#!/bin/bash

# Script to transcode all missing Bluray Movies/Shows from Raw/ to Transcode/ using HandBrakeCLI.
# Usage: transcode-incremental <category> <preset> <output-folder-name>
#  category: "Movies" or "Shows", or more specific ("Shows/Bluey (2018)")
#  preset: "5SE3v3", "AHE3", or handbrake-presets file/preset name.

# Setup:
# - Install HandBrake (from Flatpak 'Flathub' repository for recent builds; can use 'apt install', but builds are old.)
#  - Fix 'HandBrakeCLI' variable below to run your desired HandBrakeCLI version.
# - apt install mkvtoolnix (for mkvpropedit)
# - Fix 'sourceDir' and 'targetDir' paths below to match your media locations

shopt -s nullglob
scriptPath="$(dirname "$0")"

# Run HandBrakeCLI version in the Flatpak (easy current builds instead of old one from apt install)
HandBrakeCLI="flatpak run --command=HandBrakeCLI fr.handbrake.ghb"

category="${1:-Movies}"
preset="${2:-5SE3v3}"
outFolderName="${3:-Blurays}"

sourceDir="/media/scott/Expansion/Raw/Blurays/$category"
targetDir="/media/video/Transcoded/$outFolderName/$category"

echo "Transcoding '$category/' using '$preset'..."
echo "  FROM: $sourceDir"
echo "  TO:   $targetDir"
echo

# Find all MKV files under source directory
#  'mapfile' is used to allow redirecting stdout in the loop without consuming the rest of the files to loop on)
mapfile -d $'\0' files < <(find "$sourceDir" -type f -name "*.mkv" -print0)
for file in "${files[@]}"; do
    # Get input file name without extension    
    fileName=$(basename "$file" .mkv)

    # Calculate corresponding output directory
    folderPath=$(dirname "$file")
    pathUnderShows=${folderPath#"$sourceDir/"}
    outDir="$targetDir/$pathUnderShows"
    outFile="$outDir/$fileName - $preset.mkv"

    # Transcode to a temporary name first
    outTemp="$outDir/$fileName - Temp.mkv"

    # If the output video doesn't exist...
    if [ -f "$outFile" ]; then
        echo "EXISTS: '$fileName'"
    else
        echo
        echo "TRANSCODE: '$fileName'"
        echo "  FROM: $file"
        echo "  TO:   $outFile"

        mkdir -p "$outDir"

        # Transcode it, hiding all output except transcode progress
        $HandBrakeCLI --preset-import-file "$scriptPath/handbrake-presets/$preset.json" -Z "$preset" -i "$file" -o "$outTemp" 2> "$outDir/Current.log"
        
        # Recompute statistics on the result (otherwise stream size metadata tags are wrong)
        mkvpropedit "$outTemp" --add-track-statistics-tags
        
        # Rename output to the final file name only when done
        #  (so interrupting and re-running the script will redo partially completed transcodes correctly)
        mv "$outTemp" "$outFile"

        echo
    fi
done