#include <ESP32Servo.h>
#include <WiFi.h>
#include <ThingSpeak.h>
#include <NTPClient.h>
#include <time.h>
Servo solarPanel;
#define LDR_PIN 36
const float GAMMA = 0.7;
const float RL10 = 50;
float angle;
const int servoPin = 13;
char ssid[] = "Wokwi-GUEST";
char pass[] = "";
WiFiClient client;
unsigned long myChannelNumber = 2628612;
const char * myWriteAPIKey = "5E9HB4JH6FLAIXI1";
int statusCode;

WiFiUDP ntpUDP;
NTPClient timeClient(ntpUDP, "pool.ntp.org", 19800, 60000);

void setup() {
  solarPanel.attach(servoPin); 
  Serial.begin(115200);
  pinMode(LDR_PIN, INPUT);
   WiFi.mode(WIFI_STA);
  ThingSpeak.begin(client);
  wificonnection();
  delay(1500);
  timeClient.begin();
}
void wificonnection(){
      WiFi.begin(ssid, pass);
  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.println("Connecting to WiFi...");
  }
}

void channelupdation()
{
  if(statusCode == 200) { //successful writing code
Serial.println("Channel update successful.");
}
else {
Serial.println("Problem Writing data. HTTP error code :" +
String(statusCode));
}
}

void loop() {
  int analogValue = analogRead(36);
  float voltage = analogValue / 4099. * 5;
  float resistance = 2000 * voltage / (1 - voltage / 5);
  float lux = pow(RL10 * 1e3 * pow(10, GAMMA) / resistance, (1 / GAMMA));


  timeClient.update();

  time_t now = timeClient.getEpochTime();
 setenv("TZ", "Asia/Kolkata", 1);
  tzset();

  struct tm * timeinfo = localtime(&now);
  int sec = timeinfo->tm_sec;
int minute = timeinfo->tm_min;
if(sec>=5 && sec<10)
{
     angle=45;
}
else if(sec>=10 && sec<15)
{
    angle=90;
}
else if(sec>=15 && sec<20)
{
  angle=135;
}
else if(sec>=20 && sec<=25)
{
  angle=179;
}
else{
  angle=0;
}
solarPanel.write(angle);
Serial.println("Time:"+String(sec)+":"+String(minute));


  Serial.println("Angle:"+String(angle));
  Serial.println("Lux: ");
  Serial.print(lux);
  Serial.println("Voltage:"+String(voltage));
  Serial.println("<-------------------------------->");

ThingSpeak.setField(1, voltage);
ThingSpeak.setField(2, angle);
ThingSpeak.setField(3, lux);
ThingSpeak.setField(4,sec);
statusCode = ThingSpeak.writeFields(myChannelNumber,myWriteAPIKey);
 
 channelupdation(); 
  delay(15000);
}