#include <PinChangeInterrupt.h>
#include <TimerOne.h>

const int motionPin = 2;       // Pin for the PIR motion sensor (INT0)
const int irPin = 3;           // Pin for the IR sensor (INT1)
const int buttonPin = 4;       // Pin for the pushbutton (PCINT)
const int ledPin = 12;         // Pin for the LED to be triggered by all sensors

volatile bool motionDetected = false; // Volatile variable to track motion
volatile bool irDetected = false;     // Volatile variable to track IR detection
volatile bool buttonPressed = false;  // Volatile variable to track button press

bool motionPrint = false;             // Flags to control printing
bool irPrint = false;
bool buttonPrint = false;

unsigned long lastDebounceTime = 0;   // Debounce time
unsigned long debounceDelay = 50;     // Debounce delay
unsigned long ledLastDetectedTime = 0; // Last time LED was triggered
unsigned long ledOffDelay = 1000;      // Delay to turn off LED

void setup() {
  pinMode(motionPin, INPUT);
  pinMode(irPin, INPUT);
  pinMode(buttonPin, INPUT_PULLUP); // Enable internal pull-up resistor
  pinMode(ledPin, OUTPUT);
  Serial.begin(9600);  // Initialize Serial communication for UART
  Serial.println("Arduino 1 ready!");

  // Set up the external interrupts for motion and IR sensors
  attachInterrupt(digitalPinToInterrupt(motionPin), motionISR, RISING);
  attachInterrupt(digitalPinToInterrupt(irPin), irISR, RISING);

  // Set up Pin Change Interrupt for the button
  attachPCINT(digitalPinToPCINT(buttonPin), buttonISR, CHANGE);

  // Set up TimerOne interrupt
  Timer1.initialize(1000000); // Set timer to 1 second (1,000,000 microseconds)
  Timer1.attachInterrupt(timerISR);

  // Initial state of the LED
  digitalWrite(ledPin, LOW);
}

void loop() {
  // Turn off LED after delay
  if ((motionDetected || irDetected || buttonPressed) && (millis() - ledLastDetectedTime >= ledOffDelay)) {
    digitalWrite(ledPin, LOW); // Turn off external LED
    motionDetected = false;
    irDetected = false;
    buttonPressed = false;
  }

  // Print and send motion detected message if flag is set
  if (motionPrint) {
    Serial.println("Motion detected");
    sendSensorData("motion");
    motionPrint = false;
  }

  // Print and send IR detected message if flag is set
  if (irPrint) {
    Serial.println("IR sensor triggered");
    sendSensorData("ir");
    irPrint = false;
  }

  // Print and send button pressed message if flag is set
  if (buttonPrint) {
    Serial.println("Button pressed");
    sendSensorData("button");
    buttonPrint = false;
  }

  delay(1000); // Delay for 1 second
}

// ISR for motion sensor
void motionISR() {
  motionDetected = true;
  motionPrint = true;
  ledLastDetectedTime = millis();
  digitalWrite(ledPin, HIGH); // Turn on external LED
}

// ISR for IR sensor
void irISR() {
  irDetected = true;
  irPrint = true;
  ledLastDetectedTime = millis();
  digitalWrite(ledPin, HIGH); // Turn on external LED
}

// ISR for pushbutton using Pin Change Interrupt
void buttonISR() {
  unsigned long currentTime = millis();
  if ((currentTime - lastDebounceTime) > debounceDelay) {
    buttonPressed = true;
    buttonPrint = true;
    ledLastDetectedTime = currentTime;
    digitalWrite(ledPin, HIGH); // Turn on external LED
    lastDebounceTime = currentTime;
  }
}

// Timer interrupt service routine (ISR)
void timerISR() {
  // Toggle the built-in LED
  digitalWrite(LED_BUILTIN, !digitalRead(LED_BUILTIN));
  Serial.println("Timer interrupt: LED toggled");
}

// Function to send sensor data to the second Arduino
void sendSensorData(const char* sensorType) {
  if (strcmp(sensorType, "motion") == 0) {
    Serial.println("Sending: Motion Detected");
  } else if (strcmp(sensorType, "ir") == 0) {
    Serial.println("Sending: IR Detected");
  } else if (strcmp(sensorType, "button") == 0) {
    Serial.println("Sending: Button Pressed");
  }
}