class PixivApiClient
  API_VERSION = "1"
  CLIENT_ID = "bYGKuGVw91e0NMfPGp44euvGt59s"
  CLIENT_SECRET = "HP3RmkgAmEGro0gn1x9ioawQE8WMfvLXDz3ZqxpK"

  class Error < Exception ; end

  class WorksResponse
    attr_reader :json, :pages, :name, :moniker, :user_id, :page_count, :tags
    attr_reader :artist_commentary_title, :artist_commentary_desc

    def initialize(json)
      # Sample response: 
      # {
      #     "status": "success",
      #     "response": [
      #         {
      #             "id": 49270482,
      #             "title": "ツイログ",
      #             "caption": null,
      #             "tags": [
      #                 "神崎蘭子",
      #                 "双葉杏",
      #                 "アイドルマスターシンデレラガールズ",
      #                 "Star!!",
      #                 "アイマス5000users入り"
      #             ],
      #             "tools": [
      #                 "CLIP STUDIO PAINT"
      #             ],
      #             "image_urls": {
      #                 "large": "http://i3.pixiv.net/img-original/img/2015/03/14/17/53/32/49270482_p0.jpg"
      #             },
      #             "width": 1200,
      #             "height": 951,
      #             "stats": {
      #                 "scored_count": 8247,
      #                 "score": 81697,
      #                 "views_count": 191630,
      #                 "favorited_count": {
      #                     "public": 7804,
      #                     "private": 745
      #                 },
      #                 "commented_count": 182
      #             },
      #             "publicity": 0,
      #             "age_limit": "all-age",
      #             "created_time": "2015-03-14 17:53:32",
      #             "reuploaded_time": "2015-03-14 17:53:32",
      #             "user": {
      #                 "id": 341433,
      #                 "account": "nardack",
      #                 "name": "Nardack",
      #                 "is_following": false,
      #                 "is_follower": false,
      #                 "is_friend": false,
      #                 "is_premium": null,
      #                 "profile_image_urls": {
      #                     "px_50x50": "http://i1.pixiv.net/img19/profile/nardack/846482_s.jpg"
      #                 },
      #                 "stats": null,
      #                 "profile": null
      #             },
      #             "is_manga": true,
      #             "is_liked": false,
      #             "favorite_id": 0,
      #             "page_count": 2,
      #             "book_style": "none",
      #             "type": "illustration",
      #             "metadata": {
      #                 "pages": [
      #                     {
      #                         "image_urls": {
      #                             "large": "http://i3.pixiv.net/img-original/img/2015/03/14/17/53/32/49270482_p0.jpg",
      #                             "medium": "http://i3.pixiv.net/c/1200x1200/img-master/img/2015/03/14/17/53/32/49270482_p0_master1200.jpg"
      #                         }
      #                     },
      #                     {
      #                         "image_urls": {
      #                             "large": "http://i3.pixiv.net/img-original/img/2015/03/14/17/53/32/49270482_p1.jpg",
      #                             "medium": "http://i3.pixiv.net/c/1200x1200/img-master/img/2015/03/14/17/53/32/49270482_p1_master1200.jpg"
      #                         }
      #                     }
      #                 ]
      #             },
      #             "content_type": null
      #         }
      #     ],
      #     "count": 1
      # }

      @json = json
      @name = json["user"]["name"]
      @user_id = json["user"]["id"]
      @moniker = json["user"]["account"]
      @page_count = json["page_count"].to_i
      @artist_commentary_title = json["title"].to_s
      @artist_commentary_desc = json["caption"].to_s
      @tags = [json["tags"], json["tools"]].flatten.compact.reject {|x| x =~ /^http:/}

      if page_count > 1
        @pages = json["metadata"]["pages"].map {|x| x["image_urls"]["large"]}
      else
        @pages = [json["image_urls"]["large"]]
      end
    end
  end

  def works(illust_id)
    headers = {
      "Referer" => "http://www.pixiv.net",
      "User-Agent" => "#{Danbooru.config.safe_app_name}/#{Danbooru.config.version}",
      "Content-Type" => "application/x-www-form-urlencoded",
      "Authorization" => "Bearer #{access_token}"
    }
    params = {
      "image_sizes" => "large",
      "include_stats" => "true"
    }
    url = URI.parse("https://public-api.secure.pixiv.net/v#{API_VERSION}/works/#{illust_id.to_i}.json")
    url.query = URI.encode_www_form(params)
    json = nil

    Net::HTTP.start(url.host, url.port, :use_ssl => true) do |http|
      resp = http.request_get(url.request_uri, headers)
      if resp.is_a?(Net::HTTPSuccess)
        json = parse_api_json(resp.body)
      else
        raise Error.new("Pixiv API call failed (status=#{resp.code} body=#{resp.body})")
      end
    end

    WorksResponse.new(json["response"][0])
  end

private
  def parse_api_json(body)
    json = JSON.parse(body)

    if json["status"] != "success"
      raise Error.new("Pixiv API call failed (status=#{json['status']} body=#{body})")
    end

    json
  end

  def access_token
    Cache.get("pixiv-papi-access-token", 3000) do
      access_token = nil
      headers = {
        "Referer" => "http://www.pixiv.net"
      }
      params = {
        "username" => Danbooru.config.pixiv_login,
        "password" => Danbooru.config.pixiv_password,
        "grant_type" => "password",
        "client_id" => CLIENT_ID,
        "client_secret" => CLIENT_SECRET
      }
      url = URI.parse("https://oauth.secure.pixiv.net/auth/token")

      Net::HTTP.start(url.host, url.port, :use_ssl => true) do |http|
        resp = http.request_post(url.request_uri, URI.encode_www_form(params), headers)

        if resp.is_a?(Net::HTTPSuccess)
          json = JSON.parse(resp.body)
          access_token = json["response"]["access_token"]
        else
          raise Error.new("Pixiv API access token call failed (status=#{resp.code} body=#{resp.body})")
        end
      end

      access_token
    end
  end
end