#include <Wire.h>
#include <Adafruit_SSD1306.h>
#include <Servo.h>

// OLED Display setup
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 32
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

// Bluetooth setup
char voiceCommand;

// Ultrasonic Sensor setup
#define trigPin 12
#define echoPin 13
long duration;
int distance;

// L293D Motor Driver Shield pins (already predefined by the shield)
#define M1 3  // Motor A - Left Front (Enable Pin)
#define M2 11 // Motor B - Right Front (Enable Pin)
#define M3 5  // Motor C - Left Rear (Enable Pin)
#define M4 6  // Motor D - Right Rear (Enable Pin)

// IR Sensors
#define IR_LEFT 4
#define IR_RIGHT 2

// Servo setup for Ultrasonic sensor rotation
Servo myServo;

void setup() {
  // Motor pins setup (pwm speed control for motors)
  pinMode(M1, OUTPUT);
  pinMode(M2, OUTPUT);
  pinMode(M3, OUTPUT);
  pinMode(M4, OUTPUT);

  // IR Sensors
  pinMode(IR_LEFT, INPUT);
  pinMode(IR_RIGHT, INPUT);

  // Ultrasonic sensor setup
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);

  // Servo setup
  myServo.attach(3);
  myServo.write(90); // Start with the sensor facing forward

  // Bluetooth Serial setup
  Serial.begin(9600);

  // OLED Display initialization
  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println(F("SSD1306 allocation failed"));
    for(;;);
  }
  display.clearDisplay();
}

void loop() {
  // Check for Bluetooth command
  if (Serial.available() > 0) {
    voiceCommand = Serial.read();
    controlCar(voiceCommand);
  }

  // Display distance measured by the ultrasonic sensor on OLED
  displayDistance();
}

void controlCar(char command) {
  switch (command) {
    case 'F':  // Move Forward
      moveForward();
      break;
    case 'B':  // Move Backward
      moveBackward();
      break;
    case 'L':  // Turn Left
      turnLeft();
      break;
    case 'R':  // Turn Right
      turnRight();
      break;
    case 'S':  // Stop
      stopCar();
      break;
    default:
      stopCar();
  }
}

// Control functions for the motors using the shield

void moveForward() {
  analogWrite(M1, 255);  // Full speed forward for left front motor
  analogWrite(M2, 255);  // Full speed forward for right front motor
  analogWrite(M3, 255);  // Full speed forward for left rear motor
  analogWrite(M4, 255);  // Full speed forward for right rear motor
}

void moveBackward() {
  analogWrite(M1, 0);  // Reverse left front motor
  analogWrite(M2, 0);  // Reverse right front motor
  analogWrite(M3, 0);  // Reverse left rear motor
  analogWrite(M4, 0);  // Reverse right rear motor
}

void turnLeft() {
  analogWrite(M1, 0);  // Stop left front motor
  analogWrite(M2, 255);  // Full speed right front motor
  analogWrite(M3, 0);  // Stop left rear motor
  analogWrite(M4, 255);  // Full speed right rear motor
}

void turnRight() {
  analogWrite(M1, 255);  // Full speed left front motor
  analogWrite(M2, 0);    // Stop right front motor
  analogWrite(M3, 255);  // Full speed left rear motor
  analogWrite(M4, 0);    // Stop right rear motor
}

void stopCar() {
  analogWrite(M1, 0);  // Stop all motors
  analogWrite(M2, 0);
  analogWrite(M3, 0);
  analogWrite(M4, 0);
}

void displayDistance() {
  // Send trigger pulse
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  // Read echo pulse
  duration = pulseIn(echoPin, HIGH);
  distance = duration * 0.034 / 2;

  // Display the distance on the OLED
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0, 0);
  display.print("Distance: ");
  display.print(distance);
  display.println(" cm");
  display.display();
}