#include <LedControl.h>

#define CYCLE_TIME 100
#define LENGTH 4
#define GROW_STEP 5

struct pos {
  int row;
  int col;
}typedef Led_pos;

LedControl lc = LedControl(4, 3, 5, 1);
struct pos[LENGTH];

void setup() {
  /*
   The MAX72XX is in power-saving mode on startup,
   we have to do a wakeup call
   */
  lc.shutdown(0,false);
  /* Set the brightness to a medium values */
  lc.setIntensity(0, 15);
  /* and clear the display */
  lc.clearDisplay(0);
}

void loop() {
  start();
}

void start() {
  Led_pos snake[LENGTH];
  int i,j;
  int len = 8;
  int count = 1;
  int dir = 1;
  int row = 0;
  int col = -1;
  int currLength = 0;
  int chuj = -1;
  Led_pos last;
  last.col= -LENGTH-1;
  last.row = 0;
  for(i = 0; i<LENGTH; i++){
	  snake[i].col = -1-i;
	  snake[i].row = 0;
  }

  for(i = 0; i < 128; i++) {
    lc.setLed(0, last.row, last.col, false);
    switch(dir) {
      case 1:
        col++;
        break;
      case 2:
        row++;
        break;
      case 3:
        col--;
        break;
      case 4:
        row--;
        break;
    }
	lc.setLed(0, row, col, true);

	last = snake[LENGTH-1];
	for(j=LENGTH-1; j>=1;j--){
		snake[j] = snake[j-1];

	}
	snake[0].row = row;
	snake[0].col = col;
	delay(CYCLE_TIME);
    currLength++;
    if(currLength == len) {
      currLength = 0;
      count++;
      dir = dir % 4 + 1;
      if(count == 2) {
        len += chuj;
        count = 0;
      }
    }
    if(len == 0) {
      chuj = -chuj;
      len = 1;
    }
  }
}