#!/bin/bash

begin=$(date +"%s")
# saner programming env: these switches turn some bugs into errors
set -o errexit -o pipefail -o noclobber -o nounset
source="-"
dest="-"
verbose=2
help=false
temp="/tmp/converted"

CheckDeps() {
	# Check getopt
	! getopt --test > /dev/null 
	if [[ ${PIPESTATUS[0]} -ne 4 ]]; then
		VerboseOutput 5 "\`getopt --test\` failed"
		VerboseOutput 5 "Sorry, It seems that your shell is not supported"
		VerboseOutput 5 "If you're using MacOS or another unix-like system, please install GNU getopt"
		ExecTime
		exit 1
	fi

	# Check lame
	if [[ ! $(lame --version 2>/dev/null) ]]; then
		VerboseOutput 5 "\`lame --version\` failed"
		VerboseOutput 5 "Sorry, It seems that lame is not installed on your system"
		VerboseOutput 5 "Please install lame from your repositories and make sure it is available in your \$PATH"
		ExecTime
		exit 1
	fi
}

GetOptions() {

	# https://stackoverflow.com/a/29754866
	OPTIONS=s:d:t:v::h
	LONGOPTS=source:,dest:,temp:,verbose::,help

	# -use ! and PIPESTATUS to get exit code with errexit set
	# -temporarily store output to be able to check for errors
	# -activate quoting/enhanced mode (e.g. by writing out “--options”)
	# -pass arguments only via   -- "$@"   to separate them correctly
	! PARSED=$(getopt --options=$OPTIONS --longoptions=$LONGOPTS --name "$0" -- "$@")
	if [[ ${PIPESTATUS[0]} -ne 0 ]]; then
		# e.g. return value is 1
		#  then getopt has complained about wrong arguments to stdout
		Usage
		exit 2
	fi

	# read getopt’s output this way to handle the quoting right:
	eval set -- "$PARSED"

	# now enjoy the options in order and nicely split until we see --
	while true; do
		case "$1" in
			-v|--verbose)
				verbose=2
				if [[ $2 != "" ]]; then
					verbose=${2}
					shift
				fi
				shift
				;;
			-h|--help)
				help=true
				shift
				;;
			-s|--source)
				source="$2"
				shift 2
				;;
			-d|--dest)
				dest="$2"
				shift 2
				;;
			-t|--temp)
				temp="$2"
				shift 2
				;;
			--)
				shift
				break
				;;
			*)
				VerboseOutput 5 "Programming error"
				return 3
				;;
		esac
	done

	if [[ ! -z ${1+x} ]]; then
		source=$1
	fi

	if [[ ! -z ${2+x} ]]; then
		dest=$2
	fi

	if [[ $dest == "-" ]] || [[ $source == "-" ]]; then
		help=true
	fi
}

Usage() {
	echo ""
	echo "Usage:"
	echo "music-sync <options> -s|--source <source> -d|--dest <destination>"
	echo "music-sync <options> <source> <destination>"
	echo ""
	echo "Syncronises music from one folder to another."
	echo ""
	echo "Options:"
	echo " -s, --source <source>     The source folder of the music"
	echo " -d, --dest <destination>  The destionation folder of the music"
	echo " -t, --temp <folder>       The temporary cache for converted files (default: /tmp/converted)"
	echo " -v, --verbose <0-6>       Set log level (default: 2)"
	echo " -h, --help                Display this help text"
	echo ""
	echo "Log levels:"
	echo " 0 | Verbose"
	echo " 1 | Debug"
	echo " 2 | Info"
	echo " 3 | Warning"
	echo " 4 | Error"
	echo " 5 | Fatal"
	echo " 6 | Silence"
	echo ""
	echo "Exit Codes:"
	echo " 1 Dependencies not met"
	echo " 2 Invalid Argument"
	echo " 3 Source Unreachable"
	echo " 4 Destination Unreachable"
	echo " 5 Command failed"
	echo ""
}

VerboseOutput() {
	level=""
	if [[ $verbose -le $1 ]]; then
		case "$1" in
			0) 
				level="\033[1;36mVerbose\033[0m"
				;;
			1)
				level="\033[1;34m Debug \033[0m"
				;;
			2)
				level="\033[1;37m Info  \033[0m"
				;;
			3)
				level="\033[1;33mWarning\033[0m"
				;;
			4)
				level="\033[1;31m Error \033[0m"
				;;

			5)
				level="\033[1;30m Fatal \033[0m"
				;;
		esac
		echo -e "[$level] $2" >&2
	fi
}

CreateFileList() {
	# ${1} /mnt/hdd/Example-Artist/Example-Album
	# ${2} /mnt/mtp/Example-Artist/Example-Album
	# ${3} Example-Artist/Example-Album
	IFS=""
	sourcepath="${1/\[/\\\[}/*"
	sourcepath="${sourcepath/\]/\\\]}"
	for file in $sourcepath; do
		relfile="${file#"$1/"}"
		if [[ -d "${1}/$relfile" ]]; then
			newdir="${3}/$relfile"
			newdir=${newdir#"/"}
			VerboseOutput 1 "Entering $newdir"
			CreateFileList "${1}/$relfile" "${2}/$relfile" "$newdir"
		elif [[ ! -f "${2}/$relfile" || "${1}/$relfile" -nt "${2}/$relfile" ]]; then
			echo ${3}/$relfile >> /tmp/music-sync-filelist
			VerboseOutput 2 "Added: ${3}/${relfile}"
		fi
	done
}

ConvertFiles() {
	curline=0
	percentage=0
	while read -r line
	do

		if [[ ! -f "${source}/$line" ]]; then
			VerboseOutput 5 "Source-file ${source}/$line Unreachable"
			ExecTime
			exit 3
		fi

		curline=$(expr ${curline} + 1)
		total=$(cat /tmp/music-sync-filelist | wc -l)
		percentage=$(echo "scale=4;${curline}/${total}" | bc)
		percentage=$(echo "scale=2;${percentage}*100" | bc)
		VerboseOutput 1 "Converting: $line"
		VerboseOutput 2 "Progress: $curline / $total (${percentage%00}%) Step 1 of 2"

		if [[ "$temp/$line" = */* ]]; then
			mkdir -p "$temp/${line%/*}";
		fi;
		if [[ ! -f "$temp/$line" || "${source}/$line" -nt "$temp/$line" ]]; then
			lame -b 192 $source/$line $temp/$line 1>/dev/null 2>/dev/null
			VerboseOutput 2 "Converted: $line"
		else
			VerboseOutput 3 "$line already converted"
		fi;

	done < "/tmp/music-sync-filelist"
}

CopyFiles() {
	curline=0
	percentage=0
	while read -r line
	do
		if [[ ! -d "$dest" ]]; then
			VerboseOutput 5 "Destination unreachable"
			ExecTime
			exit 4
		fi

		if [[ ! -f "${temp}/$line" ]]; then
			VerboseOutput 5 "Source-file ${temp}/$line Unreachable"
			ExecTime
			exit 3
		fi

		curline=$(expr ${curline} + 1)
		total=$(cat /tmp/music-sync-filelist | wc -l)
		percentage=$(echo "scale=4;${curline}/${total}" | bc)
		percentage=$(echo "scale=2;${percentage}*100" | bc)

		VerboseOutput 1 "Copying: $line"
		VerboseOutput 2 "Progress: $curline / $total (${percentage%00}%) Step 2 of 2"
		
		if [[ "$dest/$line" = */* ]]; then
			mkdir -p "$dest/${line%/*}";
		fi;

		cp -f $temp/$line $dest/$line 1>/dev/null 2>/dev/null

		VerboseOutput 2 "Copied: $line"

	done < "/tmp/music-sync-filelist"
}

CleanUp() {
	VerboseOutput 1 "Cleaning Up"
	if [[ -f /tmp/music-sync-filelist ]]; then
		rm "/tmp/music-sync-filelist"
	fi
	VerboseOutput 1 "Done"
}

ExecTime() {
	termin=$(date +"%s")
	difftimelps=$(($termin-$begin))
	VerboseOutput 1 "$(($difftimelps / 60)) minutes and $(($difftimelps % 60)) seconds elapsed for Script Execution."
}

ErrorHandler() {
	VerboseOutput 5 "Error while executing $1"
	CleanUp
	exit 5
}

ExitHandler() {
	VerboseOutput 5 "Aborted"
	CleanUp
	exit 0
}

trap 'ExitHandler' SIGINT
trap 'ErrorHandler $BASH_COMMAND' ERR

CheckDeps
GetOptions $@
if [[ $help == true ]]; then
	Usage
	exit
fi
if [[ -f /tmp/music-sync-filelist ]]; then
	rm /tmp/music-sync-filelist
fi
CreateFileList $source $dest ""
if [[ ! -f /tmp/music-sync-filelist ]]; then
	VerboseOutput 2 "Nothing to do!"
	CleanUp
	exit 0
fi
ConvertFiles
CopyFiles
CleanUp
ExecTime