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

const byte vpin = A0;
const byte hpin = A1;

const byte data_pin = 11;
const byte chip_select_pin = 10;
const byte clock_pin = 13;
const byte max_device = 1;

ezButton button(8);

int head_y = 0;
int head_x  = 0;
int flag = 0;

String direction, prev_direction = "";

int max_x = 31, max_y = 7;

MD_MAX72XX matrix = MD_MAX72XX(MD_MAX72XX::PAROLA_HW,chip_select_pin,max_device);

int snake_x[64];
int snake_y[64];
int snake_length = 0;

long int current_time,prev_time = 0;
int threshold = 800;

int food_x = random(0,8);
int food_y = random(0,8);

int gameState = 0;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  matrix.begin();
  matrix.clear();
  button.setDebounceTime(25);
  matrix.setPoint(head_x,head_y,true);

  show_message("Welcome");
}

void loop() {
  // put your main code here, to run repeatedly:
  if(gameState == 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(gameState == 1){
    show_message("You won!!");
  }
  if(gameState == 2){
    show_message("Game over");
  }
  if(gameState){
    while(true){
      button.loop();

      if(button.isPressed()){
        head_x = 0,head_y = 0,snake_length = 0,threshold = 800;
        direction = "",prev_direction = "";
        for(int i = 0;i<64;i++){
          snake_x[i] = 0;
          snake_y[i] = 0;
        }
        gameState = 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 >= 15){
      gameState = 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(j,k,true);
      }
    }
    delay(500);
    matrix.clear();
    delay(500);
    i++;
  }
}

void show_message(char messageToShow[]){
  all_animate();
  int i = 0;
  while(messageToShow[i] != '\0'){
    matrix.setChar(6,messageToShow[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]){
      gameState = 2;
    }
  }
}