#include <Wire.h>
#include <LedControl.h>

// Define pins for buzzer, ultrasonic sensor, LEDs, and emergency button
const int trigPin = 9;          // Arduino pin for ultrasonic sensor trigger
const int echoPin = 10;         // Arduino pin for ultrasonic sensor echo
const int buzzerPin = 2;        // Arduino pin for buzzer
const int redLedPin = 4;        // Arduino pin for red LED
const int yellowLedPin = 5;     // Arduino pin for yellow LED
const int greenLedPin = 6;      // Arduino pin for green LED
const int emergencyButtonPin = 2; // Arduino pin for emergency button

// MAX7219 matrix configuration
const int dataIn = 11;  // DIN pin of MAX7219 connected to Arduino digital pin 11
const int load = 12;    // CS pin of MAX7219 connected to Arduino digital pin 12
const int clock = 13;   // CLK pin of MAX7219 connected to Arduino digital pin 13
const int devicesInUse = 1; // Number of MAX7219 devices in the chain

LedControl lc = LedControl(dataIn, clock, load, devicesInUse); // Initialize the MAX7219 library

void setup() {
  Serial.begin(9600); // Initialize serial communication for distance display
  pinMode(trigPin, OUTPUT);           // Trigger pin of ultrasonic sensor as output
  pinMode(echoPin, INPUT);            // Echo pin of ultrasonic sensor as input
  pinMode(buzzerPin, OUTPUT);         // Buzzer pin as output
  pinMode(redLedPin, OUTPUT);         // Red LED pin as output
  pinMode(yellowLedPin, OUTPUT);      // Yellow LED pin as output
  pinMode(greenLedPin, OUTPUT);       // Green LED pin as output
  pinMode(emergencyButtonPin, INPUT_PULLUP); // Emergency button pin as input

  // Initialize the MAX7219 matrix display
  lc.shutdown(0, false);       // Wake up the MAX7219 (turn off shutdown)
  lc.setIntensity(0, 8);       // Set brightness level (0 is min, 15 is max)
  lc.clearDisplay(0);          // Clear the display register

  // Display initial message or setup
  lc.setDigit(0, 7, 'H', false); // Example: Display 'H' at position 7 (character 0, digit 7)
  lc.setDigit(0, 6, 'E', false); // Example: Display 'E' at position 6 (character 0, digit 6)
  lc.setDigit(0, 5, 'L', false); // Example: Display 'L' at position 5 (character 0, digit 5)
  lc.setDigit(0, 4, 'P', false); // Example: Display 'P' at position 4 (character 0, digit 4)
  delay(1000);  // Delay to display the message for a moment
  lc.clearDisplay(0); // Clear the display after initial message
}

void loop() {
  // Check if the emergency button is pressed
  if (digitalRead(emergencyButtonPin) == LOW) {
    triggerEmergencyAlert();
    delay(1000); // Debounce delay
  }

  // Generate random distance between 10 and 1000 cm
  int distance = random(10, 1000);

  // Print distance to Serial Monitor
  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");

  // Display distance on MAX7219 matrix
  displayDistanceOnMatrix(distance);

  // Determine feedback based on distance
  if (distance < 200) {
    // Close obstacle: Red LED and high frequency buzzer sound
    digitalWrite(redLedPin, HIGH);
    digitalWrite(yellowLedPin, LOW);
    digitalWrite(greenLedPin, LOW);
    tone(buzzerPin, 384); // High frequency
  } else if (distance < 500) {
    // Medium distance: Yellow LED and medium frequency buzzer sound
    digitalWrite(redLedPin, LOW);
    digitalWrite(yellowLedPin, HIGH);
    digitalWrite(greenLedPin, LOW);
    tone(buzzerPin, 341); // Medium frequency
  } else {
    // Clear path: Green LED and low frequency buzzer sound
    digitalWrite(redLedPin, LOW);
    digitalWrite(yellowLedPin, LOW);
    digitalWrite(greenLedPin, HIGH);
    tone(buzzerPin, 256); // Low frequency
  }

  // Delay to control the frequency of readings
  delay(1000); // Adjust delay according to your preference

  // Stop the buzzer tone after the delay
  noTone(buzzerPin);

  // Turn off all LEDs at the end of each loop iteration
  digitalWrite(redLedPin, LOW);
  digitalWrite(yellowLedPin, LOW);
  digitalWrite(greenLedPin, LOW);
}

void triggerEmergencyAlert() {
  // Clear MAX7219 display
  lc.clearDisplay(0);

  // Display emergency message on MAX7219 matrix
  lc.setRow(0, 0, B11111111); // Example: Display a row of LEDs to represent an emergency alert
}

void displayDistanceOnMatrix(int distance) {
  // Example function to display distance on MAX7219 matrix
  // Convert distance to a string
  String distanceStr = String(distance);

  // Display distance string on MAX7219 matrix (up to 4 digits)
  int len = distanceStr.length();
  for (int i = 0; i < len; i++) {
    lc.setDigit(0, i, distanceStr.charAt(i), false); // Display each character of distance
  }

  // Clear remaining digits if distance is less than 4 digits
  for (int i = len; i < 4; i++) {
    lc.setDigit(0, i, ' ', false); // Clear the digit
  }
}