#include <WiFi.h>
#include <time.h>
#include <Wire.h>
#include <LiquidCrystal_I2C.h>

// Wi-Fi credentials — Wokwi default / Wokwi default credentials
// Gercek donanim icin kendi SSID ve sifrenizle degistirin!
const char* WIFI_SSID = "Wokwi-GUEST";
const char* WIFI_PASS = "";   // Wokwi-GUEST sifresizdir

// Pin tanimlari / Pin definitions
#define LED_PIN          2
#define I2C_SDA          21
#define I2C_SCL          22

// NTP sunuculari / NTP servers
const char* NTP_SERVER_1 = "tr.pool.ntp.org";
const char* NTP_SERVER_2 = "pool.ntp.org";
const char* NTP_SERVER_3 = "time.google.com";

// Turkiye sabit UTC+3 (yaz saati yok) / Turkey fixed UTC+3 (no DST)
const long GMT_OFFSET_SEC = 3 * 3600;
const int  DAYLIGHT_OFFSET_SEC = 0;

LiquidCrystal_I2C lcd(0x27, 16, 2);

const char* dayNames[] = {"Pzr","Pzt","Sal","Car","Per","Cum","Cmt"};

void splash() {
  lcd.setCursor(3, 0);
  lcd.print("BlueGrays");
  lcd.setCursor(4, 1);
  lcd.print("NTP v1.0");
  delay(3000);
  lcd.clear();
}

void showLine(uint8_t row, const char* tr, const char* en) {
  lcd.setCursor(0, row);
  if (row == 0) lcd.print(tr);
  else lcd.print(en);
}

void connectWiFi() {
  lcd.clear();
  showLine(0, "WiFi baglaniyor", "Connecting WiFi");
  showLine(1, "WiFi baglaniyor", "Connecting WiFi");

  WiFi.mode(WIFI_STA);
  WiFi.begin(WIFI_SSID, WIFI_PASS);

  unsigned long start = millis();
  while (WiFi.status() != WL_CONNECTED && millis() - start < 15000) {
    delay(500);
  }

  if (WiFi.status() == WL_CONNECTED) {
    digitalWrite(LED_PIN, HIGH);
  }
}

void syncNTP() {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Zaman aliniyor");
  lcd.setCursor(0, 1);
  lcd.print("Fetching time");

  configTime(GMT_OFFSET_SEC, DAYLIGHT_OFFSET_SEC,
             NTP_SERVER_1, NTP_SERVER_2, NTP_SERVER_3);

  struct tm timeinfo;
  unsigned long start = millis();
  while (!getLocalTime(&timeinfo) && millis() - start < 10000) {
    delay(500);
  }

  lcd.clear();
}

void setup() {
  pinMode(LED_PIN, OUTPUT);
  digitalWrite(LED_PIN, LOW);

  // V1 default I2C: SDA=21 SCL=22 / V1 I2C default
  Wire.begin(I2C_SDA, I2C_SCL);
  lcd.init();
  lcd.backlight();

  splash();
  connectWiFi();
  syncNTP();
}

void loop() {
  // WiFi koparsa yeniden bagla / Reconnect if WiFi dropped
  if (WiFi.status() != WL_CONNECTED) {
    digitalWrite(LED_PIN, (millis() / 500) % 2);
    WiFi.reconnect();
    delay(2000);
    return;
  }

  struct tm timeinfo;
  if (!getLocalTime(&timeinfo)) {
    lcd.setCursor(0, 0);
    lcd.print("Zaman alinamadi ");
    lcd.setCursor(0, 1);
    lcd.print("NTP fail        ");
    delay(1000);
    return;
  }

  // Tarih satiri: GG.AA.YYYY Gun / Date row: DD.MM.YYYY Day
  lcd.setCursor(0, 0);
  if (timeinfo.tm_mday < 10) lcd.print("0");
  lcd.print(timeinfo.tm_mday);
  lcd.print(".");
  if (timeinfo.tm_mon + 1 < 10) lcd.print("0");
  lcd.print(timeinfo.tm_mon + 1);
  lcd.print(".");
  lcd.print(timeinfo.tm_year + 1900);
  lcd.print(" ");
  lcd.print(dayNames[timeinfo.tm_wday]);

  // Saat satiri (ortali): HH:MM:SS / Time row (centered)
  lcd.setCursor(4, 1);
  if (timeinfo.tm_hour < 10) lcd.print("0");
  lcd.print(timeinfo.tm_hour);
  lcd.print(":");
  if (timeinfo.tm_min < 10) lcd.print("0");
  lcd.print(timeinfo.tm_min);
  lcd.print(":");
  if (timeinfo.tm_sec < 10) lcd.print("0");
  lcd.print(timeinfo.tm_sec);

  delay(500);
}