#include <Adafruit_NeoPixel.h>

#define PIXEL_PIN   D9
#define NUM_PIXELS  30
#define HALL_PIN    D8

// --- Thresholds (based on your calibration) ---
#define ON_THRESHOLD 3800
#define OFF_THRESHOLD 3400

Adafruit_NeoPixel strip(NUM_PIXELS, PIXEL_PIN, NEO_GRB + NEO_KHZ800);

// --- Hall sensor state ---
float filtered = 0;
bool hallState = false;

// ---------- SETUP ----------
void setup() {
  Serial.begin(115200);

  strip.begin();
  strip.setBrightness(50);
  strip.show();

  // initialize filter baseline
  filtered = analogRead(HALL_PIN);

  Serial.println("System Ready");
}

// ---------- HALL DIGITAL FUNCTION ----------
bool readHallDigital() {
  int raw = analogRead(HALL_PIN);

  // Low-pass filter (removes spikes)
  filtered = 0.8 * filtered + 0.2 * raw;

  // Hysteresis (stable switching)
  if (!hallState && filtered > ON_THRESHOLD) {
    hallState = true;
  }

  if (hallState && filtered < OFF_THRESHOLD) {
    hallState = false;
  }

  return hallState;
}

// ---------- LED CONTROL ----------
void setAllPixels(int r, int g, int b) {
  for (int i = 0; i < NUM_PIXELS; i++) {
    strip.setPixelColor(i, strip.Color(r, g, b));
  }
  strip.show();
}

// ---------- LOOP ----------
void loop() {

  static bool lastState = false;
  bool currentState = readHallDigital();

  // Update LEDs only when state changes
  if (currentState != lastState) {

    if (currentState) {
      setAllPixels(0, 255, 0);   // GREEN → magnet near
      Serial.println("MAGNET DETECTED");
    } else {
      setAllPixels(255, 0, 0);   // RED → magnet away
      Serial.println("NO MAGNET");
    }

    lastState = currentState;
  }

  delay(20);
}