#include <WiFi.h>
#include <PubSubClient.h>
#include <LiquidCrystal_I2C.h>
#include <AccelStepper.h>

// ---------- WiFi / MQTT ----------
const char* ssid        = "Wokwi-GUEST";
const char* password    = "";
const char* mqtt_server = "test.mosquitto.org";

WiFiClient espClient;
PubSubClient client(espClient);
LiquidCrystal_I2C lcd(0x27, 16, 2);

// ---------- Pins ----------
#define PIR_PIN     4
#define LDR_PIN     36          // ADC1_CH0 (VP)
#define TRIG_PIN    18
#define ECHO_PIN    19
#define RELAY_PIN   23
#define LED_RED     32
#define LED_GREEN   33
#define LED_BLUE    14
#define LED_WHITE    2          // NEW: extra white LED (wired to GPIO2)
#define BUZZER_PIN  13

// ---------- Actuators ----------
AccelStepper stepper(AccelStepper::FULL4WIRE, 27, 26, 25, 12);

// ---------- Tunables ----------
const uint16_t LDR_THRESHOLD     = 500; // lower value = darker
const uint8_t  DIST_THRESHOLD_CM = 20;  // motion by distance
const uint16_t BLINK_MS          = 500; // blue LED blink when PIR is HIGH

// ---------- State ----------
unsigned long lastMsg   = 0;
unsigned long lastBlink = 0;
bool blueLedState       = LOW;

// ---------- WiFi ----------
void setup_wifi() {
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) delay(250);
}

// ---------- MQTT callback (optional command control) ----------
void callback(char* topic, byte* payload, unsigned int length) {
  // Example: topic "home/cmd/relay" payload "ON"/"OFF"
  String t(topic);
  String p;
  for (unsigned int i = 0; i < length; i++) p += (char)payload[i];

  if (t == "home/cmd/relay") {
    digitalWrite(RELAY_PIN, (p == "ON") ? HIGH : LOW);
  } else if (t == "home/cmd/stepper") {
    if (p == "OPEN") stepper.moveTo(200);
    if (p == "CLOSE") stepper.moveTo(0);
  }
}

// ---------- MQTT reconnect ----------
void reconnect() {
  while (!client.connected()) {
    if (client.connect("ESP32Client")) {
      client.subscribe("home/cmd/relay");
      client.subscribe("home/cmd/stepper");
    } else {
      delay(2000);
    }
  }
}

// ---------- Distance (median of 3, timeout-protected) ----------
static float readDistanceOnce() {
  digitalWrite(TRIG_PIN, LOW);  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH); delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  // Timeout 30ms (~5m max range) to avoid blocking forever
  unsigned long dur = pulseIn(ECHO_PIN, HIGH, 30000UL);
  if (dur == 0) return 9999.0; // no echo
  return (dur * 0.034f * 0.5f);
}
float readDistance() {
  float a = readDistanceOnce();
  float b = readDistanceOnce();
  float c = readDistanceOnce();
  // median
  if ((a <= b && b <= c) || (c <= b && b <= a)) return b;
  if ((b <= a && a <= c) || (c <= a && a <= b)) return a;
  return c;
}

void setup() {
  // I/O directions
  pinMode(PIR_PIN, INPUT);
  pinMode(LDR_PIN, INPUT);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);

  pinMode(RELAY_PIN, OUTPUT);
  pinMode(LED_RED, OUTPUT);
  pinMode(LED_GREEN, OUTPUT);
  pinMode(LED_BLUE, OUTPUT);
  pinMode(LED_WHITE, OUTPUT);   // NEW: white LED
  pinMode(BUZZER_PIN, OUTPUT);

  // Safe defaults
  digitalWrite(RELAY_PIN, LOW);
  digitalWrite(LED_RED, LOW);
  digitalWrite(LED_GREEN, HIGH);
  digitalWrite(LED_BLUE, LOW);
  digitalWrite(LED_WHITE, LOW); // start OFF
  digitalWrite(BUZZER_PIN, LOW);

  // LCD
  lcd.init();
  lcd.backlight();
  lcd.clear();
  lcd.print("Home Automation");

  // Stepper config
  stepper.setMaxSpeed(1000);
  stepper.setAcceleration(500);

  // Network
  setup_wifi();
  client.setServer(mqtt_server, 1883);
  client.setCallback(callback);
}

void loop() {
  if (!client.connected()) reconnect();
  client.loop();

  const unsigned long now = millis();

  // ---- Periodic sensing, display, and telemetry ----
  if (now - lastMsg > 2000) {
    lastMsg = now;

    const int   pirState = digitalRead(PIR_PIN);
    const int   ldrValue = analogRead(LDR_PIN);
    const float distance = readDistance();

    // White LED = "darkness indicator" (turns on when ambient is low)
    digitalWrite(LED_WHITE, (ldrValue < LDR_THRESHOLD) ? HIGH : LOW);

    // LCD status
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Dist:");
    lcd.print(distance, 0);
    lcd.print("cm");
    lcd.setCursor(0, 1);
    lcd.print("Light:");
    lcd.print(ldrValue);

    // Rule: ACTIVE if near object OR motion OR dark
    const bool active = (distance < DIST_THRESHOLD_CM) || (pirState == HIGH) || (ldrValue < LDR_THRESHOLD);

    if (active) {
      digitalWrite(RELAY_PIN, HIGH);   // power appliance
      digitalWrite(LED_RED, HIGH);     // alert
      digitalWrite(LED_GREEN, LOW);
      digitalWrite(BUZZER_PIN, HIGH);  // beep/alarm
      stepper.moveTo(200);             // e.g., open/advance
      client.publish("home/status", "ACTIVE");
    } else {
      digitalWrite(RELAY_PIN, LOW);
      digitalWrite(LED_RED, LOW);
      digitalWrite(LED_GREEN, HIGH);   // safe/idle
      digitalWrite(BUZZER_PIN, LOW);
      stepper.moveTo(0);               // close/home
      client.publish("home/status", "IDLE");
    }

    // Telemetry
    client.publish("home/distance", String(distance, 0).c_str());
    client.publish("home/light",    String(ldrValue).c_str());
    client.publish("home/motion",   pirState ? "DETECTED" : "NONE");
    client.publish("home/dark",     (ldrValue < LDR_THRESHOLD) ? "TRUE" : "FALSE");
  }

  // ---- Blue LED: blink while PIR detects motion (non-blocking) ----
  if (digitalRead(PIR_PIN)) {
    if (now - lastBlink >= BLINK_MS) {
      lastBlink = now;
      blueLedState = !blueLedState;
      digitalWrite(LED_BLUE, blueLedState);
    }
  } else {
    digitalWrite(LED_BLUE, LOW);
  }

  // ---- Stepper service (non-blocking) ----
  stepper.run();
}