#include <LiquidCrystal_I2C.h>
#include <TM1637TinyDisplay.h>

TM1637TinyDisplay counter(2, 3);
TM1637TinyDisplay maxCounter(5, 4);
LiquidCrystal_I2C lcd(0x27,20,4);

byte snake[] = {
  B11111,
  B11111,
  B11111,
  B11111,
  B11111,
  B11111,
  B11111,
  B11111,
};


byte food[] = {
  B00100,
  B01110,
  B01110,
  B11111,
  B11111,
  B01110,
  B01110,
  B00100,
};

int score = 0, maxScore = 0;
byte snakeH[80] = {0};
byte snakeV[80] = {0};
byte foodH = 5, foodV = 2;
int vert = 0, horz = 0;
int direction = 0; // 0: stop, 1: up, 2: down, 3: left, 4: right
int frame = 0;

void setup() {
  // init data
  snakeH[80] = {0};
  snakeV[80] = {0};
  foodH = 5, foodV = 2;
  direction = 0;
  score = 0;
  // init counter
  counter.begin();
  counter.showNumber(score);
  // init max counter
  maxCounter.begin();
  maxCounter.showNumber(maxScore);
  randomSeed(analogRead(A3));
  // init analog joystick
  pinMode(A2,2);
  // init lcd
  lcd.init();
  lcd.backlight();
  lcd.createChar(0, snake);
  lcd.createChar(1, food);
  lcd.home();
  lcd.write(0);
  Serial.begin(9600);
}

void mov() {
  vert=analogRead(A0);
  horz=analogRead(A1);
  if (direction != 0) {
    for (int i = score + 1; i > 0; i--) {
      snakeH[i] = snakeH[i - 1];
      snakeV[i] = snakeV[i - 1];
    }
  }
  if(vert > 530) {
    // move up
    if (direction != 2) {
      direction = 1;
      snakeV[0]--;
    }
  }
  else if(vert < 490) {
    // move down
    if (direction != 1) {
      direction = 2;
      snakeV[0]++;
      snakeV[0] = snakeV[0] % 4;
    }
  }
  else if(horz > 530){
    // move left
    if (direction != 4) {
      direction = 3;
      snakeH[0]--;
    }
  }
  else if (horz < 490) {
    // move right
    if (direction != 3) {
      direction = 4;
      snakeH[0]++;
      snakeH[0] = snakeH[0] % 20;
    }
  } else {
    if (direction == 1) {
      snakeV[0]--;
    } else if (direction == 2) {
      snakeV[0]++;
      snakeV[0] = snakeV[0] % 4;
    } else if (direction == 3) {
      snakeH[0]--;
    } else if (direction == 4) {
      snakeH[0]++;
      snakeH[0] = snakeH[0] % 20;
    }
  }
  snakeH[0] = constrain(snakeH[0], 0, 19);
  snakeV[0] = constrain(snakeV[0], 0, 3);
}

void updateScore() {
  counter.showNumber(score);
  if (score > maxScore) {
    maxScore = score;
    maxCounter.showNumber(maxScore);
  }
}

void placeFood() {
  bool foodPlaced = false;
  while (!foodPlaced) {
    foodH = random(0, 20);
    foodV = random(0, 4);
    foodPlaced = true;
    for (int i = 0; i < score; i++) {
      if (snakeH[i] == foodH && snakeV[i] == foodV) {
        foodPlaced = false;
        break;
      }
    }
  }
}

void display() {
  lcd.clear();
  for (int i = 0; i <= score; i++) {
    lcd.setCursor(snakeH[i], snakeV[i]);
    lcd.write(0);
  }
  lcd.setCursor(foodH, foodV);
  lcd.write(1);
}

bool checkGameOver() {
  for (int i = 1; i <= score; i++) {
    if (snakeH[0] == snakeH[i] && snakeV[0] == snakeV[i]) {
      return true;
    }
  }
  return false;
}

void loop() {
  frame = (frame + 1) % 3;
  if (frame == 0) {
    mov();
  } else {
    if (snakeH[0] == foodH && snakeV[0] == foodV) {
      score++;
      placeFood();
    }
    if (checkGameOver()) {
      lcd.clear();
      lcd.print("Game Over!");
      delay(3000);
      setup();
      return;
    }
    display();
    updateScore();
    delay(200);
  }
}