#include <WiFi.h>
#include <WebServer.h>
#include <Wire.h>
#include <Preferences.h>

#define SDA_PIN 2
#define SCL_PIN 10
#define LED_CE_PIN 5
#define AS5600_ADDR 0x36
#define AS5600_RAW_ANGLE_H 0x0C

const char* AP_SSID = "AZIMUT-LAMP";
const char* AP_PASS = ""; // Open Wi-Fi, no password
WebServer server(80);
Preferences prefs;

const int PWM_FREQ = 1000;
const int PWM_RES = 8;
const int PWM_MAX = 255;
const float FULL_ON_DEG = 3.0;
const float FADE_OUT_DEG = 35.0;
float targetAngleDeg = 0.0;
bool calibrated = false;

float normalizeDeg(float a) {
  while (a < 0) a += 360.0;
  while (a >= 360.0) a -= 360.0;
  return a;
}

float angleDiffDeg(float a, float b) {
  float d = a - b;
  while (d > 180.0) d -= 360.0;
  while (d < -180.0) d += 360.0;
  return d;
}

bool as5600Present() {
  Wire.beginTransmission(AS5600_ADDR);
  return Wire.endTransmission() == 0;
}

float readAS5600Deg() {
  Wire.beginTransmission(AS5600_ADDR);
  Wire.write(AS5600_RAW_ANGLE_H);
  if (Wire.endTransmission(false) != 0) return -1;
  Wire.requestFrom(AS5600_ADDR, (uint8_t)2);
  if (Wire.available() < 2) return -1;
  uint8_t high = Wire.read();
  uint8_t low = Wire.read();
  uint16_t raw = ((high & 0x0F) << 8) | low;
  return raw * 360.0 / 4096.0;
}

void setLed(int pwm) {
  pwm = constrain(pwm, 0, PWM_MAX);
  ledcWrite(LED_CE_PIN, pwm);
}

int computeLedPWM(float currentDeg) {
  if (!calibrated) return 0;
  float diff = abs(angleDiffDeg(currentDeg, targetAngleDeg));
  if (diff <= FULL_ON_DEG) return PWM_MAX;
  if (diff >= FADE_OUT_DEG) return 0;
  float t = (FADE_OUT_DEG - diff) / (FADE_OUT_DEG - FULL_ON_DEG);
  t = t * t * (3.0 - 2.0 * t);
  return round(t * PWM_MAX);
}

// ... (ส่วนการตั้งค่า HTML String / Web Server Functions ถูกละไว้เพื่อความกระชับ) ...

void setup() {
  Serial.begin(115200);
  delay(1200);
  pinMode(LED_CE_PIN, OUTPUT);
  digitalWrite(LED_CE_PIN, LOW);
  
  Wire.begin(SDA_PIN, SCL_PIN);
  Wire.setClock(100000);
  
  ledcAttach(LED_CE_PIN, PWM_FREQ, PWM_RES);
  setLed(0);
  
  prefs.begin("azimut", false);
  calibrated = prefs.getBool("calibrated", false);
  targetAngleDeg = prefs.getFloat("target", 0.0);
  
  WiFi.mode(WIFI_AP);
  WiFi.softAP(AP_SSID);
  
  // server.on("/", HTTP_GET, handleRoot);
  // server.on("/calibrate", HTTP_GET, handleCalibrate);
  // server.on("/reset", HTTP_GET, handleReset);
  // server.on("/status", HTTP_GET, handleStatus);
  server.begin();
}

void loop() {
  server.handleClient();
  float currentDeg = readAS5600Deg();
  if (currentDeg < 0) {
    setLed(0);
    return;
  }
  int pwm = computeLedPWM(currentDeg);
  setLed(pwm);
}