#include <SPI.h>

#include <MFRC522.h>

#include <LiquidCrystal_I2C.h>

#include <Wire.h>

#include <Servo.h>

#define RST_PIN         5          // Configurable, see typical pin layout above

#define SS_PIN          53         // Configurable, see typical pin layout above

MFRC522 mfrc522(SS_PIN, RST_PIN);  // Create MFRC522 instance

LiquidCrystal_I2C lcd(0x27,16,2);

String uid1 = "53 2C 91 0D";

String uid2 = "32 D7 46 1E";


Servo myservo1;

int IR1 = 2;
int IR2 = 4;

int Slot = 4;           //Enter Total number of parking Slots

int flag1 = 0;
int flag2 = 0;

int A = 0;

void setup()
{

  lcd.backlight();
  pinMode(IR1, INPUT);
  pinMode(IR2, INPUT);
  
  myservo1.attach(3);
  myservo1.write(0);

  lcd.init(); 

  lcd.init();

  Serial.begin(9600);   // Initiate a serial communication

  SPI.begin();      // Initiate  SPI bus

  mfrc522.PCD_Init();   // Initiate MFRC522

  Serial.println("Approximate your card to the reader...");

  Serial.println();

}

void loop() 
{
  String content= "";

  for (byte i = 0; i < mfrc522.uid.size; i++)
  {

    Serial.print(mfrc522.uid.uidByte[i] < 0x10 ? " 0" : " ");

    Serial.print(mfrc522.uid.uidByte[i], HEX);

    content.concat(String(mfrc522.uid.uidByte[i] < 0x10 ? " 0" : " "));

    content.concat(String(mfrc522.uid.uidByte[i], HEX));

  }

  String allowedUIDs[] = {"uid1", "uid2"};

  int numAllowedUIDs = sizeof(allowedUIDs) / sizeof(allowedUIDs[0]);
  bool uidMatched = false;

  for (int i = 0; i < numAllowedUIDs; i++) {
  if (content == allowedUIDs[i]) 
  {
    uidMatched = true;
    break;
  }
  }


   // Reset the loop if no new card present on the sensor/reader. This saves the entire process when idle.

  if ( ! mfrc522.PICC_IsNewCardPresent()) 
  {
    return;
  }
  // Select one of the cards

  if ( ! mfrc522.PICC_ReadCardSerial())
  {
    return;
  }


  Serial.print("UID tag :");
  byte letter;
  content.toUpperCase();

  if(digitalRead (IR1) == LOW && flag1==0)
  {
    if(Slot>0)
    {

      if (uidMatched && A==0)
      {
        flag1=1;
        A=1;
        if(flag2==0)
        {
          lcd.setCursor (0,0);
          lcd.print("Welcome Mr.Ali");
          myservo1.write(90); Slot = Slot-1;
        }
      }

      else
      {
        Serial.println(" Access Denied");

        lcd.setCursor(3,0);

        lcd.clear();

        lcd.print("Unknown");

        lcd.setCursor(0,1);

        lcd.print("Access Denied");
    
        delay(3000);

        lcd.clear();
      }
    }
  
    else
    {
      lcd.setCursor (0,0);
      lcd.print("    SORRY :(    ");  
      lcd.setCursor (0,1);
      lcd.print("  Parking Full  "); 
      delay (3000);
      lcd.clear(); 
    }
  }

  if(digitalRead (IR2) == LOW && flag2==0)
  {
    flag2=1;
    if (uidMatched && A==1)
    {
      if(flag1==0)
      {
         lcd.setCursor (0,0);
          lcd.print("Goodbye Mr.Ali");
        myservo1.write(90); Slot = Slot+1;
      }
    }
  }

  if(flag1==1 && flag2==1)
  {
    delay (1000);
    myservo1.write(0);
    flag1=0, flag2=0;
  }
  
  lcd.setCursor(0,0);
  lcd.print("    Scan Tag    ");
  lcd.setCursor (0,1);
  lcd.print("Slot Left: ");
  lcd.print(Slot);
  delay(1000);
  }