require 'fileutils'
require 'RMagick'
require 'streamio-ffmpeg'

class Turmeric
  DEFAULT_OPTIONS = {
    tmp_dir: "./tmp/",
    resolution: "200x100",
    duration: ->(movie){ movie.duration.to_i.times }
  }.freeze

  attr_accessor :tmp_dir, :resolution, :duration
  attr_reader :frames

  def initialize(filename, **options)
    @movie = FFMPEG::Movie.new(filename)
    reset(**options)
  end

  def reset(**options)
    @frames = []
    @tmp_dir = options[:tmp_dir] || DEFAULT_OPTIONS[:tmp_dir]
    @resolution = options[:resolution] || DEFAULT_OPTIONS[:resolution]
    @duration = options[:duration] || DEFAULT_OPTIONS[:duration]
  end

  def logger
    FFMPEG.logger
  end

  def logger=(logger)
    FFMPEG.logger = logger
  end

  def screenshot(path, **options)
    @movie.screenshot(path, resolution: resolution,  **options)
  end

  def ensure_output_directory
    FileUtils.mkdir_p(tmp_dir)
  end

  def to_animation(output_file = "result.gif")
    ensure_output_directory unless File.exist?(tmp_dir)
    each_duration do |second|
      path = "#{tmp_dir}#{second}.png"
      begin
        screenshot(path, seek_time: second)
      ensure
        frames << path
      end
    end
    Magick::ImageList.new(*frames).coalesce.write(output_file)
  ensure
    FileUtils.rm(Dir.glob(File.join(tmp_dir, "*")))
  end
  alias to_anime to_animation

  def each_duration(&block)
    if @duration.respond_to?(:call)
      @duration.call @movie
    else
      @duration.instance_of?(Range) ? @duration : @duration.times
    end.each(&block)
  end
end