module Qtpay
  module Service

    # ==== params ====
    # (required)
    # out_user: customer uniq id
    #
    # (optional)
    # mobile: customer mobile number
    # weixin_openid: WeiXin open id
    # mchnt_id: merchant id
    # out_mchnt: developer defined merchant id
    # expires: token expires time in seconds (default 86400)

    def self.get_user_token(params, options = {})
      make_request(:get, get_user_token_url(params, options))
    end

    # ==== params ====
    # (required)
    # total_amt: total payment amount in cents
    # out_sn: order serial number, must be uniq in all requests
    #
    # (optional)
    # mchnt_id: merchant id
    # out_mchnt: developer defined merchant id
    # token: auth token created in get_user_token
    # qrcode:
    # openid: openid when creating qrcode
    # expire_time: order expires time, format YYYY-mm-dd HH:MM:SS

    def self.create_pre_order(params, options = {})
      make_request(:post, create_pre_order_url(params, options))
    end

    GET_USER_TOKEN_REQUIRED_PARAMS = %w( out_user )
    def self.get_user_token_url(params, options = {})
      params = Utils.stringify_keys(params)
      check_required_params(params, GET_USER_TOKEN_REQUIRED_PARAMS)

      params = {
          'caller' => 'server',
          'app_code' => options[:app_code] || Qtpay.app_code,
      }.merge(params)

      request_uri('/auth/v1/token', params, options)
    end

    CREATE_PRE_ORDER_REQUIRED_PARAMS = %w( total_amt out_sn )
    def self.create_pre_order_url(params, options = {})
      params = Utils.stringify_keys(params)
      check_required_params(params, CREATE_PRE_ORDER_REQUIRED_PARAMS)

      params = {
          'caller' => 'server',
          'app_code' => options[:app_code] || Qtpay.app_code,
      }.merge(params)

      request_uri('/order/v1/pre_create', params, options)
    end

    def self.request_uri(path, params, options = {})
      uri = URI("#{Qtpay.gateway_url}#{path}")
      uri.query = URI.encode_www_form(sign_params(params, options))
      uri
    end

    def self.sign_params(params, options = {})
      params.merge(
          'sign' => Qtpay::Sign.generate(params, options)
      )
    end

    def self.check_required_params(params, names)
      return if !Qtpay.debug_mode?

      names.each do |name|
        warn("Qtpay Warn: missing required option: #{name}") unless params.has_key?(name)
      end
    end

    def self.make_request(request_type, url)
      request_type = case request_type
        when :get
          :get_response
        when :post
          :post_form
        else
          request_type
      end

      if request_type == :get_response
        res = Net::HTTP.send(request_type, url)
      else
        res = Net::HTTP.send(request_type, url, {})
      end
      if res.respond_to?(:body)
        JSON.parse(res.body)
      else # unknown error
        res
      end

    end
  end

end