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

// Countdown Timer with LCD Output in Minutes and Seconds, LED indicator (Custom Buttons for Start, Reset, Increase, Decrease)

const int startButtonPin = 12;    // Pin for the start button input
const int resetButtonPin = 13;    // Pin for the reset button input
const int increaseButtonPin = 19; // Pin for the increase button input
const int decreaseButtonPin = 18; // Pin for the decrease button input
const int ledPin = 17;            // Pin for the LED indicator

unsigned long startTime;
unsigned long countdownDuration = 5 * 60 * 1000;  // 5 minutes in milliseconds
unsigned long lastUpdateTime = 0;
unsigned long updateInterval = 1000;  // Update interval in milliseconds
bool timerActive = false;

// Variables for button debouncing
unsigned long debounceDelay = 50;  // Debounce time in milliseconds
unsigned long lastStartButtonState = HIGH;
unsigned long lastResetButtonState = HIGH;
unsigned long lastIncreaseButtonState = HIGH;
unsigned long lastDecreaseButtonState = HIGH;
unsigned long startButtonState;
unsigned long resetButtonState;
unsigned long increaseButtonState;
unsigned long decreaseButtonState;

// Initialize the LCD
LiquidCrystal_I2C lcd(0x27, 20, 4);  // Set the LCD address to 0x27 for a 20 chars and 4 line display

void setup() {
  pinMode(startButtonPin, INPUT_PULLUP);
  pinMode(resetButtonPin, INPUT_PULLUP);
  pinMode(increaseButtonPin, INPUT_PULLUP);
  pinMode(decreaseButtonPin, INPUT_PULLUP);
  pinMode(ledPin, OUTPUT);
  lcd.init();                      // Initialize the LCD
  lcd.backlight();                 // Turn on the backlight
  
  lcd.setCursor(0, 0);
  lcd.print("----Robots Live-----");
  lcd.setCursor(0, 2);
  lcd.print("Battle Controller v2");
  lcd.setCursor(0, 3);
  lcd.print("--------------------");

  delay(5000);
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Press start button");
  lcd.setCursor(0, 1);
  lcd.print("to begin timer");

  Serial.begin(9600);
}

void loop() {
  // Read the state of the start button
  startButtonState = digitalRead(startButtonPin);

  // Check if the start button has been pressed and debounced
  if (startButtonState != lastStartButtonState) {
    delay(debounceDelay);
    if (startButtonState != lastStartButtonState) {
      if (startButtonState == LOW) {
        startTimer();
      }
    }
  }

  // Read the state of the reset button
  resetButtonState = digitalRead(resetButtonPin);

  // Check if the reset button has been pressed and debounced
  if (resetButtonState != lastResetButtonState) {
    delay(debounceDelay);
    if (resetButtonState != lastResetButtonState) {
      if (resetButtonState == LOW) {
        resetTimer();
      }
    }
  }

  // Read the state of the increase button
  increaseButtonState = digitalRead(increaseButtonPin);

  // Check if the increase button has been pressed and debounced
  if (increaseButtonState != lastIncreaseButtonState) {
    delay(debounceDelay);
    if (increaseButtonState != lastIncreaseButtonState) {
      if (increaseButtonState == LOW) {
        increaseTime();
      }
    }
  }

  // Read the state of the decrease button
  decreaseButtonState = digitalRead(decreaseButtonPin);

  // Check if the decrease button has been pressed and debounced
  if (decreaseButtonState != lastDecreaseButtonState) {
    delay(debounceDelay);
    if (decreaseButtonState != lastDecreaseButtonState) {
      if (decreaseButtonState == LOW) {
        decreaseTime();
      }
    }
  }

  // Continue updating the timer if it's active
  if (timerActive) {
    updateTimer();
  }

  // Update LED indicator
  digitalWrite(ledPin, timerActive ? HIGH : LOW);

  // Update the last button states
  lastStartButtonState = startButtonState;
  lastResetButtonState = resetButtonState;
  lastIncreaseButtonState = increaseButtonState;
  lastDecreaseButtonState = decreaseButtonState;
}

void startTimer() {
  Serial.println("Countdown Timer Started");
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Countdown started");
  startTime = millis();  // Record the start time
  timerActive = true;
}

void updateTimer() {
  unsigned long currentTime = millis();
  unsigned long elapsedTime = currentTime - startTime;

  if (elapsedTime >= countdownDuration) {
    // Countdown has reached 0, indicate completion
    Serial.println("Countdown Complete");
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Countdown complete");
    timerActive = false;
  }

  // Check if it's time to update
  if (currentTime - lastUpdateTime >= updateInterval) {
    lastUpdateTime = currentTime;

    unsigned long remainingTime = countdownDuration - elapsedTime;
    unsigned long remainingMinutes = remainingTime / (60 * 1000);
    unsigned long remainingSeconds = (remainingTime % (60 * 1000)) / 1000;

    // Output remaining time to LCD
    lcd.setCursor(0, 2);
    lcd.print("Time left: ");
    lcd.print(remainingMinutes);
    lcd.print("m ");
    lcd.print(remainingSeconds);
    lcd.print("s ");
  }
}

void resetTimer() {
  Serial.println("Timer Reset");
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Timer reset");
  while (digitalRead(resetButtonPin) == LOW) {
    // Wait for the reset button to be released
  }
  lcd.setCursor(0, 2);
  lcd.print("                 ");
  lcd.setCursor(0, 3);
  lcd.print("                 ");
  lcd.setCursor(0, 0);
  lcd.print("Press start button");
  lcd.setCursor(0, 1);
  lcd.print("to begin timer");
  timerActive = false;
}

void increaseTime() {
  countdownDuration += 10 * 1000;  // Increase by 10 seconds
  Serial.print("Increased time to: ");
  Serial.print(countdownDuration / (60 * 1000));
  Serial.print(" minutes and ");
  Serial.print((countdownDuration % (60 * 1000)) / 1000);
  Serial.println(" seconds");

  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Increased time to: ");
  lcd.print(countdownDuration / (60 * 1000));
  lcd.print("m ");
  lcd.print((countdownDuration % (60 * 1000)) / 1000);
  lcd.print("s ");
}

void decreaseTime() {
  if (countdownDuration > 10 * 1000) {
    countdownDuration -= 10 * 1000;  // Decrease by 10 seconds
    Serial.print("Decreased time to: ");
    Serial.print(countdownDuration / (60 * 1000));
    Serial.print(" minutes and ");
    Serial.print((countdownDuration % (60 * 1000)) / 1000);
    Serial.println(" seconds");

    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Decreased time to: ");
    lcd.print(countdownDuration / (60 * 1000));
    lcd.print("m ");
    lcd.print((countdownDuration % (60 * 1000)) / 1000);
    lcd.print("s ");
  }
}