hensei-api/app/services/preview_service/coordinator.rb

# app/services/preview/coordinator.rb
module PreviewService
  class Coordinator
    PREVIEW_FOLDER = 'previews'
    PREVIEW_WIDTH = 1200
    PREVIEW_HEIGHT = 630
    PREVIEW_EXPIRY = 30.days
    GENERATION_TIMEOUT = 5.minutes
    LOCAL_STORAGE_PATH = Rails.root.join('storage', 'party-previews')

    # Initialize the party preview service
    #
    # @param party [Party] The party to generate a preview for
    def initialize(party)
      @party = party
      @image_fetcher = ImageFetcherService.new(AwsService.new)
      @grid_service = Grid.new
      @canvas_service = Canvas.new(@image_fetcher)
      setup_storage
    end

    # Retrieves the URL for the party's preview image
    #
    # @return [String] A URL pointing to the party's preview image
    def preview_url
      if preview_exists?
        Rails.env.production? ? generate_s3_url : local_preview_url
      else
        schedule_generation unless generation_in_progress?
        default_preview_url
      end
    end

    # Generates a preview image for the party
    #
    # @return [Boolean] True if preview generation was successful, false otherwise
    def generate_preview
      return false unless should_generate?

      begin
        Rails.logger.info("Starting preview generation for party #{@party.id}")
        set_generation_in_progress

        # Generate the preview image
        image = create_preview_image
        save_preview(image)

        # Update party state
        @party.update!(
          preview_state: :generated,
          preview_generated_at: Time.current
        )
        true
      rescue => e
        handle_preview_generation_error(e)
        false
      ensure
        @image_fetcher.cleanup
        clear_generation_in_progress
      end
    end

    # Forces regeneration of the party's preview image
    #
    # @return [Boolean] Result of the preview generation attempt
    def force_regenerate
      delete_preview if preview_exists?
      generate_preview
    end

    # Deletes the existing preview image for the party
    def delete_preview
      if Rails.env.production?
        delete_s3_preview
      else
        delete_local_previews
      end

      @party.update!(
        preview_state: :pending,
        preview_generated_at: nil
      )
    rescue => e
      Rails.logger.error("Failed to delete preview for party #{@party.id}: #{e.message}")
    end

    private

    # Sets up the appropriate storage system based on environment
    def setup_storage
      # Always initialize AWS service for potential image fetching
      @aws_service = AwsService.new

      # Create local storage paths in development
      FileUtils.mkdir_p(LOCAL_STORAGE_PATH) unless Dir.exist?(LOCAL_STORAGE_PATH.to_s)
    end

    # Creates the preview image for the party
    #
    # @return [MiniMagick::Image] The generated preview image
    def create_preview_image
      # Create blank canvas
      canvas = @canvas_service.create_blank_canvas
      image = MiniMagick::Image.new(canvas.path)

      # Fetch job icon
      job_icon = nil
      if @party.job.present?
        job_icon = @image_fetcher.fetch_job_icon(@party.job.granblue_id)
      end

      # Add party name with job icon
      text_result = @canvas_service.add_text(image, @party.name, job_icon: job_icon, user: @party.user)
      image = text_result[:image]

      # Calculate grid layout
      grid_layout = @grid_service.calculate_layout(
        canvas_height: Canvas::PREVIEW_HEIGHT,
        title_bottom_y: text_result[:text_bottom_y]
      )

      # Organize and draw weapons
      image = organize_and_draw_weapons(image, grid_layout)

      image
    end

    # Adds the job icon to the preview image
    #
    # @param image [MiniMagick::Image] The base image
    # @param job_icon [MiniMagick::Image] The job icon to add
    # @return [MiniMagick::Image] The updated image
    def add_job_icon(image, job_icon)
      job_icon.resize '200x200'
      image.composite(job_icon) do |comp|
        comp.compose "Over"
        comp.geometry "+40+120"
      end
    end

    # Organizes and draws weapons on the preview image
    #
    # @param image [MiniMagick::Image] The base image
    # @return [MiniMagick::Image] The updated image with weapons
    def organize_and_draw_weapons(image, grid_layout)
      mainhand_weapon = @party.weapons.find(&:mainhand)
      grid_weapons = @party.weapons.reject(&:mainhand)

      # Draw mainhand weapon
      if mainhand_weapon
        weapon_image = @image_fetcher.fetch_weapon_image(mainhand_weapon.weapon, mainhand: true)
        image = @grid_service.draw_grid_item(image, weapon_image, 'mainhand', 0, grid_layout) if weapon_image
      end

      # Draw grid weapons
      grid_weapons.each_with_index do |weapon, idx|
        weapon_image = @image_fetcher.fetch_weapon_image(weapon.weapon)
        image = @grid_service.draw_grid_item(image, weapon_image, 'weapon', idx, grid_layout) if weapon_image
      end

      image
    end

    # Draws the mainhand weapon on the preview image
    #
    # @param image [MiniMagick::Image] The base image
    # @param weapon_image [MiniMagick::Image] The weapon image to add
    # @return [MiniMagick::Image] The updated image
    def draw_mainhand_weapon(image, weapon_image)
      target_size = Grid::GRID_CELL_SIZE * 1.5
      weapon_image.resize "#{target_size}x#{target_size}"

      image.composite(weapon_image) do |c|
        c.compose "Over"
        c.gravity "northwest"
        c.geometry "+150+150"
      end
    end

    # Saves the preview image to the appropriate storage system
    #
    # @param image [MiniMagick::Image] The image to save
    def save_preview(image)
      if Rails.env.production?
        upload_to_s3(image)
      else
        save_to_local_storage(image)
      end
    end

    # Uploads the preview image to S3
    #
    # @param image [MiniMagick::Image] The image to upload
    def upload_to_s3(image)
      temp_file = Tempfile.new(['preview', '.png'])
      begin
        image.write(temp_file.path)

        File.open(temp_file.path, 'rb') do |file|
          @aws_service.s3_client.put_object(
            bucket: S3_BUCKET,
            key: preview_key,
            body: file,
            content_type: 'image/png',
            acl: 'private'
          )
        end
      ensure
        temp_file.close
        temp_file.unlink
      end
    end

    # Saves the preview image to local storage
    #
    # @param image [MiniMagick::Image] The image to save
    def save_to_local_storage(image)
      # Remove any existing previews for this party
      Dir.glob(LOCAL_STORAGE_PATH.join("#{@party.shortcode}_*.png").to_s).each do |file|
        File.delete(file)
      end

      # Save new version
      image.write(local_preview_path)
    end

    # Generates a timestamped filename for the preview image
    #
    # @return [String] Filename in format "shortcode_YYYYMMDDHHMMSS.png"
    def preview_filename
      timestamp = Time.current.strftime('%Y%m%d%H%M%S')
      "#{@party.shortcode}_#{timestamp}.png"
    end

    # Returns the full path for storing preview images locally
    #
    # @return [Pathname] Full path where the preview image should be stored
    def local_preview_path
      LOCAL_STORAGE_PATH.join(preview_filename)
    end

    # Returns the URL for accessing locally stored preview images
    #
    # @return [String] URL path to access the preview image in development
    def local_preview_url
      latest_preview = Dir.glob(LOCAL_STORAGE_PATH.join("#{@party.shortcode}_*.png").to_s)
                          .max_by { |f| File.mtime(f) }
      return default_preview_url unless latest_preview

      "/party-previews/#{File.basename(latest_preview)}"
    end

    # Generates the S3 key for the party's preview image
    #
    # @return [String] The S3 object key for the preview image
    def preview_key
      "#{PREVIEW_FOLDER}/#{@party.shortcode}.png"
    end

    # Checks if a preview image exists for the party
    #
    # @return [Boolean] True if a preview exists, false otherwise
    def preview_exists?
      return false unless @party.preview_state == 'generated'

      if Rails.env.production?
        @aws_service.s3_client.head_object(bucket: S3_BUCKET, key: preview_key)
        true
      else
        !Dir.glob(LOCAL_STORAGE_PATH.join("#{@party.shortcode}_*.png").to_s).empty?
      end
    rescue Aws::S3::Errors::NotFound
      false
    end

    # Generates a pre-signed S3 URL for the preview image
    #
    # @return [String] A pre-signed URL to access the preview image
    def generate_s3_url
      signer = Aws::S3::Presigner.new(client: @aws_service.s3_client)
      signer.presigned_url(
        :get_object,
        bucket: S3_BUCKET,
        key: preview_key,
        expires_in: 1.hour
      )
    end

    # Determines if a new preview should be generated
    #
    # @return [Boolean] True if a new preview should be generated, false otherwise
    def should_generate?
      return false if generation_in_progress?
      return true if @party.preview_state.in?(['pending', 'failed'])

      if @party.preview_state == 'generated'
        return @party.preview_generated_at < PREVIEW_EXPIRY.ago
      end

      false
    end

    # Checks if a preview generation is currently in progress
    #
    # @return [Boolean] True if a preview is being generated, false otherwise
    def generation_in_progress?
      Rails.cache.exist?("party_preview_generating_#{@party.id}")
    end

    # Marks the preview generation as in progress
    def set_generation_in_progress
      Rails.cache.write(
        "party_preview_generating_#{@party.id}",
        true,
        expires_in: GENERATION_TIMEOUT
      )
    end

    # Clears the in-progress flag for preview generation
    def clear_generation_in_progress
      Rails.cache.delete("party_preview_generating_#{@party.id}")
    end

    # Schedules a background job to generate the preview
    def schedule_generation
      GeneratePartyPreviewJob
        .set(wait: 30.seconds)
        .perform_later(@party.id)

      @party.update!(preview_state: :queued)
    end

    # Provides a default preview URL based on party attributes
    #
    # @return [String] A URL to a default preview image
    def default_preview_url
      if @party.element.present?
        "/default-previews/#{@party.element}.png"
      else
        "/default-previews/default.png"
      end
    end

    # Deletes the preview from S3
    def delete_s3_preview
      @aws_service.s3_client.delete_object(
        bucket: S3_BUCKET,
        key: preview_key
      )
    end

    # Deletes local preview files
    def delete_local_previews
      Dir.glob(LOCAL_STORAGE_PATH.join("#{@party.shortcode}_*.png").to_s).each do |file|
        File.delete(file)
      end
    end

    # Handles errors during preview generation
    #
    # @param error [Exception] The error that occurred
    def handle_preview_generation_error(error)
      Rails.logger.error("Preview generation failed for party #{@party.id}")
      Rails.logger.error("Error: #{error.class} - #{error.message}")
      Rails.logger.error("Backtrace:\n#{error.backtrace.join("\n")}")
      @party.update!(preview_state: :failed)
    end
  end
end