#include <Arduino.h>
#include <LiquidCrystal.h>

#define TOGGLE_LED_PIN 5
#define INCREMENT_PIN 6
#define DECREMENT_PIN 7
#define MAIN_LED_PIN 8
#define AUX_LED_PIN 9

LiquidCrystal lcdDisplay(A0, A1, A2, A3, A4, A5);

bool isLedOn = false;
int blinkDuration = 1000;
unsigned long systemStartTime; // Variable to store the system start time

const int MIN_BLINK_DURATION = 100;
const int MAX_BLINK_DURATION = 2000;
const int LCD_COLUMNS = 16;
const int LCD_ROWS = 2;

void setup() {
  pinMode(TOGGLE_LED_PIN, INPUT);
  pinMode(INCREMENT_PIN, INPUT);
  pinMode(DECREMENT_PIN, INPUT);
  pinMode(MAIN_LED_PIN, OUTPUT);
  pinMode(AUX_LED_PIN, OUTPUT);

  Serial.begin(9600);
  lcdDisplay.begin(LCD_COLUMNS, LCD_ROWS);

  // Configure Timer1 for auxiliary LED blinking
  TCCR1A = 0;
  TCCR1B = 0;
  TCCR1B |= (1 << CS11) | (1 << CS10); // 64 prescaler
  TCNT1 = 40535; // Reload value for timer
  TIMSK1 |= (1 << TOIE1); // Enable timer overflow interrupt

  systemStartTime = millis(); // Record system start time
}

ISR(TIMER1_OVF_vect) {
  TCNT1 = 40535; // Reload timer value
  digitalWrite(LED_BUILTIN, !digitalRead(LED_BUILTIN)); // Toggle AUX LED
}

void loop() {
  handleButtonAndLed();
  taskBlinkAuxLed();
  taskChangeBlinkDuration();
  displaySystemUptime(); // New task to display system uptime
}

void refreshLcd() {
  lcdDisplay.clear();
  lcdDisplay.print("LED is ");
  lcdDisplay.print(isLedOn ? "On " : "Off");

  lcdDisplay.setCursor(0, 1);
  lcdDisplay.print("Blink:");
  lcdDisplay.print(blinkDuration);
  lcdDisplay.print("ms");
}

void handleButtonAndLed() {
  static bool previousButtonState = LOW;
  bool currentButtonState = digitalRead(TOGGLE_LED_PIN);
  if (currentButtonState != previousButtonState && currentButtonState == HIGH) {
    isLedOn = !isLedOn;
    analogWrite(MAIN_LED_PIN, isLedOn ? 255 : 0);
    refreshLcd();
  }
  previousButtonState = currentButtonState;
}

void taskBlinkAuxLed() {
  static unsigned long lastMillis = 0;
  if (!isLedOn && (millis() - lastMillis >= blinkDuration)) {
    lastMillis = millis();
    digitalWrite(AUX_LED_PIN, !digitalRead(AUX_LED_PIN));
  } else if (isLedOn) {
    digitalWrite(AUX_LED_PIN, LOW);
  }
}

void taskChangeBlinkDuration() {
  if (digitalRead(INCREMENT_PIN) == HIGH) {
    blinkDuration = max(MIN_BLINK_DURATION, blinkDuration - 100);
    refreshLcd();
    delay(200);
  } else if (digitalRead(DECREMENT_PIN) == HIGH) {
    blinkDuration = min(MAX_BLINK_DURATION, blinkDuration + 100);
    refreshLcd();
    delay(200);
  }
}

void displaySystemUptime() {
  static unsigned long lastDisplayTime = 0;
  unsigned long currentTime = millis();

  // Update the display every 5 seconds
  if (currentTime - lastDisplayTime >= 5000) {
    unsigned long uptime = currentTime - systemStartTime; // Calculate system uptime
    lcdDisplay.setCursor(0, 0);
    lcdDisplay.print("Uptime: ");
    lcdDisplay.print(uptime / 1000); // Convert milliseconds to seconds
    lcdDisplay.print("s");
    lastDisplayTime = currentTime; // Update the last display time
  }
}