#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 snake_x[64];
int snake_y[64];

int snake_length = 0;
int gameState=0;

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


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

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

// 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);
  
  show_message("WELCOME");

}

void loop() {

  if(gameState==0){
    current_time = millis();
    check_direction();
    // put your main code here, to run repeatedly:
    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_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;
        }
        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";

  //  updating prev_direction
  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_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 x = 0; x < 8; x++){
      for (int y = 0; y < 8; y++){
        matrix.setPoint(y,x,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;
    }
  }
}