#include <Servo.h> //includes the servo library
#include <Wire.h> 
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27,16,2);

Servo myservo;

#define ir_enter 7
#define ir_back  6

#define ir_car1 10
#define ir_car2 9
#define ir_car3 8

int S1=0, S2=0, S3=0;
int flag1=0, flag2=0; 
int slot = 3;  

void setup(){
Serial.begin(9600);

pinMode(ir_car1, INPUT);
pinMode(ir_car2, INPUT);
pinMode(ir_car3, INPUT);

pinMode(ir_enter, INPUT);
pinMode(ir_back, INPUT);
  
myservo.attach(3);
myservo.write(90);

lcd.begin(16, 2);  
lcd.setCursor (0,0);
lcd.print("    Car  parking  ");
lcd.setCursor (0,1);
lcd.print("       System     ");
delay (2000);
lcd.clear();   

Read_Sensor();

int total = S1+S2+S3;
slot = slot-total; 
}

void loop(){

Read_Sensor();

lcd.setCursor (0,0);
lcd.print("HaveSlot:"); 
lcd.print(slot);
lcd.print("    ");  

lcd.setCursor (11,0);
if(S1==1){lcd.print("S1:F");}
     else{lcd.print("S1:E");}

lcd.setCursor (0,1);
if(S2==1){lcd.print("S2:F");}
     else{lcd.print("S2:E");}

lcd.setCursor (9,1);
if(S3==1){lcd.print("S3:F");}
     else{lcd.print("S3:E");}
   

if(digitalRead (ir_enter) == 0 && flag1==0){
if(slot>0){flag1=1;
if(flag2==0){myservo.write(180); slot = slot-1;}
}else{
lcd.setCursor (0,0);
lcd.print(" Sorry Parking Full ");  
delay(1500);
}   
}

if(digitalRead (ir_back) == 0 && flag2==0){flag2=1;
if(flag1==0){myservo.write(180); slot = slot+1;}
}

if(flag1==1 && flag2==1){
delay (1000);
myservo.write(90);
flag1=0, flag2=0;
}

delay(1);
}

void Read_Sensor(){
S1=0, S2=0, S3=0;

if(digitalRead(ir_car1) == 0){S1=1;}
if(digitalRead(ir_car2) == 0){S2=1;}
if(digitalRead(ir_car3) == 0){S3=1;} 
}