/*
  Date: 25-06-21
  Code written by: Dharmik
  ESP32 sending a message to WhatsApp messenger
  Find more on www.TechTOnions.com
*/
#include <WiFi.h>         //Including wifi.h library it will take care of all wifi related task
#include <HTTPClient.h>   //Including HTTPClient.h library to use all api

const char* ssid = "Wokwi-GUEST";             //Add your WiFi ssid
const char* password =  "12345678";    //Add your WiFi password

String apiKey = "8967953";              //Add your Token number that bot has sent you on WhatsApp messenger
String phone_number = "+5491128334084"; //Add your WhatsApp app registered phone number (same number that bot send you in url)

String url;                            //url String will be used to store the final generated URL

void setup() 
{
  Serial.begin(115200);

  WiFi.begin(ssid,"", 6);              // Try to connect with the given SSID and PSS
  Serial.println("Connecting to WiFi");
  while (WiFi.status() != WL_CONNECTED) {  // Wait until WiFi is connected
    delay(500);
    Serial.print(".");
  }
  Serial.println();
  Serial.println("Connected to the WiFi network"); // Print wifi connect message

  // use message_to_whatsapp function to send your own message
  message_to_whatsapp("El tanque principal y de emrgencia se quedaron sin agua, ven rapidamente a cargar agua.");  // you send your own message just change "hello from TechTOnions" to your message.
}

void loop()
{
  //loop will do nothing for this example
}

void  message_to_whatsapp(String message)       // user define function to send meassage to WhatsApp app
{
  //adding all number, your api key, your message into one complete url
  url = "https://api.callmebot.com/whatsapp.php?phone=" + phone_number + "&apikey=" + apiKey + "&text=" + urlencode(message);

  postData(); // calling postData to run the above-generated url once so that you will receive a message.
}

void postData()     //userDefine function used to call api(POST data)
{
  int httpCode;     // variable used to get the responce http code after calling api
  HTTPClient http;  // Declare object of class HTTPClient
  http.begin(url);  // begin the HTTPClient object with generated url
  httpCode = http.POST(url); // Finaly Post the URL with this function and it will store the http code
  if (httpCode == 200)      // Check if the responce http code is 200
  {
    Serial.println("Sent ok."); // print message sent ok message
  }
  else                      // if response HTTP code is not 200 it means there is some error.
  {
    Serial.println("Error."); // print error message.
  }
  http.end();          // After calling API end the HTTP client object.
}

String urlencode(String str)  // Function used for encoding the url
{
    String encodedString="";
    char c;
    char code0;
    char code1;
    char code2;
    for (int i =0; i < str.length(); i++){
      c=str.charAt(i);
      if (c == ' '){
        encodedString+= '+';
      } else if (isalnum(c)){
        encodedString+=c;
      } else{
        code1=(c & 0xf)+'0';
        if ((c & 0xf) >9){
            code1=(c & 0xf) - 10 + 'A';
        }
        c=(c>>4)&0xf;
        code0=c+'0';
        if (c > 9){
            code0=c - 10 + 'A';
        }
        code2='\0';
        encodedString+='%';
        encodedString+=code0;
        encodedString+=code1;
        //encodedString+=code2;
      }
      yield();
    }
    return encodedString;
}