#include "U8glib.h"

U8GLIB_SSD1306_128X64 u8g(U8G_I2C_OPT_DEV_0 | U8G_I2C_OPT_NO_ACK | U8G_I2C_OPT_FAST);

bool useBuzzer = false;

// Joystick
float joystickX = 0.0;
float joystickY = 0.0;
bool joystickPressed = false;
bool joystickPressCheck = false;
bool joystickJustPressed = false;

// Cursor
int cursorX = 128 - 12;
int cursorY = 64 - 12;

// Menu
int selectedApp = 0;
bool appSelected = false;

// Keyboard App
const char* keyboardDisplay = "";

// Bitmaps
static unsigned char cursorBitmap[] = {
   0x01, 0x00, 0x06, 0x00, 0x1e, 0x00, 0x7c, 0x00, 0xfc, 0x00, 0x78, 0x00,
   0x38, 0x00, 0x10, 0x00, 0x00, 0x00, 0x00, 0x00 };

char *apps[] =
{
  "Keyboard",
  "Snake"
};

void setup()
{
  // Joystick
  pinMode(2, INPUT);
  digitalWrite(2, HIGH);
  Serial.begin(115200);

  // Buzzer
  if (useBuzzer)
    Serial.begin(9600);

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

void loop()
{
  // Joystick
  joystickX = getJoystickX();
  joystickY = getJoystickY();
  joystickPressed = getJoystickPressed();

  // Cursor
  cursorX += round(joystickX * 10);
  cursorY -= round(joystickY * 10);

  if (cursorX < 0) cursorX = 0;
  if (cursorX > (128 - 10)) cursorX = (128 - 1);

  if (cursorY < 0) cursorY = 0;
  if (cursorY > (64 - 10)) cursorY = (64 - 1);

  // Click
  joystickJustPressed = checkForPress();

  // Screen
  u8g.firstPage();

  do
  {
    if (!appSelected)
    {
      u8g.setPrintPos(5, 15);
    
      for (int i = 0; i < (sizeof(apps) / sizeof(apps[0])); i++)
      {
        if (buttonPressed(2, (17 * i) + 2, 100, 15, apps[i]))
        {
          selectedApp = i;
          appSelected = true;
        }
      }
    }
    else
    {
      if (selectedApp == 0)
      {
        if (buttonPressed(2, 2, 10, 13, "q")) keyboardDisplay = join(keyboardDisplay, "q");
        if (buttonPressed(14, 2, 10, 13, "w")) keyboardDisplay = join(keyboardDisplay, "w");
        if (buttonPressed(26, 2, 10, 13, "e")) keyboardDisplay = join(keyboardDisplay, "e");
        if (buttonPressed(38, 2, 10, 13, "r")) keyboardDisplay = join(keyboardDisplay, "r");
        if (buttonPressed(50, 2, 10, 13, "t")) keyboardDisplay = join(keyboardDisplay, "t");
        if (buttonPressed(62, 2, 10, 13, "y")) keyboardDisplay = join(keyboardDisplay, "y");
        if (buttonPressed(74, 2, 10, 13, "u")) keyboardDisplay = join(keyboardDisplay, "u");
        if (buttonPressed(86, 2, 10, 13, "i")) keyboardDisplay = join(keyboardDisplay, "i");
        if (buttonPressed(98, 2, 10, 13, "o")) keyboardDisplay = join(keyboardDisplay, "o");
        if (buttonPressed(110, 2, 10, 13, "p")) keyboardDisplay = join(keyboardDisplay, "p");
        if (buttonPressed(2, 17, 10, 13, "a")) keyboardDisplay = join(keyboardDisplay, "a");
        if (buttonPressed(14, 17, 10, 13, "s")) keyboardDisplay = join(keyboardDisplay, "s");
        if (buttonPressed(26, 17, 10, 13, "d")) keyboardDisplay = join(keyboardDisplay, "d");
        if (buttonPressed(38, 17, 10, 13, "f")) keyboardDisplay = join(keyboardDisplay, "f");
        if (buttonPressed(50, 17, 10, 13, "g")) keyboardDisplay = join(keyboardDisplay, "g");
        if (buttonPressed(62, 17, 10, 13, "h")) keyboardDisplay = join(keyboardDisplay, "h");
        if (buttonPressed(74, 17, 10, 13, "j")) keyboardDisplay = join(keyboardDisplay, "j");
        if (buttonPressed(86, 17, 10, 13, "k")) keyboardDisplay = join(keyboardDisplay, "k");
        if (buttonPressed(98, 17, 10, 13, "l")) keyboardDisplay = join(keyboardDisplay, "l");
        if (buttonPressed(110, 17, 10, 13, "z")) keyboardDisplay = join(keyboardDisplay, "z");
        if (buttonPressed(2, 32, 10, 13, "x")) keyboardDisplay = join(keyboardDisplay, "x");
        if (buttonPressed(14, 32, 10, 13, "c")) keyboardDisplay = join(keyboardDisplay, "c");
        if (buttonPressed(26, 32, 10, 13, "v")) keyboardDisplay = join(keyboardDisplay, "v");
        if (buttonPressed(38, 32, 10, 13, "b")) keyboardDisplay = join(keyboardDisplay, "b");
        if (buttonPressed(50, 32, 10, 13, "n")) keyboardDisplay = join(keyboardDisplay, "n");
        if (buttonPressed(62, 32, 10, 13, "m")) keyboardDisplay = join(keyboardDisplay, "m");
        if (buttonPressed(74, 32, 10, 13, " ")) keyboardDisplay = join(keyboardDisplay, " ");
        if (buttonPressed(86, 32, 34, 13, "DEL")) keyboardDisplay = backspace(keyboardDisplay);

        if (buttonPressed(116, 47, 10, 13, "<")) appSelected = false;

        u8g.drawStr(3, 60, keyboardDisplay);
      }
    }

    u8g.drawXBM(cursorX, cursorY, 10, 10, cursorBitmap);
    joystickJustPressed = false;
  }
  while ( u8g.nextPage() );
}

bool checkForPress()
{
  if (joystickPressCheck != joystickPressed)
  {
    bool returnWhat = false;

    if (joystickPressCheck == false)
      returnWhat = true;

    joystickPressCheck = joystickPressed;

    return returnWhat;
  }

  return false;
}

float getJoystickX() { return 0 - (analogRead(0) / 1023.0 * 2 - 1); }
float getJoystickY() { return analogRead(1) / 1023.0 * 2 - 1; }
bool getJoystickPressed() { return digitalRead(2) == 0 ? true : false; }

bool buttonPressed(int x, int y, int w, int h, const char* text)
{
  u8g.drawBox(x, y, w, h);

  u8g.setColorIndex(0);
  u8g.drawStr(x + 1, y + 11, text);
  u8g.setColorIndex(1);

  if (cursorX > (x - 1) && cursorX < (x + (w + 1)) && cursorY > (y - 1) && cursorY < (y + (h + 1)) && joystickJustPressed)
    return true;

  return false;
}

char* join(char* str1, char* str2)
{
  char* result = (char*)malloc(strlen(str1) + strlen(str2) + 1);

  strcpy(result, str1);
  strcat(result, str2);

  return result;
}

char* backspace(char* str)
{
  char* result = str;

  result[strlen(result) - 1] = '\0';

  return result;
}