# frozen_string_literal: true

class Upload < ApplicationRecord
  extend Memoist
  class Error < StandardError; end

  MAX_FILES_PER_UPLOAD = 100

  # The maximum number of 'pending' or 'processing' media assets a single user can have at once.
  MAX_QUEUED_ASSETS = 250

  attr_accessor :files

  belongs_to :uploader, class_name: "User"
  has_many :upload_media_assets, dependent: :destroy
  has_many :media_assets, through: :upload_media_assets
  has_many :posts, through: :media_assets

  normalize :source, :normalize_source

  validates :files, length: { maximum: MAX_FILES_PER_UPLOAD, message: "can't have more than #{MAX_FILES_PER_UPLOAD} files per upload" }
  validates :source, format: { with: %r{\Ahttps?://}i, message: "is not a valid URL" }, if: -> { source.present? }
  validates :referer_url, format: { with: %r{\Ahttps?://}i, message: "is not a valid URL" }, if: -> { referer_url.present? }
  validate :validate_file_and_source, on: :create
  validate :uploader_is_not_limited, on: :create

  after_create :async_process_upload!

  scope :pending, -> { where(status: "pending") }
  scope :completed, -> { where(status: "completed") }
  scope :failed, -> { where(status: "error") }

  def self.visible(user)
    if user.is_admin?
      all
    else
      where(uploader: user)
    end
  end

  concerning :StatusMethods do
    def is_pending?
      status == "pending"
    end

    def is_processing?
      status == "processing"
    end

    def is_completed?
      status == "completed"
    end

    def is_errored?
      status == "error"
    end

    def is_finished?
      is_completed? || is_errored?
    end
  end

  concerning :ValidationMethods do
    def validate_file_and_source
      if files.present? && source.present?
        errors.add(:base, "Can't give both a file and a source")
      elsif files.blank? && source.blank?
        errors.add(:base, "No file or source given")
      end
    end

    def uploader_is_not_limited
      queued_asset_count = uploader.upload_media_assets.unfinished.count

      if queued_asset_count > MAX_QUEUED_ASSETS
        errors.add(:base, "You have too many images queued for upload (queued: #{queued_asset_count}; limit: #{MAX_QUEUED_ASSETS}). Try again later.")
      end
    end
  end

  concerning :SourceMethods do
    class_methods do
      # percent-encode unicode characters in the URL
      def normalize_source(url)
        Danbooru::URL.parse(url)&.to_normalized_s.presence || url
      end
    end
  end

  def self.ai_tags_match(tag_string, score_range: (50..))
    upload_media_assets = AITagQuery.search(tag_string, relation: UploadMediaAsset.all, foreign_key: :media_asset_id, score_range: score_range)
    where(upload_media_assets.where("upload_media_assets.upload_id = uploads.id").arel.exists)
  end

  def self.search(params)
    q = search_attributes(params, :id, :created_at, :updated_at, :source, :referer_url, :status, :media_asset_count, :uploader, :upload_media_assets, :media_assets, :posts)

    if params[:ai_tags_match].present?
      min_score = params.fetch(:min_score, 50).to_i
      q = q.ai_tags_match(params[:ai_tags_match], score_range: (min_score..))
    end

    if params[:is_posted].to_s.truthy?
      q = q.where.not(id: Upload.where.missing(:posts))
    elsif params[:is_posted].to_s.falsy?
      q = q.where(id: Upload.where.missing(:posts))
    end

    case params[:order]
    when "id", "id_desc"
      q = q.order(id: :desc)
    when "id_asc"
      q = q.order(id: :asc)
    else
      q = q.apply_default_order(params)
    end

    q
  end

  def async_process_upload!
    if files.present?
      process_upload!
    elsif source.present?
      ProcessUploadJob.perform_later(self)
    else
      raise "No file or source given" # Should never happen
    end
  end

  def process_upload!
    update!(status: "processing")

    if files.present?
      upload_media_assets = files.map do |_index, file|
        UploadMediaAsset.new(upload: self, file: file.tempfile, source_url: "file://#{file.original_filename}")
      end
    elsif source.present?
      page_url = source_extractor.page_url
      image_urls = source_extractor.image_urls

      if image_urls.empty?
        raise Error, "#{source} doesn't contain any images"
      end

      upload_media_assets = image_urls.map do |image_url|
        UploadMediaAsset.new(upload: self, source_url: image_url, page_url: page_url, media_asset: nil)
      end
    else
      raise Error, "No file or source given" # Should never happen
    end

    transaction do
      update!(media_asset_count: upload_media_assets.size)
      upload_media_assets.each(&:save!)
    end
  rescue Exception => e
    update!(status: "error", error: e.message)
  end

  def source_extractor
    return nil if source.blank?
    Source::Extractor.find(source, referer_url)
  end

  def self.available_includes
    [:uploader, :upload_media_assets, :media_assets, :posts]
  end

  memoize :source_extractor
end