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

LiquidCrystal_I2C lcd(0x27, 16, 4);

const int buttonPin = 2;
const int redPin = 12;
const int greenPin = 14;
const int bluePin = 27;

unsigned long startTime = 0;
unsigned long elapsedTime = 0;
unsigned long lastUpdateTime = 0;
bool running = false;
int colorIndex = 0;

const int numColors = 4;
const int colors[numColors][3] = {
  {0, 255, 0},    // Green
  {255, 255, 0},  // Yellow
  {255, 0, 0},    // Red
  {0, 0, 255}     // Blue
};

void setup() {
  Serial.begin(115200);
  
  lcd.init();
  lcd.backlight();
  lcd.clear();
  lcd.setCursor(0, 1);
  lcd.print("Press to Start");

  pinMode(buttonPin, INPUT_PULLUP);
  pinMode(redPin, OUTPUT);
  pinMode(greenPin, OUTPUT);
  pinMode(bluePin, OUTPUT);

  attachInterrupt(digitalPinToInterrupt(buttonPin), buttonInterrupt, FALLING);

  setColor(colors[colorIndex][0], colors[colorIndex][1], colors[colorIndex][2]);

  // WiFi setup (for future use)
  // WiFi.begin("SSID", "PASSWORD");
  // while (WiFi.status() != WL_CONNECTED) {
  //   delay(1000);
  //   Serial.println("Connecting to WiFi...");
  // }
  // Serial.println("Connected to WiFi");
}

void loop() {
  unsigned long currentTime = millis();
  
  if (running && (currentTime - lastUpdateTime >= 100)) { // Update every 100ms
    elapsedTime = currentTime - startTime;
    updateDisplay();
    lastUpdateTime = currentTime;
  }
}

void buttonInterrupt() {
  if (!running) {
    startTime = millis() - elapsedTime; // Resume from last stopped time
    running = true;
    lcd.clear();
  } else {
    running = false;
  }
  
  // Change LED color
  colorIndex = (colorIndex + 1) % numColors;
  setColor(colors[colorIndex][0], colors[colorIndex][1], colors[colorIndex][2]);
}

void updateDisplay() {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Time:");
  lcd.setCursor(0, 1);
  lcd.print(formatTime(elapsedTime));
  lcd.setCursor(0, 2);
  lcd.print(running ? "Running" : "Paused");
}

String formatTime(unsigned long timeInMillis) {
  unsigned long totalSeconds = timeInMillis / 1000;
  unsigned long hours = totalSeconds / 3600;
  unsigned long minutes = (totalSeconds % 3600) / 60;
  unsigned long seconds = totalSeconds % 60;
  unsigned long centiseconds = (timeInMillis % 1000) / 10;

  char buffer[13];
  snprintf(buffer, 13, "%02lu:%02lu:%02lu.%02lu", hours, minutes, seconds, centiseconds);
  return String(buffer);
}

void setColor(int red, int green, int blue) {
  analogWrite(redPin, red);
  analogWrite(greenPin, green);
  analogWrite(bluePin, blue);
}