// ESP32 + Wokwi + MQTT (PubSubClient) + DHT22 + Buttons + LWT
#include <WiFi.h>
#include <PubSubClient.h>
#include "DHT.h"

// Readable Aliases
#define ON  HIGH
#define OFF LOW

// Pin Assignments
const int led1   = 18; // BLUE LED
const int led2   = 13; // RED LED
const int btn1   = 12; // RED Button (wired to GND) -> INPUT_PULLUP
const int btn2   = 14; // BLUE Button (wired to GND) -> INPUT_PULLUP
const int potPin = 34; // Analog input
const int dhtPin = 4;  // DHT22 data pin

// WiFi (Wokwi virtual AP)
const char* ssid     = "Wokwi-GUEST";
const char* password = "";
const uint8_t wifi_channel = 6; // IMPORTANT for Wokwi

// MQTT Broker
const char* mqtt_server = "test.mosquitto.org";
const uint16_t mqtt_port = 1883;

// MQTT Topics
const char* topicTemp        = "Brownies/Azriel/dht22/temperature";
const char* topicHum         = "Brownies/Azriel/dht22/humidity";
const char* topicPot         = "Brownies/Azriel/potentiometer";
const char* topicStatus      = "Brownies/Azriel/sensor/status";    // presence topic
const char* topicLed1Control = "Brownies/Azriel/led1/control";     // BLUE
const char* topicLed2Control = "Brownies/Azriel/led2/control";     // RED

// LWT configuration
const char* deviceId       = "ESP32-Taufiq"; // unique per device
const char* willMsgOffline = "offline";
const char* msgOnline      = "online";
const int   willQos        = 1;
const bool  willRetain     = true;

WiFiClient   espClient;
PubSubClient client(espClient);
DHT dht(dhtPin, DHT22);

unsigned long lastPublish = 0;

// Variables to remember App states
bool appLed1State = false; // BLUE LED
bool appLed2State = false; // RED LED

// --- MQTT message callback ---
void callback(char* topic, byte* payload, unsigned int length) {
  String message;
  message.reserve(length);
  for (unsigned int i = 0; i < length; i++) message += (char)payload[i];

  Serial.printf("MQTT [%s]: %s\n", topic, message.c_str());

  if (String(topic) == topicLed1Control) {
    appLed1State = (message == "ON");
  } else if (String(topic) == topicLed2Control) {
    appLed2State = (message == "ON");
  }
}

// --- Robust Wi‑Fi connect (Wokwi) ---
void setup_wifi() {
  Serial.println();
  Serial.printf("Connecting to %s\n", ssid);

  WiFi.mode(WIFI_STA);
  WiFi.persistent(false);
  WiFi.setSleep(false);

  // In Wokwi, specifying channel 6 avoids long scans and “infinite dots”
  WiFi.begin(ssid, password, wifi_channel);

  const uint32_t t0 = millis();
  const uint32_t timeoutMs = 12000; // 12s timeout
  while (WiFi.status() != WL_CONNECTED && (millis() - t0) < timeoutMs) {
    delay(250);
    Serial.print(".");
  }
  Serial.println();

  if (WiFi.status() == WL_CONNECTED) {
    Serial.print("WiFi connected, IP: ");
    Serial.println(WiFi.localIP());
  } else {
    Serial.println("WiFi connect timed out. In Wokwi, ensure the Wi‑Fi icon is enabled.");
  }
}

// --- MQTT reconnect with LWT ---
void reconnectMqtt() {
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection... ");

    // Connect with Last Will
    // connect(clientID, willTopic, willQos, willRetain, willMessage)
    bool ok = client.connect(deviceId, topicStatus, willQos, willRetain, willMsgOffline);
    if (ok) {
      Serial.println("connected");

      // Publish presence = "online" (retained)
      client.publish(topicStatus, msgOnline, true);

      // Subscribe to control topics
      client.subscribe(topicLed1Control);
      client.subscribe(topicLed2Control);
    } else {
      Serial.printf("failed, rc=%d. Retrying in 3s\n", client.state());
      delay(3000);
    }
  }
}

void setup() {
  Serial.begin(115200);
  delay(100);

  pinMode(led1, OUTPUT);
  pinMode(led2, OUTPUT);

  // Buttons wired to GND -> use INPUT_PULLUP (pressed = LOW)
  pinMode(btn1, INPUT_PULLUP);
  pinMode(btn2, INPUT_PULLUP);

  dht.begin();
  setup_wifi();

  client.setServer(mqtt_server, mqtt_port);
  client.setCallback(callback);
}

void loop() {
  if (WiFi.status() != WL_CONNECTED) {
    // If Wi‑Fi dropped, try to rejoin quickly
    setup_wifi();
  }

  if (!client.connected()) {
    reconnectMqtt();
  }
  client.loop(); // keep MQTT traffic flowing

  // --- LED Logic ---
  // BLUE LED on pin 18: controlled by app OR physical button 12
  digitalWrite(led1, (appLed1State || digitalRead(btn1) == LOW) ? ON : OFF);

  // RED LED on pin 13: controlled by app OR physical button 14
  digitalWrite(led2, (appLed2State || digitalRead(btn2) == LOW) ? ON : OFF);

  // --- SENSOR DATA PUBLISHING (every 2 seconds) ---
  unsigned long now = millis();
  if (now - lastPublish > 2000) {
    lastPublish = now;

    float t = dht.readTemperature();
    float h = dht.readHumidity();
    int   potValue = analogRead(potPin);

    // Only publish valid DHT readings
    if (!isnan(t) && !isnan(h)) {
      client.publish(topicTemp, String(t).c_str());
      client.publish(topicHum,  String(h).c_str());
    } else {
      Serial.println("DHT read failed (NaN). Skipping publish.");
    }

    client.publish(topicPot, String(potValue).c_str());

    Serial.print("Sent -> Temp: "); Serial.print(t);
    Serial.print(" | Hum: ");      Serial.print(h);
    Serial.print(" | Pot: ");      Serial.println(potValue);
  }
}