sources: rename Sources::Strategies to Source::Extractor.

Rename Sources::Strategies to Source::Extractor. A Source::Extractor
represents a thing that extracts information from a given URL.

app/logical/source/extractor/fantia.rb

@@ -0,0 +1,163 @@
+# frozen_string_literal: true
+
+class Source::Extractor
+  class Fantia < Source::Extractor
+    def self.enabled?
+      Danbooru.config.fantia_session_id.present?
+    end
+
+    def match?
+      Source::URL::Fantia === parsed_url
+    end
+
+    def image_urls
+      return [parsed_url.full_image_url] if parsed_url.image_url?
+      return [image_from_downloadable(parsed_url)] if parsed_url.downloadable?
+
+      images = images_for_post.presence || images_for_product.presence || []
+
+      full_images = images.compact.map do |image|
+        parsed = Source::URL.parse(image)
+        if parsed&.image_url?
+          parsed.full_image_url
+        elsif parsed&.downloadable?
+          image_from_downloadable(parsed)
+        else
+          image
+        end
+      end
+      full_images.compact.uniq
+    end
+
+    def image_from_downloadable(url)
+      resp = http.head(url)
+      return url if resp.status != 200
+      resp.uri.to_s
+    end
+
+    def images_for_post
+      return [] unless api_response.present?
+      images = [api_response.dig("post", "thumb_micro")]
+      api_response.dig("post", "post_contents").to_a.map do |content|
+        next if content["visible_status"] != "visible"
+
+        case content["category"]
+        when "photo_gallery"
+          content["post_content_photos"].to_a.map { |i| images << i.dig("url", "original") }
+        when "file"
+          images << image_from_downloadable("https://www.fantia.jp/#{content["download_uri"]}")
+        when "blog"
+          begin
+            sub_json = JSON.parse(content["comment"])
+          rescue Json::ParserError
+            sub_json = {}
+          end
+          sub_json["ops"].to_a.map { |js| images << js.dig("insert", "fantiaImage", "url") }
+        end
+      end
+      images
+    end
+
+    def images_for_product
+      html_response&.css(".product-gallery-item .img-fluid").to_a.map do |element|
+        element["src"] unless element["src"] =~ %r{/fallback/}
+      end.compact
+    end
+
+    def page_url
+      parsed_url.page_url || parsed_referer&.page_url
+    end
+
+    def tags
+      case work_type
+      when "post"
+        api_response&.dig("post", "tags").to_a.map do |tag|
+          [tag["name"], "https://fantia.jp/posts?tag=#{tag["name"]}"]
+        end
+      when "product"
+        html_response&.css(".product-category a").to_a.map do |element|
+          tag_name = element.text.delete_prefix("#")
+          [tag_name, "https://fantia.jp/products?product_category=##{tag_name}"]
+        end
+      else
+        []
+      end
+    end
+
+    def other_names
+      case work_type
+      when "post"
+        [api_response&.dig("post", "fanclub", "creator_name")].compact
+      when "product"
+        [html_response&.at(".fanclub-name a")&.text].compact
+      end
+    end
+
+    def profile_url
+      case work_type
+      when "post"
+        fanclub_id = api_response&.dig("post", "fanclub", "id")
+        return unless fanclub_id.present?
+        "https://fantia.jp/fanclubs/#{fanclub_id}"
+      when "product"
+        href = html_response&.at(".fanclub-name a")&.[]("href")
+        return unless href.present?
+        URI.join("https://fantia.jp/", href).to_s
+      end
+    end
+
+    def artist_commentary_title
+      case work_type
+      when "post"
+        api_response&.dig("post", "title")
+      when "product"
+        html_response&.at(".product-title")&.text
+      end
+    end
+
+    def artist_commentary_desc
+      case work_type
+      when "post"
+        api_response&.dig("post", "comment")
+      when "product"
+        html_response&.at(".product-description")&.text
+      end
+    end
+
+    def dtext_artist_commentary_desc
+      DText.from_html(artist_commentary_desc)
+    end
+
+    def work_type
+      parsed_url.work_type || parsed_referer&.work_type
+    end
+
+    def work_id
+      parsed_url.work_id || parsed_referer&.work_id
+    end
+
+    def api_response
+      return {} unless work_type == "post"
+      api_url = "https://fantia.jp/api/v1/posts/#{work_id}"
+
+      response = http.cache(1.minute).get(api_url)
+      return {} unless response.status == 200
+
+      JSON.parse(response)
+    rescue JSON::ParserError
+      {}
+    end
+
+    def html_response
+      return nil unless work_type == "product"
+      response = http.cache(1.minute).get("https://fantia.jp/products/#{work_id}")
+
+      return nil unless response.status == 200
+      response.parse
+    end
+
+    def http
+      Danbooru::Http.new.cookies(_session_id: Danbooru.config.fantia_session_id)
+    end
+  end
+end