/**
 * Line/word diff helpers (no deps). LCS-based for readable patches.
 */
export type DiffOpType = 'equal' | 'insert' | 'delete';
export type DiffOp = {
    type: DiffOpType;
    value: string;
    /** 1-based line number in the "before" text */
    oldLine?: number;
    /** 1-based line number in the "after" text */
    newLine?: number;
};
export type SplitRow = {
    left: {
        type: 'equal' | 'delete' | 'empty';
        text: string;
        line?: number;
    } | null;
    right: {
        type: 'equal' | 'insert' | 'empty';
        text: string;
        line?: number;
    } | null;
    /** Word-level parts when both sides are a change pair */
    leftParts?: DiffPart[];
    rightParts?: DiffPart[];
};
export type DiffPart = {
    text: string;
    changed: boolean;
};
export type DiffStats = {
    additions: number;
    deletions: number;
    unchanged: number;
};
/** Line-level diff via LCS backtrack. */
export declare function diffLines(before: string, after: string): DiffOp[];
/** Word-level parts highlighting differences between two strings. */
export declare function diffWords(before: string, after: string): {
    left: DiffPart[];
    right: DiffPart[];
};
export declare function diffStats(ops: DiffOp[]): DiffStats;
/**
 * Build side-by-side rows. Consecutive delete+insert pairs become a single
 * modification row with optional word highlighting.
 */
export declare function toSplitRows(ops: DiffOp[], wordDiff?: boolean): SplitRow[];