# Feature Page of Payment

// functional-pages/request-payment.js
exports.beforeRequestPayment = function (paymentArgs, callback) {
  // Note:
  // The feature page function (this function) should not require other files outside the functional-pages directory.
  // Other files outside the functional-pages directory should not require files in this directory.
  // Such a require call will not be supported in the future.
  //
  // Files in the functional-pages directory can be required.
  var getOpenIdURL = require('./URL').getOpenIdURL;
  var paymentURL = require('./URL').paymentURL;

  // Custom parameter. The value should be 'A' passed from a plug-in.
  var customArgument = paymentArgs.customArgument;

  // Step 1: Obtain code by calling the wx.login method, and exchange the openId of the order placer with the code by calling the Weixin API on the server.
  // For specific documentation, visit https://mp.weixin.qq.com/debug/wxadoc/dev/api/api-login.html?t=20161230#wxloginobject.
  wx.login({
    success: function (data) {
      wx.request({
        url: getOpenIdURL,
        data: { code: data.code },
        success: function (res) {
          // The openid of the user is obtained.
          // Step 2: Call the unified order placement API on the server for payment. Payment parameters are returned. Development of this is the same as that of the common wx.requestPayment.
          // For specific documentation, visit https://pay.weixin.qq.com/wiki/doc/api/wxa/wxa_api.php?chapter=7_4&index=3.
          wx.request({
            url: paymentURL,
            data: { openid: res.data.openid },
            method: 'POST',
            success: function (res) {
              console.log('unified order success, response is:', res);
              var payargs = res.data.payargs;
              // Step 3: Call the callback function callback to complete payment.
              // The callback function must return two parameters: err and requestPaymentArgs.
              // The err parameter should be set to null (or some failure information).
              // The requestPaymentArgs parameter is used to call wx.requestPayment. The success, fail, and complete functions are not supported.
              // Other included parameters should be the same as those of wx.requestPayment.
              var error = null;
              var requestPaymentArgs = {
                timeStamp: payargs.timeStamp,
                nonceStr: payargs.nonceStr,
                package: payargs.package,
                signType: payargs.signType,
                paySign: payargs.paySign,
              };
              callback(error, requestPaymentArgs);
            }
          });
        },
        fail: function (res) {
          console.log(' Failed to obtain the openid of the user, so services such as open APIs are unavailable.', res);
          // The first parameter of the callback function is error information. Error information is returned.
          callback(res);
        }
      });
    },
    fail: function (err) {
      console.log('wx.login  Failed to call the API, so services such as open interfaces are unavailable.', err)
      // The first parameter of the callback function is error information. Error information is returned.
      callback(err);
    }
  });
}