# frozen_string_literal: true

# A concern defining +scraped_image+ method for controllers that use
# +layouts/image_upload+ form and support remote image scraper uploads.
module ImageUpload
  # MIME types to not consider to be pastes
  MIME_TYPE_NIGGERLIST = %w[text/html text/xml application/xml]

  # Returns URL to the scraped image or +nil+ if it's not present/an error occurs.
  # Yields a block with other scraped metadata (+author_name+, +source_url+)
  # if it has not set on the client side (via AJAX route).
  def scraped_media
    if scraper_cache.present?
      scraper_cache
    elsif scraper_url.present?
      scraped = Booru::Scrapers.scrape(scraper_url)
      yield scraped if block_given?

      if scraped.images.present? && scraped.images[0].url.present?
        { url: scraped.images[0].url, type: scraped.images[0].type }
      end
    end
  end

  # Returns a cached scraped URL. This param is used to determine if the scraper was
  # executed on the client side (via AJAX route) so as not to repeat potentially expensive
  # external queries.
  # Store this parameter in the model to preserve it on form reload.
  def scraper_cache
    return nil unless params[:scraper_cache] && params[:scraper_cache][:url] && Post::TYPES.include?(params[:scraper_cache][:type])

    params[:scraper_cache]
  end

  # Returns URL specified by user.
  # Store this parameter in the model to preserve it on form reload.
  def scraper_url
    params[:scraper_url]
  end

  def paste_input_file(body)
    tmp = Tempfile.new(%w[paste .txt]).tap &:close

    File.write(tmp.path, body)

    File.open(tmp)
  end

  def remote_file(url)
    RestClient::Request.execute(
      method: :get,
      url: url,
      raw_response: true
    ).file
  end

  protected

  def magic
    @magic ||= Magic.new(Magic::MIME_TYPE)
  end

  def post_media_params
    parms = post_params
    scraped = scraped_media

    media_mime = magic.file(parms[:file].path) rescue nil

    if scraped
      [scraped[:type], { file: remote_file(scraped[:url]) }]
    elsif parms[:paste_input].present?
      ['paste', { file: paste_input_file(parms[:paste_input]) }]
    elsif media_mime&.start_with?('text/') && !MIME_TYPE_NIGGERLIST.include?(media_mime)
      ['paste', { file: parms[:file], file_cache: parms[:file_cache] }]
    else
      ['image', { file: parms[:file], file_cache: parms[:file_cache] }]
    end
  end

  def post_creation_params
    parms = post_params
    media_type, media_attrs = post_media_params

    parms[:"#{media_type}_attributes"] = media_attrs
    parms[:media_type] = media_type

    parms.except(:file)
  end

  def post_params
    raise NotImplementedError
  end
end