#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <SPI.h>
#include <Wire.h>
#include <Bounce2.h>

#define BUZZER_PIN 10

#define SNAKE_PART 3
#define NUMBUTTONS 4
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define SNAKE_SIZE_I 5
#define MAP_X 20
#define MAP_Y 20
#define BUTTOM_DEBOUNCE_I 15
#define TAM_MAX_SNAKE 100

#define DELAY_SNAKE 10

const byte buttons[] = {2, 3, 5, 4};

uint8_t fruit[2];

uint8_t snake[TAM_MAX_SNAKE][2];
uint8_t snake_length;

Bounce* bounce_buttons = new Bounce[NUMBUTTONS];

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire);

typedef enum{
  MAIN_MENU,
  SETTINGS,
  PLAYING,
  GAMEOVER
} State;

typedef enum{
  RIGHT,
  LEFT,
  TOP,
  BOTTOM
} Direction;

State app_state = MAIN_MENU;
Direction direc;
Direction newDirec;

void setup(){
  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
  display.display();
  delay(1000);
  display.clearDisplay();
  for (int i = 0; i < NUMBUTTONS; i++){
    bounce_buttons[i].attach(buttons[i], INPUT_PULLUP);
    bounce_buttons[i].interval(BUTTOM_DEBOUNCE_I);
  }
  randomSeed(analogRead(0));
}

void text(const char *text, int x, int y, float tam,
          uint16_t textColor = SSD1306_WHITE){
  display.setTextSize(tam);
  display.setTextColor(textColor);

  display.setCursor(x, y);
  display.print(text);
}

uint8_t cursor = 20;
uint16_t score = 0;

void main_menu(){
  text("Menu Principal", 25, 1, 1);
  text("Play", 53, 20, 0.5);
  text("Settings", 40, 35, 0.5);
  text("Exit", 53, 50, 0.5);

  if (cursor > 50) cursor = 20;
  else if (cursor < 20) cursor = 50;
  text(">", 30, cursor, 0.3);
}

void reset(){
  snake_length = SNAKE_SIZE_I;
  direc = RIGHT;
  for (int i = 0; i < snake_length; i++) {
    snake[i][0] = MAP_X / 2 - i;
    snake[i][1] = MAP_Y / 2;
  }
};

void exec_main(){
  int8_t aux = (cursor - 20) / 2;
  switch (aux) {
    case 0: app_state = PLAYING; reset(); break;
    case 7: app_state = SETTINGS; break;
    case 15: display.ssd1306_command(SSD1306_DISPLAYOFF); break;
  }
}

void settings_menu(){

}

void generateFruit(){
  bool b = false;
  do {
    b = false;
    fruit[0] = random(0, MAP_X);
    fruit[1] = random(0, MAP_Y);
    for (int i = 0; i < snake_length; i++) {
      if (fruit[0] == snake[i][0] && fruit[1] == snake[i][1]) {
        b = true;
        continue;
      }
    }
  } while (b);
}

void moveSnake(){
  int8_t x = snake[0][0];
  int8_t y = snake[0][1];
  switch (direc){
    case TOP:
      y--;
      break;
    case BOTTOM:
      y++;
      break;
    case LEFT:
      x--;
      break;
    case RIGHT:
      x++;
      break;
  }
  for (int i = snake_length - 1; i > 0; i--){
    snake[i][0] = snake[i - 1][0];
    snake[i][1] = snake[i - 1][1];
  }

  if (collisionCheck(x, y)){
    app_state = GAMEOVER;
  }

  snake[0][0] = x;
  snake[0][1] = y;

  colide_apple();
}

bool collisionCheck(int8_t x, int8_t y){
  for (int i = 1; i < snake_length; i++){
    if (x == snake[i][0] && y == snake[i][1]) return true;
  }
  if (x < 0 || y < 0 || x >= MAP_X || y >= MAP_Y) return true;
  return false;
}

void colide_apple(){
  if (snake[0][0] == fruit[0] && snake[0][1] == fruit[1]) {
    tone(BUZZER_PIN, 500, 100);
    generateFruit();
    snake_length++;
    score++;
  }
}

void drawMap(){
  const int offsetMapX = SCREEN_WIDTH - SNAKE_PART * MAP_X - 2;
  const int offsetMapY = 2;

  display.drawRect(fruit[0] * SNAKE_PART + offsetMapX, fruit[1] * SNAKE_PART + offsetMapY, SNAKE_PART, SNAKE_PART, SSD1306_INVERSE);
  display.drawRect(offsetMapX - 2, 0, SNAKE_PART * MAP_X + 4, SNAKE_PART * MAP_Y + 4, SSD1306_WHITE);
  for (int i = 0; i < snake_length; i++) {
    display.fillRect(snake[i][0] * SNAKE_PART + offsetMapX, snake[i][1] * SNAKE_PART + offsetMapY, SNAKE_PART, SNAKE_PART, SSD1306_WHITE);
  }
}

uint8_t moveTime = 0;

void loop() {
  display.clearDisplay();
  for (int i = 0; i < NUMBUTTONS; i++) {
    bounce_buttons[i].update();
    if (bounce_buttons[i].fell()) {
      if (app_state == MAIN_MENU) {
        if (i == 0){
          cursor -= 15;
        }
        if (i == 1){
          exec_main();
        }
        if (i == 2){
          cursor += 15;
        }
        if (i == 3){}
      }
      else if (app_state == PLAYING){
        if (i == 0 && direc != BOTTOM){
          direc = TOP;
        }
        else if (i == 1 && direc != LEFT){
          direc = RIGHT;
        }
        else if (i == 2 && direc != TOP){
          direc = BOTTOM;
        }
        else if (i == 3 && direc != RIGHT){
          direc = LEFT;
        }
      }
    }
  }

  switch (app_state){
    case MAIN_MENU:
      main_menu();
      break;
    case SETTINGS:
      settings_menu();
      break;
    case PLAYING:
      moveTime++;
      if (moveTime >= DELAY_SNAKE){
        moveSnake();
        moveTime = 0;
      }
      drawMap();
      String S_score = "Score: " + String(score);
      const char* score_char = S_score.c_str();
      text(score_char, 0, 10, 0.2);
      break;
    case GAMEOVER:
      break;
  }
  display.display();
}