#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 = 18;

char ssid[] = "Wokwi-GUEST";
char pass[] = "";
WiFiClient client;
unsigned long myChannelNumber =2640744;
const char * myWriteAPIKey = "FFDT5E57MR42HEKJ";
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);
  delay(1000);
}

void getwifi() {
  if(WiFi.status()!=WL_CONNECTED)
  {
     Serial.print("Attempting to Connect.....!");
     while(WiFi.status()!=WL_CONNECTED)
    {
      WiFi.begin(ssid,pass);
      delay(5000);
    }
  }
  Serial.println("\nConnected...");
}

void loop() {
  getwifi();
  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 hour = timeinfo->tm_hour;
  int minute = timeinfo->tm_min;

if(hour>=7 && hour<11)
{ angle=45; }

else if(hour>=11 && hour<14)
{ angle=90; }

else if(hour>=14 && hour<17)
{ angle=135; }

else if(hour>=17 && hour<=18)
{ angle=179; }

else{ angle=0; }

  solarPanel.write(angle);
  Serial.println("Time:"+String(hour)+":"+String(minute));
  Serial.println("Angle:"+String(angle));
  Serial.println("Lux:"+String(lux));
  Serial.println("Voltage:"+String(voltage));

ThingSpeak.setField(1,hour);
ThingSpeak.setField(2,minute);
ThingSpeak.setField(3,angle);
ThingSpeak.setField(4,lux);
ThingSpeak.setField(5,voltage);
statusCode = ThingSpeak.writeFields(myChannelNumber,myWriteAPIKey);
 
  if(statusCode==200)
  {
    Serial.println("Channel Update Successful...");
  }
  else
  {
    Serial.println("Problem Writing data: HTTp error code:"+String(statusCode));
  }
  delay(15000);  
}