// https://forum.arduino.cc/t/has-anyone-ever-tried-making-emergency-lights-with-2-independent-neopixel-matrix-4x4-tiles/1267869/
// red blue... red blue... blue blue... red red... white white...

#include <FastLED.h>
#define buttonPin 2
#define pixelPin  12
#define NUM_PIX 4 * 4 * 2 // number of NeoPixels
CRGB led[NUM_PIX];
byte maxBright = 255;
int wait = 250, strobe = 4; // time between on and off

unsigned long lastButtonRead, timer, debounceTimeout; // timers for button reading
bool currentButtonState, currentButtonRead; // states for button reading

void setup() {
  Serial.begin(115200);

  // configure pins
  pinMode (pixelPin, OUTPUT); // Neopixel data pin
  pinMode (buttonPin, INPUT_PULLUP); // Neopixel data pin

  // configure FastLED
  FastLED.addLeds<WS2812B, pixelPin, GRB>(led, NUM_PIX); // led = object, NUM_PIX = total Pixels
  FastLED.setBrightness(maxBright); // limit the brightness of each pixel to this value
  FastLED.clear(); // clear the buffer
  FastLED.show(); // display the buffer

  while (digitalRead(buttonPin)); // hold program here until button is pressed
}

void loop() {
  // use functions for a modular sketch
  redblu(2);
  blublk(2);
  redblu(2);
  redred(2);
  whtwht(4);
}

void redblu(int r) {
  for (int i = 0; i < r; i++) {
    fill_solid(led, NUM_PIX, CRGB::Red);
    fill_solid(led, NUM_PIX / 2, CRGB::Blue);

    FastLED.show();
    delay(wait);

    fill_solid(led, NUM_PIX, CRGB::Blue);
    fill_solid(led, NUM_PIX / 2, CRGB::Red);

    FastLED.show();
    delay(wait);
  }
}

void blublk(int r) {
  for (int i = 0; i < r; i++) {
    fill_solid(led, NUM_PIX, CRGB::Black);
    fill_solid(led, NUM_PIX / 2, CRGB::Blue);

    FastLED.show();
    delay(wait);

    fill_solid(led, NUM_PIX, CRGB::Blue);
    fill_solid(led, NUM_PIX / 2, CRGB::Black);

    FastLED.show();
    delay(wait);
  }
}

void redred(int r) {
  for (int i = 0; i < r; i++) {
    fill_solid(led, NUM_PIX, CRGB::Red);
    fill_solid(led, NUM_PIX / 2, CRGB::Black);

    FastLED.show();
    delay(wait);

    fill_solid(led, NUM_PIX, CRGB::Black);
    fill_solid(led, NUM_PIX / 2, CRGB::Red);

    FastLED.show();
    delay(wait);
  }
}

void whtwht(int r) {
  for (int i = 0; i < r; i++) {
    fill_solid(led, NUM_PIX, CRGB::White);
    fill_solid(led, NUM_PIX / 2, CRGB::Black);

    FastLED.show();
    delay(wait / strobe);

    FastLED.clear();
    FastLED.show();

    delay(wait / strobe);

    fill_solid(led, NUM_PIX, CRGB::White);
    fill_solid(led, NUM_PIX / 2, CRGB::Black);

    FastLED.show();
    delay(wait);

    fill_solid(led, NUM_PIX, CRGB::Black);
    fill_solid(led, NUM_PIX / 2, CRGB::White);

    FastLED.show();
    delay(wait / strobe);

    FastLED.clear();
    FastLED.show();

    delay(wait / strobe);

    fill_solid(led, NUM_PIX, CRGB::Black);
    fill_solid(led, NUM_PIX / 2, CRGB::White);

    FastLED.show();
    delay(wait);
  }
}