import type { MemoryEntry, MemoryScope } from '../types/memory.js';
import type { WstackPaths } from '../utils/wstack-paths.js';
export interface MemoryBackend {
    readonly kind: string;
    remember(scope: MemoryScope, entry: MemoryEntry, filePath: string): Promise<void>;
    forget(scope: MemoryScope, query: string, filePath: string): Promise<number>;
    readAll(scope: MemoryScope, filePath: string): Promise<string>;
    list(scope: MemoryScope, filePath: string, limit?: number | undefined): Promise<MemoryEntry[]>;
    search(scope: MemoryScope, query: string, filePath: string, limit?: number | undefined): Promise<MemoryEntry[]>;
    /** Find memories related to the given text via graph traversal. Optional — falls back to search. */
    findRelated?(scope: MemoryScope, filePath: string, text: string, limit: number): Promise<MemoryEntry[]>;
    clear(scope: MemoryScope, filePath: string): Promise<void>;
    consolidate(scope: MemoryScope, filePath: string): Promise<number>;
}
interface IndexedEntry {
    entry: MemoryEntry;
    /** Lower-cased words extracted from text. */
    words: string[];
    /** Lower-cased tags. */
    tags: string[];
}
interface InvertedIndex {
    /** word -> entry indices */
    wordMap: Map<string, number[]>;
    /** tag -> entry indices */
    tagMap: Map<string, number[]>;
    entries: IndexedEntry[];
    /** Last known file mtime for cache invalidation. */
    mtimeMs: number;
}
export declare function buildInvertedIndex(entries: MemoryEntry[]): InvertedIndex;
export declare function searchIndex(index: InvertedIndex, query: string, limit?: number): MemoryEntry[];
export interface FileMemoryBackendOptions {
    paths: WstackPaths;
}
export declare class FileMemoryBackend implements MemoryBackend {
    readonly kind = "file";
    private readonly files;
    /** Cache of parsed entries per file path. */
    private readonly entryCache;
    /** Inverted index per file path. */
    private readonly indexCache;
    /** File mtime cache for invalidation. */
    private readonly mtimeCache;
    constructor(opts: FileMemoryBackendOptions);
    private resolveFile;
    private getMtime;
    private invalidateCache;
    /**
     * Load (and cache) the parsed entries for a file. Callers that have already
     * stat'd the file this tick (e.g. `getIndex`) can pass the known `mtime` to
     * avoid a redundant `fs.stat` — otherwise it's fetched here.
     */
    private loadEntries;
    private getIndex;
    remember(scope: MemoryScope, entry: MemoryEntry, filePath: string): Promise<void>;
    forget(scope: MemoryScope, query: string, filePath: string): Promise<number>;
    readAll(scope: MemoryScope, filePath: string): Promise<string>;
    list(scope: MemoryScope, filePath: string, limit?: number): Promise<MemoryEntry[]>;
    search(scope: MemoryScope, query: string, filePath: string, limit?: number): Promise<MemoryEntry[]>;
    clear(scope: MemoryScope, filePath: string): Promise<void>;
    consolidate(scope: MemoryScope, filePath: string): Promise<number>;
}
export declare function parseEntries(raw: string, scope?: MemoryScope): MemoryEntry[];
export {};
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