#include <SPI.h>  // Required for shield communication
#include <WiFi.h>

char ssid[] = "Wokwi-GUEST";   // your network SSID (name) 
char pass[] = "";   // your network password
int LED_PIN = 13;

WiFiClient  client;

unsigned long myTalkBackID = 49817;
const char * myTalkBackKey = "WWXPSAFJIHHO9P8A";

void setup() {
  Serial.begin(115200);          // Initialize serial
  pinMode(LED_PIN,OUTPUT);
}

void loop() {

  // Connect or reconnect to Wi-Fi
  if(WiFi.status() != WL_CONNECTED){
    Serial.print("Attempting to connect to SSID: ");
    Serial.println(String(ssid));
    while(WiFi.status() != WL_CONNECTED){
      WiFi.begin(ssid, pass);  
      Serial.print(".");
      delay(2000);     
    } 
    Serial.println("\nConnected.");
  }

  // Create the TalkBack URI
  String tbURI = String("/talkbacks/") + String(myTalkBackID) + String("/commands/execute");
  
  // Create the message body for the POST out of the values
  String postMessage =  String("api_key=") + String(myTalkBackKey);                      
                       
   // Make a string for any commands in the queue
  String newCommand = String();

  // Make the POST to ThingSpeak
  int x = httpPOST(tbURI, postMessage, newCommand);
  client.stop();
  
  // Check the result
  if(x == 200){
    Serial.println("checking queue..."); 
    // check for a command returned from TalkBack
    if(newCommand.indexOf("led on") == -1 && newCommand.indexOf("led off") == -1){

      Serial.println("  No command or syntax error!");

    }
    else{

      if(newCommand.indexOf("led on") != -1){
        Serial.println("  New command: Turn led on");
        digitalWrite(LED_PIN, HIGH);
      }
      else if(newCommand.indexOf("led off") != -1){
        Serial.println("  New command: Turn led off");
        digitalWrite(LED_PIN, LOW);
      }
    }
    
  }
  else{
    Serial.println("Problem checking queue. HTTP error code " + String(x));
  }

  
  delay(5000); // Wait 5 seconds to check queue again
}

// General function to POST to ThingSpeak
int httpPOST(String uri, String postMessage, String &response){

  bool connectSuccess = false;
  connectSuccess = client.connect("api.thingspeak.com",80);

  if(!connectSuccess){
      return -301;   
  }
  
  postMessage += "&headers=false";
  
  String Headers =  String("POST ") + uri + String(" HTTP/1.1\r\n") +
                    String("Host: api.thingspeak.com\r\n") +
                    String("Content-Type: application/x-www-form-urlencoded\r\n") +
                    String("Connection: close\r\n") +
                    String("Content-Length: ") + String(postMessage.length()) +
                    String("\r\n\r\n");

  client.print(Headers);
  client.print(postMessage);

  long startWaitForResponseAt = millis();
  while(client.available() == 0 && millis() - startWaitForResponseAt < 5000){
      delay(100);
  }

  if(client.available() == 0){       
    return -304; // Didn't get server response in time
  }

  if(!client.find(const_cast<char *>("HTTP/1.1"))){
      return -303; // Couldn't parse response (didn't find HTTP/1.1)
  }
  
  int status = client.parseInt();
  if(status != 200){
    return status;
  }

  if(!client.find(const_cast<char *>("\n\r\n"))){
    return -303;
  }

  String tempString = String(client.readString());
  response = tempString;
  
  return status;
    
}