#include <Arduino.h>          // Required for ESP32
#include <ESP32Servo.h>       // ESP32-specific servo library
#include <LiquidCrystal_I2C.h>// I2C LCD library

// --- PIN DEFINITIONS ---
#define IR_GATE_PIN 27         // IR sensor for vehicle detection
#define IR_SPOT1_PIN 14        // IR sensor for Spot 1
#define IR_SPOT2_PIN 15        // IR sensor for Spot 2
#define SERVO_PIN 2            // Servo motor for gate control
#define RED_LED_PIN 26         // Red LED (gate closed/error)
#define GREEN_LED_PIN 25       // Green LED (gate open/success)

// Initialize LCD (address 0x27 for common I2C LCDs)
LiquidCrystal_I2C lcd(0x27, 16, 2);
Servo gate; // ESP32-compatible servo object

void setup() {
  Serial.begin(115200);
  
  // Initialize pins
  pinMode(IR_GATE_PIN, INPUT);
  pinMode(IR_SPOT1_PIN, INPUT);
  pinMode(IR_SPOT2_PIN, INPUT);
  pinMode(RED_LED_PIN, OUTPUT);
  pinMode(GREEN_LED_PIN, OUTPUT);
  
  // Attach servo with ESP32-specific PWM settings
  gate.setPeriodHertz(50); // Standard 50Hz PWM frequency
  gate.attach(SERVO_PIN, 500, 2400); // Min 500µs, max 2400µs pulse
  
  // Initialize LCD
  lcd.init();
  lcd.backlight();
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Smart Parking");
  lcd.setCursor(0, 1);
  lcd.print("Demo Mode");
  delay(2000);
  lcd.clear();

  // Start with gate closed and red LED on
  gate.write(0); 
  digitalWrite(RED_LED_PIN, HIGH);
  digitalWrite(GREEN_LED_PIN, LOW);
}

void loop() {
  // Check for vehicle approach (gate trigger)
  if (digitalRead(IR_GATE_PIN) == LOW) { // Vehicle detected
    openGate();
  }

  // Read IR sensors for spot availability
  bool spot1Available = (digitalRead(IR_SPOT1_PIN) == HIGH); // HIGH = no car (available)
  bool spot2Available = (digitalRead(IR_SPOT2_PIN) == HIGH); // HIGH = no car (available)

  // Update LCD with spot status
  updateLCD(spot1Available, spot2Available);
  delay(500); // Update LCD every 500ms
}

// Open the gate when a vehicle approaches
void openGate() {
  digitalWrite(RED_LED_PIN, LOW); // Turn off red LED
  digitalWrite(GREEN_LED_PIN, HIGH); // Turn on green LED
  gate.write(90); // Rotate servo to 90° (open gate)
  delay(2000); // Keep gate open for 2 seconds
  gate.write(0); // Close gate
  digitalWrite(GREEN_LED_PIN, LOW); // Turn off green LED
  digitalWrite(RED_LED_PIN, HIGH); // Turn on red LED
}

// Update LCD with spot availability
void updateLCD(bool spot1Avail, bool spot2Avail) {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Spot 1: ");
  lcd.print(spot1Avail ? "Available" : "Full");
  lcd.setCursor(0, 1);
  lcd.print("Spot 2: ");
  lcd.print(spot2Avail ? "Available" : "Full");
}