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

// matrix controls
const byte data_pin = 11;
const byte chip_select_pin = 10;
const byte clock_pin = 13;
const byte max_devices = 1;

ezButton button(8);

int head_y = 0;
int head_x = 0;
int flag = 0;
int snake_x[64];
int snake_y[64];
int snake_length = 0;
int threshold = 800;
int max_x = 7, max_y = 7;
int food_x = random(0, 8);
int food_y = random(0, 8);
int game_state = 0;
long int current_time, prev_time = 0;

String direction = "", prev_direction = "";

// creating matrix object
MD_MAX72XX matrix = MD_MAX72XX(MD_MAX72XX::PAROLA_HW, chip_select_pin, max_devices);

// define the joystick controls
const byte hpin = A0;
const byte vpin = A1;

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

  matrix.begin();
  matrix.clear();

  button.setDebounceTime(25);

  matrix.setPoint(head_x, head_y, true);

  show_message("Welcome!");
}

void loop(){
  if(game_state == 0) {
    
    current_time = millis();

    check_direction();

    if(current_time - prev_time >= threshold) {
      prev_time = current_time;

      matrix.clear();

      move_sprite();
      update_snake();
      draw_sprites();
    }

    food_eat_check();

    snake_collision_check();
  }

  if(game_state == 1)show_message("You Win!!!");
  if(game_state == 2)show_message("Game Over!!!");

  if(game_state) {
    while(true) {
      button.loop();

      if(button.isPressed()) {
        head_y = 0, head_x = 0, snake_length = 0, threshold = 800;
        direction = "", prev_direction = "";

        for(int i = 0; i < 64; i++) {
          snake_x[i] = 0;
          snake_y[i] = 0;
        }

        game_state = 0;
      }
    }
  }
}

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();

  if(button.isPressed()) {
    Serial.println("The button is pressed!");

    flag = 1;
  }
}

void draw_sprites() {
  matrix.setPoint(food_y, food_x, true);

  for(int i = 0; i <= snake_length; i++) {
    matrix.setPoint(snake_y[i], snake_x[i], true);
  }
}

void update_snake() {
  for(int i = snake_length; 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;
    }
  }
}

void food_eat_check() {
  if(head_x == food_x && head_y == food_y) {
    food_x = random(0, 8);
    food_y = random(0, 8);

    snake_length++;

    if(snake_length >= 5)game_state = 1;

    threshold = threshold - 50;

    if(threshold < 100)threshold = 80;
  }
}

void all_animate() {
  int i = 0;

  while(i < 3) {
    for(int j = 0; j < 8; j++) {
      for(int k = 0; k < 8; k++) {
        matrix.setPoint(k, j, true);
      }
    }

    delay(500);

    matrix.clear();

    delay(500);

    i++;
  }
}

void show_message(char message_to_show[]) {
  all_animate();

  int i = 0;

  while(message_to_show[i] != '\0') {
    matrix.setChar(6, message_to_show[i]);

    delay(500);

    matrix.clear();

    delay(500);

    i++;
  }
}

void snake_collision_check() {
  for(int i = 1; i < snake_length; i++) {
    if(snake_x[0] == snake_x[i] && snake_y[0] == snake_y[i])game_state = 2;
  }
}