#!/bin/bash

# functions
# strip chars: awk '{gsub(/^[ \t]+| [ \t]+$/,""); print $0}'
function dependencies {
	dependencies=(opustags ffmpeg mp3val flakeybrakey)
	echo "Checking dependencies..."
	for i in "${dependencies[@]}"
	do
		echo -n "$i: "
		if [[ $(command -v "$i") ]]
		then
			echo -e "\e[32mpresent\e[39m"
		else
			echo -e "\e[31mmissing\e[39m"
		fi
	done
	exit 1
	}

function encode {
	# variables
	bitrate="20k"
	compression="10"
	codec="libopus"
	extension="opus"
	_ffmpeg="ffmpeg -hide_banner -loglevel error -nostats"
	_ffmpeg_options=(-acodec "$codec" -ac 1 -b:a "$bitrate" -vbr on -compression_level "$compression")
	if [ -n "$2" ]
	then
		if [ -f "$2" ]
		then
			filename="$(basename "$2" ".${2##*.}")"
			if [ "${2##*.}" = mp3 ]
			then
				printf "Fixing possible source errors... "
				mp3val -f -nb "$2" 1> /dev/null
				printf "done\\n"
			fi
			printf "Encoding file... "
			$_ffmpeg -i "$2" "${_ffmpeg_options[@]}" "$filename.$extension"
			printf "done\\n"
		elif [ -d "$2" ]
		then
			echo "Encoding directory..."
			# apostrophe check
			for f in *\'*
			do
				mv "${f}" "${f/\'/}"
			done
			common=$(find . -maxdepth 1 -type f | sed 's/.*\.//' | sort | uniq -ci | sort -rn | awk '{print $2;exit}')
			if [ "$common" = mp3 ]
			then
				printf "Fixing possible source errors... "
				for i in *.mp3
				do
					mp3val -f -nb "$i" 1> /dev/null
				done
				printf "done\\n"
			fi
			printf "Encoding file... "
			output_filename="../${PWD##*/}.$extension"
			$_ffmpeg -f concat -safe 0 -i <(for f in ./*."$common"; do echo "file '$PWD/$f'"; done) "${_ffmpeg_options[@]}" "$output_filename"
			printf "done\\n"
		else # failure state
			printf "Not sure where we\'re working..." && exit 1
		fi
	else
		printf "Encoding current directory...\\n"


	fi
	}
function tagger {

	# check for opustags
	if [[ ! "$(command -v opustags)" ]]; then
		printf "Opustags is required to run this script, please install\n"
		exit 1
	fi

	# strip whitespace function
	function _strip { awk '{gsub(/^[ \t]+| [ \t]+$/,""); print $0}' ; }

	for i in *.opus; do
		printf "Tagging: %s... " "$i"
		opustags -i -D "$i"
		opustags -i -s "GENRE=Audiobook" "$i"
		artist=$(printf "%s" "$i" | awk -F\- '{print $1}' | _strip)
		opustags -i -s "ARTIST=$artist" "$i"
		if [[ "$i" == *"#"* ]]; then
			# series
			album=$(printf "%s" "$i" | awk -F"-" '{print $2}' | awk -F"#" '{print $1}' | _strip)
			track=$(printf "%s" "$i" | awk -F"-" '{print $2}' | awk -F"#" '{print $2}' | awk '{gsub ("^0*",""); print}' | _strip)
			title=$(printf "%s" "$i" | awk -F"-" '{gsub(".opus",""); print $3}' | _strip)
			opustags -i -s "ALBUM=$album" "$i"
			opustags -i -s "TRACKNUMBER=$track" "$i"
			opustags -i -s "TITLE=$title" "$i"
		else
			# single
			title=$(printf "%s" "$i" | awk -F"-" '{gsub(".opus",""); print $2}' | _strip)
			opustags -i -s "TITLE=$title" "$i"
		fi
		printf "Done.\n"
	done

	}

# main loop
function main {
	case "$1" in
		dep) dependencies ;;
		tag) tagger "$@" ;;
		enc) encode "$@" ;;
		*) echo "$0" && awk '/^function main/,/\tesac/' "$0" | awk -F"\t|)" '{print $3}' | tr -d "*" | sort | xargs ;;
	esac
}
main "$@"