#include 
#include 

LiquidCrystal_I2C lcd(0x27, 16, 2);

// Pin definitions
const int buzzerPin = 2;
const int led1Pin = 4;
const int led2Pin = 5;
const int buttonRed = 8;
const int buttonYellow = 9;
const int buttonGreen = 10;
const int buttonBlue = 11;

// Timer states
enum TimerState { IDLE, SET_SS, SET_MM, SET_HH, READY, RUNNING, PAUSED, FINISHED };
TimerState state = IDLE;

// Time variables
int seconds = 0, minutes = 0, hours = 0;
unsigned long previousMillis = 0;
unsigned long ledBlinkMillis = 0;
bool ledState = false;

// Setting process control
int settingStage = 0;
unsigned long totalSeconds = 0;

// Button state tracking
bool lastYellowState = HIGH;
bool lastGreenState = HIGH;
bool lastBlueState = HIGH;

// Variables for enhanced red button handling
unsigned long redLastTriggered = 0;
bool redHandled = false;

void setup() {
  Serial.begin(9600);
  lcd.init();
  lcd.backlight();
  showTitle("Timer");

  pinMode(buzzerPin, OUTPUT);
  pinMode(led1Pin, OUTPUT);
  pinMode(led2Pin, OUTPUT);

  // Use internal pull-up resistor for buttons
  pinMode(buttonRed, INPUT_PULLUP);
  pinMode(buttonYellow, INPUT_PULLUP);
  pinMode(buttonGreen, INPUT_PULLUP);
  pinMode(buttonBlue, INPUT_PULLUP);

  updateDisplay();
}

void loop() {
  handleButtons();

  if (state == RUNNING) {
    // Update timer every second
    if (millis() - previousMillis >= 1000) {
      previousMillis = millis();
      Serial.print("Tick: ");
      Serial.println(totalSeconds);
      if (totalSeconds > 0) {
        totalSeconds--;
        convertTotalSeconds();
        updateDisplay();
      } else {
        state = FINISHED;
        showTitle("Time's up!");
        tone(buzzerPin, 1000);
        previousMillis = millis();
        Serial.println("Countdown finished. Entered FINISHED state.");
      }
    }
    handleLEDBlink(500);
  } else if (state == FINISHED) {
    handleLEDBlink(200);
    // After 3 seconds, stop alarm and reset
    if (millis() - previousMillis >= 3000) {
      noTone(buzzerPin);
      state = IDLE;
      resetTimer();
      updateDisplay();
      Serial.println("Finished alert done. Returning to IDLE.");
    }
  }
}

void handleButtons() {
  // Enhanced red button with debouncing
  bool currentRed = digitalRead(buttonRed);
  if (!redHandled && currentRed == LOW && millis() - redLastTriggered > 200) {
    redHandled = true;              // Mark this press as handled
    redLastTriggered = millis();    // Update last trigger time
    Serial.println("Red button triggered.");
    Serial.print("Current state: "); Serial.println(state);

    if (state == READY || state == PAUSED) {
      // Calculate total time in seconds from hours, minutes, and seconds
      totalSeconds = seconds + minutes * 60 + hours * 3600;
      Serial.print("Computed totalSeconds: "); Serial.println(totalSeconds);
      if (totalSeconds > 0) {
        state = RUNNING;            // Start countdown
        previousMillis = millis();
        Serial.println("Switched to RUNNING.");
      } else {
        showTitle("Time = 0!");
        Serial.println("Time is 0. Cannot start.");
        for (int i = 0; i < 4; i++) {
          tone(buzzerPin, 2000);
          digitalWrite(led1Pin, HIGH);
          digitalWrite(led2Pin, HIGH);
          delay(100);
          noTone(buzzerPin);
          digitalWrite(led1Pin, LOW);
          digitalWrite(led2Pin, LOW);
          delay(100);
        }
      }
    } else if (state == RUNNING) {
      state = PAUSED;              // Pause the countdown if running
      Serial.println("Switched to PAUSED.");
    }
  }
  if (currentRed == HIGH) redHandled = false;

  // Blue button: step through time setting stages
  bool currentBlue = digitalRead(buttonBlue);
  if (lastBlueState == LOW && currentBlue == HIGH) {
    Serial.println("Blue button released.");
    if (state == IDLE || state == SET_SS || state == SET_MM || state == SET_HH || state == READY) {
      settingStage++;
      Serial.print("Setting stage: "); Serial.println(settingStage);
      if (settingStage == 1) state = SET_SS;
      else if (settingStage == 2) state = SET_MM;
      else if (settingStage == 3) state = SET_HH;
      else {
        totalSeconds = seconds + minutes * 60 + hours * 3600;
        state = READY;
        settingStage = 0;
        Serial.print("Time set to: "); Serial.println(totalSeconds);
        Serial.println("Entered READY state.");
      }
      updateDisplay();
    }
  }
  lastBlueState = currentBlue;

  // Green button: increase time value
  bool currentGreen = digitalRead(buttonGreen);
  if (lastGreenState == LOW && currentGreen == HIGH) {
    Serial.println("Green button released.");
    if (state == SET_SS) {
      seconds = (seconds + 1) % 60;
      Serial.print("Seconds set to: "); Serial.println(seconds);
    } else if (state == SET_MM) {
      minutes = (minutes + 1) % 60;
      Serial.print("Minutes set to: "); Serial.println(minutes);
    } else if (state == SET_HH) {
      hours = (hours + 1) % 100;
      Serial.print("Hours set to: "); Serial.println(hours);
    }
    updateDisplay();
  }
  lastGreenState = currentGreen;

  // Yellow button: reset timer
  bool currentYellow = digitalRead(buttonYellow);
  if (lastYellowState == LOW && currentYellow == HIGH) {
    Serial.println("Yellow button released. Resetting timer.");
    state = IDLE;
    resetTimer();
    updateDisplay();
  }
  lastYellowState = currentYellow;
}

void updateDisplay() {
  // Format and center the time string on the LCD
  String timeStr = formatTime(hours) + " : " + formatTime(minutes) + " : " + formatTime(seconds);
  int padding = (16 - timeStr.length()) / 2;
  lcd.setCursor(0, 1);
  lcd.print("                "); // Clear second line
  lcd.setCursor(padding, 1);
  lcd.print(timeStr);

  // Set title text based on current state
  if (state == SET_SS) showTitle("Set Timer SS");
  else if (state == SET_MM) showTitle("Set Timer MM");
  else if (state == SET_HH) showTitle("Set Timer HH");
  else if (state == READY || state == PAUSED || state == RUNNING) showTitle("Timer");
  else if (state == IDLE) showTitle("Timer");
}

String formatTime(int val) {
  // Convert time value to two-digit string
  return (val < 10) ? "0" + String(val) : String(val);
}

void convertTotalSeconds() {
  // Convert totalSeconds into hours, minutes, and seconds
  hours = totalSeconds / 3600;
  minutes = (totalSeconds % 3600) / 60;
  seconds = totalSeconds % 60;
}

void resetTimer() {
  // Reset all time values and outputs
  hours = minutes = seconds = totalSeconds = 0;
  digitalWrite(led1Pin, LOW);
  digitalWrite(led2Pin, LOW);
  noTone(buzzerPin);
  settingStage = 0;
  Serial.println("Timer reset.");
}

void handleLEDBlink(int interval) {
  // Blink LEDs at the given interval
  if (millis() - ledBlinkMillis >= interval) {
    ledBlinkMillis = millis();
    ledState = !ledState;
    digitalWrite(led1Pin, ledState);
    digitalWrite(led2Pin, ledState);
  }
}

void showTitle(String text) {
  // Clear the title line and display centered text
  lcd.setCursor(0, 0);
  lcd.print("                "); // Clear first line
  int spaces = (16 - text.length()) / 2;
  lcd.setCursor(spaces, 0);
  lcd.print(text);
}