/**
 * MQTT Sink Trait
 *
 * Publish object state changes to MQTT topics.
 * Supports retained messages, QoS levels, and automatic serialization.
 *
 * @version 1.0.0
 */
import type { TraitHandler, HSPlusNode } from '@holoscript/core';
import { MQTTClient, type QoS } from '@holoscript/engine/runtime/protocols/MQTTClient';
export interface MQTTSinkConfig {
    /** MQTT broker URL */
    broker: string;
    /** Topic to publish to (can include {placeholders} for dynamic topics) */
    topic: string;
    /** Retain messages on broker */
    retain: boolean;
    /** QoS level (0, 1, or 2) */
    qos: QoS;
    /** Client ID (optional, auto-generated if not provided) */
    clientId?: string;
    /** Username for authentication */
    username?: string;
    /** Password for authentication */
    password?: string;
    /** State fields to publish (default: all) */
    fields?: string[];
    /** Throttle interval in ms (min time between publishes) */
    throttle?: number;
    /** Publish only on state change */
    onChangeOnly?: boolean;
    /** Auto-connect on attach */
    autoConnect?: boolean;
    /** Serialize as JSON */
    serializeJson?: boolean;
    /** Include timestamp in payload */
    includeTimestamp?: boolean;
}
export interface MQTTSinkState {
    /** Whether connected to broker */
    connected: boolean;
    /** Total messages published */
    publishCount: number;
    /** Last publish timestamp */
    lastPublished: number;
    /** Connection error if any */
    error: string | null;
    /** MQTT client instance */
    client: MQTTClient | null;
    /** Last published state hash for change detection */
    lastStateHash: string | null;
}
export declare const mqttSinkHandler: TraitHandler<MQTTSinkConfig>;
/**
 * Check if a node has the @mqtt_sink trait
 */
export declare function hasMQTTSinkTrait(node: HSPlusNode): boolean;
/**
 * Get the MQTT sink state from a node
 */
export declare function getMQTTSinkState(node: HSPlusNode): MQTTSinkState | null;
/**
 * Get the MQTT client from a node with @mqtt_sink trait
 */
export declare function getMQTTSinkClient(node: HSPlusNode): MQTTClient | null;
/**
 * Check if MQTT sink is connected
 */
export declare function isMQTTSinkConnected(node: HSPlusNode): boolean;
/**
 * Manually trigger a publish
 */
export declare function publishToMQTTSink(node: HSPlusNode, payload?: unknown, topic?: string): Promise<void>;
export default mqttSinkHandler;
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