/**
 * LandscapeAgent — Environment topology tracker
 *
 * Polls {@link EnvironmentManager.list} on a fixed interval and writes a
 * health record for each known environment to the blackboard under
 * `landscape:health:<env>`.  TransportAgent reads these records before
 * starting a DRAINING phase to detect degraded destinations early.
 *
 * Health logic:
 *   - `missing`  — environment directory does not exist
 *   - `degraded` — last transport targeting this env failed or rolled back
 *   - `healthy`  — otherwise
 *
 * Blackboard keys written:
 *   landscape:health:<env>  — {@link EnvironmentHealth} record (overwritten each poll)
 *
 * @module LandscapeAgent
 * @version 1.0.0
 */
import type { LockedBlackboard } from './locked-blackboard';
import type { EnvironmentManager, EnvName } from './env-manager';
import type { TransportStatusRecord } from './transport-agent';
/** Status of a single environment as seen by {@link LandscapeAgent}. */
export type EnvironmentHealthStatus = 'healthy' | 'degraded' | 'missing';
/** Health record written to `landscape:health:<env>`. */
export interface EnvironmentHealth {
    env: EnvName;
    status: EnvironmentHealthStatus;
    /** Number of config keys present in the environment directory. */
    keyCount: number;
    /** ISO-8601 timestamp of the last successful poll. */
    lastChecked: string;
    /** Status of the most recent transport that targeted this environment. */
    lastTransportStatus?: TransportStatusRecord['status'];
    /** Transport request ID of the most recent completed transport. */
    lastTransportId?: string;
}
/** Options for constructing a {@link LandscapeAgent}. */
export interface LandscapeAgentOptions {
    /** Blackboard used to publish health records. */
    blackboard: LockedBlackboard;
    /** Environment manager for querying known environments. */
    envManager: EnvironmentManager;
    /** Agent ID used for blackboard writes. Default: `'basis:landscape'`. */
    agentId?: string;
    /** Poll interval in milliseconds. Default: 30 000. */
    pollIntervalMs?: number;
}
/**
 * Slow-poll environment topology tracker.
 *
 * @example
 * ```typescript
 * const landscape = new LandscapeAgent({ blackboard, envManager });
 * landscape.start();
 *
 * // Read health for a specific environment:
 * const entry = blackboard.read('landscape:health:prod');
 * const health = entry?.value as EnvironmentHealth;
 * ```
 */
export declare class LandscapeAgent {
    private readonly _blackboard;
    private readonly _envManager;
    private readonly _agentId;
    private readonly _pollIntervalMs;
    private _pollHandle;
    private _running;
    constructor(options: LandscapeAgentOptions);
    /**
     * Start the poll loop.  The first poll fires immediately.
     */
    start(): void;
    /** Stop the poll loop. */
    stop(): void;
    /** Whether the agent is currently running. */
    get isRunning(): boolean;
    /**
     * Perform a single health poll and write results to the blackboard.
     * Can be called manually (e.g. from tests) without starting the loop.
     */
    poll(): Promise<EnvironmentHealth[]>;
    private _poll;
    private _computeHealth;
    /** Scan `transport:status:*` keys for the most recent TR that targeted `env`. */
    private _findLastTransport;
}
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