#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 = 2670825;
const char *myWriteAPIKey = "MKKCRSALW7KB4CO8";
const int ledPin = 13; 
int statusCode;

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

void setup() {
  solarPanel.attach(servoPin);
  Serial.begin(115200);
  pinMode(ledPin, OUTPUT);
  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) { 
    Serial.println("Channel update successful.");
  } else {
    Serial.println("Problem Writing data. HTTP error code: " + String(statusCode));
  }
}

void loop() {
  int analogValue = analogRead(LDR_PIN);
  float voltage = analogValue / 4095.0 * 5.0; 
  float resistance = 2000 * voltage / (1 - voltage / 5);
  float lux = pow(RL10 * 1e3 * pow(10, GAMMA) / resistance, (1 / GAMMA));

  // Update time
  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;
  int day = timeinfo->tm_mday;        // Get the day of the month
  int month = timeinfo->tm_mon + 1;   // Get the month (0-11, so add 1)
  int year = timeinfo->tm_year + 1900; // Get the year since 1900

  // Set angle based on time of day
  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;
  }

  // Adjust angle based on light intensity (lux)
  if (lux < 100) { 
    angle = 0; 
  } else if (lux < 200) {
    angle = 45; 
  } else if (lux < 400) {
    angle = 90; 
  } else {
    angle = 135; 
  }

  solarPanel.write(angle);
  Serial.println("Date: " + String(day) + "/" + String(month) + "/" + String(year));
  Serial.println("Time: " + String(hour) + ":" + String(minute));
  Serial.println("Angle: " + String(angle));
  Serial.print("Lux: ");
  Serial.println(lux);
  Serial.println("Voltage: " + String(voltage));
  Serial.println("<-------------------------------->");

  // Update ThingSpeak fields
  ThingSpeak.setField(1, voltage);
  ThingSpeak.setField(2, angle);
  ThingSpeak.setField(3, lux);
  ThingSpeak.setField(4, hour);
  ThingSpeak.setField(5, minute);
  ThingSpeak.setField(6, String(day) + "/" + String(month) + "/" + String(year)); // Send date
  statusCode = ThingSpeak.writeFields(myChannelNumber, myWriteAPIKey);
  
  channelupdation();
  delay(15000);
}