module SiteIconManager
  extend GlobalPath

  @cache = DistributedCache.new('icon_manager')

  SKETCH_LOGO_ID = -6

  ICONS = {
    digest_logo: { width: nil, height: nil, settings: [:digest_logo, :logo], fallback_to_sketch: false, resize_required: false },
    mobile_logo: { width: nil, height: nil, settings: [:mobile_logo, :logo], fallback_to_sketch: false, resize_required: false },
    large_icon: { width: nil, height: nil, settings: [:large_icon, :logo_small], fallback_to_sketch: true, resize_required: false },
    manifest_icon: { width: 512, height: 512, settings: [:manifest_icon, :large_icon, :logo_small], fallback_to_sketch: true, resize_required: true },
    favicon: { width: 32, height: 32, settings: [:favicon, :large_icon, :logo_small], fallback_to_sketch: true, resize_required: false },
    apple_touch_icon: { width: 180, height: 180, settings: [:apple_touch_icon, :large_icon, :logo_small], fallback_to_sketch: true, resize_required: false },
    opengraph_image: { width: nil, height: nil, settings: [:opengraph_image, :large_icon, :logo_small, :logo], fallback_to_sketch: true, resize_required: false },
  }

  WATCHED_SETTINGS = ICONS.keys + [:logo, :logo_small]

  def self.ensure_optimized!
    unless @disabled
      ICONS.each do |name, info|
        icon = resolve_original(info)

        if info[:height] && info[:width]
          OptimizedImage.create_for(icon, info[:width], info[:height])
        end
      end
    end
    @cache.clear
  end

  ICONS.each do |name, info|
    define_singleton_method(name) do
      icon = resolve_original(info)
      if info[:height] && info[:width]
        result = OptimizedImage.find_by(upload: icon, height: info[:height], width: info[:width])
      end
      result = icon if !result && !info[:resize_required]
      result
    end

    define_singleton_method("#{name}_url") do
      get_set_cache("#{name}_url") do
        icon = self.public_send(name)
        icon ? full_cdn_url(icon.url) : ''
      end
    end
  end

  # Used in test mode
  def self.disable
    @disabled = true
  end

  def self.enable
    @disabled = false
  end

  private

  def self.get_set_cache(key)
    @cache[key] ||= yield
  end

  def self.resolve_original(info)
    info[:settings].each do |setting_name|
      value = SiteSetting.send(setting_name)
      return value if value
    end
    return Upload.find(SKETCH_LOGO_ID) if info[:fallback_to_sketch]
    nil
  end

end