# frozen_string_literal: true

module Migrations::Uploader
  module Tasks
    class Optimizer < Base
      def initialize(databases, settings)
        super(databases, settings)

        initialize_existing_ids_tracking_sets
        initialize_discourse_resources
        @max_count = 0
      end

      def run!
        puts "", "Creating optimized images..."

        disable_optimized_image_lock

        start_tracking_sets_loader_threads.each(&:join)
        status_thread = start_status_thread
        consumer_threads = start_consumer_threads
        producer_thread = start_producer_thread

        producer_thread.join
        work_queue.close
        consumer_threads.each(&:join)
        status_queue.close
        status_thread.join
      end

      private

      def initialize_existing_ids_tracking_sets
        @optimized_upload_ids = Set.new
        @post_upload_ids = Set.new
        @avatar_upload_ids = Set.new
      end

      def initialize_discourse_resources
        @avatar_sizes = Discourse.avatar_sizes
        @system_user = Discourse.system_user
        @category_id = Category.last.id
      end

      def disable_optimized_image_lock
        # allow more than 1 thread to optimized images at the same time
        OptimizedImage.lock_per_machine = false
      end

      def start_tracking_sets_loader_threads
        [
          start_optimized_upload_ids_loader_thread,
          start_post_upload_ids_loader_thread,
          start_avatar_upload_ids_loader_thread,
          start_max_count_loader_thread,
        ]
      end

      def handle_status_update(params)
        @current_count += 1

        case params.delete(:status)
        when :ok
          uploads_db.insert(<<~SQL, params)
            INSERT INTO optimized_images (id, optimized_images)
            VALUES (:id, :optimized_images)
          SQL
        when :error
          @error_count += 1
        when :skipped
          @skipped_count += 1
        end
      end

      def start_optimized_upload_ids_loader_thread
        Thread.new do
          @uploads_db
            .db
            .query("SELECT id FROM optimized_images") { |row| @optimized_upload_ids << row[:id] }
        end
      end

      def start_post_upload_ids_loader_thread
        Thread.new do
          sql = <<~SQL
          SELECT upload_ids
            FROM posts
           WHERE upload_ids IS NOT NULL
        SQL

          @intermediate_db
            .db
            .query(sql) { |row| JSON.parse(row[:upload_ids]).each { |id| @post_upload_ids << id } }
        end
      end

      def start_avatar_upload_ids_loader_thread
        Thread.new do
          sql = <<~SQL
          SELECT avatar_upload_id
            FROM users
           WHERE avatar_upload_id IS NOT NULL
        SQL

          @intermediate_db.db.query(sql) { |row| @avatar_upload_ids << row[:avatar_upload_id] }
        end
      end

      def start_max_count_loader_thread
        Thread.new do
          @max_count =
            @uploads_db.db.query_single_splat(
              "SELECT COUNT(*) FROM uploads WHERE upload IS NOT NULL",
            )
        end
      end

      def enqueue_jobs
        sql = <<~SQL
            SELECT id AS upload_id, upload ->> 'sha1' AS upload_sha1, markdown
              FROM uploads
             WHERE upload IS NOT NULL
             ORDER BY rowid
          SQL

        @uploads_db
          .db
          .query(sql) do |row|
            upload_id = row[:upload_id]

            if @optimized_upload_ids.include?(upload_id) || !row[:markdown].start_with?("![")
              status_queue << { id: row[:upload_id], status: :skipped }
              next
            end

            if @post_upload_ids.include?(upload_id)
              row[:type] = "post"
              work_queue << row
            elsif @avatar_upload_ids.include?(upload_id)
              row[:type] = "avatar"
              work_queue << row
            else
              status_queue << { id: row[:upload_id], status: :skipped }
            end
          end
      end

      def start_consumer_threads
        Jobs.run_immediately!

        super
      end

      def log_status
        error_count_text = error_count > 0 ? "#{error_count} errors".red : "0 errors"

        print "\r%7d / %7d (%s, %d skipped)" %
                [current_count, @max_count, error_count_text, skipped_count]
      end

      def instantiate_task_resource
        PostCreator.new(
          @system_user,
          raw: "Topic created by uploads_importer",
          acting_user: @system_user,
          skip_validations: true,
          title: "Topic created by uploads_importer - #{SecureRandom.hex}",
          archetype: Archetype.default,
          category: @category_id,
        ).create!
      end

      def process_upload(row, post)
        result = with_retries { attempt_optimization(row, post) }
        status_queue << (result || { id: row[:upload_id], status: :error })
      end

      def attempt_optimization(row, post)
        upload = Upload.find_by(sha1: row[:upload_sha1])
        optimized_images = create_optimized_images(row[:type], row[:markdown], upload, post)

        return if optimized_images.blank?

        processed_optimized_images = process_optimized_images(optimized_images)

        if images_valid?(processed_optimized_images)
          {
            id: row[:upload_id],
            optimized_images: serialize_optimized_images(processed_optimized_images),
            status: :ok,
          }
        end
      end

      def images_valid?(images)
        !images.nil? && images.all?(&:present?) && images.all?(&:persisted?) &&
          images.all? { |o| o.errors.blank? }
      end

      def serialize_optimized_images(images)
        images.presence&.to_json(only: OptimizedImage.column_names)
      end

      def create_optimized_images(type, markdown, upload, post)
        case type
        when "post"
          post.update_columns(baked_at: nil, cooked: "", raw: markdown)
          post.reload
          post.rebake!

          OptimizedImage.where(upload_id: upload.id).to_a
        when "avatar"
          @avatar_sizes.map { |size| OptimizedImage.create_for(upload, size, size) }
        end
      rescue StandardError => e
        puts e.message
        puts e.stacktrace

        nil
      end

      def process_optimized_images(images)
        begin
          images.map! do |image|
            next if image.blank?

            image_path = add_multisite_prefix(discourse_store.get_path_for_optimized_image(image))

            unless file_exists?(image_path)
              image.destroy
              image = nil
            end

            image
          end
        rescue StandardError
          images = nil
        end

        images
      end
    end
  end
end