#define PIN_TRIGL 10
#define PIN_ECHOL 9
#define LED_L 11
#define PIN_TRIGR 8
#define PIN_ECHOR 7
#define LED_R 6

#include <LiquidCrystal_I2C.h>

#define I2C_ADDR    0x27
#define LCD_COLUMNS 16
#define LCD_LINES   2
int parkings = 0;
LiquidCrystal_I2C lcd(I2C_ADDR, LCD_COLUMNS, LCD_LINES);
void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  pinMode(LED_R,OUTPUT);
  pinMode(LED_L,OUTPUT);
  pinMode(PIN_TRIGL, OUTPUT);
  pinMode(PIN_ECHOL, INPUT);
  pinMode(PIN_TRIGR, OUTPUT);
  pinMode(PIN_ECHOR, INPUT);
  lcd.init();
  lcd.backlight();
  // Print something
  lcd.setCursor(0, 0);
  lcd.print("Smart Parking");
  lcd.setCursor(3, 1);
  lcd.print("System");
  delay(1000);
}
int LeftOn = 0;
int RightOn = 0;
int status = 0;
void loop() {
  // put your main code here, to run repeatedly:
  digitalWrite(PIN_TRIGL, HIGH);
  delayMicroseconds(10);
  digitalWrite(PIN_TRIGL, LOW);
  // Read the result:
  int duration1 = pulseIn(PIN_ECHOL, HIGH);
  int cm1 = duration1 / 58;
  digitalWrite(PIN_TRIGR, HIGH);
  delayMicroseconds(10);
  digitalWrite(PIN_TRIGR, LOW);
  int duration2 = pulseIn(PIN_ECHOR, HIGH);
  int cm2 = duration2 / 58;
  Serial.print("Distance in CM on Left Sensor: ");
  Serial.println(cm1);
  Serial.print("Distance in CM on Right Sensor: ");
  Serial.println(cm2);
  if (cm1 < 100){
    digitalWrite(LED_L,1);
    if (LeftOn==0){
      parkings += 1;
      LeftOn = 1;
    }
  }
  else {
    digitalWrite(LED_L,0);
    if (LeftOn==1){
      parkings -= 1;
      LeftOn = 0;
    }
  }
  if (cm2 < 100){
    digitalWrite(LED_R,1);
    if (RightOn==0){
      parkings += 1;
      RightOn = 1;
    }
  }
  else {
    digitalWrite(LED_R,0);
    if (RightOn==1){
      parkings -= 1;
      RightOn = 0;
    }
  }
  
  if (LeftOn == 0 && RightOn == 0){
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Empty Parking.");
    status = 0;
  }
  else {
    lcd.clear();
    if (LeftOn == 0){
      lcd.setCursor(0, 0);
      lcd.print("L_Parking Free");
    }
    else if (RightOn == 0){
      lcd.setCursor(0, 0);
      lcd.print("R_Parking Free");
    }
    // if (status == 0){
    // lcd.clear();
    lcd.setCursor(0, 1);
    lcd.print("Total Parkings:");
    lcd.print((parkings));
    delay(200);
    // status = 1;
    // }
  }
  
}