import type { HistoryEntry } from './history-entry.js';
/** How many recent entries to keep in memory at all times. */
export declare const MAX_MEMORY_ENTRIES = 150;
/** Number of entries loaded from disk per scroll-back page. */
export declare const ARCHIVE_PAGE_SIZE = 100;
/**
 * Disk-backed archive of TUI history entries.
 *
 * Usage:
 * ```ts
 * const archive = new HistoryArchive(sessionDir);
 * await archive.append(entry);       // write to JSONL
 * const entries = await archive.loadRange(0, 100); // load by index
 * await archive.close();
 * ```
 *
 * The archive file lives at `<sessionDir>/history-archive.jsonl`.
 * It is append-only; entries are never removed (they are the durable
 * record). The in-memory window management is handled by the reducer.
 */
export declare class HistoryArchive {
    private readonly filePath;
    private handle;
    private closed;
    /** Byte-offset index: index → { offset, length }. Built on first load. */
    private index;
    /** Total entries written so far (monotonic counter). */
    private writeChain;
    private drainToken;
    constructor(sessionDir: string);
    /**
     * Append an entry to the archive. Fire-and-forget: the write is queued
     * on an internal promise chain so callers never block. Returns immediately.
     */
    append(entry: HistoryEntry): void;
    /**
     * Load a range of entries by index. Indices are 0-based and sequential
     * across the entire file (index 0 = oldest archived entry).
     *
     * Returns the loaded entries in chronological order (oldest first).
     * When the range exceeds the available data, returns whatever fits.
     */
    loadRange(startIndex: number, count: number): Promise<HistoryEntry[]>;
    /** How many entries are archived on disk. */
    get archivedCount(): number;
    /**
     * Close the file handle and release resources. Idempotent.
     * The write chain is drained before closing so no in-flight write
     * is lost.
     */
    close(): Promise<void>;
    private ensureOpen;
    /**
     * Build the byte-offset index by scanning the archive file.
     * Rebuilds when `this.index` is null (first use or after rotation).
     * The index is cached for the lifetime of the archive object.
     */
    private buildIndex;
    /** Serialise writes through a FIFO promise chain with fresh-token coalescing. */
    private enqueueWrite;
}
/**
 * Build the archive file path from a session directory.
 * Exported so the TUI can create the archive path from the session dir
 * without importing the class.
 */
export declare function historyArchivePath(sessionDir: string): string;
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