#!/bin/bash
IFS=' '

root_directories='/mnt/hosts/nas/media/movies/ /mnt/hosts/nas/media/tv/ /mnt/hosts/nas/media/anime/'
min_file_size=$((1024**2*400)) #400 MiB - smallest file size to consider for transcoding
max_file_bit_rate=$((1024**3*10*8/90/60)) #5GiB * 8 bits per byte / 90 mins / 60 secs per min = 7767 Kibps
max_video_bit_depth=8
allowed_video_codecs='avc1 V_MPEG4/ISO/AVC V_VP8 XVID DIVX'
ffmpeg_timeout_multiplier=5 #multiply by video duration to get ffmpeg timeout
ffmpeg_timeout_minimum=$((60*1)) #1 minute - in case $min_file_size is very small
ffmpeg_timeout_maximum=$((60*60*6)) #6 hours
transcode_directory='/mnt/transcode/'

target_file_bitrate=$((1024**3*3*8/90/60)) #3GiB * 8 bits per byte / 90 mins / 60 secs per min = 4660 Kibps

kodi_url='http://127.0.0.1:8080/jsonrpc'
kodi_json_scan='{"jsonrpc":"2.0","id":1,"method":"VideoLibrary.Scan"}'

log_file='/mnt/hosts/nas/files/scripts/media/media-transcode.log'
history_file='/mnt/hosts/nas/files/scripts/media/media-transcode.history'

required_binaries='find mktemp mediainfo xpath awk timeout ffmpeg curl cat'

for required_binary in $required_binaries
do
    which "$required_binary" > /dev/null
    if [ $? -ne 0 ]
    then
        echo "$required_binary was not found. Exiting"
        exit 1
    fi
done

if [ ! -f "$log_file" ]
then
    echo "Result,Timestamp,Bitrate,Bitdepth,Codec,Duration,Filename" > "$log_file"
fi

rm -rf "$transcode_directory*"

while [ true ]
do
    for root_directory in $root_directories
    do
        IFS='
    '
        for file in $(find "$root_directory" -type f -size +${min_file_size}c -exec ls -S1 {} +) #sort by size descending
        do
            IFS=' '
            # don't start a new transcode between 22:00 and 07:00
            # while [ $(date +%k) -ge 22 ] || [ $(date +%k) -lt 7 ]
            # do
            #   sleep 15m
            # done
            echo $file
            mediainfo_file=$(mktemp)
            # echo $mediainfo_file
            mediainfo "$file" --Output=XML > "$mediainfo_file"
            # ints as strings. convert further down
            file_bit_rate=$(xpath -q -e 'MediaInfo/media/track[@type="General"]/OverallBitRate/text()' $mediainfo_file )
            file_duration=$(xpath -q -e 'MediaInfo/media/track[@type="General"]/Duration/text()' $mediainfo_file )
            file_frames=$(xpath -q -e 'MediaInfo/media/track[@type="General"]/FrameCount/text()' $mediainfo_file )
            file_size=$(xpath -q -e 'MediaInfo/media/track[@type="General"]/FileSize/text()' $mediainfo_file )
            video_bit_depth=$(xpath -q -e 'MediaInfo/media/track[@type="Video"]/BitDepth/text()' $mediainfo_file )

            file_frame_rate=$(xpath -q -e 'MediaInfo/media/track[@type="General"]/FrameRate/text()' $mediainfo_file ) #want to preserve decimals - keep as string
            video_codec=$(xpath -q -e 'MediaInfo/media/track[@type="Video"]/CodecID/text()' $mediainfo_file )

            rm "$mediainfo_file"

            #convert to integers so that we can use them for maths
            file_bit_rate=$(echo $file_bit_rate | awk '{print int($1+0.5)}')
            file_duration=$(echo $file_duration | awk '{print int($1+0.5)}')
            file_frames=$(echo $file_frames | awk '{print int($1+0.5)}')
            file_size=$(echo $file_size | awk '{print int($1+0.5)}')
            if [ "$video_bit_depth" = '' ] # not all formats (webm) expose the bit depth and mediainfo doesn't seem to return a useful exit code
            then
                video_bit_depth=8
            else
                video_bit_depth=$(echo $video_bit_depth | awk '{print int($1+0.5)}')
            fi

            echo "Rate $((file_bit_rate/1024/1024))Mibps / $((file_bit_rate/1024))Kibps"
            echo "Max  $(($max_file_bit_rate/1024/1024))Mibps / $(($max_file_bit_rate/1024))Kibps"
            echo "$video_bit_depth bit $video_codec"
            echo "$(($file_duration/60))m / ${file_duration}s"
            echo "$file_frames frames @ ${file_frame_rate}fps"
            echo "$((file_size/1024/1024/1024))GiB / $((file_size/1024/1024))MiB"

            echo " $allowed_video_codecs " | grep -q " $video_codec "
            if [ $? -eq 0 ] #contains operator
            then
                bad_codec=false
            else
                bad_codec=true
            fi

            if [ $file_bit_rate -gt $max_file_bit_rate ] || [ $video_bit_depth -gt $max_video_bit_depth ] || [ $bad_codec = true ]
            then

                previously_transcoded=false
                for history_item in $(cat "$history_file" 2> /dev/null)
                do
                    if [ "$history_item" = "$file" ]
                    then
                        previously_transcoded=true
                        break
                    fi
                done

                if [ $previously_transcoded = true ]
                then
                    echo "Error: File has already been transcoded"
                    echo "repeat,$(date +%Y-%m-%d-%H:%M:%S),$file_bit_rate,$video_bit_depth,$video_codec,$file_duration,$file" >> "$log_file"
                else
                    echo "Transcoding"
                    timeout=$(($file_duration*$ffmpeg_timeout_multiplier))
                    if [ $timeout -le $ffmpeg_timeout_minimum ]
                    then
                        timeout=$ffmpeg_timeout_minimum
                    elif [ $timeout -ge $ffmpeg_timeout_maximum ]
                    then
                        timeout=$ffmpeg_timeout_maximum
                    fi
                    filename=$(basename "$file")
                    #ffmpeg's built-in -timeout is finicky
                    timeout --foreground $timeout ffmpeg -loglevel warning -hide_banner -stats -y -i "$file" -bitrate $(($target_file_bitrate/1024)) -c:v libx264 -preset medium -tune film -c:a copy -threads 0 "$transcode_directory${filename%.*}.mkv"
                    if [ $? -eq 0 ]
                    then
                        echo "Transcode sucessful"
                        rm "$file"
                        mv "$transcode_directory${filename%.*}.mkv" "${file%.*}.mkv"
                        echo "transcoded,$(date +%Y-%m-%d-%H:%M:%S),$file_bit_rate,$video_bit_depth,$video_codec,$file_duration,$file" >> "$log_file"
                        echo "$file" >> "$history_file"
                        curl -X POST $kodi_url -d $kodi_json_scan
                    else
                        echo "Transcode failed"
                        rm "$transcode_directory${filename%.*}.mkv"
                        echo "failed,$(date +%Y-%m-%d-%H:%M:%S),$file_bit_rate,$video_bit_depth,$video_codec,$file_duration,$file" >> "$log_file"
                    fi
                fi
            else
                echo "No need to transcode"
                echo "skipped,$(date +%Y-%m-%d-%H:%M:%S),$file_bit_rate,$video_bit_depth,$video_codec,$file_duration,$file" >> "$log_file"
            fi
        done
        IFS=' '
    done
    sleep 60m
done