#include <DHT.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

// ===== Pins (đổi nếu bạn nối khác) =====
#define DHT_PIN    4
#define DHT_TYPE   22
#define RELAY_PIN  5
#define OLED_SDA  21
#define OLED_SCL  22
#define LUX_ADC   34
#define BUZZ_PIN  14
#define BTN_PIN   12
#define LED_PIN    2
#define RELAY_ACTIVE_LEVEL HIGH   // nhiều relay active-LOW -> đổi LOW nếu thấy đảo

// ===== Logic =====
#define TEMP_THRESHOLD_C 30.0f
#define TEMP_HYSTERESIS  1.5f
#define LUX_THRESHOLD    30      // % ánh sáng, < ngưỡng => bật đèn
#define READ_MS          1500UL
#define BUZZ_MS          200UL

DHT dht(DHT_PIN, DHT_TYPE);
Adafruit_SSD1306 display(128, 64, &Wire, -1);

bool fanOn = false;
bool lampOn = false;
float lastT = NAN, lastH = NAN;
uint8_t lastLux = 0;
unsigned long tRead = 0, tBuzzOff = 0;

void setRelay(bool on) {
  fanOn = on;
  digitalWrite(RELAY_PIN,
    (RELAY_ACTIVE_LEVEL == HIGH) ? (on ? HIGH : LOW)
                                 : (on ? LOW  : HIGH));
}

void setLamp(bool on) {
  lampOn = on;
  digitalWrite(LED_PIN, on ? HIGH : LOW);
}

void beep(uint16_t ms = BUZZ_MS) {
  ledcAttachPin(BUZZ_PIN, 0);
  ledcWriteTone(0, 2200);             // 2.2 kHz beep
  tBuzzOff = millis() + ms;
}

uint8_t readLuxPct() {
  int adc = analogRead(LUX_ADC);      // 0..4095
  int pct = map(adc, 0, 4095, 0, 100);
  return (uint8_t)constrain(pct, 0, 100);
}

void drawOLED(float t, float h, uint8_t lux) {
  display.clearDisplay();
  display.setTextColor(SSD1306_WHITE);
  display.setTextSize(1);
  display.setCursor(0, 0);  display.println("Multi-sensor Smart Home");
  display.setCursor(0, 16); display.print("T: "); display.print(t, 1); display.println(" C");
  display.print("H: ");     display.print(h, 1); display.println(" %");
  display.print("Lux: ");   display.print(lux);  display.println(" %");
  display.print("Fan: ");   display.println(fanOn ? "ON" : "OFF");
  display.print("Lamp: ");  display.println(lampOn ? "ON" : "OFF");
  display.display();
}

void handleButton() {
  static uint8_t last = HIGH;
  static unsigned long deb = 0;
  uint8_t cur = digitalRead(BTN_PIN);
  if (cur != last && millis() - deb > 40) {
    deb = millis(); last = cur;
    if (cur == LOW) {                 // nhấn -> toggle quạt
      setRelay(!fanOn);
      beep();
      Serial.print("[BTN] Fan -> "); Serial.println(fanOn ? "ON" : "OFF");
    }
  }
}

void setup() {
  Serial.begin(115200);
  delay(200);
  Serial.println("Project #2 – Multi-sensor Smart Home (Local)");

  pinMode(RELAY_PIN, OUTPUT); setRelay(false);
  pinMode(LED_PIN, OUTPUT);   setLamp(false);
  pinMode(BUZZ_PIN, OUTPUT);
  pinMode(BTN_PIN, INPUT_PULLUP);

  dht.begin();
  Wire.begin(OLED_SDA, OLED_SCL);
  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println("[OLED] Not found (addr 0x3C).");
  } else {
    display.clearDisplay(); display.display();
  }
}

void loop() {
  handleButton();

  // stop buzzer
  if (tBuzzOff && millis() > tBuzzOff) { ledcWriteTone(0, 0); tBuzzOff = 0; }

  if (millis() - tRead >= READ_MS) {
    tRead = millis();

    float h = dht.readHumidity();
    float t = dht.readTemperature();
    if (isnan(h) || isnan(t)) {
      Serial.println("[DHT] Read failed");
      return;
    }
    uint8_t lux = readLuxPct();

    lastT = t; lastH = h; lastLux = lux;

    // --- Fan control (hysteresis) ---
    bool prevFan = fanOn;
    if (!fanOn && t >= TEMP_THRESHOLD_C) {
      setRelay(true); beep();
      Serial.println("[FAN] ON  (temp >= threshold)");
    } else if (fanOn && t <= (TEMP_THRESHOLD_C - TEMP_HYSTERESIS)) {
      setRelay(false);
      Serial.println("[FAN] OFF (temp <= threshold - hyst)");
    }

    // --- Lamp control by Lux ---
    bool prevLamp = lampOn;
    setLamp(lux < LUX_THRESHOLD);
    if (prevLamp != lampOn) {
      Serial.print("[LAMP] "); Serial.println(lampOn ? "ON  (dark)" : "OFF (bright)");
    }

    // --- OLED & Log ---
    drawOLED(t, h, lux);
    Serial.print("[DATA] T="); Serial.print(t, 1);
    Serial.print("C H="); Serial.print(h, 1);
    Serial.print("% Lux="); Serial.print(lux);
    Serial.print("% Fan="); Serial.print(fanOn ? "ON" : "OFF");
    Serial.print(" Lamp="); Serial.println(lampOn ? "ON" : "OFF");
  }
}