// ESP32 Door Interlocking System with Emergency Mode, Serial Commands, and Fast Blinking

const int doorButtons[] = {12, 13, 14};      // Door control buttons
const int emergencyButton = 27;              // Emergency button
const int redLEDs[] = {4, 18, 21};           // Red LEDs for doors (locked)
const int greenLEDs[] = {2, 5, 19};          // Green LEDs for doors (unlocked)

bool doorStates[] = {false, false, false};   // Track door states
unsigned long doorTimers[] = {0, 0, 0};
bool emergencyMode = false;
bool lastEmergencyState = false;

void setup() {
  Serial.begin(115200);
  for (int i = 0; i < 3; i++) {
    pinMode(doorButtons[i], INPUT_PULLUP);
    pinMode(redLEDs[i], OUTPUT);
    pinMode(greenLEDs[i], OUTPUT);
    digitalWrite(redLEDs[i], HIGH);
    digitalWrite(greenLEDs[i], LOW);
  }
  pinMode(emergencyButton, INPUT_PULLUP);
  Serial.println("System Ready. All doors locked.");
}

void loop() {
  handleSerial();
  handleButtons();
  handleTimers();
  if (emergencyMode) blinkAllFast();
}

void handleSerial() {
  if (Serial.available()) {
    String cmd = Serial.readStringUntil('\n');
    cmd.trim();
    if (cmd == "door1") openDoor(0);
    else if (cmd == "door2") openDoor(1);
    else if (cmd == "door3") openDoor(2);
    else if (cmd == "emergency") toggleEmergency();
    else Serial.println("Unknown command");
  }
}

void handleButtons() {
  for (int i = 0; i < 3; i++) {
    if (digitalRead(doorButtons[i]) == LOW) {
      delay(100);
      if (!emergencyMode) openDoor(i);
    }
  }
  bool currentEmergencyState = digitalRead(emergencyButton) == LOW;
  if (currentEmergencyState && !lastEmergencyState) {
    toggleEmergency();
  }
  lastEmergencyState = currentEmergencyState;
}

void openDoor(int door) {
  if (emergencyMode) {
    Serial.println("Emergency mode: All doors already open.");
    return;
  }
  if (anyOtherOpen(door)) {
    Serial.print("Access Denied: Door ");
    Serial.print(door + 1);
    Serial.println(" cannot open while another door is open.");
    return;
  }
  doorStates[door] = true;
  doorTimers[door] = millis();
  digitalWrite(redLEDs[door], LOW);
  digitalWrite(greenLEDs[door], HIGH);
  Serial.print("Door "); Serial.print(door + 1); Serial.println(" opened.");
}

bool anyOtherOpen(int skip) {
  for (int i = 0; i < 3; i++) {
    if (i != skip && doorStates[i]) return true;
  }
  return false;
}

void handleTimers() {
  if (emergencyMode) return;
  for (int i = 0; i < 3; i++) {
    if (doorStates[i] && millis() - doorTimers[i] >= 10000) {
      lockDoor(i);
    }
  }
}

void lockDoor(int door) {
  doorStates[door] = false;
  digitalWrite(redLEDs[door], HIGH);
  digitalWrite(greenLEDs[door], LOW);
  Serial.print("Door "); Serial.print(door + 1); Serial.println(" locked.");
}

void toggleEmergency() {
  emergencyMode = !emergencyMode;
  if (emergencyMode) {
    Serial.println("EMERGENCY MODE ACTIVATED! All doors unlocked!");
    forceOpenAll();
  } else {
    Serial.println("EMERGENCY MODE DEACTIVATED! All doors locked.");
    for (int i = 0; i < 3; i++) lockDoor(i);
  }
}

void forceOpenAll() {
  for (int i = 0; i < 3; i++) {
    doorStates[i] = true;
    digitalWrite(redLEDs[i], HIGH);
    digitalWrite(greenLEDs[i], HIGH);
  }
}

void blinkAllFast() {
  static unsigned long lastBlink = 0;
  static bool on = false;
  if (millis() - lastBlink >= 100) {
    on = !on;
    for (int i = 0; i < 3; i++) {
      digitalWrite(redLEDs[i], on);
      digitalWrite(greenLEDs[i], on);
    }
    lastBlink = millis();
  }
}