#include "U8glib.h"
//#include "SdFat.h"

// U8glib
U8GLIB_SSD1306_128X64 u8g(U8G_I2C_OPT_DEV_0); // Add " | U8G_I2C_OPT_NO_ACK | U8G_I2C_OPT_FAST" if the screen isn't working

// Classes
#include "bitmaps.h"

// Pins
#define jsXPin 0
#define jsYPin 1
#define jsSWPin 2
//#define mcSDPin 10

// Screen
#define screenWidth 128
#define screenHeight 64

// MicroSD
//#define SPI_SPEED SD_SCK_MHZ(4)
//#define CS_PIN 10
//SdFat SD;
//File SDroot;

// Joystick
byte jsX = 0;
byte jsY = 0;
bool jsXReversed = false;
bool jsYReversed = false;
bool jsSW = false;
bool jsSWD = false;

// Cursor
byte cursorX = round(screenWidth / 2);
byte cursorY = round(screenHeight / 2);
bool hideCursor = false;
#define cursorSpeed 10

// Snake Variables
byte snakeX = 0;
byte snakeY = 0;
byte appleX = 0;
byte appleY = 0;
byte snakeDirection = 0;
byte snakeTimer = 0;
byte snakePoints = 0;

// Application Class
typedef struct
{
  unsigned char* bits;
  byte width;
  byte height;
} application;

// Home
byte selectedApp = 0;
bool appSelected = false;
application apps[] =
{
  {notesBMP_bits, notesBMP_width, notesBMP_height},
  {snakeBMP_bits, snakeBMP_width, snakeBMP_height},
};

void setup()
{
  // Joystick
  digitalWrite(jsSWPin, HIGH);

  // MicroSD
  //SD.begin(mcSDPin, SPI_SPEED);
  //SDroot = SD.open("/");

  // Screen
  u8g.setFont(u8g_font_tpssb);
  u8g.setColorIndex(1);
}

void loop()
{
  // Joystick
  getJoystickInput();

  // Cursor
  cursorX = constrain(cursorX + ((jsXReversed ? -1 : 1) * round(jsX * 0.1 * cursorSpeed)), 0, screenWidth - 1);
  cursorY = constrain(cursorY - ((jsYReversed ? -1 : 1) * round(jsY * 0.1 * cursorSpeed)), 0, screenHeight - 1);
  hideCursor = false;

  // Screen
  u8g.firstPage();
  do
  {
    if (!appSelected)
      draw();
    else
    {
      switch (selectedApp)
      {
        case 0:
          notesDraw();
          break;
        case 1:
          snakeDraw();
          break;
      }
    }

    // Joystick
    jsSWD = false;

    // Cursor
    if (!hideCursor)
      u8g.drawXBM(cursorX, cursorY, cursorBMP_width, cursorBMP_height, cursorBMP_bits);
  } while ( u8g.nextPage() );
}

void draw()
{
  // Applications
  byte x = 2, y = 2;
  for (byte i = 0; i < (sizeof apps / sizeof apps[0]); i++)
  {
    application app = apps[i];

    if (bitmapPressed(x, y, app.width, app.height, app.bits))
    {
      selectedApp = i;

      switch (selectedApp)
      {
        case 1:
          snakeX = round(round(screenWidth / 2) / 2) * 2;
          snakeY = round(round(screenHeight / 2) / 2) * 2;
          appleX = round(randomNumber(0, screenWidth - 1) / 2) * 2;
          appleY = round(randomNumber(20, screenHeight - 1) / 2) * 2;
          snakeDirection = 0;
          snakeTimer = 0;
          snakePoints = 0;
          break;
      }

      appSelected = true;
    }

    x += app.width + 2;

    if (x > screenWidth)
    {
      x = 2;
      y += app.height + 2;
    }
  }

  u8g.drawStr(1, screenHeight - 2, "Welcome user!");
}

void getJoystickInput()
{
  int oldJsX = (0.0 - (analogRead(jsXPin) / 1023.0 * 2 - 1)) * 10;
  int oldJsY = (analogRead(jsYPin) / 1023.0 * 2 - 1) * 10;

  jsX = round(abs(oldJsX));
  jsY = round(abs(oldJsY));

  jsXReversed = oldJsX < 0;
  jsYReversed = oldJsY < 0;

  bool reading = !digitalRead(jsSWPin);

  if (jsSW != reading)
  {
    jsSW = reading;

    if (jsSW == true)
      jsSWD = true;
  }
  else
    jsSWD = false;
}

bool bitmapPressed(int x, int y, int w, int h, unsigned char* bits)
{
  u8g.drawXBM(x, y, w, h, bits);
  return cursorX > (x - 1) && cursorX < (x + w + 1) && cursorY > (y - 1) && cursorY < (y + h + 1) && jsSWD;
}

int randomNumber(int minValue, int maxValue)
{
  randomSeed(millis() + maxValue * minValue);
  return random(minValue, maxValue);
}

// Applications

void notesDraw()
{
  
}

void snakeDraw()
{
  // Cursor
  cursorX = round(screenWidth / 2);
  cursorY = round(screenHeight / 2);
  hideCursor = true;

  // Joysick
  if (jsSWD) appSelected = false;
  if (round(jsX) > 0 && !jsXReversed) snakeDirection = 0;
  if (round(jsY) > 0 && !jsYReversed) snakeDirection = 1;
  if (round(jsX) > 0 && jsXReversed) snakeDirection = 2;
  if (round(jsY) > 0 && jsYReversed) snakeDirection = 3;

  if (snakeTimer > 10)
  {
    snakeTimer = 0;

    switch (snakeDirection)
    {
      case 0:
        snakeX += 2;
        break;
      case 1:
        snakeY -= 2;
        break;
      case 2:
        snakeX -= 2;
        break;
      case 3:
        snakeY += 2;
        break;
    }
  }
  else
    snakeTimer++;

  // Screen
  u8g.drawBox(snakeX, snakeY, 2, 2);
  u8g.drawBox(appleX, appleY, 2, 2);

  // Apple
  if (snakeX == appleX && snakeY == appleY)
  {
    appleX = round(randomNumber(0, screenWidth - 1) / 2) * 2;
    appleY = round(randomNumber(20, screenHeight - 1) / 2) * 2;

    snakePoints++;
  }

  if (snakeX < 2) snakeX = round((screenWidth - 2) / 2) * 2;
  if (snakeX > screenWidth + 4) snakeX = 2;
  if (snakeY < 20) snakeY = round((screenHeight - 2) / 2) * 2;
  if (snakeY > screenHeight + 4) snakeY = 20;

  u8g.drawStr(5, 15, "Apples:");
  u8g.setPrintPos(50, 15);
  u8g.print(snakePoints);
}