#include <Arduino.h>
#include <ESP8266WiFi.h>
#include <ESP8266HTTPClient.h>
#include <WiFiClientSecureBearSSL.h>
#include <ArduinoJson.h>

//WiFi连接信息（注意：需要自行修改以下内容否则ESP8266无法连接WiFi）
#define ssid "SSID"   //WiFi名称 
#define password "PASSWORD"  //WiFi密码

//https://qyapi.weixin.qq.com网站的指纹。
//esp通过https访问网站，都需要自己通过浏览器获取指纹，获取方法可自行搜索，在参考资料中也有文章，指纹一般几个月就需要更新一次。浏览器打开https://qyapi.weixin.qq.com/cgi-bin/gettoken获取指纹，而不只是只有主机名。
const char fingerprint[] PROGMEM = "790e6e32485bb89503ac6da87d948f5e634322a7";

//HTTPS端口443
const int httpsPort = 443;  
// 企业微信api相关
String tokenUrl = "https://qyapi.weixin.qq.com/cgi-bin/gettoken";
String sendMsgUrl = "https://qyapi.weixin.qq.com/cgi-bin/message/send?access_token=";
//以下信息需要替换，这里的均不可用
String corpid = "ww98b3k1b63788a7ad";//你的企业id
String corpsecret = "Kh8asfasfaTrbSwRBGK5H0osnfasakjkmSYCqV3Tgcs";//你的企业应用密钥
String agentid = "1000002";//你的企业应用id

//获取企业微信access_token
String get_token(){
  String token = "123";
  String requestUrl = tokenUrl + "?corpid="+corpid+"&corpsecret="+corpsecret;
  //https需要创建一个加密路径
  std::unique_ptr<BearSSL::WiFiClientSecure>client(new BearSSL::WiFiClientSecure);
  client->setFingerprint(fingerprint);
  //创建一个HTTP客户端
  HTTPClient https;
  //http和https的区别就是https.begin中的*client。如果没有*client,那么发送出去的就是http请求
  //建立连接
  if (https.begin(*client, requestUrl)) {  // HTTPS
      Serial.print("[HTTPS] GET...\n");
      // 发送get请求
      int httpCode = https.GET();
	  //如果httpCode小于零则连接错误
      if (httpCode > 0) {
        Serial.printf("[HTTPS] GET... code: %d\n", httpCode);

        // file found at server
        if (httpCode == HTTP_CODE_OK || httpCode == HTTP_CODE_MOVED_PERMANENTLY) {
          //将返回的json序列，放到json变量
          String json = https.getString();
          Serial.println(json);
          // 创建DynamicJsonDocument对象，json中的参数为4个。
          const size_t capacity = JSON_OBJECT_SIZE(4) + 290;
          DynamicJsonDocument doc(capacity);
          //反序列化数据
          deserializeJson(doc, json);
          if(doc["errcode"].as<int>()==0){
              token = doc["access_token"].as<String>();
          }
        }
      } else {
        Serial.printf("[HTTPS] GET... failed, error: %s\n", https.errorToString(httpCode).c_str());
      }

      https.end();
    } else {
      Serial.printf("[HTTPS] Unable to connect\n");
    }

    return token;
}

 //调用企业微信api，发送信息。
 void send_msg(String msg){
   //调用get_token函数，获取token
   String token = get_token();
   //token=123表示get_token()函数请求token失败。
   //如果失败，可能还需要其他步骤，比如重新获取。这里没有完善。
   if (token == "123"){
      Serial.println("not get token");
     return;
   }else{
      Serial.println("got token");
    }
   //构造请求url
   String requestUrl = sendMsgUrl + token;
   std::unique_ptr<BearSSL::WiFiClientSecure>client(new BearSSL::WiFiClientSecure);
   client->setFingerprint(fingerprint);
   HTTPClient httpClient;
   
   //与微信服务器建立连接
   httpClient.begin(*client,requestUrl);
   //构建json数据，用于发送请求内容
   String json = "{\"touser\":\"@all\",\"msgtype\":\"text\",\"agentid\":1000002,\"text\":{\"content\":\""+msg+"\"},\"safe\":0,\"enable_id_trans\":0,\"enable_duplicate_check\":0,\"duplicate_check_interval\":1800}";
   //发送请求内容
   Serial.println(json);
   //将请求数据放到POST()中。
   int httpCode = httpClient.POST(json);
   //这里没有读取服务器返回的json数据，最好还是提取出来，判断是否发送成功。可自行添加代码
   if (httpCode > 0) {
     //将服务器响应头打印到串口
     Serial.println("[HTTP] POST... code:"+ httpCode);
     //将从服务器获取的数据打印到串口
     if (httpCode == HTTP_CODE_OK) {
       Serial.println("Send success");
       Serial.println("return str:"+httpClient.getString());
     }
   } else {
     Serial.println("send failure");
   }
   //关闭ESP8266与服务器连接
   httpClient.end();
 }

//Wifi init
void wifi_init(){
  Serial.begin(9600);
  WiFi.mode(WIFI_STA);        //设置ESP8266为无线终端工作模式
  
  WiFi.begin(ssid, password); //连接WiFi
  Serial.println("");
 
  Serial.println("Connecting"); Serial.println("");
  
  // 等待连接
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
 
  //成功连接后通过串口监视器显示WiFi名称以及ESP8266的IP地址。
  Serial.println("");
  Serial.print("Connected to ");
  Serial.println(ssid);
  Serial.print("IP address: ");
  Serial.println(WiFi.localIP()); 
}

void setup() {
  wifi_init();
  send_msg("hello world!");
}

void loop() {
}

/*
 * ESP8266 Deep sleep mode example
 * Rui Santos 
 * Complete Project Details https://randomnerdtutorials.com
 */
 
void setup() {
  Serial.begin(115200);
  Serial.setTimeout(2000);

  // Wait for serial to initialize.
  while(!Serial) { }
  
  // Deep sleep mode for 30 seconds, the ESP8266 wakes up by itself when GPIO 16 (D0 in NodeMCU board) is connected to the RESET pin
  Serial.println("I'm awake, but I'm going into deep sleep mode for 30 seconds");
  ESP.deepSleep(30e6); 

}

void loop() {
}

/*
 * ESP8266 Deep sleep mode example
 * Rui Santos 
 * Complete Project Details https://randomnerdtutorials.com
 */
 
void setup() {
  Serial.begin(115200);
  Serial.setTimeout(2000);

  // Wait for serial to initialize.
  while(!Serial) { }
    
  // Deep sleep mode until RESET pin is connected to a LOW signal (for example pushbutton or magnetic reed switch)
  Serial.println("I'm awake, but I'm going into deep sleep mode until RESET pin is connected to a LOW signal");
  ESP.deepSleep(0); 
}

void loop() {
}