require 'omniauth/oauth'
require 'multi_json'
require 'digest/md5'
require 'net/http'

module OmniAuth
  module Strategies
    # Authenticate to Renren utilizing OAuth 2.0 and retrieve
    # basic user information.
    #
    # @example Basic Usage
    # use OmniAuth::Strategies::TaoBao, 'client_id', 'client_secret'
    class Taobao < OmniAuth::Strategies::OAuth2
      # @param [Rack Application] app standard middleware application parameter
      # @param [String] client_id the app key at taobao open platform
      # @param [String] client_secret  the app secret at taobao open platform
      # @option options [String]

      def initialize(app, client_id=nil, client_secret=nil, options={}, &block)
        client_options = {
          :authorize_url => 'https://oauth.taobao.com/authorize',
          :token_url => 'https://oauth.taobao.com/token',
        }
        super(app, :taobao, client_id, client_secret, client_options, options, &block)
      end

      def auth_hash
        OmniAuth::Utils.deep_merge(
          super, {
            'uid' => user_data['uid'],
            'user_info' => user_info,
            'extra' => {
              'user_hash' => user_data,
            },
          }
        )
      end

      def user_data
        # TODO to be moved in options
        url = 'http://gw.api.taobao.com/router/rest'

        query_param = {
          :app_key => client_id,

          # TODO to be moved in options
          # TODO add more default fields (http://my.open.taobao.com/apidoc/index.htm#categoryId:1-dataStructId:3)
          :fields => 'user_id,uid,nick,sex,buyer_credit,seller_credit,location,created,last_visit,birthday,type,status,alipay_no,alipay_account,alipay_account,email,consumer_protection,alipay_bind',
          :format => 'json',
          :method => 'taobao.user.get',
          :session => @access_token.token,
          :sign_method => 'md5',
          :timestamp   => Time.now.strftime('%Y-%m-%d %H:%M:%S'),
          :v => '2.0'
        }
        query_param = generate_sign(query_param)
        res = Net::HTTP.post_form(URI.parse(url), query_param)
        @data ||= MultiJson.decode(res.body)['user_get_response']['user']
      end

      def request_phase
        options[:state] ||= '1'
        super
      end

      def user_info
        {
          'name' => user_data['nick'],
          'email' => (user_data['email'] if user_data['email']),
        }
      end

      def generate_sign(params)
        # params.sort.collect { |k, v| "#{k}#{v}" }
        str = client_secret + params.sort {|a,b| "#{a[0]}"<=>"#{b[0]}"}.flatten.join + client_secret
        params['sign'] = Digest::MD5.hexdigest(str).upcase!
        params
      end
    end
  end
end