#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 CONTROL_A A0

//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 PADDLE_WIDTH 4
#define PADDLE_HEIGHT 10
#define PADDLE_PADDING 10
#define SCORE_PADDING 10

int paddleLocationA = 0;
int paddleLocationB = 0;

int lastPaddleLocationA = 0;
int lastPaddleLocationB = 0;

int scoreA = 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() 
{
  int controlA = analogRead(CONTROL_A); // Ambos paddles se mueven por la salida de un mismo potenciometro.

  paddleLocationA = map(controlA, 0, 1023, 0, SCREEN_HEIGHT - PADDLE_HEIGHT);
  paddleLocationB = map(controlA, 0, 1023, 0, SCREEN_HEIGHT - PADDLE_HEIGHT); // Paddle B tiene los mismos movimientos de paddle A

  int paddleSpeedA = paddleLocationA - lastPaddleLocationA;
  int paddleSpeedB = paddleLocationB - lastPaddleLocationB;

  //set last paddle locations
  lastPaddleLocationA = paddleLocationA;
  lastPaddleLocationB = paddleLocationB;  
  scoreA = paddleLocationA;
}

void draw() 
{
  display.clearDisplay(); 

  //--------------- Dibujar paddles ----------------------------------------
  //draw paddle A
  display.fillRect(PADDLE_PADDING,paddleLocationA,PADDLE_WIDTH,PADDLE_HEIGHT,WHITE);

  //draw paddle B
  display.fillRect(SCREEN_WIDTH-PADDLE_WIDTH-PADDLE_PADDING,paddleLocationB,PADDLE_WIDTH,PADDLE_HEIGHT,WHITE);

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

  //--------------- Puntaje equivalente a posición en Y ----------------------------------------
  int scoreAWidth = 5 * FONT_SIZE;
  if (scoreA > 9) scoreAWidth += 6 * FONT_SIZE;
  if (scoreA > 99) scoreAWidth += 6 * FONT_SIZE;

  // Se ubica el cursor en la posición del valor izquierdo.
  display.setCursor(SCREEN_WIDTH/2 - SCORE_PADDING - scoreAWidth,0);
  // Se imprime para actualizar el valor.
  display.print(scoreA);

  // Se ubica el cursor en la posición del valor derecho.
  display.setCursor(SCREEN_WIDTH/2 + SCORE_PADDING+1,0); //+1 because of dotted line.
  // Se imprime para actualizar el valor.
  display.print(scoreA);
  
  display.display();
}