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

// Initialize LCD
LiquidCrystal_I2C lcd(0x27, 20, 4);

// Define input pins
const int h1p1 = 2, h1p2 = 3, h1p3 = 4;
const int h2p1 = 5, h2p2 = 6, h2p3 = 7;
const int h3p1 = 8, h3p2 = 9, h3p3 = 10;
const int h4p1 = 11, h4p2 = 12, h4p3 = 13;
const int buzzer = 1;

// Initialize home states
int homeStates[4] = {0, 0, 0, 0};
int prevHomeStates[4] = {0, 0, 0, 0};

// Buzzer timing
unsigned long buzzerStartTime = 0;
bool buzzerActive = false;
const unsigned long buzzerDuration = 2000; // 2 seconds

// Define messages
const char* welcomeMsg[] = {"WELCOME TO EMERGENCY", "    HEADQUARTER    "};
const char* emergencyMsg = "   EMERGENCY ALERT  ";
const char* homePrefix = "Home ";
const char* medicalEmerg = "MEDICAL_EMERG";
const char* rescueEmerg = "RESCUE_EMERG";
const char* securityEmerg = "SECURITY_EMER";

void setup() {
  // Initialize LCD
  lcd.init();
  lcd.backlight();
  
  // Initialize input pins
  pinMode(h1p1, INPUT_PULLUP);
  pinMode(h1p2, INPUT_PULLUP);
  pinMode(h1p3, INPUT_PULLUP);
  
  pinMode(h2p1, INPUT_PULLUP);
  pinMode(h2p2, INPUT_PULLUP);
  pinMode(h2p3, INPUT_PULLUP);
  
  pinMode(h3p1, INPUT_PULLUP);
  pinMode(h3p2, INPUT_PULLUP);
  pinMode(h3p3, INPUT_PULLUP);
  
  pinMode(h4p1, INPUT_PULLUP);
  pinMode(h4p2, INPUT_PULLUP);
  pinMode(h4p3, INPUT_PULLUP);
  pinMode(buzzer, OUTPUT);
  
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print(welcomeMsg[0]);
  lcd.setCursor(0, 1);
  lcd.print(welcomeMsg[1]);
}

void loop() {
  // Read input states
  int h1S1 = digitalRead(h1p1);
  int h1S2 = digitalRead(h1p2);
  int h1S3 = digitalRead(h1p3);
  
  int h2S1 = digitalRead(h2p1);
  int h2S2 = digitalRead(h2p2);
  int h2S3 = digitalRead(h2p3);
  
  int h3S1 = digitalRead(h3p1);
  int h3S2 = digitalRead(h3p2);
  int h3S3 = digitalRead(h3p3);
  
  int h4S1 = digitalRead(h4p1);
  int h4S2 = digitalRead(h4p2);
  int h4S3 = digitalRead(h4p3);
  
  // Determine home states
  homeStates[0] = getHomeState(h1S1, h1S2, h1S3);
  homeStates[1] = getHomeState(h2S1, h2S2, h2S3);
  homeStates[2] = getHomeState(h3S1, h3S2, h3S3);
  homeStates[3] = getHomeState(h4S1, h4S2, h4S3);
  
  // Check if home states changed
  bool statesChanged = false;
  for (int i = 0; i < 4; i++) {
    if (homeStates[i] != prevHomeStates[i]) {
      statesChanged = true;
      break;
    }
  }
  
  if (statesChanged) {
    // Copy current states to previous states
    for (int i = 0; i < 4; i++) {
      prevHomeStates[i] = homeStates[i];
    }

    // Display emergency alert or welcome message
    bool allZero = true;
    for (int i = 0; i < 4; i++) {
      if (homeStates[i] != 0) {
        allZero = false;
        break;
      }
    }

    if (allZero) {
      // Display welcome message
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print(welcomeMsg[0]);
      lcd.setCursor(0, 1);
      lcd.print(welcomeMsg[1]);
    } else {
      // Display emergency alert
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print(emergencyMsg);

      // Display home states
      int lineNumber = 1;
      int messageIndex = 0;
      for (int i = 3; i >= 0; i--) {
        if (homeStates[i] != 0) {
          lcd.setCursor(0, lineNumber);
          lcd.print(homePrefix);
          lcd.print(i + 1);
          lcd.print(" ");
          if (homeStates[i] == 1) lcd.print(medicalEmerg);
          else if (homeStates[i] == 2) lcd.print(rescueEmerg);
          else if (homeStates[i] == 3) lcd.print(securityEmerg);
          lineNumber++;
          messageIndex++;
          if (messageIndex >= 3) break;
        }
      }
      
      // Activate buzzer
      buzzerActive = true;
      buzzerStartTime = millis();
      digitalWrite(buzzer, HIGH);
    }
  }

  // Handle buzzer timing
  if (buzzerActive) {
    if (millis() - buzzerStartTime >= buzzerDuration) {
      digitalWrite(buzzer, LOW);
      buzzerActive = false; // Reset buzzer status
    }
  }

  delay(500);
}

// Function to determine home state
int getHomeState(int s1, int s2, int s3) {
  if (s1 == LOW && s2 == HIGH && s3 == HIGH) return 1;
  else if (s1 == HIGH && s2 == LOW && s3 == HIGH) return 2;
  else if (s1 == HIGH && s2 == HIGH && s3 == LOW) return 3;
  else return 0;
}