#!/bin/bash

# the function "round()" was taken from 
# http://stempell.com/2009/08/rechnen-in-bash/

# the round function:
round()
{
	echo $(printf %.$2f $(echo "scale=$2;(((10^$2)*$1)+0.5)/(10^$2)" | bc))
};

calc() { awk "BEGIN{print $*}"; }


########
# Init Variables
# Available Environment Variables:

# VIDEO_FORMATS_LOCATION: Pass a location to a different json file holding video convert configurations
# VIDEO_LOCATION: Pass a location to a different folder which holds the videos
# VIDEO_FORMATS: Pass all video formats which should trigger the conversion, seperated by ":". Example: .mp4:.wmv
# VIDEO_FFMPEG_PATH: Path to ffmpeg executable
########

########
# Environment variables as a base
########

# Video formats location
if [ -n $VIDEO_FORMATS_LOCATION ]
then
	video_formats_location=$VIDEO_FORMATS_LOCATION
fi

# Video location
if [ -n $VIDEO_LOCATION ]
then
	video_location=$VIDEO_LOCATION
fi

# All video formats
if [ -n $VIDEO_FORMATS ]
then
	video_formats_string=$VIDEO_FORMATS
fi

# ffmpeg executable
if [ -n $VIDEO_FFMPEG_PATH ]
then
	video_ffmpeg_path=$VIDEO_FFMPEG_PATH
fi

########
# Passed Options, any passed option will overwrite a previously set environment variable
########

while getopts ":c:p:v:p:h" opt; do
  case $opt in
    c)
      video_formats_location=$OPTARG
      ;;
    p)
      video_location=$OPTARG
      ;;
    v)
      video_formats_string=$OPTARG
      ;;
    f)
      video_ffmpeg_path=$OPTARG
      ;;
    h)
      echo "AVAILABLE OPTIONS: 
 
-c: Video Formats Location. Pass a path with a JSON config file for conversion. Defaults to 'video_formats.json' in current folder. 
-p: Video Location. Pass a location to a different folder which holds the videos. Defaults to currents folder. 
-v: Video Formats. Pass all video formats which should trigger the conversion, seperated by ':'. Example: .mp4:.wmv 
-f: Path to ffmpeg executable. Defaults to 'ffmpeg'
-h: Print this help message.

ENVIRONMENT VARIABLES: 
All settings can also be done via environment variables. However, a passed option will overwrite a previously set environment variable. 
 
VIDEO_FORMATS_LOCATION: Pass a location to a different json file holding video convert configurations 
VIDEO_LOCATION: Pass a location to a different folder which holds the videos 
VIDEO_FORMATS: Pass all video formats which should trigger the conversion, seperated by ':. Example: .mp4:.wmv 
VIDEO_FFMPEG_PATH: Path to ffmpeg executable 
 
Copyright 2017 K. Langenberg 
Licensed under GNU GPLv3"
	  exit 0
      ;;
    \?)
      echo "Invalid option: -$OPTARG. Use -h to print all available options." >&2
      exit 1
      ;;
    :)
      echo "Option -$OPTARG requires an argument. Use -h to print all available options." >&2
      exit 1
      ;;
  esac
done

########
# Defaults
########

# Video Formats Location
if [ -z $video_formats_location ]
then 
	video_formats_location=$PWD/video_formats.json
fi

# Video Location
if [ -z $video_location ]
then 
	video_location=$PWD
fi

# Video Formats
if [ -z $video_formats_string ]
then 
	video_formats_string='.mp4'
fi

# Default ffmpeg path
if [ -z $video_ffmpeg_path ]
then
	video_ffmpeg_path=ffmpeg
fi

########
# Checks
########
# Check if the converterfile exists
if [ ! -f $video_formats_location ]
then
	echo "Video Formats .json file ($video_formats_location) does not exist!"
	exit 1;
fi

# Check if the video folder exists
if [ ! -d $video_location ]
then
	echo "Video location folder ($video_location) does not exist!"
	exit 1;
fi

# Remove end slash in video location
video_location=${video_location%/}

# Loop through our convertfile
video_formats_file=$(<$video_formats_location)

########
# Run every 5 seconds
########

while true; do
	# Remove Spaces in filename (because bash doesn't like them and would throw an error)
	rename 's/ /_/g' *
	
	# loop through all files
	for file in $video_location/*; do
		# Check if the current file is a video
		file_format=${file: -4}
		if [ "${video_formats_string/$file_format}" != "$video_formats_string" ]
		then

			# If it is a videofile, if no "locker" already exists, create one and start converting
			if [ ! -f $file.lock ]
			then

				# Tell the User what we're doing
				echo "================"
				echo "Found file: $file"

				# Get the video width and height
				# Hack to get the height even if the audio and video stream are in reverse order
				codec_type=$(ffprobe -v quiet -show_streams -print_format json "$file" | jq --raw-output '.streams [0] .codec_type')
				if [ "$codec_type" = "video" ]; then
					video_height=$(ffprobe -v quiet -show_streams -print_format json "$file" | jq '.streams [0] .height')
					video_width=$(ffprobe -v quiet -show_streams -print_format json "$file" | jq '.streams [0] .width')
				else
					video_height=$(ffprobe -v quiet -show_streams -print_format json "$file" | jq '.streams [1] .height')
					video_width=$(ffprobe -v quiet -show_streams -print_format json "$file" | jq '.streams [1] .width')
				fi

				# Calculate aspect ratio
				video_aspect_ratio=$( echo $video_width / $video_height | bc -l )

				# Check if the file is a video file
				if [ "$codec_type" = "null"  ]; then
					echo "$file is not a video file"

				else

					# Create Lock file
					touch $file.lock

					# Create the output folder
					mkdir $file.out

					# Loop through all videoformats and convert them
					for row in $(echo "${video_formats_file}" | jq -r '.[] | @base64'); do  
						_jq() {
							echo ${row} | base64 --decode | jq -r ${1}
						}

						# Check if the video is larger or as large as the format we want to convert it to
						if [ "$(_jq '.height')" -le "$video_height" ]
						then

							# Calculate the new width based on aspect ratio
							new_width="$(echo $video_aspect_ratio*$(_jq '.height') | bc | awk '{printf("%d\n",$1 + 0.5)}' )"
							resolution="$new_width:$(_jq '.height')"
							
							echo "Converting to $(_jq '.name'), Resolution: $resolution, Bitrate: $(_jq '.video_bitrate'), Framerate: $(_jq '.framerate')"

							# Make Framerate optional, don't modify the framerate if it is not set
							framerate=""
							if [ "$(_jq '.framerate')" != "null" ]
							then
								framerate=" -r $(_jq '.framerate')"
							fi

							# Convert
							$video_ffmpeg_path -i $file -b:v $(_jq '.video_bitrate') $framerate -c:v $(_jq '.video_codec') -vf scale=$resolution -c:a $(_jq '.audio_codec') -b:a $(_jq '.audio_bitrate') $file.out/$(basename "$file" "$file_format")_$(_jq '.name').$(_jq '.file_ending') &
						fi
					done

					# Wait until all formats are created
					wait

					# Cleanup: Remove the lockfile, move the original to the converted folder.
					mv $file $file.out/$(basename "$file" "$file_format")_orig"$file_format"
					rm $file.lock
					touch $file.out/$(basename "$file" "$file_format").done

					echo "Finished Converting $file"

				fi

				echo "================"
			fi
		fi
	done

	# Every 5 seconds...
	sleep 5s
done