export interface SessionChunk {
    index: number;
    content: string;
    tokenEstimate: number;
}
export interface SessionSearchResult {
    sessionId: string;
    isCurrentSession: boolean;
    content_snippet: string;
    score: number;
    chunkIndex: number;
}
/**
 * Manages a single session document — an append-only markdown file
 * that accumulates conversation context, chunked and embedded for
 * semantic search alongside regular messages.
 */
export declare class SessionManager {
    readonly sessionId: string;
    readonly sessionsDir: string;
    readonly sessionPath: string;
    readonly startedAt: number;
    private exchangeCount;
    private threadName;
    constructor(sessionsDir: string, threadName: string, existingSessionId?: string);
    getSessionId(): string;
    /**
     * Create the session file with its header.
     */
    initialize(): Promise<void>;
    /**
     * Append an exchange to the session document.
     * Does not re-embed — that happens lazily at search time.
     */
    appendExchange(userMsg: string, assistantMsg: string): Promise<void>;
    /**
     * Read the session file and chunk it on exchange boundaries,
     * accumulating exchanges until the chunk reaches ~DEFAULT_CHUNK_SIZE tokens.
     */
    getChunks(): Promise<SessionChunk[]>;
    /**
     * Generate embeddings for new/changed chunks and merge them into the thread's
     * consolidated session blob ({thread}.sessions/_sessions.embeddings.bin).
     * Only the last chunk can change (we only append), so earlier chunks are skipped.
     * Called fire-and-forget after each turn (embed-on-write) — keeps the active
     * session current so search regenerates nothing in steady state.
     */
    generateMissingEmbeddings(): Promise<void>;
    /**
     * Search ALL sessions in a directory against a query embedding.
     *
     * Reads the consolidated binary blob once (cached in memory — 0 reads warm),
     * scans it in memory, and lazily reads the `.md` file only for sessions that
     * actually matched. Replaces the old per-file fan-out (~2N stat + 2N read for
     * N sessions) that became the 21–24s contended `searchSessions` long pole.
     */
    static searchAllSessions(sessionsDir: string, queryEmbedding: number[], currentSessionId: string, threshold?: number): Promise<SessionSearchResult[]>;
    /**
     * Reconstruct chunk content from parts given a chunk index.
     * Mirrors the chunking logic in getChunks().
     */
    private static getChunkContent;
}
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