//Include the necessary libraries
#include <Ultrasonic.h>
#include <Tone.h>

//Define the pins for the ultrasonic sensor, buzzer and LED
#define trigPin 7
#define echoPin 8
#define buzzerPin 9
#define ledPin 13

//Create an instance of the Ultrasonic and Tone libraries
Ultrasonic ultrasonic(trigPin, echoPin);
Tone buzzer;

//Create a variable to store the distance value
int distance;

//Create a variable to keep track of whether the song has been played or not
bool songPlayed = false;

//Create a variable to keep track of the time the song has been playing
unsigned long songStartTime;

//Create an array to store the notes for the song
int song[14] = {NOTE_C4,NOTE_C4,NOTE_G4,NOTE_G4,NOTE_A4,NOTE_A4,NOTE_G4,NOTE_F4,NOTE_F4,NOTE_E4,NOTE_E4,NOTE_D4,NOTE_D4,NOTE_C4};

//Create an array to store the duration of the notes
int duration[14] = {4,4,4,4,4,4,4,4,4,4,4,4,4,4};

void setup() {
  //Initialize the serial communication
  Serial.begin(9600);
  
  //Set the LED pin to output mode
  pinMode(ledPin, OUTPUT);
  
  //Turn on the red LED by default
  digitalWrite(ledPin, HIGH);
}

void loop() {
  //Get the distance value from the ultrasonic sensor
  distance = ultrasonic.distanceRead(CM);
  
  //Print the distance value to the serial monitor
  Serial.println(distance);
  
  //Check if the distance is less than 6 cm
  if(distance < 6) {
    //Turn off the red LED
    digitalWrite(ledPin, LOW);
  }
  else {
    //Turn on the red LED
    digitalWrite(ledPin, HIGH);
  }

  // Check if the red LED is turned off
  if(digitalRead(ledPin) == LOW) {
    //Check if the song has not been played
    if(!songPlayed) {
      //Play the song note by note
      for(int i=0; i<14; i++) {
        buzzer.play(song[i], duration[i]*500);
        delay(duration[i]*500);
      }
      //Mark the song as played and store the start time
      songPlayed = true;
      songStartTime = millis();
    } else {
        // Check if the song has been playing for 30 seconds
        if (millis() -songStartTime >= 30000){
            //stop playing the song
            buzzer.stop();
            songPlayed = false;
        }
    }
  }
  else {
    //Reset songPlayed variable
    songPlayed = false;
  }
  
  //Delay for 100 milliseconds
  delay(100);
}

// #step #2, buzzer to start the music and make it fun