// Define pin assignments
const int LED_PIN = 9;
const int BTN1_PIN = 2;
const int BTN2_PIN = 3;
const int POT1_PIN = A0;
const int POT2_PIN = A1;
const int POT3_PIN = A2;

// Define debounce delay
const unsigned long DEBOUNCE_DELAY = 150;

// Define state persistence delay
const unsigned long STATE_PERSISTENCE_DELAY = 2000;

// Define transition time for Auto Mode
const unsigned long TRANSITION_TIME = 2000;

// Variables to track the current state
bool isManualMode = true;
unsigned long lastStateChangeTime = 0;

// Variables for button debouncing
bool btn1LastState = HIGH;
bool btn2LastState = HIGH;
unsigned long lastBtn1DebounceTime = 0;
unsigned long lastBtn2DebounceTime = 0;

// Variables for Auto Mode
unsigned long lastTransitionTime = 0;
bool isIncreasing = true;
int currentBrightness = 0;

void setup() {
  // Initialize pins
  pinMode(LED_PIN, OUTPUT);
  pinMode(BTN1_PIN, INPUT_PULLUP);
  pinMode(BTN2_PIN, INPUT_PULLUP);

  // Initialize the LED to off at startup
  analogWrite(LED_PIN, 0);
}

void loop() {
  unsigned long currentTime = millis();

  // Read button states
  bool btn1Reading = digitalRead(BTN1_PIN);
  bool btn2Reading = digitalRead(BTN2_PIN);

  // Handle button 1 debouncing
  if (btn1Reading != btn1LastState) {
    lastBtn1DebounceTime = currentTime;
  }

  // Handle button 2 debouncing
  if (btn2Reading != btn2LastState) {
    lastBtn2DebounceTime = currentTime;
  }

  // Check if a debounced button 1 press has occurred
  if ((currentTime - lastBtn1DebounceTime) > DEBOUNCE_DELAY) {
    if (btn1Reading == LOW && btn1LastState == HIGH) {
      // Button 1 has been pressed
      if (isManualMode && (currentTime - lastStateChangeTime) > STATE_PERSISTENCE_DELAY) {
        // Switch to Auto Mode
        isManualMode = false;
        lastStateChangeTime = currentTime;
        lastTransitionTime = currentTime;
        isIncreasing = true;
      }
    }
  }

  // Check if a debounced button 2 press has occurred
  if ((currentTime - lastBtn2DebounceTime) > DEBOUNCE_DELAY) {
    if (btn2Reading == LOW && btn2LastState == HIGH) {
      // Button 2 has been pressed
      if (!isManualMode && (currentTime - lastStateChangeTime) > STATE_PERSISTENCE_DELAY) {
        // Switch to Manual Mode
        isManualMode = true;
        lastStateChangeTime = currentTime;
      }
    }
  }

  // Update button states
  btn1LastState = btn1Reading;
  btn2LastState = btn2Reading;

  // Handle the current mode
  if (isManualMode) {
    // In Manual Mode, control the LED brightness with pot1
    int pot1Value = analogRead(POT1_PIN);
    int brightness = map(pot1Value, 0, 1023, 0, 255);
    analogWrite(LED_PIN, brightness);
  } else {
    // In Auto Mode, cycle the LED brightness between min and max values

    // Read the min and max brightness from pot2 and pot3
    int minBrightness = map(analogRead(POT2_PIN), 0, 1023, 0, 255);
    int maxBrightness = map(analogRead(POT3_PIN), 0, 1023, 0, 255);

    // Ensure minBrightness is not greater than maxBrightness
    if (minBrightness > maxBrightness) {
      int temp = minBrightness;
      minBrightness = maxBrightness;
      maxBrightness = temp;
    }

    // Calculate the time elapsed since the last transition
    unsigned long elapsedTime = currentTime - lastTransitionTime;

    // Calculate the new brightness based on the elapsed time
    if (isIncreasing) {
      // Increasing brightness
      currentBrightness = map(elapsedTime, 0, TRANSITION_TIME, minBrightness, maxBrightness);

      if (elapsedTime >= TRANSITION_TIME) {
        isIncreasing = false;
        lastTransitionTime = currentTime;
      }
    } else {
      // Decreasing brightness
      currentBrightness = map(elapsedTime, 0, TRANSITION_TIME, maxBrightness, minBrightness);

      if (elapsedTime >= TRANSITION_TIME) {
        isIncreasing = true;
        lastTransitionTime = currentTime;
      }
    }

    // Apply the brightness to the LED
    analogWrite(LED_PIN, currentBrightness);
  }
}