/**
 * session-state.ts
 *
 * Per-Claude-session active-project marker files.
 * Located in ~/.hmem/sessions/<session_id>.json and keyed by the session_id
 * that Claude Code passes in every hook's stdin JSON.
 */
export interface SessionMarker {
    sessionId: string;
    projectId: string | null;
    hmemPath: string;
    updatedAt: string;
    pid: number;
    /** Written by 'hmem deactivate' after /clear — distinguishes explicit deactivation from default null */
    deactivated?: boolean;
    /** L2 O-sub-node ID for this session (e.g. "O0048.114"). Set by Stop-Hook after first exchange. */
    oSessionId?: string | null;
}
export interface SessionMarkerInput {
    projectId?: string | null;
    hmemPath?: string;
    deactivated?: boolean;
    oSessionId?: string | null;
}
export declare function sessionMarkerDir(): string;
export declare function writeSessionMarker(sessionId: string, input: SessionMarkerInput): void;
export declare function readSessionMarker(sessionId: string): SessionMarker | null;
export declare function clearSessionMarker(sessionId: string): void;
export declare function purgeStaleSessionMarkers(maxAgeDays: number): number;
export interface PpidMapping {
    sessionId: string;
    hmemPath: string;
    updatedAt: string;
}
/**
 * Write a mapping from a parent process id to a session id + hmem path.
 * Used as a bridge between hooks (which know the session id) and MCP servers
 * (which don't, but share the same parent pid = Claude Code's pid).
 */
export declare function writePpidMapping(ppid: number, sessionId: string, hmemPath: string): void;
export declare function readPpidMapping(ppid: number): PpidMapping | null;
/**
 * Resolve the current session id by chaining: env var > ppid-bridge file.
 * Caches the result in process.env.HMEM_SESSION_ID so repeated calls are cheap.
 *
 * Linux/macOS: process.ppid is the Claude Code PID shared between the hook and
 * MCP server, so the ppid-bridge file written by the hook is readable here.
 * Windows: process.ppid may be unavailable in older Node versions — in that case
 * currentSessionId() returns undefined and the system falls through to legacy
 * DB-flag behavior.
 */
export declare function currentSessionId(): string | undefined;
export declare function activeProjectFilePath(claudePid: number): string;
export declare function writeActiveProjectFile(claudePid: number, projectId: string): void;
export declare function readActiveProjectFile(claudePid: number): string | null;
/**
 * Read the PPID of any process from /proc (Linux only).
 * Returns null on non-Linux or if the file cannot be read.
 */
export declare function getParentPid(pid: number): number | null;
/**
 * Find the active project for the current process, walking up the process
 * tree to handle the bash-intermediary case:
 *   Claude Code → bash → this process
 *   File key = Claude Code PID = grandparent PID of this process
 */
export declare function readActiveProjectForCurrentProcess(): string | null;
export declare function getActiveDevice(): string | null;
export declare function setActiveDevice(id: string): void;