import { type Finding } from './diff.js';
/**
 * Shared-chrome tier (#193): group surfaces that changed identically and promote
 * persistent frame elements (nav, header, footer) that moved on every hosting view.
 */
/** A surface's diff distilled to just what grouping needs: its key and the
 *  findings kept after noise-cleaning. */
export type SurfaceFindings = {
    surface: string;
    findings: Finding[];
};
/** Surfaces that changed the SAME way, collapsed to one group + a representative. */
export type SignatureGroup = {
    surfaces: string[];
    rep: SurfaceFindings;
    findings: Finding[];
};
/**
 * Group surfaces that changed identically (same signature) into one group each,
 * keeping the widest surface as the representative. The rects differ per width;
 * the change itself does not. Callers pass the already-prepared per-surface
 * findings (missing/one-sided surfaces excluded upstream).
 */
export declare function groupBySignature(prepared: SurfaceFindings[]): SignatureGroup[];
/**
 * The set of element paths that changed as SHARED CHROME — a persistent frame
 * element (nav rail, header, footer) that every view renders and that moved on
 * every view that renders it.
 *
 * The rule is STRUCTURAL, deliberately NOT a tunable percentage. For each changed
 * path we compare two base-key sets:
 *   - `hosting`  — the surface bases whose style map contains the path at all;
 *   - `changed`  — the surface bases where the path appears in a finding.
 * The path is chrome iff it is hosted on MORE THAN ONE base and it changed on
 * EVERY base that hosts it (`changed ⊇ hosting`). "Every surface that has this
 * element changed it" is exactly what shared chrome means; it needs no threshold
 * to tune or defend. A content element (hosted on one base) fails the >1 guard; a
 * partial change (some hosting bases unchanged) fails the coverage guard.
 *
 * Widths of one base collapse to the base key, so a nav present at @1280 and @390
 * counts once. `surfacePaths` maps each captured surface key → the element paths
 * it renders (union of both sides from the caller).
 */
export declare function chromePaths(changedOnSurfaces: Array<{
    path: string;
    surfaces: string[];
}>, surfacePaths: Map<string, Set<string>>, surfaceKeyOf?: (captureKey: string) => string | undefined): Set<string>;
/**
 * Split signature groups into the shared-chrome tier and the rest. A group is
 * promoted only when EVERY one of its affected element paths is a chrome path
 * (see `chromePaths`) — a group that entangles a frame change with a view's own
 * content change stays in `rest` and renders in place, so we never hide a
 * content change under a chrome banner.
 */
export declare function classifyChrome<G extends {
    surfaces: string[];
    findings: Finding[];
}>(groups: G[], surfacePaths: Map<string, Set<string>>, surfaceKeyOf?: (captureKey: string) => string | undefined): {
    chrome: G[];
    rest: G[];
    chromePaths: Set<string>;
};