#include <MD_MAX72xx.h>
#include <ezButton.h>

const byte cs_pin = 10;
const byte max_dev = 1;
const byte hpin = A0;
const byte vpin = A1;

ezButton button(8);
MD_MAX72XX matrix = MD_MAX72XX(MD_MAX72XX::PAROLA_HW, cs_pin, max_dev);

int snake_x[64] = { 3 };
int snake_y[64] = { 3 };
int head_x = 4;
int head_y = 3;
int snake_len = 1;

int food_x = random(8);
int food_y = random(8);

long int currentTime, prevTime = 0;
int threshold = 100;

String direction = "", prev_direction = "";
int max_x = 7, max_y = 7;
int game_state = 0;

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

  button.setDebounceTime(25);
  matrix.begin();
  matrix.clear();

  showMsg("Welcome");

  delay(100);
}

void loop() {
  if (game_state == 0) {
    check_direction();
    food_eat_check();

    currentTime = millis();
    if (currentTime - prevTime >= threshold) {
      prevTime = currentTime;
      matrix.clear();
      move_sprite();
      update_snake();
      draw_sprites();
    }
    collision_check();
  } else if (game_state == 1) {
    showMsg("You Win");
    restart();
  } else if (game_state == 2) {
    showMsg("Game Over");
    restart();
  }
}

void restart() {
  while (1) {
    button.loop();
    if (button.isPressed()) {
      snake_len = 1;
      head_x = 4;
      head_y = 3;
      threshold = 100;
      direction, prev_direction = "";
      for (int i = 0; i < 64; i++) {
        snake_x[i], snake_y[i] = 0;
      }
      game_state = 0;
      break;
    }
  }
}

void animate() {
  int i = 0;
  while (i < 3) {
    for (int y = 0; y < 8; y++) {
      for (int x = 0; x < 8; x++) {
        matrix.setPoint(x, y, true);
      }
    }
    delay(50);
    matrix.clear();
    delay(50);
    i++;
  }
}

void showMsg(char msg[]) {
  animate();
  int i = 0;
  while (msg[i] != '\0') {
    matrix.setChar(6, msg[i]);
    delay(50);
    matrix.clear();
    delay(50);
    i++;
  }
}

void window_check() {
  if (head_x > max_x) head_x = 0;
  else if (head_x < 0) head_x = max_x;
  else if (head_y > max_y) head_y = 0;
  else if (head_y < 0) head_y = max_y;
}

void check_direction() {
  if (analogRead(hpin) > 512 && prev_direction != "right")
    direction = "left";
  else if (analogRead(hpin) < 512 && prev_direction != "left")
    direction = "right";
  else if (analogRead(vpin) > 512 && prev_direction != "down")
    direction = "up";
  else if (analogRead(vpin) < 512 && prev_direction != "up")
    direction = "down";

  prev_direction = direction;
}

void move_sprite() {
  if (direction == "left") head_x++;
  else if (direction == "right") head_x--;
  else if (direction == "up") head_y--;
  else if (direction == "down") head_y++;

  window_check();
}

void draw_sprites() {
  matrix.setPoint(food_y, food_x, true);
  for (int i = 0; i < snake_len; i++) {
    matrix.setPoint(snake_y[i], snake_x[i], true);
  }
}

void collision_check() {
  for (int i = 1; i < snake_len; i++) {
    if (snake_x[i] == head_x && snake_y[i] == head_y) {
      game_state = 2;
    }
  }
}

void food_eat_check() {
  if (food_x == head_x && food_y == head_y) {
    food_x = random(8);
    food_y = random(8);
    snake_len++;
    if (snake_len > 15) {
      game_state = 1;
    }
  }
}

void update_snake() {
  for (int i = snake_len; i >= 0; i--) {
    if (i != 0) {
      snake_x[i] = snake_x[i - 1];
      snake_y[i] = snake_y[i - 1];
    } else {
      snake_x[i] = head_x;
      snake_y[i] = head_y;
    }
  }
}