class UploadService
  module ControllerHelper
    def self.prepare(url, ref = nil)
      upload = Upload.new

      if url
        Preprocessor.new(source: url).delay(queue: "default").start!(CurrentUser.user.id)

        download = Downloads::File.new(url)
        normalized_url, _, _ = download.before_download(url, {})
        post = if normalized_url.nil?
          Post.where("SourcePattern(lower(posts.source)) = ?", url).first
        else
          Post.where("SourcePattern(lower(posts.source)) IN (?)", [url, normalized_url]).first
        end

        begin
          source = Sources::Site.new(url, :referer_url => ref)
          remote_size = download.size
        rescue Exception
        end

        return [upload, post, source, normalized_url, remote_size]
      end

      return [upload]
    end

    def self.batch(url, ref = nil)
      if url
        source = Sources::Site.new(url, :referer_url => ref)
        source.get
        return source
      end
    end
  end

  module Utils
    def self.file_header_to_file_ext(file)
      case File.read(file.path, 16)
      when /^\xff\xd8/n
        "jpg"
      when /^GIF87a/, /^GIF89a/
        "gif"
      when /^\x89PNG\r\n\x1a\n/n
        "png"
      when /^CWS/, /^FWS/, /^ZWS/
        "swf"
      when /^\x1a\x45\xdf\xa3/n
        "webm"
      when /^....ftyp(?:isom|3gp5|mp42|MSNV|avc1)/
        "mp4"
      when /^PK\x03\x04/
        "zip"
      else
        "bin"
      end
    end

    def self.delete_file(md5, file_ext)
      if Post.where(md5: md5).exists?
        return
      end

      Danbooru.config.storage_manager.delete_file(nil, md5, file_ext, :original)
      Danbooru.config.storage_manager.delete_file(nil, md5, file_ext, :large)
      Danbooru.config.storage_manager.delete_file(nil, md5, file_ext, :preview)
      Danbooru.config.backup_storage_manager.delete_file(nil, md5, file_ext, :original)
      Danbooru.config.backup_storage_manager.delete_file(nil, md5, file_ext, :large)
      Danbooru.config.backup_storage_manager.delete_file(nil, md5, file_ext, :preview)
    end

    def self.calculate_ugoira_dimensions(source_path)
      folder = Zip::File.new(source_path)
      Tempfile.open("ugoira-dim-") do |tempfile|
        folder.first.extract(tempfile.path) { true }
        image_size = ImageSpec.new(tempfile.path)
        return [image_size.width, image_size.height]
      end
    end

    def self.calculate_dimensions(upload, file)
      if upload.is_video?
        video = FFMPEG::Movie.new(file.path)
        yield(video.width, video.height)

      elsif upload.is_ugoira?
        w, h = calculate_ugoira_dimensions(file.path)
        yield(w, h)

      else
        image_size = ImageSpec.new(file.path)
        yield(image_size.width, image_size.height)
      end
    end

    def self.distribute_files(file, record, type)
      [Danbooru.config.storage_manager, Danbooru.config.backup_storage_manager].each do |sm|
        sm.store_file(file, record, type)
      end
    end

    def self.is_downloadable?(source)
      source.match?(/^https?:\/\//)
    end

    def self.generate_resizes(file, upload)
      if upload.is_video?
        video = FFMPEG::Movie.new(file.path)
        preview_file = generate_video_preview_for(video, Danbooru.config.small_image_width, Danbooru.config.small_image_width)

      elsif upload.is_ugoira?
        preview_file = PixivUgoiraConverter.generate_preview(file)
        sample_file = PixivUgoiraConverter.generate_webm(file, upload.context["ugoira"]["frame_data"])

      elsif upload.is_image?
        preview_file = DanbooruImageResizer.resize(file, Danbooru.config.small_image_width, Danbooru.config.small_image_width, 85)

        if upload.image_width > Danbooru.config.large_image_width
          sample_file = DanbooruImageResizer.resize(file, Danbooru.config.large_image_width, upload.image_height, 90)
        end
      end

      [preview_file, sample_file]
    end

    def self.generate_video_preview_for(video, width, height)
      dimension_ratio = video.width.to_f / video.height
      if dimension_ratio > 1
        height = (width / dimension_ratio).to_i
      else
        width = (height * dimension_ratio).to_i
      end

      output_file = Tempfile.new(binmode: true)
      video.screenshot(output_file.path, {:seek_time => 0, :resolution => "#{width}x#{height}"})
      output_file
    end

    def self.process_file(upload, file)
      upload.file = file
      upload.file_ext = Utils.file_header_to_file_ext(file)
      upload.file_size = file.size
      upload.md5 = Digest::MD5.file(file.path).hexdigest

      Utils.calculate_dimensions(upload, file) do |width, height|
        upload.image_width = width
        upload.image_height = height
      end

      upload.tag_string = "#{upload.tag_string} #{Utils.automatic_tags(upload, file)}"

      preview_file, sample_file = Utils.generate_resizes(file, upload)

      begin
        Utils.distribute_files(file, upload, :original)
        Utils.distribute_files(sample_file, upload, :large) if sample_file.present?
        Utils.distribute_files(preview_file, upload, :preview) if preview_file.present?
      ensure
        preview_file.try(:close!)
        sample_file.try(:close!)
      end

      # in case this upload never finishes processing, we need to delete the
      # distributed files in the future
      Danbooru.config.other_server_hosts.each do |host|
        UploadService::Utils.delay(queue: host, run_at: 10.minutes.from_now).delete_file(upload.md5, upload.file_ext)
      end
    end

    # these methods are only really used during upload processing even 
    # though logically they belong on upload. post can rely on the 
    # automatic tag that's added.
    def self.is_animated_gif?(upload, file)
      return false if upload.file_ext != "gif"

      # Check whether the gif has multiple frames by trying to load the second frame.
      result = Vips::Image.gifload(file.path, page: 1) rescue $ERROR_INFO
      if result.is_a?(Vips::Image)
        true
      elsif result.is_a?(Vips::Error) && result.message =~ /too few frames in GIF file/
        false
      else
        raise result
      end
    end

    def self.is_animated_png?(upload, file)
      upload.file_ext == "png" && APNGInspector.new(file.path).inspect!.animated?
    end

    def self.is_video_with_audio?(upload, file)
      video = FFMPEG::Movie.new(file.path)
      upload.is_video? && video.audio_channels.present?
    end

    def self.automatic_tags(upload, file)
      return "" unless Danbooru.config.enable_dimension_autotagging

      tags = []
      tags << "video_with_sound" if is_video_with_audio?(upload, file)
      tags << "animated_gif" if is_animated_gif?(upload, file)
      tags << "animated_png" if is_animated_png?(upload, file)
      tags.join(" ")
    end
  end

  class Preprocessor
    attr_reader :params

    def initialize(params)
      @params = params
    end

    def source
      params[:source]
    end

    def in_progress?
      Upload.where(status: "preprocessing", source: source).exists?
    end

    def predecessor
      Upload.where(status: ["preprocessed", "preprocessing"], source: source).first
    end

    def completed?
      predecessor.present?
    end

    def start!(uploader_id)
      if !Utils.is_downloadable?(source)
        return
      end

      if Post.where(source: source).exists?
        return
      end

      if Upload.where(source: source, status: "completed").exists?
        return
      end

      if Upload.where(source: source).where("status like ?", "error%").exists?
        return
      end

      params[:rating] ||= "q"
      params[:tag_string] ||= "tagme"

      CurrentUser.as(User.find(uploader_id)) do
        upload = Upload.create!(params)

        upload.update(status: "preprocessing")

        begin
          file = download_from_source(source, referer_url: upload.referer_url) do |context|
            upload.downloaded_source = context[:downloaded_source]
            upload.source = context[:source]

            if context[:ugoira]
              upload.context = { ugoira: context[:ugoira] }
            end
          end

          Utils.process_file(upload, file)

          upload.rating = params[:rating]
          upload.tag_string = params[:tag_string]
          upload.status = "preprocessed"
          upload.save!
        rescue Exception => x
          upload.update(status: "error: #{x.class} - #{x.message}", backtrace: x.backtrace.join("\n"))
        end

        return upload
      end
    end

    def finish!
      pred = self.predecessor()
      pred.attributes = self.params
      pred.status = "completed"
      pred.save
      return pred
    end

    def download_from_source(source, referer_url: nil)
      download = Downloads::File.new(source, referer_url: referer_url)
      file = download.download!
      context = {
        downloaded_source: download.downloaded_source,
        source: download.source
      }

      if download.data[:is_ugoira]
        context[:ugoira] = {
          frame_data: download.data[:ugoira_frame_data],
          content_type: download.data[:ugoira_content_type]
        }
      end

      yield(context)

      return file
    end
  end

  attr_reader :params, :post, :upload

  def initialize(params)
    @params = params
  end

  def start!
    preprocessor = Preprocessor.new(params)

    if preprocessor.in_progress?
      delay(queue: "default", run_at: 5.seconds.from_now).start!
      return preprocessor.predecessor
    end

    if preprocessor.completed?
      @upload = preprocessor.finish!
      create_post_from_upload(@upload)
      return @upload
    end

    params[:rating] ||= "q"
    params[:tag_string] ||= "tagme"
    @upload = Upload.create!(params)

    begin
      if @upload.invalid?
        return @upload
      end

      @upload.update(status: "processing")

      if @upload.file.present?
        Utils.process_file(upload, @upload.file)
      else
        # sources will be handled in preprocessing now
      end

      @upload.save!
      @post = create_post_from_upload(@upload)
      return @upload

    rescue Exception => x
      @upload.update(status: "error: #{x.class} - #{x.message}", backtrace: x.backtrace.join("\n"))
      @upload
    end
  end

  def warnings
    return [] if @post.nil?
    return @post.warnings.full_messages
  end

  def source
    params[:source]
  end

  def include_artist_commentary?
    params[:include_artist_commentary].to_s.truthy?
  end

  def create_post_from_upload(upload)
    @post = convert_to_post(upload)
    @post.save!

    @upload.update(status: "error: " + @post.errors.full_messages.join(", "))

    if upload.context && upload.context["ugoira"]
      PixivUgoiraFrameData.create(
        post_id: @post.id,
        data: upload.context["ugoira"]["frame_data"],
        content_type: upload.context["ugoira"]["content_type"]
      )
    end

    if include_artist_commentary?
      @post.create_artist_commentary(
        :original_title => params[:artist_commentary_title],
        :original_description => params[:artist_commentary_desc]
      )
    end

    notify_cropper(@post) if ImageCropper.enabled?
    upload.update(status: "completed", post_id: @post.id)
    @post
  end

  def convert_to_post(upload)
    Post.new.tap do |p|
      p.tag_string = upload.tag_string
      p.md5 = upload.md5
      p.file_ext = upload.file_ext
      p.image_width = upload.image_width
      p.image_height = upload.image_height
      p.rating = upload.rating
      p.source = upload.source
      p.file_size = upload.file_size
      p.uploader_id = upload.uploader_id
      p.uploader_ip_addr = upload.uploader_ip_addr
      p.parent_id = upload.parent_id

      if !upload.uploader.can_upload_free? || upload.upload_as_pending?
        p.is_pending = true
      end
    end
  end

  def notify_cropper(post)
    # ImageCropper.notify(post)
  end
end