import { type StatusSurfaceStreams } from "./status-surface.js";
/**
 * Single background producer of tmux status-bar text.
 *
 * The 2026-07-31 spawn storm: the installed surface embedded
 * `#(h2a status --bar ...)` in status-left AND status-right, and tmux re-runs
 * both commands once per status-interval for EVERY session — two node
 * startups per session per 5s (~16/s at 40 sessions, measured load 197). The
 * surface now embeds only `#(cat <file>)`; this writer is the one process
 * that computes every session's bar text and publishes it to those files.
 *
 * Self-limiting by construction: a lease makes it single-instance per h2a
 * root, it exits once no installed session remains, and each tick costs two
 * bounded tmux list calls plus in-process rendering — never a subprocess per
 * session.
 */
/** Duplicated in @sentropic/h2a-runtime (tmux.ts): the CLI is a peer, not an import. */
export declare const STATUS_BAR_WRITER_LOCK_FILE = "writer.lock";
export interface WriterLeaseProbe {
    readonly pid: number;
    readonly isAlive: (pid: number) => boolean;
    readonly staleMs?: number;
}
/**
 * Take the single-writer lease. A held lock only blocks us while its holder
 * is alive AND fresh: liveness alone is not enough (pid reuse after a crash),
 * freshness alone is not enough (a hung writer keeps refreshing nothing).
 */
export declare function acquireStatusBarWriterLease(dir: string, probe: WriterLeaseProbe): boolean;
/** Touch the lock so ensure-side staleness checks see a live writer. */
export declare function refreshStatusBarWriterLease(dir: string, pid: number): boolean;
export declare function releaseStatusBarWriterLease(dir: string, pid: number): void;
export interface StatusBarWriterOptions {
    readonly root: string;
    readonly signal?: AbortSignal;
    readonly intervalMs?: number;
}
export declare function runStatusBarWriter(options: StatusBarWriterOptions, streams: StatusSurfaceStreams): Promise<number>;
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