sources: factor out Source::URL::PixivSketch.

Add upload support for Pixiv Sketch. Fetch tags, commentary, and artist,
and rewrite sample images to full images.

Authentication isn't required. R18 images are hidden in the browser but
visible in the API.

app/logical/source/url.rb

@@ -28,6 +28,7 @@ module Source
       Source::URL::Moebooru,
       Source::URL::Nijie,
       Source::URL::Newgrounds,
+      Source::URL::PixivSketch,
       Source::URL::Plurk,
       Source::URL::Skeb,
       Source::URL::TwitPic,

app/logical/source/url/pixiv_sketch.rb

@@ -0,0 +1,47 @@
+# frozen_string_literal: true
+
+module Source
+  class URL::PixivSketch < Source::URL
+    attr_reader :work_id, :username, :full_image_url
+
+    def self.match?(url)
+      url.host.in?(%w[sketch.pixiv.net img-sketch.pixiv.net img-sketch.pximg.net])
+    end
+
+    def parse
+      case [host, *path_segments]
+
+      # https://sketch.pixiv.net/items/5835314698645024323
+      in "sketch.pixiv.net", "items", work_id
+        @work_id = work_id
+
+      # https://img-sketch.pixiv.net/uploads/medium/file/4463372/8906921629213362989.jpg (page: https://sketch.pixiv.net/items/5835314698645024323)
+      # https://img-sketch.pximg.net/c!/w=540,f=webp:jpeg/uploads/medium/file/4463372/8906921629213362989.jpg
+      # https://img-sketch.pixiv.net/c/f_540/uploads/medium/file/9986983/8431631593768139653.jpg
+      in *, "uploads", "medium", "file", dir, file if image_url?
+        @full_image_url = "https://img-sketch.pixiv.net/uploads/medium/file/#{dir}/#{file}"
+
+      # https://sketch.pixiv.net/@user_ejkv8372
+      # https://sketch.pixiv.net/@user_ejkv8372/followings
+      in "sketch.pixiv.net", /^@/ => username, *rest
+        @username = username.delete_prefix("@")
+
+      else
+      end
+    end
+
+    def image_url?
+      url.host.in?(%w[img-sketch.pixiv.net img-sketch.pximg.net])
+    end
+
+    def page_url
+      # https://sketch.pixiv.net/items/5835314698645024323
+      "https://sketch.pixiv.net/items/#{work_id}" if work_id.present?
+    end
+
+    def api_url
+      # https://sketch.pixiv.net/api/items/5835314698645024323.json (won't work in the browser; use curl)
+      "https://sketch.pixiv.net/api/items/#{work_id}.json" if work_id.present?
+    end
+  end
+end

app/logical/sources/strategies.rb

@@ -16,6 +16,7 @@ module Sources
         Strategies::HentaiFoundry,
         Strategies::Fanbox,
         Strategies::Mastodon,
+        Strategies::PixivSketch,
         Strategies::Weibo,
         Strategies::Newgrounds,
         Strategies::Skeb,

app/logical/sources/strategies/pixiv.rb

@@ -88,16 +88,12 @@ module Sources
       def match?
         return false if parsed_url.nil?
         return false if url.include? "/fanbox/"
+        return false if Source::URL::PixivSketch === parsed_url
         parsed_url.domain.in?(domains) || parsed_url.host == "tc-pximg01.techorus-cdn.com"
       end
 
       def site_name
-        # XXX pixiv sketch should be in a separate strategy
-        if parsed_url.host.in?(%w[sketch.pixiv.net img-sketch.pixiv.net img-sketch.pximg.net])
-          "Pixiv Sketch"
-        else
-          "Pixiv"
-        end
+        "Pixiv"
       end
 
       def image_urls

app/logical/sources/strategies/pixiv_sketch.rb

@@ -0,0 +1,88 @@
+# frozen_string_literal: true
+
+# @see Source::URL::PixivSketch
+module Sources
+  module Strategies
+    class PixivSketch < Base
+      extend Memoist
+
+      def match?
+        Source::URL::PixivSketch === parsed_url
+      end
+
+      def site_name
+        parsed_url.site_name
+      end
+
+      def image_urls
+        if parsed_url.image_url?
+          [parsed_url.full_image_url]
+        else
+          image_urls_from_api
+        end
+      end
+
+      def image_urls_from_api
+        api_response.dig("data", "media").to_a.pluck("photo").pluck("original").pluck("url2x")
+      end
+
+      def profile_url
+        "https://sketch.pixiv.net/@#{artist_name}" if artist_name.present?
+      end
+
+      def artist_name
+        api_response.dig("data", "user", "unique_name")
+      end
+
+      def other_names
+        [artist_name, display_name].compact
+      end
+
+      def profile_urls
+        [profile_url, pixiv_profile_url].compact
+      end
+
+      def artist_commentary_desc
+        api_response.dig("data", "text")
+      end
+
+      def tags
+        api_response.dig("data", "tags").to_a.map do |tag|
+          [tag, "https://sketch.pixiv.net/tags/#{tag}"]
+        end
+      end
+
+      def display_name
+        api_response.dig("data", "user", "name")
+      end
+
+      def pixiv_profile_url
+        "https://www.pixiv.net/users/#{pixiv_user_id}" if pixiv_user_id.present?
+      end
+
+      def pixiv_user_id
+        api_response.dig("data", "user", "pixiv_user_id")
+      end
+
+      # curl https://sketch.pixiv.net/api/items/5835314698645024323.json | jq
+      def api_response
+        return {} if api_url.blank?
+
+        response = http.cache(1.minute).get(api_url)
+        return {} if response.status == 404
+
+        response.parse
+      end
+
+      def page_url
+        parsed_url.page_url || parsed_referer&.page_url
+      end
+
+      def api_url
+        parsed_url.api_url || parsed_referer&.api_url
+      end
+
+      memoize :api_response
+    end
+  end
+end