/*
 * =============================================================================
 *  Fab Academy 2026 — Week 15 — Yaroslav Artsishevskiy
 *  Simple rainbow blinking LED strip
 * -----------------------------------------------------------------------------
 *  30 WS2812B LEDs connected to the XIAO ESP32-C3 expansion board:
 *     Data line   -->  D0 (the A0/D0 Grove connector)
 *     5V          -->  5V pad on the expansion board
 *     GND         -->  any GND pad
 *
 *  What it does:
 *     Every half-second, the whole strip flashes a different rainbow color.
 *     One color at a time, all 30 LEDs the same color, then it changes.
 *
 *  Library needed:
 *     FastLED (Arduino IDE → Library Manager → search "FastLED" → install)
 * =============================================================================
 */

#include <FastLED.h>

#define LED_PIN     D0    // data pin — A0/D0 Grove connector
#define NUM_LEDS    30    // 30 LEDs in the strip
#define BRIGHTNESS  60    // out of 255 — keep it modest for USB power safety

// FastLED's framebuffer — one CRGB color per LED
CRGB leds[NUM_LEDS];

// Which hue to show next. Hue is 0..255 in FastLED (a full color wheel).
// We add 32 each time so we step through ~8 distinct colors before looping.
uint8_t currentHue = 0;

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

  // Tell FastLED about the strip
  FastLED.addLeds<WS2812B, LED_PIN, GRB>(leds, NUM_LEDS);
  FastLED.setBrightness(BRIGHTNESS);
  FastLED.clear();
  FastLED.show();

  Serial.println("Rainbow blink ready");
}

void loop() {
  // ---- Show: fill the whole strip with the current hue ----
  // CHSV is "color from hue, saturation, value":
  //   hue        = currentHue  (which color on the wheel)
  //   saturation = 255         (fully saturated, no white mixed in)
  //   value      = 255         (full brightness — global brightness still caps it)
  fill_solid(leds, NUM_LEDS, CHSV(currentHue, 255, 255));
  FastLED.show();
  delay(500);   // stay on this color for half a second

  // ---- Hide: turn the strip off briefly (the "blink" part) ----
  FastLED.clear();
  FastLED.show();
  delay(150);   // off for 150 ms

  // ---- Step to the next color in the rainbow ----
  currentHue += 32;
}