# frozen_string_literal: true

class ExternalAPIImage < ApplicationRecord
  class Error < StandardError; end
  CACHE_TIME = 2.days
  IGNORED_ARTISTS = %w[avoid_posting conditional_dnp sound_warning epilepsy_warning].freeze

  Site = Struct.new(:name, :value, :format)
  SITES = [
    Site.new("E621", "e621", "https://e621.net/posts/%s"),
    Site.new("Femboy Fans", "femboyfans", "https://femboy.fan/posts/%s"),
  ].freeze

  belongs_to :api_image

  validates :site, inclusion: { in: SITES.map(&:value) }
  validate :not_deleted, on: :create

  enum site: SITES.to_h { |s| [s.value, s.value] }

  module DataMethods
    def url
      case site
      when "e621"
        "https://e621.net/posts/#{external_id}"
      when "femboyfans"
        "https://femboy.fan/posts/#{external_id}"
      else
        data_error("format url")
      end
    end

    def file_url
      return nil if is_deleted?
      case site
      when "e621", "femboyfans"
        cache.dig("file", "url")
      else
        data_error("format file_url")
      end
    end

    def width
      case site
      when "e621", "femboyfans"
        cache.dig("file", "width")
      else
        data_error("format width")
      end
    end

    def height
      case site
      when "e621", "femboyfans"
        cache.dig("file", "height")
      else
        data_error("format height")
      end
    end

    def size
      case site
      when "e621", "femboyfans"
        cache.dig("file", "size")
      else
        data_error("format size")
      end
    end

    def ext
      case site
      when "e621", "femboyfans"
        cache.dig("file", "ext")
      else
        data_error("format ext")
      end
    end

    def md5
      case site
      when "e621", "femboyfans"
        cache.dig("file", "md5")
      else
        data_error("format md5")
      end
    end

    def image_changed?
      case site
      when "e621", "femboyfans"
        cached_data.try(:dig, "file", "md5") != cached_data_before_last_save.try(:dig, "file", "md5")
      else
        data_error("format image_changed?")
      end
    end

    def is_deleted?
      case site
      when "e621", "femboyfans"
        cache.dig("flags", "deleted")
      else
        false
      end
    end

    def artists
      case site
      when "e621", "femboyfans"
        cache.dig("tags", "artist") - IGNORED_ARTISTS
      else
        data_error("format artists")
      end
    end

    def sources
      case site
      when "e621", "femboyfans"
        [url] + cache["sources"].select { |s| s.start_with?("http") }
      else
        data_error("format sources")
      end
    end

    def report_url
      case site
      when "e621", "femboyfans"
        url
      end
    end

    def data_error(text)
      raise(Error, "Don't know how to #{text} for ExternalApiImage #{id}: #{site}")
    end
  end

  module CacheMethods
    def cache
      update_cache! if cached_data.blank?
      update_cache if cache_expired?
      cached_data
    end

    def cache_expired?
      cache_last_updated_at < CACHE_TIME.ago
    end

    def update_cache
      return if @cache_updated
      UpdateExternalCacheJob.perform_later(self)
      @cache_updated = true
    end

    def update_cache!
      case site
      when "e621"
        data = Requests::E621.get_post(id: external_id)
      when "femboyfans"
        data = Requests::FemboyFans.get_post(id: external_id)
      else
        data_error("update cache")
      end
      update(cached_data: data, cache_last_updated_at: Time.now)
      if is_deleted?
        api_image.remove_iqdb
      elsif image_changed?
        api_image.update_iqdb
      end
      api_image.update(is_viewable: !is_deleted?)
    end
  end

  include CacheMethods
  include DataMethods

  def not_deleted
    if is_deleted?
      errors.add(:external_id, "is deleted")
      throw(:abort)
    end
  end
end