export interface SessionLease {
    ownerId: string;
    sessionId: string;
    pid: number;
    leaseTokenHash: string;
    endpoint: {
        kind: "unix-socket" | "fifo";
        path: string;
    } | null;
    eventsPath: string;
    heartbeatAt: string;
    expiresAt: string;
    leaseEpoch: number;
    writer: {
        ownerId: string;
        leaseEpoch: number;
    };
}
export declare class LeaseError extends Error {
    readonly code: string;
    constructor(message: string, code: string);
}
export type LeaseStatus = "missing" | "live" | "expiredAlive" | "dead" | "epermAlive";
type PidStatus = "alive" | "dead" | "eperm";
export declare function readLease(root: string, sessionId: string): Promise<SessionLease | null>;
export declare function isExpired(lease: SessionLease, clock?: () => number): boolean;
export declare function classifyLeaseStatus(lease: SessionLease | null, opts?: {
    clock?: () => number;
    probe?: (pid: number) => PidStatus;
}): LeaseStatus;
/** Liveness probe via signal 0. Defaults to the real process table; injectable for tests. */
export declare function isOwnerAlive(pid: number, probe?: (pid: number) => boolean): boolean;
export declare function isStale(lease: SessionLease, opts?: {
    clock?: () => number;
    probe?: (pid: number) => boolean;
}): boolean;
export interface AcquireOptions {
    ownerId: string;
    pid: number;
    endpoint?: SessionLease["endpoint"];
    eventsPath: string;
    ttlMs: number;
    clock?: () => number;
    probe?: (pid: number) => boolean | PidStatus;
}
export interface AcquiredLease {
    lease: SessionLease;
    token: string;
}
/**
 * Acquire (or take over a stale) lease. Fails closed with `lease_held` when a live,
 * unexpired lease is held by a different owner. Re-acquiring as the current owner refreshes.
 */
export declare function acquireLease(root: string, sessionId: string, opts: AcquireOptions): Promise<AcquiredLease>;
/** Refresh the lease expiry. Only the recorded owner may heartbeat (single-writer). */
export declare function heartbeat(root: string, sessionId: string, ownerId: string, ttlMs: number, clock?: () => number): Promise<SessionLease>;
/** Whether `ownerId` is the live, unexpired single writer permitted to append events. */
export declare function canWriteEvents(lease: SessionLease, ownerId: string, clock?: () => number): boolean;
/** Release the lease (owner shutdown). Only the holder may release. */
export declare function releaseLease(root: string, sessionId: string, ownerId: string): Promise<void>;
export declare function reapDeadOwnerArtifacts(root: string, sessionId: string, expectedOwnerId: string, expectedEpoch: number, opts?: {
    clock?: () => number;
    probe?: (pid: number) => PidStatus;
}): Promise<boolean>;
export {};