import type { GraphDescription } from '../types/graph.js';
/** A node placed on the diagram. */
export interface LaidOutNode {
    /** The node's id. */
    id: string;
    /** Left edge, in diagram units. */
    x: number;
    /** Top edge, in diagram units. */
    y: number;
    /** Box width. */
    width: number;
    /** Box height. */
    height: number;
    /** `start` and `end` are the graph's entry and exit; everything else is a `node`. */
    kind: 'start' | 'end' | 'node';
    /** True when the node waits for every branch before it runs. */
    defer?: boolean;
    /** True when the node reuses results through a cache. */
    cache?: boolean;
}
/** An edge between two placed nodes. */
export interface LaidOutEdge {
    /** The node it leaves. */
    from: string;
    /** The node it reaches. */
    to: string;
    /** Chosen by a router rather than always taken. */
    conditional?: boolean;
    /** The router's key for this branch. */
    label?: string;
    /** True when it points back up the diagram, as a cycle does. */
    back: boolean;
}
/** A graph laid out for drawing. */
export interface GraphLayout {
    /** Every node, placed. */
    nodes: LaidOutNode[];
    /** Every edge. */
    edges: LaidOutEdge[];
    /** Diagram width. */
    width: number;
    /** Diagram height. */
    height: number;
}
/**
 * Lays a graph out in layers: each node sits one layer below the nearest node that leads to it.
 *
 * Breadth-first distance rather than longest path, so a cycle cannot push a node down forever; an
 * edge that goes back up is marked, and the drawing curves it round the side. Done here rather than
 * in the browser so neither the studio nor `toSvg()` needs a diagram library, and so the layout can be
 * tested.
 */
export declare function layoutGraph(graph: GraphDescription | {
    describe(): GraphDescription;
}): GraphLayout;