#include "WiFi.h"
#include <PubSubClient.h>

// WiFi credentials
const char* ssid = "Wokwi-GUEST";
const char* password = "";

// MQTT broker details
const char* mqtt_server = "192.168.29.98"; // Replace with your laptop's IP address
const int mqtt_port = 1883;

// MQTT client setup
WiFiClient espClient;
PubSubClient client(espClient);

// Device details
String device_id;

// Function to connect to WiFi
void connectToWiFi() {
    Serial.print("Connecting to WiFi...");
    WiFi.begin(ssid, password);

    while (WiFi.status() != WL_CONNECTED) {
        delay(1000);
        Serial.print(".");
    }

    Serial.println("\nWiFi connected");
    Serial.print("IP Address: ");
    Serial.println(WiFi.localIP());

    // Generate device ID from MAC address
    device_id = "device_" + WiFi.macAddress();
    Serial.println("Device ID: " + device_id);
}

// Function to connect to MQTT broker
void connectToMQTT() {
    while (!client.connected()) {
        Serial.println("Connecting to MQTT broker...");
        if (client.connect(device_id.c_str())) {
            Serial.println("MQTT connected");

            // Publish availability status
            client.publish((device_id + "/status").c_str(), "{\"status\":\"online\"}", true);

            // Send discovery information
            sendDeviceDiscovery();

            // Subscribe to device-specific command topic
            client.subscribe((device_id + "/commands").c_str());
            Serial.println("Subscribed to: " + device_id + "/commands");
        } else {
            Serial.print("Failed to connect. State: ");
            Serial.println(client.state());
            delay(5000);
        }
    }
}

// Function to send device discovery data
void sendDeviceDiscovery() {
    String discoveryPayload = "{";
    discoveryPayload += "\"id\":\"" + device_id + "\",";
    discoveryPayload += "\"firmware\":\"1.0.0\",";
    discoveryPayload += "\"capabilities\":[\"temperature\",\"battery\",\"humidity\"]";
    discoveryPayload += "}";
    client.publish("global/discovery", discoveryPayload.c_str());
    Serial.println("Published discovery data: " + discoveryPayload);
}

// Function to send telemetry data
void sendTelemetry() {
    // Simulate sensor data
    float temperature = random(20, 30) + random(0, 100) / 100.0;
    float battery = random(30, 100) / 10.0;
    float humidity = random(30, 70) + random(0, 100) / 100.0;
    unsigned long timestamp = millis(); // Placeholder timestamp

    String telemetryPayload = "{";
    telemetryPayload += "\"temperature\":" + String(temperature, 2) + ",";
    telemetryPayload += "\"battery\":" + String(battery, 2) + ",";
    telemetryPayload += "\"humidity\":" + String(humidity, 2) + ",";
    telemetryPayload += "\"timestamp\":" + String(timestamp);
    telemetryPayload += "}";

    client.publish((device_id + "/telemetry").c_str(), telemetryPayload.c_str());
    Serial.println("Published telemetry to " + device_id + "/telemetry: " + telemetryPayload);
}

// Callback function to handle incoming MQTT messages
void callback(char* topic, byte* payload, unsigned int length) {
    Serial.print("Message arrived on topic: ");
    Serial.println(topic);

    String message;
    for (int i = 0; i < length; i++) {
        message += (char)payload[i];
    }
    Serial.println("Message: " + message);

    // Handle reboot command
    if (String(topic).endsWith("/commands") && message == "{\"action\":\"reboot\"}") {
        Serial.println("Reboot command received!");
        ESP.restart();
    }
}

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

    // Connect to WiFi
    connectToWiFi();

    // Set MQTT server and callback
    client.setServer(mqtt_server, mqtt_port);
    client.setCallback(callback);

    // Connect to MQTT broker
    connectToMQTT();
}

void loop() {
    if (!client.connected()) {
        connectToMQTT();
    }
    client.loop();

    // Send telemetry every 5 seconds
    static unsigned long lastTelemetry = 0;
    if (millis() - lastTelemetry >= 5000) {
        sendTelemetry();
        lastTelemetry = millis();
    }
}