#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

//--------------- OLED ----------------------------------------
// Initialise the display
#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels

// Declaration for an SSD1306 display connected to I2C (SDA, SCL pins)
#define OLED_RESET     4 // Reset pin # (or -1 if sharing Arduino reset pin)
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

//Define Pins
#define OLED_RESET 4
#define BEEPER 3

//Define Visuals
#define FONT_SIZE 2
#define SCREEN_WIDTH 127  //real size minus 1, because coordinate system starts with 0
#define SCREEN_HEIGHT 63  //real size minus 1, because coordinate system starts with 0
#define BALL_SIZE 3
#define SCORE_PADDING 10

float ballX = SCREEN_WIDTH/2;
float ballY = SCREEN_HEIGHT/2;
float ballSpeedX = 1;
float ballSpeedY = 1;

int scoreA = 0;
int scoreB = 0;

//--------------- SETUP Y LOOP ----------------------------------------
void setup() 
{
  display.begin(SSD1306_SWITCHCAPVCC, 0x3D);  // initialize with the I2C addr 0x3D (for the 128x64)
  // initialise the display
  // SSD1306_SWITCHCAPVCC = generate display voltage from 3.3V internally
  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { // Address 0x3C for 128x64
    Serial.println(F("SSD1306 allocation failed"));
    for (;;); // Don't proceed, loop forever
  } 
  display.setTextWrap(false);
  display.setTextColor(WHITE);
  display.setTextSize(FONT_SIZE);
  display.clearDisplay(); 
}

void loop()
{
  calculateMovement();
  draw();
}
//-------------------------------------------------------

void calculateMovement() 
{
  ballX += ballSpeedX;
  ballY += ballSpeedY;

  //bounce from top, bottom, left and right
  if (ballY >= SCREEN_HEIGHT - BALL_SIZE || ballY <= 0 || ballX >= SCREEN_WIDTH - BALL_SIZE || ballX <= 0) {
    if (ballY >= SCREEN_HEIGHT - BALL_SIZE || ballY <= 0) {
      ballSpeedY *= -1;
    }
    if (ballX >= SCREEN_WIDTH - BALL_SIZE || ballX <= 0) {
      ballSpeedX *= -1;
    }
    soundBounce();
  }

  //score points if ball hits wall behind paddle
  if (ballX >= SCREEN_WIDTH - BALL_SIZE || ballX <= 0) {
    if (ballSpeedX > 0) {
      scoreA++;
      soundBounce();
    }
    //
    if (ballSpeedX < 0) {
      scoreB++;
      soundBounce();
    }

    soundPoint();   
  }
}

void draw() 
{
  display.clearDisplay(); 

  //draw center line
  for (int i=0; i<SCREEN_HEIGHT; i+=4) {
    display.drawFastVLine(SCREEN_WIDTH/2, i, 2, WHITE);
  }

  //draw ball
  display.fillRect(ballX,ballY,BALL_SIZE,BALL_SIZE,WHITE);

  //print scores

  //backwards indent score A. This is dirty, but it works ... ;)
  int scoreAWidth = 5 * FONT_SIZE;
  if (scoreA > 9) scoreAWidth += 6 * FONT_SIZE;
  if (scoreA > 99) scoreAWidth += 6 * FONT_SIZE;
  if (scoreA > 999) scoreAWidth += 6 * FONT_SIZE;
  if (scoreA > 9999) scoreAWidth += 6 * FONT_SIZE;

  display.setCursor(SCREEN_WIDTH/2 - SCORE_PADDING - scoreAWidth,0);
  display.print(scoreA);

  display.setCursor(SCREEN_WIDTH/2 + SCORE_PADDING+1,0); //+1 because of dotted line.
  display.print(scoreB);
  
  display.display();
} 

void soundStart() 
{
  tone(BEEPER, 250);
  delay(100);
  tone(BEEPER, 500);
  delay(100);
  tone(BEEPER, 1000);
  delay(100);
  noTone(BEEPER);
}

void soundBounce() 
{
  tone(BEEPER, 500, 50);
}

void soundPoint() 
{
  tone(BEEPER, 150, 150);
}