/**
 * Semantic hashing engine — pure algorithms, zero I/O.
 *
 * Ported from the Jups.tr notebook diff UI: the "golden logic" of
 * shingling + MinHash + Jaccard + DP alignment + surgical token diff,
 * hardened for server-side use with deterministic seeds.
 *
 * Design decisions:
 *   • Deterministic PRNG for MinHash permutations — same seed always
 *     produces the same signature, safe for cross-cycle cache comparison.
 *   • Section-aware chunking so markdown files get per-heading signatures.
 *   • Surgical token diff only fires on *modified* pairs (never on
 *     unchanged or added/deleted) to keep cost proportional to change.
 */
export interface DiffOp {
    /** -1 = deletion, 0 = equal, 1 = insertion */
    type: -1 | 0 | 1;
    text: string;
}
export interface MarkdownSection {
    heading: string;
    /** 0-based inclusive */
    lineStart: number;
    /** 0-based inclusive */
    lineEnd: number;
    content: string;
}
export interface AlignedPair {
    type: "MATCH" | "MODIFIED" | "INSERT" | "DELETE";
    left: MarkdownSection | null;
    right: MarkdownSection | null;
    similarity: number;
}
/**
 * Character k-shingles for approximate set similarity.
 * Normalises whitespace so formatting changes don't dominate.
 */
export declare function getShingles(text: string, k?: number): Set<string>;
export declare function calculateJaccard(setA: Set<string>, setB: Set<string>): number;
export declare class MinHash {
    readonly numPermutations: number;
    private readonly prime;
    private readonly maxHash;
    private readonly permuteFuncs;
    /**
     * @param numPermutations Hash function count (default 128)
     * @param seed            Deterministic seed — MUST be constant across runs
     *                        for cached signatures to remain comparable.
     */
    constructor(numPermutations?: number, seed?: number);
    /** djb2 string → uint32 */
    private hashString;
    /** Compute a MinHash signature for a set of shingles. */
    computeSignature(shingles: Set<string>): number[];
    /** Estimate Jaccard similarity from two signatures. */
    estimateSimilarity(sigA: number[], sigB: number[]): number;
}
/**
 * Split a markdown document into sections at heading boundaries.
 * A section runs from one heading to the next (or EOF).
 * Content before the first heading is labelled "(preamble)".
 */
export declare function splitMarkdownSections(text: string): MarkdownSection[];
/**
 * Align two ordered sequences of sections using similarity-based DP.
 * Uses MinHash estimated similarity with a configurable threshold
 * (default 0.4 for sections which are more granular than whole files).
 *
 * Returns an ordered list of aligned pairs.
 */
export declare function alignSections(leftSections: MarkdownSection[], rightSections: MarkdownSection[], mh: MinHash, similarityThreshold?: number, shingleSize?: number): AlignedPair[];
/**
 * Tokenize preserving whitespace and punctuation boundaries,
 * then LCS-align tokens for a precise word-level diff.
 * Only call on MODIFIED pairs — unnecessary for MATCH/INSERT/DELETE.
 */
export declare function surgicalTokenDiff(text1: string, text2: string): DiffOp[];
/**
 * Render a DiffOp[] into a compact text summary suitable for agent
 * consumption: lines prefixed with ` `, `+`, `-`.
 */
export declare function renderDiffSummary(ops: DiffOp[]): string;
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