#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27,20,4);
// set the LCD address to 0x27 for a 16 chars and 2 line display

// Initialization
#define ECHO_PIN 2
#define TRIG_PIN 3

int inputPin = 1;                       // Input pin (for PIR sensor)
int pirState = LOW;                     // we start, assuming no motion detected

const int redLed = 12;
const int greenLed = 10;
const int interrupt = 13;
const int buzzerPin = 11;
const int loudness = 1000;              // loudness of the buzzer
const int timer = 100;                  // delay ( 1s )
const int min_distance = 100;           // minimum security distance ( 1 m )
const float BETA = 3950;                // should match the Beta Coefficient of the thermistor
const float min_temp = 20;              // minimum temperature to support ( °C )
const float max_temp = 40;              // maximum temperature to support ( °C )


void setup() {
  Serial.begin(115200);
  pinMode(interrupt, INPUT_PULLUP);
  pinMode(redLed, OUTPUT);
  pinMode(greenLed, OUTPUT);
  pinMode(buzzerPin, OUTPUT);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  lcd.init();	// initialize the lcd
  lcd.backlight();
  lcd.print("  --> Welcome <--   ");
	delay(2000);
	lcd.clear();
}

float readDistanceCM() {
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  int duration = pulseIn(ECHO_PIN, HIGH);
  return duration * 0.034 / 2;
}

char print_on_lcd(float distance , float celsius, char* message="info: RAS.."){
  lcd.setCursor(1,0);
	lcd.print("Distance");
	lcd.setCursor(14,0);
	lcd.print("Temp");
	lcd.setCursor(2,1);
	lcd.print(distance, 1);
	lcd.setCursor(14,1);
	lcd.print(celsius, 1);
  lcd.setCursor(1,3);
  lcd.print(message);
	delay(1000);
	lcd.clear();
 return;
}

bool checkTemp(float celsius, float distance) {
  bool temp_OutOfRange = false;
  if (celsius > max_temp || celsius < min_temp) {
      // turn on RED Led and buzzer
      tone(buzzerPin, loudness, timer);
      digitalWrite(redLed, HIGH);
      print_on_lcd(distance, celsius, "info: abnorm Temp!");
      temp_OutOfRange = true;
  }
  return temp_OutOfRange;
}

void loop() {
  // Read interrupt state
  int interruptState = digitalRead(interrupt);
  // Get the distance
  float distance = readDistanceCM();
  // If distance < 1m ring the buzzer
  bool isNearby = distance < min_distance;
  // Read Motion sensor state
  int motionState = digitalRead(inputPin);
  // Read analogValue from Temperature sensor
  int analogValue = analogRead(A0);
  float celsius = 1 / (log(1 / (1023. / analogValue - 1)) / BETA + 1.0 / 298.15) - 273.15;

  if (interruptState == HIGH && isNearby == false && motionState == LOW && checkTemp(celsius, distance) == false){
    print_on_lcd(distance, celsius);
    checkTemp(celsius, distance);
  }
  // If interrupt is ON and Distance < min_distance
  if (interruptState == HIGH && isNearby == true) {
    if (motionState == HIGH && pirState == LOW){
      pirState = HIGH;
      // turn on GREEN led
      digitalWrite(greenLed, HIGH);
      print_on_lcd(distance, celsius, "info: Mov detect!");
    }
    // turn on RED Led and buzzer
    tone(buzzerPin, loudness, timer);
    digitalWrite(redLed, HIGH);
    print_on_lcd(distance, celsius, "info: Too close!");
    checkTemp(celsius, distance);
  }
  // If interrupt is ON and Distance > min_distance and Motion detected
  if (interruptState == HIGH && isNearby == false && motionState == HIGH){
    if (pirState == LOW) {
      pirState = HIGH;
    }
    // turn on Green LED
    digitalWrite(greenLed, HIGH);
    print_on_lcd(distance, celsius, "info: Mov detect!");
    checkTemp(celsius, distance);

  } else { // If interrupt is OFF = Nothing happens
    if (pirState == HIGH) {
        pirState = LOW;
      }
    // turn off LEDs and buzzer
    digitalWrite(redLed, LOW);
    digitalWrite(greenLed, LOW);
    noTone(buzzerPin);
    lcd.clear();
  }
}