# frozen_string_literal: true
require_relative 'shell_helper'

module Booru
  module ImageProcessing
    class GifProcessor < Processor
      include ShellHelper

      def initialize(original_path, directory, metadata)
        super(original_path, directory, metadata)

        # We keep around references to the Tempfile objects so that they don't get GC'd (and deleted) too early.
        @palette_tempfile = Tempfile.new(%w[palette .png]).tap(&:close)
        @palette_path = @palette_tempfile.path

        @rasterized_tempfile = Tempfile.new(%w[still .png]).tap(&:close)
        @rasterized = @rasterized_tempfile.path

        # @palette_path = File.join(@directory, 'palette.png')
        # @rasterized = File.join(@directory, 'still.png')
      end

      def pre_process
        write_log 'pre_process'

        # generate a palette for use in later processing
        ffmpeg '-i', @original_path,
               '-vf', 'palettegen=stats_mode=diff',
               @palette_path

        generate_rasterized
      end

      def generate_rasterized
        # generate a still image for use in intensities generation
        median_time = @metadata[:duration] / 2.0
        generate_thumb @original_path, median_time, @rasterized
      end

      def generate_version(dimensions, destination_path)
        write_log "generate_version #{dimensions} #{destination_path}"

        width, height = dimensions

        # okay, this is a little bit fucking complicated, I will give you that.
        # https://engineering.giphy.com/how-to-make-gifs-with-ffmpeg/
        # TL;DR: It's a big ol' pipeline that resizes the image and uses a palette when resizing it (this makes a better looking gif, somehow),
        ffmpeg '-i', @original_path,
               '-i', @palette_path,
               '-filter_complex', "scale=w=#{width}:h=#{height}:force_original_aspect_ratio=decrease [x]; [x][1:v] paletteuse=dither=bayer:bayer_scale=5:diff_mode=rectangle:alpha_threshold=255",
               destination_path
      end

      # def generate_compressed_version(dimensions, destination_path)
      #   write_log "generate_compressed_version #{dimensions} #{destination_path}"
      #
      #   width, height = dimensions
      #
      #   ffmpeg '-i', @original_path,
      #          '-i', @palette_path,
      #          '-filter_complex', "scale=w=#{width}:h=#{height}:force_original_aspect_ratio=decrease [x]; [x][1:v] paletteuse=dither=bayer:bayer_scale=5:diff_mode=rectangle:alpha_threshold=255",
      #          '-vcodec', 'libwebp',
      #          '-lossless', '0',
      #          '-vsync', '0',
      #          '-loop', '0',
      #          destination_path
      # end

      def post_process
        write_log 'post_process'

        # clean up the palette we generated
        FileUtils.rm(@palette_path)
        # clean up still image
        FileUtils.rm(@rasterized)
      end

      def additional_process
        write_log 'additional_process'
        output_file = "#{@directory}/full.webm"

        # Generate full WebM from original gif
        ffmpeg '-f', 'gif',
               '-i', @original_path,
               '-pix_fmt', 'yuv420p',
               '-c:v', 'libvpx',
               '-quality', 'good',
               '-cpu-used', '0',
               '-crf', '6',
               '-b:v', '1M',
               '-r', '25',
               '-an', output_file
      end
    end
  end
end