#include <FastLED.h>

#define LED_PIN 9

#define COLOR_ORDER GRB
#define CHIPSET     WS2812

#define NUM_LEDS    64
#define BRIGHTNESS  64
#define NUM_ROWS    8
#define NUM_COLS    8

CRGB leds[NUM_LEDS];
int color_idx = 0;

void setup() {
  int index = 0;
  Serial.begin(115200);
  FastLED.addLeds<CHIPSET, LED_PIN, COLOR_ORDER>(leds, NUM_LEDS).setCorrection(TypicalSMD5050);
  FastLED.setBrightness( BRIGHTNESS );

  // Zet alles uit.
  fill_solid(leds, NUM_LEDS, CRGB(0,0,25));
  FastLED.show();
  delay(200);
  fill_solid(leds, NUM_LEDS, CRGB::Black);
  FastLED.show();
  delay(400);
}

void LED_uit(int x, int y)
{
  int index = x;
  index += y*8;
  leds[index] = CRGB::Black ; 
  FastLED.show();
}

void LED_aan(int x, int y,  CRGB& color)
{
  int index = x;
  index += y*8;
  leds[index] = color ; 
  FastLED.show();
}

int color_idx_inc(int color_idx)
{
 color_idx = color_idx + 4; 
  if (color_idx >= 255) 
    return 0;
  else 
    return color_idx;
}

int direction_find(int x, int y) {
int direction = 90; 
 if ((x == 0) && (y > 0))
  direction = 0;
 if ((x == NUM_COLS -1) && (y < NUM_COLS-1))
  direction = 180; 
 if ((x < NUM_COLS-1)&& (y == 0))
  direction = 90; 
 if ((x > 0) && (y == NUM_ROWS -1))
  direction = 270 ; 
  return direction;
}

int next_x(int x, int direction){
 if (direction == 90 )
  return ++x;
 else if (direction == 270)
  return --x;
 else 
  return x;
}

int next_y(int y, int direction){
 if (direction == 180 )
  return ++y;
 else if (direction == 0)
  return --y;
 else 
  return y;
}

void loop() {
  char error_string[256]; 
  static int x = 0;
  static int y = 0;
  struct CRGB color = CHSV(0,255,255) ;
  static int color_idx =0 ; 
  int direction = 90; 

  direction = direction_find(x,y);
  x = next_x(x, direction );
  y = next_y(y, direction );
  
  sprintf(error_string, "x: %i, y: %i direction: %03i, color_idx: %03i", x, y, direction, color_idx);
  Serial.println(error_string);
  color_idx = color_idx_inc(color_idx);
  color = CHSV(color_idx,255,255);
  LED_aan(x, y, color);
  FastLED.show();
  delay(100); 
  LED_uit(x, y);
}