#!/bin/sh

#
# Section: Argument parsing
#

options="sim run full"

if [ $# -ne 2 ]; then
  echo "reencode <$( echo "$options" | sed 's/ /|/g' )> <directory>"
  exit 1
fi

mode=""

for opt in $options; do 
	if [ "$opt" = "$1" ]; then 
		mode="$opt"
	fi
done

if [ "$mode" = "" ]; then
	echo "'$1' is not a valid option"
	exit 1
fi

path="$2"
cd "$path"

if [ $? -ne 0 ]; then
	echo "Path does not exist: $path"
	exit 1
fi 

echo "Searching for MKVs in $( pwd )"

#
# Section: Functions
# 

do_ffprobe() {
	ffprobe -v quiet -select_streams v:0 -show_entries $1 -of csv=p=0:nk=1 "$2"
}

get_codec() {
	do_ffprobe stream=codec_name "$1"
}

get_bitrate() {
	do_ffprobe format=bit_rate "$1"
}

get_resolution() {
	do_ffprobe stream=height,width "$1"
}

file_size() {
	du -sb "$1" | awk '{print $1}'
}

format_size() {
	echo "$1" | numfmt --to=iec-i | awk '{print $1"B"}'
}

format_rate() {
	echo "$1" | numfmt --to=si | awk '{print $1"bps"}'
} 

encode_file() {
	process=$( echo $1 | awk -v FPAT="([^' ]+)|'([^']+)'" '{print $1}' )
	filesize=$( echo $1 | awk -v FPAT="([^' ]+)|'([^']+)'" '{print $2}' )
	bitrate=$( echo $1 | awk -v FPAT="([^' ]+)|'([^']+)'" '{print $3}' )
	codec=$( echo $1 | awk -v FPAT="([^' ]+)|'([^']+)'" '{print $4}' )
	infile=$( echo $1 | awk -v FPAT="([^' ]+)|'([^']+)'" '{print $5}' | sed "s/^'\|'\$//g" )
	outfile=$( echo $1 | awk -v FPAT="([^' ]+)|'([^']+)'" '{print $6}' | sed "s/^'\|'\$//g" )

	if [ "$process" = "Ignore" ]; then
		return 1
	fi

	tmpfile="$infile.bak"

	ffmpeg -nostdin -hide_banner -i "$infile" -c:v hevc_nvenc -c:a copy -c:s copy -map 0 -vtag hvc1 output.mkv

	if [ $? -ne 0 ]; then
		echo "FFMPEG re-encode failed: $infile"
		return 1
	fi

	mv "$infile" "$tmpfile"

	if [ $? -ne 0 ]; then
		echo "Failed to make backup file: $infile"
		rm output.mkv
		return 2
	fi

	mv output.mkv "$outfile"

	if [ $? -ne 0 ]; then
		echo "Failed final move to: $outfile"
		mv -f "$tmpfile" "$infile"
		rm output.mkv
		return 2
	fi 

	echo "Output file: $outfile"

	rm "$tmpfile"
	oldsize=$( format_size $filesize )
	oldbitr=$( format_rate $bitrate )
	newsize=$( format_size $( file_size "$outfile" ) )
	newbitr=$( format_rate $( get_bitrate "$outfile" ) )
	echo "Converted $infile:" >> summary.txt
	echo "\t$oldsize ($oldbitr) => $newsize ($newbitr)\n" >> summary.txt
	return 0
}

get_file_info() {
	# Args:
	# 	$1 - video file name
	#
	# Returns a single line:
	# 	filesize bitrate codec
	echo "$( file_size "$1" ) $( get_bitrate "$1" ) $( get_codec "$1" )"
}

select_file() {
	# Arg: 
	# 	$1 - filename
	# 	$2 - filesize
	# 	$3 - bitrate
	# 	$4 - codec
	# 	
	# Note: args line up with return values from get_file_info
	#
	# Echo "Ignore" or "Process" with an optional reason
	file=$1
	size=$2
	bitrate=$3
	codec=$4

	#if [ "$codec" = "hevc" ]; then
	#	echo "Ignore Already HEVC"
	#	return
	#fi

	if [ $bitrate -lt 4000000 ]; then
		echo "Ignore bitrate too low"
	else
		echo "Process"
	fi
}

simulate_file() {
	# Arg:
	# 	$1 - video file name
	#
	# Prints out a line to simulate.txt formatted like so:
	# 	process filesize bitrate codec infile outfile
	fileinfo=$( get_file_info "$1" )
	selected=$( select_file "$1" $fileinfo )
	outputfile="${1%.*}.mkv"

	reason=${selected#* }
	selected=$( echo "$selected" | awk '{print $1}' )

	if [ "$selected" = "Ignore" ]; then
		echo "$selected $fileinfo '$1' '$reason'" >> simulation.txt
		echo "Ignored $1"
		echo "\t => $reason"
	else
		echo "$selected $fileinfo '$1' '$outputfile' '$reason'" >> simulation.txt
		echo "Selected $1"
	fi
}

#
# Section: Main code - do mode-specific stuff
#

if [ "$mode" != "run" ]; then
	# if mode is not run (sim or full) then we're doing a simulation
	rm -f simulation.txt

	find -type f \( -name "*.mkv" -o -name "*.mp4" \) | while read file; do
		simulate_file "$file"
	done
fi

if [ "$mode" != "sim" ]; then 
	# if mode is not sim (run or full) then we're actually executing re-encodings
	rm -f output.mkv

	if [ ! -f "simulation.txt" ]; then
		echo "No simulation file found. Cannot proceed."
		exit 1
	fi

	cat simulation.txt | while read line; do
		encode_file "$line"
		if [ $? -eq 2 ]; then
			exit 2
		fi
	done
fi