/**
 * MQTT connectivity and topic management for Homebridge plugins.
 *
 * @module
 */
import type { HomebridgePluginLogging } from "./util.js";
/**
 * MQTT connectivity and topic management class for Homebridge plugins.
 *
 * This class manages connection, publishing, subscription, and message handling for an MQTT broker, and provides convenience methods for Homebridge accessories to
 * interact with MQTT topics using a standard topic prefix.
 *
 * @example
 *
 * ```ts
 * const mqtt = new MqttClient("mqtt://localhost:1883", "homebridge", log);
 *
 * // Publish a message to a topic.
 * mqtt.publish("device1", "status", "on");
 *
 * // Subscribe to a topic.
 * mqtt.subscribe("device1", "status", (msg) => {
 *
 *   console.log(msg.toString());
 * });
 *
 * // Subscribe to a 'get' topic and automatically publish a value in response.
 * mqtt.subscribeGet("device1", "temperature", "Temperature", () => "21.5");
 *
 * // Subscribe to a 'set' topic and handle value changes.
 * mqtt.subscribeSet("device1", "switch", "Switch", (value) => {
 *
 *   console.log("Switch set to", value);
 * });
 *
 * // Unsubscribe from a topic.
 * mqtt.unsubscribe("device1", "status");
 * ```
 */
export declare class MqttClient {
    private brokerUrl;
    private isConnected;
    private reconnectInterval;
    private log;
    private mqtt;
    private subscriptions;
    private topicPrefix;
    /**
     * Creates a new MQTT client for connecting to a broker and managing topics with a given prefix.
     *
     * @param brokerUrl          - The MQTT broker URL (e.g., "mqtt://localhost:1883").
     * @param topicPrefix        - Prefix to use for all MQTT topics (e.g., "homebridge").
     * @param log                - Logger for debug and info messages.
     * @param reconnectInterval  - Optional. Interval (in seconds) to wait between reconnection attempts. Defaults to 60 seconds.
     *
     * @example
     *
     * ```ts
     * const mqtt = new MqttClient("mqtt://localhost", "homebridge", log);
     * ```
     *
     * @remarks URL must conform to formats supported by {@link https://github.com/mqttjs/MQTT.js | MQTT.js}.
     */
    constructor(brokerUrl: string, topicPrefix: string, log: HomebridgePluginLogging, reconnectInterval?: number);
    /**
     * Initializes and connects the MQTT client to the broker, setting up event handlers for connection, messages, and errors.
     *
     * Catches invalid broker URLs and logs errors. Handles all major MQTT client events internally.
     */
    private configure;
    /**
     * Publishes a message to a topic for a specific device.
     *
     * Expands the topic using the topic prefix and device ID, then publishes the provided message string.
     *
     * @param id      - The device or accessory identifier.
     * @param topic   - The topic name to publish to.
     * @param message - The message payload to publish.
     *
     * @example
     *
     * ```ts
     * mqtt.publish("device1", "status", "on");
     * ```
     */
    publish(id: string, topic: string, message: string): void;
    /**
     * Subscribes to a topic for a specific device and registers a handler for incoming messages.
     *
     * The topic is expanded using the prefix and device ID, and the callback will be called for each message received.
     *
     * @param id       - The device or accessory identifier.
     * @param topic    - The topic name to subscribe to.
     * @param callback - Handler function called with the message buffer.
     *
     * @example
     *
     * ```ts
     * mqtt.subscribe("device1", "status", (msg) => {
     *
     *   console.log(msg.toString());
     * });
     * ```
     */
    subscribe(id: string, topic: string, callback: (cbBuffer: Buffer) => Promise<void> | void): void;
    /**
     * Subscribes to a '<topic>/get' topic and publishes a value in response to "true" messages.
     *
     * When a message "true" is received on the '<topic>/get' topic, this method will publish the result of `getValue()` on the main topic. The log will record each status
     * publication event.
     *
     * @param id       - The device or accessory identifier.
     * @param topic    - The topic name to use.
     * @param type     - A human-readable label for log messages (e.g., "Temperature").
     * @param getValue - Function to get the value to publish as a string.
     * @param log      - Optional logger for status output. Defaults to the class logger.
     *
     * @example
     *
     * ```ts
     * mqtt.subscribeGet("device1", "temperature", "Temperature", () => "21.5");
     * ```
     */
    subscribeGet(id: string, topic: string, type: string, getValue: () => string, log?: HomebridgePluginLogging): void;
    /**
     * Subscribes to a '<topic>/set' topic and calls a setter when a message is received.
     *
     * The `setValue` function is called with both a normalized value and the raw string. Handles both synchronous and promise-based setters. Logs when set messages are
     * received and when errors occur.
     *
     * @param id        - The device or accessory identifier.
     * @param topic     - The topic name to use.
     * @param type      - A human-readable label for log messages (e.g., "Switch").
     * @param setValue  - Function to call when a value is set. Can be synchronous or return a Promise.
     * @param log       - Optional logger for status output. Defaults to the class logger.
     *
     * @example
     *
     * ```ts
     * mqtt.subscribeSet("device1", "switch", "Switch", (value) => {
     *
     *   console.log("Switch set to", value);
     * });
     * ```
     */
    subscribeSet(id: string, topic: string, type: string, setValue: (value: string, rawValue: string) => Promise<void> | void, log?: HomebridgePluginLogging): void;
    /**
     * Unsubscribes from a topic for a specific device, removing its message handler.
     *
     * @param id    - The device or accessory identifier.
     * @param topic - The topic name to unsubscribe from.
     *
     * @example
     *
     * ```ts
     * mqtt.unsubscribe("device1", "status");
     * ```
     */
    unsubscribe(id: string, topic: string): void;
    /**
     * Expands a topic string into a fully-formed topic path including the prefix and device ID.
     *
     * Returns `null` if the device ID is missing or empty.
     *
     * @param id    - The device or accessory identifier.
     * @param topic - The topic name to expand.
     *
     * @returns The expanded topic string, or `null` if the ID is missing.
     *
     * @example
     *
     * ```ts
     * const topic = mqtt['expandTopic']("device1", "status");
     * // topic = "homebridge/device1/status"
     * ```
     */
    private expandTopic;
}