#include <MD_MAX72xx.h>
#include <LiquidCrystal_I2C.h>

// Joystick pins
#define BUTTON 2
#define VERT A4
#define HORZ A5

volatile int vert, horz;
volatile bool button;

// Variables for if the joystick is used
volatile bool isUp = false, isDown = false, isRight = false, isLeft = false;

// LCD attributes
#define i2c_addr 0x27
#define lcd_rows 2
#define lcd_columns 16
LiquidCrystal_I2C lcd(i2c_addr, lcd_columns, lcd_rows);

// Arrows for the LCD
const byte arrowUp[8] = {B00100,B01110,B11111,B00100,B00100,B00100,B00100,B00100}, arrowDown[8] = {B00100,B00100,B00100,B00100,B00100,B11111,B01110,B00100}, arrowRight[8] = {B00000,B00100,B00110,B11111,B00110,B00100,B00000,B00000}, arrowLeft[8] = {B00000,B00100,B01100,B11111,B01100,B00100,B00000,B00000}, arrowUpH[8] = {B11011,B10001,B00000,B11011,B11011,B11011,B11011,B11011}, arrowDownH[8] = {B11011,B11011,B11011,B11011,B11011,B00000,B10001,B11011}, arrowRightH[8] = {B11111,B11011,B11001,B00000,B11001,B11011,B11111,B11111}, arrowLeftH[8] = {B11111,B11011,B10011,B00000,B10011,B11011,B11111,B11111};

// Some strings for the LCD
#define MAINNAME "   SNAKE GAME   "
#define MAINSCROLL "      Press down joystick to play.      "
#define DEADSCROLL "YOU DIED! Press reset to restart.   "

// Specify display hardware type
#define HARDWARE_TYPE MD_MAX72XX::PAROLA_HW

// Display Size and CS Pin
#define MAX_DEVICES 4
#define CS_PIN 12

// Create a display object
MD_MAX72XX display = MD_MAX72XX(HARDWARE_TYPE, CS_PIN, MAX_DEVICES);

//some defined matrix states
const uint16_t main1[16] PROGMEM = {0x0000, 0x7FFE, 0x4002, 0x5FFA, 0x500A, 0x57EA, 0x542A, 0x55AA, 0x55AA, 0x542A, 0x57EA, 0x500A, 0x5FFA, 0x4002, 0x7FFE, 0x0000}, main2[16] PROGMEM = {0xFFFF, 0x8001, 0xBFFD, 0xA005, 0xAFF5, 0xA815, 0xABD5, 0xAA55, 0xAA55, 0xABD5, 0xA815, 0xAFF5, 0xA005, 0xBFFD, 0x8001, 0xFFFF};
const uint16_t start1[16] PROGMEM = {0x0000, 0x0000, 0x0FF0, 0x0FF0, 0x0180, 0x0180, 0x0180, 0x0180, 0x0180, 0x0180, 0x0180, 0x0180, 0x0F80, 0x0F80, 0x0000, 0x0000}, start2[16] PROGMEM = {0x0000, 0x0000, 0x0FF0, 0x0FF0, 0x0C00, 0x0C00, 0x0C00, 0x0FF0, 0x0FF0, 0x0030, 0x0030, 0x0030, 0x0FF0, 0x0FF0, 0x0000, 0x0000}, start3[16] PROGMEM = {0x0000, 0x0000, 0x0FF0, 0x0FF0, 0x0030, 0x0030, 0x0030, 0x0FF0, 0x0FF0, 0x0030, 0x0030, 0x0030, 0x0FF0, 0x0FF0, 0x0000, 0x0000};
const uint16_t skull[16] PROGMEM = {0x0000, 0x07E0, 0x0A50, 0x0A50, 0x0FF0, 0x1FF8, 0x3E7C, 0x3F7C, 0x3FFC, 0x399C, 0x399C, 0x3FFC, 0x1FF8, 0x0FF0, 0x0000};

//postions of the snake and food
uint8_t snakehead = 0x98;
uint16_t snakebody[256] = {0x88, 0x78, 0x68, 0x100, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
uint8_t food;

//the game score
int score = 0;
bool dead = false;

//clock cycles
int c;

//all functions that are defined later
void matrixImage(uint16_t [16]);
int snakelength();
void checkforcollision();
void placefood();

// Whether it is the game or the main menu
#define MAINMENU false
#define GAME true
bool scene;

//check if it is setting up the game
#define SETUP true
#define INGAME false
bool gamescene;

// Directions
#define UP 0
#define RIGHT 1
#define DOWN 2
#define LEFT 3
int dir = RIGHT;

void setup() {

  //the interrupt stuff
  //enables port C and D
  PCICR |= B00000110;
  //enables pin A4 and A5
  PCMSK1 |= B00110000;
  //enables pins D2
  PCMSK2 |= B00000100;

  scene = MAINMENU;
  gamescene = SETUP;

  randomSeed(analogRead(A0));

  pinMode(BUTTON, INPUT);
  pinMode(VERT, INPUT);
  pinMode(HORZ, INPUT);
  // Intialize the display objects
  display.begin();
  lcd.init();

  // Set the intensity (brightness) of the display (0-15) and backlight of LCD
  display.control(MD_MAX72XX::INTENSITY, 10);
  lcd.setBacklight(HIGH);

  // Creating custom arrow characters
  lcd.createChar(0, arrowUp);lcd.createChar(1, arrowDown);lcd.createChar(2, arrowRight);lcd.createChar(3, arrowLeft);lcd.createChar(4, arrowUpH);lcd.createChar(5, arrowDownH);lcd.createChar(6, arrowRightH);lcd.createChar(7, arrowLeftH);

}

void loop() {
  
  switch (scene){
  
  case MAINMENU:
  
    //prints main text
    lcd.setCursor(0,0);
    for (int i=0; i<16; i++) lcd.print(((c)%16)-i?MAINNAME[i]:' ');

    //prints scrolling text
    lcd.setCursor(0, 1);
    for(int i=0; i<16; i++) lcd.print(MAINSCROLL[((i+c)%40)]);

    matrixImage((c/3)%2?(main1):(main2), true);

    if (button){ scene = GAME; lcd.clear(); }
    
    break;

  case GAME:
    switch (gamescene){

      case SETUP:

        lcd.setCursor(0,0);
        lcd.print("starting...");

        matrixImage(start3, true);
        delay(1000);
        matrixImage(start2, true);
        delay(1000);
        matrixImage(start1, true);
        delay(1000);
        display.clear();

        gamescene = INGAME;
        placefood();
        lcd.clear();

        break;
    
      case INGAME:
        if (collision()) dead = true;

        bool grow;
        if (dead){
          matrixImage(skull, true);
          lcd.setCursor(0, 1);
          lcd.print("Final score: ");lcd.print(score);
          lcd.setCursor(0, 0);
          for(int i=0; i<16; i++) lcd.print(DEADSCROLL[((i+c)%36)]);

        }
        else{

          //dynamic arrows
          lcd.setCursor(0,0);
          if (isUp) lcd.write((byte)4);
          else lcd.write((byte)0);

          lcd.setCursor(1,0);
          if (isDown) lcd.write((byte)5);
          else lcd.write((byte)1);

          lcd.setCursor(0,1);
          if (isRight) lcd.write((byte)6);
          else lcd.write((byte)2);

          lcd.setCursor(1,1);
          if (isLeft) lcd.write((byte)7);
          else lcd.write((byte)3);

          //rest of the lcd stuff
          lcd.setCursor(3,1);
          lcd.print("Score:");
          lcd.print(score);


          grow = false;
          if (snakehead==food){
            placefood();
            grow = true;
            score+=(snakelength()/16)+1;
          }

          if (isUp&&(dir!=DOWN)) dir = UP; if (isDown&&(dir!=UP)) dir = DOWN; if (isRight&&(dir!=LEFT)) dir = RIGHT; if (isLeft&&(dir!=RIGHT)) dir = LEFT;

          int sl = snakelength()-(grow?0:2);
          for (int i=sl; i>0; i--){
            snakebody[i] = snakebody[i-1];
          }
          snakebody[0] = snakehead;
          switch (dir){
            case UP:
              snakehead = ((snakehead&15)==15)?snakehead&B11110000:snakehead+1;
              break;
            case RIGHT:
              snakehead = ((snakehead>>4)==15)?snakehead&B00001111:snakehead+16;
              break;
            case DOWN:
              snakehead = ((snakehead&15)==0)?snakehead|B00001111:snakehead-1;
              break;
            case LEFT:
              snakehead = ((snakehead>>4)==0)?snakehead|B11110000:snakehead-16;
              break;
          }
          
          //rendering the snakeposition
          uint16_t snakeimage[16] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};

          int headx = snakehead>>4, heady = snakehead&15;
          snakeimage[heady] += (0x8000)>>headx;

          for (int i=(snakelength()-2); i>=0; i--)
          {
            int px = snakebody[i]>>4, py = snakebody[i]&15;
            snakeimage[py] += (0x8000)>>px;
          }

          snakeimage[food&15] |= (0x8000)>>(food>>4);
          
          matrixImage(snakeimage, false);

          }
        break;
    }
  break;
  }

  isUp = false, isDown = false, isRight = false, isLeft = false;
  c++;

}

int conx(int ogx, int ogy) {return ((ogy<8)?(16+ogx):(15-ogx));}

int cony(int ogy) {return ((ogy<8)?(ogy):(15-ogy));}

int snakelength(){
  int sbp = 0;
  do
  {
    sbp++;
  }
  while (snakebody[sbp]!=0x100);
  snakebody[sbp]=0x100;
  return sbp+1;
}

bool collision() {
  for (int i=0; i<snakelength(); i++) if (snakebody[i] == snakehead) {return true;}
  return false;
}

//displays a 16x16 image on the led matrix
void matrixImage(unsigned int* image, bool flash){
  for (int b=0; b<16; b++)
  {
    for (int a=0; a<16; a++)
    { 
      display.setPoint(cony(b), conx(a, b), (((flash?(pgm_read_word(&image[b])):image[b])>>(15-a))&1));
    }
  }
  display.update();
}

bool insnake(int n){
  if (n==snakehead) return true;
  for (int k=0; k<snakelength()-2; k++){
    if (n==snakebody[k]) return true;
  }
  return false;
}

void placefood(){
  int rando = random((256-snakelength()));
  do{
      rando++;
      rando%=256;
  }
  while(insnake(rando));
  food = rando;
}

ISR (PCINT1_vect){
  // Reads the horizontal and vertical values
  horz = map(analogRead(HORZ), 0, 1023, 1, -1);
  vert = map(analogRead(VERT), 0, 1023, -1, 1);

  if (vert==1&&!(isRight||isLeft)) isUp=true;
  if (vert==-1&&!(isRight||isLeft)) isDown=true;
  if (horz==1&&!(isUp||isDown)) isRight=true;
  if (horz==-1&&!(isUp||isDown)) isLeft=true;
}

ISR (PCINT2_vect){
  // Reads the joystick's button
  button = digitalRead(BUTTON);
}