/**
 * astroengine counterfactual -- a real chart, perturbed, and what changed.
 *
 * The `counterfactual` realm: take a resolved chart and ask "what if". Shift the
 * instant ("born an hour later") or the place -- a real ephemeris recompute --
 * or splice a body to a new longitude ("Mars in the next sign") -- a geometry
 * what-if that keeps everything else and recomputes the aspects it touches.
 * {@link chartDiff} reports the difference so the change is legible, not buried
 * in two full charts.
 */
import { Engine, Chart, ChartOptions, Aspect } from "./chart.js";
import { AnchorRegistry } from "./provenance.js";
import { AnchoredChart, RealizedChart } from "./anchored.js";
/** A perturbation of a resolved chart. */
export interface CounterfactualEdit {
    /** Shift the resolved instant by a duration (e.g. `"1h"`, `"-30m"`, `"P1D"`). */
    shiftTime?: string;
    /** Recompute at a different place. */
    place?: {
        lat: number;
        lonEast: number;
        altM?: number;
    };
    /** Move bodies to given ecliptic longitudes (degrees), keeping everything else
     *  -- a geometry what-if. The moved body's house and the touched aspects are
     *  recomputed; the angles and other bodies are untouched. */
    setLongitudes?: Record<string, number>;
}
/** A body whose sign or house changed between two charts. */
export interface BodyChange {
    body: string;
    /** Signed degrees the body moved (`b` minus `a`). */
    dLon: number;
    signFrom: string;
    signTo: string;
    houseFrom: number;
    houseTo: number;
}
/** An angle whose sign changed. */
export interface AngleChange {
    angle: string;
    from: string;
    to: string;
}
/** What differs between two charts. */
export interface ChartDiff {
    /** Bodies whose sign or house changed. */
    bodies: BodyChange[];
    /** Aspects present in the variant but not the original. */
    aspectsGained: Aspect[];
    /** Aspects present in the original but not the variant. */
    aspectsLost: Aspect[];
    /** Angles whose sign changed. */
    angles: AngleChange[];
}
/** Diff two charts: body sign/house shifts, aspects gained/lost, angle sign
 *  changes. Bodies and angles that did not change sign/house are omitted. */
export declare function chartDiff(a: Chart, b: Chart): ChartDiff;
/** A counterfactual: a base chart and a perturbed variant, with the diff. */
export interface Counterfactual {
    edit: CounterfactualEdit;
    /** The realized base (its `chart` is the original). */
    original: RealizedChart;
    /** The perturbed chart, or null when the base had no chart to perturb. */
    variant: Chart | null;
    diff: ChartDiff | null;
    note: string;
}
/**
 * Realize an {@link AnchoredChart}, then apply a {@link CounterfactualEdit} and
 * diff the result -- "a real event, perturbed." A time/place edit recomputes the
 * ephemeris; a `setLongitudes` edit splices the geometry.
 *
 * @param engine The engine.
 * @param base The base chart to perturb (realized via {@link realize}).
 * @param edit The perturbation.
 * @param registry Anchor lookups for the base.
 * @param opts Chart options (house system, zodiac).
 * @returns A {@link Counterfactual}; `variant`/`diff` are null when the base
 *   produced no chart (e.g. a constraints-only form).
 */
export declare function counterfactual(engine: Engine, base: AnchoredChart, edit: CounterfactualEdit, registry?: AnchorRegistry, opts?: ChartOptions): Counterfactual;