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

// Pin Definitions based on your diagram.json
#define BUTTON_SEAT   13
#define BUTTON_DROWSY 12
#define BUTTON_DOOR   14
#define BUZZER        27

// Initialize LCD: address 0x27 is standard for 16x2 I2C displays in Wokwi
LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup() {
  Serial.begin(115200);
  
  // Configure input pins with internal pull-up resistors
  pinMode(BUTTON_SEAT, INPUT_PULLUP);
  pinMode(BUTTON_DROWSY, INPUT_PULLUP);
  pinMode(BUTTON_DOOR, INPUT_PULLUP);
  
  // Configure buzzer pin
  pinMode(BUZZER, OUTPUT);
  noTone(BUZZER); // Ensure buzzer starts silent

  // Initialize LCD
  lcd.init();
  lcd.backlight();
  
  // Welcome screen
  lcd.setCursor(0, 0);
  lcd.print("  SYSTEM READY  ");
  delay(2000);
  lcd.clear();
}

void loop() {
  // Read button states (LOW = Pressed/Active, HIGH = Released/Normal)
  bool isSeatBeltUnfastened = (digitalRead(BUTTON_SEAT) == LOW);
  bool isDriverDrowsy       = (digitalRead(BUTTON_DROWSY) == LOW);
  bool isDoorOpen           = (digitalRead(BUTTON_DOOR) == LOW);

  bool triggerAlarm = false;
  int toneFrequency = 1000; // Default warning frequency (1000 Hz)
  
  lcd.setCursor(0, 0);

  // System State Logic Priority
  if (isDriverDrowsy) {
    lcd.print("! DROWSY ALERT !");
    lcd.setCursor(0, 1);
    lcd.print("  WAKE UP DRIVER ");
    toneFrequency = 1500; // High urgency pitch
    triggerAlarm = true;
  } 
  else if (isDoorOpen) {
    lcd.print("WARNING: DOOR   ");
    lcd.setCursor(0, 1);
    lcd.print("IS NOT CLOSED!  ");
    toneFrequency = 800;  // Medium urgency pitch
    triggerAlarm = true;
  } 
  else if (isSeatBeltUnfastened) {
    lcd.print("WARNING: FASTEN ");
    lcd.setCursor(0, 1);
    lcd.print("YOUR SEATBELT!  ");
    toneFrequency = 500;  // Lower urgency pitch
    triggerAlarm = true;
  } 
  else {
    // Normal Operating Conditions
    lcd.print("STATUS: SAFE    ");
    lcd.setCursor(0, 1);
    lcd.print("DRIVE CAREFULLY ");
    triggerAlarm = false;
  }

  // Handle Buzzer Audio Signal
  if (triggerAlarm) {
    // Play the tone at the designated frequency
    tone(BUZZER, toneFrequency);
    delay(150);
    noTone(BUZZER);
    delay(150);
  } else {
    noTone(BUZZER);
    delay(200); // Small stability delay when state is normal
  }
}