#include <FastLED.h>

// Matrix and Pin Configuration
#define DATA_PIN          2         // ESP8266 Pin D4 is GPIO 2
#define LED_TYPE          WS2812B
#define COLOR_ORDER       GRB
#define MATRIX_WIDTH      25
#define MATRIX_HEIGHT     8
#define NUM_LEDS          (MATRIX_WIDTH * MATRIX_HEIGHT)

// Global Settings
#define BRIGHTNESS        196        // Set brightness 0-255. Start low to save power!
#define FRAMES_PER_SECOND 60        // Animation speed

CRGB leds[NUM_LEDS];
uint16_t timeValue = 0; // A variable that increments to animate the effect

// This function maps an X,Y coordinate to the correct index in the leds[] array.
// It assumes a "serpentine" or "zigzag" layout, which is common for matrices.
// Adjust this if your matrix is wired differently (e.g., all rows left-to-right).
uint16_t XY(uint8_t x, uint8_t y) {
  uint16_t i;

  if (y & 0x01) {
    // Odd rows run right to left
    uint8_t reverseX = (MATRIX_WIDTH - 1) - x;
    i = (y * MATRIX_WIDTH) + reverseX;
  } else {
    // Even rows run left to right
    i = (y * MATRIX_WIDTH) + x;
  }

  return i;
}


void setup() {
  Serial.begin(115200); // For debugging
  delay(1000); // Power-on delay

  // Initialize the FastLED library
  FastLED.addLeds<LED_TYPE, DATA_PIN, COLOR_ORDER>(leds, NUM_LEDS);

  // Set a global brightness limit. IMPORTANT for power management.
  FastLED.setBrightness(BRIGHTNESS);

  Serial.println("Setup complete. Starting animation.");
}


void loop() {
  // Call the function that draws the rainbow wave pattern
  drawRainbowWave();

  // Update the LEDs with the new data
  FastLED.show();

  // Limit the frame rate to control the speed
  FastLED.delay(1000 / FRAMES_PER_SECOND);
}


void drawRainbowWave() {
  // Increment the time variable for animation. The amount you add controls the speed.
  timeValue += 2;

  // Loop through every pixel (x,y) of the matrix
  for (int x = 0; x < MATRIX_WIDTH; x++) {
    for (int y = 0; y < MATRIX_HEIGHT; y++) {

      // Calculate a hue value based on the pixel's position and the current time.
      // The constants (e.g., 8, 6) control the angle and density of the rainbow bands.
      // Experiment with these values to change the look of the wave.
      uint8_t hue = (x * 8) + (y * 6) + timeValue;

      // Get the matrix index for the current (x,y) coordinate
      uint16_t index = XY(x, y);

      // Assign the color to the pixel in the leds array using HSV color space.
      // CHSV(Hue, Saturation, Value/Brightness)
      leds[index] = CHSV(hue, 255, 255);
    }
  }
}