import { Component } from 'vue';
import { PrefetchConfig } from './prefetch';
import { AnyFunction } from './utilities';
/**
 * A single view: what to render, how to get its props, and how to prefetch it. `component` is optional
 * because a route can bind props to the nested RouterView it renders without declaring a component.
 *
 * @template TProps - What this view's props getter returns, carried so parent props can be typed from it.
 */
export type RouteView<TProps = undefined> = {
    component?: Component;
    props?: AnyFunction<TProps>;
    prefetch?: PrefetchConfig;
};
/**
 * The views for a single route, keyed by view name (the unnamed view under 'default'). Indexed by depth in
 * `route.views` — parallel to how `route.matches` indexes the matched options, which is where a route's id
 * comes from at a given depth.
 */
export type RouteViews = Record<string, RouteView<unknown>>;
/**
 * The props a child sees for a parent's views. A lone unnamed view is given directly rather than under a
 * 'default' key, matching how the props argument is written. Each view's props are always a promise,
 * since the parent's props may not have been computed when the child's getter runs.
 */
export type ViewsPropsReturnType<TViews> = keyof ViewsWithProps<TViews> extends never ? undefined : keyof ViewsWithProps<TViews> extends 'default' ? ParentViewProps<Extract<ViewsWithProps<TViews>, {
    default: unknown;
}>['default']> : {
    [K in keyof ViewsWithProps<TViews>]: ParentViewProps<ViewsWithProps<TViews>[K]>;
};
type ViewsWithProps<TViews> = {
    [K in keyof TViews as HasViewProps<TViews[K]> extends true ? K : never]: TViews[K];
};
/**
 * A view has props unless its getter is absent, which is carried as props resolving to undefined. Asked
 * both ways because a getter that only ever throws resolves to never, which is assignable to undefined
 * without being the absent case.
 */
type HasViewProps<TView> = [ViewProps<TView>] extends [undefined] ? [undefined] extends [ViewProps<TView>] ? false : true : true;
type ViewProps<TView> = TView extends {
    props?: AnyFunction<infer TProps>;
} ? TProps : undefined;
type ParentViewProps<TView> = Promise<Awaited<ViewProps<TView>>>;
export {};