#include <WiFi.h>
#include <WiFiUdp.h>
#include <MD_MAX72xx.h>
#include <SPI.h>

// Set your WiFi credentials
const char* ssid = "YOUR_WIFI_SSID";
const char* password = "YOUR_WIFI_PASSWORD";

// NTP Server details
const char* ntpServer = "pool.ntp.org";
const int ntpPort = 123;

// Time offset in seconds for your timezone
const int timeZoneOffset = 3600; // Example: GMT+1 (1 hour = 3600 seconds)

// LED Matrix configuration
const uint8_t numOfModules = 1; // Number of MAX7219 modules connected
const uint8_t dataPin = 23;     // GPIO23 pin on ESP32
const uint8_t clockPin = 18;    // GPIO18 pin on ESP32
const uint8_t csPin = 5;        // GPIO5 pin on ESP32

// Create instances of necessary objects
WiFiUDP udp;
MD_MAX72XX mx = MD_MAX72XX(dataPin, clockPin, csPin, numOfModules);

void setup() {
  // Initialize serial communication
  Serial.begin(115200);

  // Connect to Wi-Fi
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.println("Connecting to WiFi...");
  }

  Serial.println("Connected to WiFi");

  // Initialize LED Matrix
  mx.begin();
  mx.setIntensity(0);  // Set the brightness level (0-15)
  mx.clear();

  // Initialize UDP for NTP
  udp.begin(ntpPort);

  // Set time offset
  configTime(timeZoneOffset, 0, ntpServer);
}

void loop() {
  // Update the time from NTP server every 60 seconds
  static unsigned long lastUpdate = 0;
  if (millis() - lastUpdate >= 60000) {
    updateTime();
    lastUpdate = millis();
  }

  // Display the current time
  displayTime();
}

void updateTime() {
  // Get the current time from the NTP server
  udp.flush();
  IPAddress ntpServerIP;
  while (udp.parsePacket() > 0)
    ;  // Discard any previously received packets
  if (WiFi.hostByName(ntpServer, ntpServerIP)) {
    Serial.println("Sending NTP request...");
    byte packetBuffer[48];
    memset(packetBuffer, 0, 48);
    packetBuffer[0] = 0xE3;
    udp.beginPacket(ntpServerIP, ntpPort);
    udp.write(packetBuffer, 48);
    udp.endPacket();
  }

  while (udp.parsePacket() == 0)
    ;  // Wait until a valid NTP packet is received

  byte packetBuffer[48];
  udp.read(packetBuffer, 48);

  unsigned long highWord = word(packetBuffer[40], packetBuffer[41]);
  unsigned long lowWord = word(packetBuffer[42], packetBuffer[43]);
  unsigned long ntpTime = highWord << 16 | lowWord;

  // Set the system time to the received NTP time
  struct timeval tv;
  tv.tv_sec = ntpTime - 2208988800UL; // Convert NTP time to UNIX timestamp
  tv.tv_usec = 0;
  settimeofday(&tv, nullptr);
}

void displayTime() {
  // Get the current time
  struct tm timeinfo;
  if (!getLocalTime(&timeinfo)) {
    Serial.println("Failed to obtain time");
    return;
  }

  // Extract individual time components
  int hour = timeinfo.tm_hour;
  int minute = timeinfo.tm_min;
  int second = timeinfo.tm_sec;

  // Format the time as a string
  String timeString = String(hour) + ":" +
                      (minute < 10 ? "0" : "") + String(minute) + ":" +
                      (second < 10 ? "0" : "") + String(second);

  // Display the time on the LED Matrix
  mx.clear();
  mx.setChar(0, 0, timeString.charAt(0));
  mx.setChar(1, 0, timeString.charAt(1));
  mx.setChar(2, 0, timeString.charAt(3));
  mx.setChar(3, 0, timeString.charAt(4));
  mx.setChar(4, 0, timeString.charAt(6));
  mx.setChar(5, 0, timeString.charAt(7));
  mx.commit();
}