#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <WiFi.h>
#include <time.h>

#define OLED_ADDR 0x3C
#define OLED_SDA 21
#define OLED_SCL 22
#define OLED_RST 16
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64

// Replace with your network credentials
const char* ssid = "Wokwi-GUEST";
const char* password = "";

// Define time zone (GMT +5:30)
const long timezoneOffset = 5.5 * 3600;  // in seconds

// Create an OLED display instance
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RST);

void setup() {
  Serial.begin(9600);

  // 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 the OLED display
  if (!display.begin(SSD1306_SWITCHCAPVCC, OLED_ADDR)) {
    Serial.println(F("SSD1306 allocation failed"));
    for (;;);
  }

  // Set the system time from an NTP server
  configTime(timezoneOffset, 0, "pool.ntp.org", "time.nist.gov");

  // Wait for time to be set
  time_t now;
  Serial.print("Waiting for time");
  while ((now = time(nullptr)) < 24 * 3600) {
    delay(500);
    Serial.print(".");
  }
  Serial.println();

  // Print the obtained time
  Serial.println("Time set!");

  // Adjust time zone offset
  now += timezoneOffset;
  struct tm timeinfo;
  gmtime_r(&now, &timeinfo);
  setenv("TZ", "GMT+5:30", 1);
  tzset();
}

void loop() {
  // Get the current time
  time_t now = time(nullptr);
  struct tm timeinfo;
  localtime_r(&now, &timeinfo);

  // Clear the display
  display.clearDisplay();

  // Display time
  display.setTextSize(2);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(10, 10);
  display.print(String(timeinfo.tm_hour) + ":" + String(timeinfo.tm_min) + ":" + String(timeinfo.tm_sec));

  // Display date
  display.setTextSize(1);
  display.setCursor(10, 40);
  display.print(String(timeinfo.tm_mday) + "/" + String(timeinfo.tm_mon + 1) + "/" + String(1900 + timeinfo.tm_year));

  // Display the content on the OLED
  display.display();

  delay(1000); // Update every second
}