#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <RTClib.h>

// Pin definitions
const int BTN_PINS[] = {26, 25, 33, 32};  // Green, Yellow, Red, Blue
const int LED_PINS[] = {13, 12, 14, 27};  // Green, Yellow, Red, Blue
const int NUM_COLORS = 4;

// LCD setup
LiquidCrystal_I2C lcd(0x27, 16, 2);

// RTC setup
RTC_DS1307 rtc;

// Variables
const char* COLOR_NAMES[] = {"GREEN", "YELLOW", "RED", "BLUE"};
int currentColor = 0;  // Start with green (index 0)
unsigned long stopwatchStart = 0;
unsigned long lastUpdate = 0;

// Variables to store previous values for comparison
char prevStopwatchStr[9] = "";
char prevBottomLine[17] = "";

void setup() {
  for (int i = 0; i < NUM_COLORS; i++) {
    pinMode(BTN_PINS[i], INPUT_PULLUP);
    pinMode(LED_PINS[i], OUTPUT);
  }

  Wire.begin();
  lcd.init();
  lcd.backlight();

  if (!rtc.begin()) {
    lcd.print("RTC failed");
    while (1);
  }

  // Uncomment to set the RTC time
  // rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));

  // Set initial color to green
  setColor(0);
  updateDisplay();
}

void loop() {
  for (int i = 0; i < NUM_COLORS; i++) {
    if (digitalRead(BTN_PINS[i]) == LOW) {
      delay(50);  // Debounce
      if (digitalRead(BTN_PINS[i]) == LOW) {
        setColor(i);
        while (digitalRead(BTN_PINS[i]) == LOW);  // Wait for release
      }
    }
  }

  if (millis() - lastUpdate >= 1000) {
    updateDisplay();
    lastUpdate = millis();
  }
}

void setColor(int color) {
  digitalWrite(LED_PINS[currentColor], LOW);
  currentColor = color;
  digitalWrite(LED_PINS[currentColor], HIGH);
  stopwatchStart = millis();
}

void updateDisplay() {
  // Stopwatch
  unsigned long elapsed = (millis() - stopwatchStart) / 1000;
  int hours = elapsed / 3600;
  int minutes = (elapsed % 3600) / 60;
  int seconds = elapsed % 60;
  
  char stopwatchStr[9];
  sprintf(stopwatchStr, "%02d:%02d:%02d", hours, minutes, seconds);

  // Color and current time
  DateTime now = rtc.now();
  char bottomLine[17];
  sprintf(bottomLine, "%-5s  -  %02d:%02d", 
          COLOR_NAMES[currentColor], 
          now.hour(), now.minute());

  // Update the LCD only if the content has changed
  if (strcmp(stopwatchStr, prevStopwatchStr) != 0) {
    lcd.setCursor((16 - strlen(stopwatchStr)) / 2, 0);
    lcd.print(stopwatchStr);
    strcpy(prevStopwatchStr, stopwatchStr);
  }

  if (strcmp(bottomLine, prevBottomLine) != 0) {
    lcd.setCursor((16 - strlen(bottomLine)) / 2, 1);
    lcd.print(bottomLine);
    strcpy(prevBottomLine, bottomLine);
  }
}