to}" = "flac" ]] && from=""
		[[ "${to}" = "mka" ]] && from=""
		[[ "${to}" = "mkv" ]] && from=""

		# Send convert.
		case "${from}-${to}" in
			"gz-xz"|"tgz-txz")
				_transcode_gz-xz "${target}" "${output}"
				;;
			"xz-gz"|"txz-tgz")
				_transcode_xz-gz "${target}" "${output}"
				;;
			"-mp3")
				_transcode_mp3 "${target}" "${output}"
				;;
			"-flac")
				_transcode_flac "${target}" "${output}"
				;;
			"-mka")
				_transcode_mka "${target}" "${output}"
				;;
			"-mkv")
				_transcode_mkv "${target}" "${output}"
				;;
			*)
				echo -e "${color_yellow}Conversion ${target##*.}-${to} not supported.${color_default}"
				false
				;;
		esac

		# Show error.
		if [[ ${?} != 0 ]]; then
			echo -e "${color_bred}${status}: Failed.${color_default}"
			((failed++))
		fi
	done

	if [[ ${skipped} != 0 ]]; then
		echo -e "${color_byellow}Skipped: ${skipped}.${color_default}"
		return 1
	fi

	if [[ ${failed} != 0 ]]; then
		echo -e "${color_bred}Failed: ${failed}.${color_default}"
		false
	fi
}

function _transcode_gz-xz() {
	[[ -f "${2}" ]] && return 1
	pv "${1}" | gzip -d | xz -9e > "${2}"
}

function _transcode_xz-gz() {
	[[ -f "${2}" ]] && return 1
	pv "${1}" | xz -d | gzip -1 > "${2}"
}

function _transcode_mp3() {
	ffmpeg -n -i "${1}" -c:a libmp3lame -b:a 320k -f mp3 "${2}"
}

function _transcode_flac() {
	ffmpeg -n -i "${1}" -c:a flac -f flac "${2}"
}

function _transcode_mka() {
	local braudio=$(_ffprobe_ba "${1}")
	[[ ${braudio} -gt 128 ]] && braudio=128

	ffmpeg -n -i "${1}" -ac 2 -c:a libopus -b:a ${braudio}k -vn "${2}"
}

function _transcode_mkv() {
	local keyint=$(_ffprobe_keyint "${1}")
	local braudio=$(_ffprobe_ba "${1}")
	[[ ${braudio} -gt 128 ]] && braudio=128

	# ffmpeg -n -i "${1}" -c:a libopus -b:a ${braudio}k -c:v libsvtav1 -crf 30 -svtav1-params "fast-decode=1:tune=0" -preset 8 -pix_fmt yuv420p10le -g ${keyint} -vf "scale=-2:min'(1080,ih)'" "${2}"
	ffmpeg -n -i "${1}" -map 0 -map -v -map V -map -t -c:s srt -ac 2 -c:a libopus -b:a ${braudio}k -c:v libsvtav1 -crf 30 -svtav1-params "tune=0" -pix_fmt yuv420p10le -g ${keyint} -vf "scale=-2:min'(1080,ih)'" "${2}"
}