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

#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels
#define OLED_RESET    -1 // Reset pin # (or -1 if sharing Arduino reset pin)

#define PIXEL_WIDTH 4
#define PIXEL_HEIGHT 4

#define TILE_WIDTH  8
#define TILE_HEIGHT 8

#define COUNT_TILES 216
#define MAX_FRAMES_ANIMATION_WALKING 3

#define CENTER 8
#define WALK_CYCLE_COUNT 32

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

const uint8_t guiTileDatabase[COUNT_TILES] = {
    0b00000000, 0b00000111, 0b00001000, 0b00011011, 0b01100001, 0b10000011,
    0b11110000, 0b01000000, 0b00000000, 0b11000000, 0b00100000, 0b00010000,
    0b10010000, 0b10001000, 0b00001000, 0b00001000, 0b00111110, 0b00011000,
    0b00101000, 0b00111000, 0b00001100, 0b00110011, 0b01010010, 0b01111110,
    0b00010000, 0b01010000, 0b10001000, 0b11101000, 0b00100100, 0b11000100,
    0b10101010, 0b11111110, 0b00000000, 0b00000000, 0b00000011, 0b00000100,
    0b00001101, 0b00110000, 0b01000001, 0b01111000, 0b00000000, 0b00000000,
    0b11100000, 0b00010000, 0b10001000, 0b11001000, 0b11000100, 0b00000100,
    0b00100000, 0b00011111, 0b00001100, 0b00010100, 0b00010100, 0b00011010,
    0b00101001, 0b00111111, 0b00000100, 0b00001000, 0b00101000, 0b01000100,
    0b01010100, 0b00100010, 0b11010101, 0b01111111, 0b00000111, 0b01111000,
    0b10000001, 0b01110011, 0b00001011, 0b00001000, 0b00111000, 0b01000000,
    0b11100000, 0b00100000, 0b10010000, 0b00010000, 0b00001000, 0b00001000,
    0b00001000, 0b00001000, 0b00000000, 0b00000000, 0b00000011, 0b00000100,
    0b00001100, 0b00110000, 0b01000010, 0b01110001, 0b00000000, 0b00000000,
    0b11100000, 0b00010000, 0b00001000, 0b00001000, 0b00000100, 0b10000100,
    0b01111111, 0b10010000, 0b10011111, 0b10110101, 0b10101010, 0b10011111,
    0b10000000, 0b01111111, 0b11111100, 0b00010010, 0b11110010, 0b01011010,
    0b10101010, 0b11110010, 0b00000010, 0b11111100, 0b00111111, 0b01001000,
    0b01001111, 0b01011010, 0b01010101, 0b01001111, 0b01000000, 0b00111111,
    0b11111110, 0b00001001, 0b11111001, 0b10101101, 0b01010101, 0b11111001,
    0b00000001, 0b11111110, 0b00000000, 0b00000000, 0b00000111, 0b00001000,
    0b00010001, 0b01100010, 0b10000000, 0b11111000, 0b00000000, 0b00000000,
    0b11000000, 0b00100000, 0b00010000, 0b00010000, 0b00001000, 0b00001000,
    0b01000100, 0b01110000, 0b10001000, 0b11111000, 0b00001000, 0b00110100,
    0b01010011, 0b01111110, 0b00001000, 0b00011100, 0b00000010, 0b00011110,
    0b01001000, 0b10000100, 0b10101010, 0b11111110, 0b00000111, 0b01111000,
    0b10000001, 0b01110010, 0b00001000, 0b00001000, 0b00111000, 0b01000000,
    0b11100000, 0b00100000, 0b10010000, 0b01010000, 0b00001000, 0b00001000,
    0b00001000, 0b00001000, 0b00000000, 0b00000000, 0b00000011, 0b00000100,
    0b00001100, 0b00110000, 0b01000001, 0b01111000, 0b00000000, 0b00000000,
    0b11100000, 0b00010000, 0b00001000, 0b00001000, 0b00000100, 0b11000100,
    0b00000000, 0b00000000, 0b11100000, 0b00010000, 0b00001000, 0b00001000,
    0b11000100, 0b00000100, 0b00000000, 0b01100000, 0b11111000, 0b11111110,
    0b11111111, 0b11111110, 0b11111000, 0b01100000, 0b00000000, 0b00000000,
    0b00000000, 0b00000000, 0b00000000, 0b00000000, 0b00000000, 0b00000000,
};

const uint16_t guiSpriteTileIndexAgumon0[] = {0, 8, 16, 24};
const uint16_t guiSpriteTileIndexAgumon1[] = {32, 40, 48, 56};
const uint16_t guiSpriteTileIndexAgumon2[] = {64, 72, 16, 24};
const uint16_t guiSpriteTileIndexAgumon3[] = {80, 88, 96, 104};
const uint16_t guiSpriteTileIndexAgumon4[] = {80, 88, 112, 120};
const uint16_t guiSpriteTileIndexAgumon5[] = {128, 136, 144, 152};
const uint16_t guiSpriteTileIndexAgumon6[] = {160, 168, 16, 24};
const uint16_t guiSpriteTileIndexAgumon7[] = {176, 184, 48, 56};
const uint16_t guiSpriteTileIndexAgumon8[] = {176, 192, 48, 56};
const uint16_t guiSpriteTileIndexAgumon9[] = {200};

const uint8_t *const guiDigimonProjectileSprites = &guiTileDatabase[200];

const uint16_t
    *const guiDigimonWalkingAnimationDatabase[MAX_FRAMES_ANIMATION_WALKING] = {
        guiSpriteTileIndexAgumon0, guiSpriteTileIndexAgumon1,
         guiSpriteTileIndexAgumon2,
};

static const int8_t uiWalkCycleMove[WALK_CYCLE_COUNT] = {
    -2, -2, 0, 2, 0,  -2, -2, 2, -2, -2, 2,  0, 0,  0,  2,  2,
    2,  2,  2, 0, -2, 0,  2,  0, 2,  2,  -2, 2, -2, -2, -2, -2};
static const uint8_t uiWalkCycleFlips[WALK_CYCLE_COUNT] = {0, 0, 1, 1, 0, 0, 0, 1, 0, 0, 0,
                                           0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 1,
                                           1, 0, 1, 1, 1, 1, 1, 0, 0, 0};
static const uint8_t uiWalkCycleIndices[WALK_CYCLE_COUNT] = {
0, 1, 1, 0, 0, 1, 1, 1, 1, 2, 1,
2, 1, 1, 1, 0, 0, 0, 1, 1, 0, 0,
0, 1, 1, 2, 1, 2, 1, 1, 0, 0};

void drawTile(uint8_t* tile, uint8_t x, uint8_t y, bool flip) {
  for (size_t i = y; i < y + TILE_HEIGHT; i++) {
    uint8_t currentLine = *tile;
      
    if (flip) {
      currentLine = (currentLine & 0xF0) >> 4 |
                          (currentLine & 0x0F) << 4;
      currentLine = (currentLine & 0xCC) >> 2 |
                          (currentLine & 0x33) << 2;
      currentLine = (currentLine & 0xAA) >> 1 |
                          (currentLine & 0x55) << 1;
    }

    for (size_t j = x; j < x + TILE_WIDTH; j++) {
      const uint8_t currentPixel = (currentLine & 0b10000000) >> 7;
      currentLine <<= 1;

      if (currentPixel) {
        display.fillRect(
          j * PIXEL_WIDTH, 
          i * PIXEL_HEIGHT, 
          PIXEL_WIDTH, 
          PIXEL_HEIGHT, 
          SSD1306_BLACK
        );
      }
    }
    tile++;
  }
}

void drawSprite(uint16_t* sprite, uint8_t x, uint8_t y, bool flip) {
  uint8_t xLeft = flip ? x + TILE_WIDTH : x;
  uint8_t xRight = flip ? x : x + TILE_WIDTH;

  drawTile(guiTileDatabase + sprite[0], xLeft, y, flip);
  drawTile(guiTileDatabase + sprite[1], xRight, y, flip);
  drawTile(guiTileDatabase + sprite[2], xLeft, y + TILE_HEIGHT, flip);
  drawTile(guiTileDatabase + sprite[3], xRight, y + TILE_HEIGHT, flip);
}

static uint8_t indexWalkCycle = 0xff;
static uint8_t xPos = CENTER;

void setup() {
  Serial.begin(9600);

  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3c)) {
    Serial.println(F("SSD1306 allocation failed"));
    for(;;);
  }
}

void loop() {
  // put your main code here, to run repeatedly:
  display.clearDisplay();
  display.fillRect(
    0, 
    0, 
    SCREEN_WIDTH, 
    SCREEN_HEIGHT, 
    SSD1306_WHITE
  );
  drawSprite(
    guiDigimonWalkingAnimationDatabase[indexWalkCycle == 0xff ? 0 : uiWalkCycleIndices[indexWalkCycle]], 
    xPos, 
    0, 
    uiWalkCycleFlips[indexWalkCycle]
  );
  display.display();
  
  delay(500);
  indexWalkCycle = (indexWalkCycle + 1) % WALK_CYCLE_COUNT;
  xPos += uiWalkCycleMove[indexWalkCycle];
}