// Home Automation System - ESP32 on Wokwi (compatible with Arduino-ESP32 core 3.0+)
// Features:
//   - Automatic Street Light: LDR darkness → LED ON
//   - Smart Fan/AC: Temp > 30°C → Relay ON + Fan spins (servo via LEDC PWM)
// Pins match your diagram.json

#define LDR_PIN       34     // Analog (AO from photoresistor)
#define DHT_PIN       4      // Data from DHT22
#define LED_PIN       2      // Street light LED
#define RELAY_PIN     5      // Relay IN (active LOW)
#define SERVO_PIN     18     // Servo PWM signal

#define TEMP_THRESHOLD       30.0f   // °C to turn fan on
#define LDR_DARK_THRESHOLD  1800     // Tune: higher = activates in darker conditions (0-4095)

#include <DHTesp.h>   // Install via Wokwi Library Manager: "DHT sensor library for ESPx"

DHTesp dht;

const uint32_t PWM_FREQ       = 50;       // Servo standard: 50 Hz
const uint8_t  PWM_RESOLUTION = 16;       // 16-bit → good precision for pulse timing

bool fanIsOn = false;

void setup() {
  Serial.begin(115200);
  delay(1000);
  Serial.println("\nHome Automation System started (LDR + DHT22 + LEDC PWM Servo - core 3.0+)");

  // Outputs
  pinMode(LED_PIN, OUTPUT);
  pinMode(RELAY_PIN, OUTPUT);
  digitalWrite(LED_PIN, LOW);
  digitalWrite(RELAY_PIN, HIGH);   // Relay OFF (active LOW)

  // DHT22 init
  dht.setup(DHT_PIN, DHTesp::DHT22);

  // LEDC PWM setup for servo (new API in core 3.0+)
  // ledcAttach(pin, frequency, resolution) → auto channel assignment
  ledcAttach(SERVO_PIN, PWM_FREQ, PWM_RESOLUTION);
  setServoAngle(0);   // Start stopped (0°)

  delay(2000);   // Stabilize sensors
}

void loop() {
  // ────────────── Street Light (LDR) ──────────────
  int ldrValue = analogRead(LDR_PIN);   // ~0 bright sunlight, ~4095 very dark
  bool isDark = (ldrValue > LDR_DARK_THRESHOLD);

  digitalWrite(LED_PIN, isDark ? HIGH : LOW);

  // ────────────── Temperature & Fan Control ──────────────
  TempAndHumidity newData = dht.getTempAndHumidity();

  if (dht.getStatus() == 0) {   // 0 = ERROR_NONE
    float temp = newData.temperature;

    Serial.printf("Temp: %.1f °C | LDR: %d | Light: %s | Fan: %s\n",
                  temp, ldrValue,
                  isDark ? "ON" : "OFF",
                  fanIsOn ? "ON" : "OFF");

    // Fan logic: relay powers servo + PWM moves it
    if (temp > TEMP_THRESHOLD && !fanIsOn) {
      Serial.println("→ High temp → Fan ON");
      digitalWrite(RELAY_PIN, LOW);     // Relay ON → 5V to servo
      fanIsOn = true;
      setServoAngle(90);                // "Spin" (mid-speed simulation; adjust to 60-120)
    }
    else if (temp <= TEMP_THRESHOLD && fanIsOn) {
      Serial.println("→ Temp OK → Fan OFF");
      setServoAngle(0);                 // Stop
      digitalWrite(RELAY_PIN, HIGH);    // Relay OFF → no power to servo
      fanIsOn = false;
    }
  } else {
    Serial.println("DHT22 error: " + String(dht.getStatusString()));
  }

  delay(2000);   // Refresh every 2s
}

// Helper: Set servo position 0–180°
// Maps angle to pulse: ~544µs (0°) to ~2400µs (180°) — typical for SG90
void setServoAngle(int angle) {
  if (angle < 0)   angle = 0;
  if (angle > 180) angle = 180;

  // Pulse width in µs
  int pulse_us = map(angle, 0, 180, 544, 2400);

  // Duty cycle for 16-bit resolution @ 50 Hz (20 ms period = 20000 µs)
  uint32_t duty = (pulse_us * (1UL << PWM_RESOLUTION)) / 20000UL;

  // New API: ledcWrite now uses pin (not channel)
  ledcWrite(SERVO_PIN, duty);
}