import { type ReactiveController, type ReactiveControllerHost } from "@knyt/tasker";
import type { KnytContent } from "@knyt/weaver";
import type { PromiseReference } from "./PromiseReference.ts";
/**
 * @internal scope: module
 */
type DeferredContentHost = ReactiveControllerHost & HTMLElement;
/**
 * @internal scope: module
 */
export declare class DeferredContentRenderer<T extends PromiseReference.Collection<any>> implements ReactiveController {
    #private;
    constructor(host: DeferredContentHost, references: T);
    /**
     * @internal scope: module
     */
    hostConnected(): void;
    /**
     * @internal scope: module
     */
    hostDisconnected(): void;
    /**
     * Creates a render function that defers rendering while any of the
     * promises of the previously given references are unresolved.
     *
     * @remarks
     *
     * Whenever any of the references change, the rendering will be deferred again
     * until all new promises have resolved.
     *
     * While the rendering is deferred, a `DeferredContent` component higher in the
     * DOM tree may display a placeholder UI while loading is in progress.
     *
     * When all promises have resolved, the provided render function is called
     * with the resolved values, and its result is rendered. However, if any other
     * elements are being deferred under the `DeferredContent` element, the
     * placeholder will continue to be shown until all deferred content is ready.
     */
    thenRender(renderFn: (...data: PromiseReference.Collection.Unwrapped<T>) => KnytContent | Promise<KnytContent>): () => KnytContent | Promise<KnytContent>;
    /**
     * Cleans up resources used by the controller and removes it from the host.
     */
    destroy(): void;
}
/**
 * Signals a parent `DeferredContent` element to delay revealing its
 * content until the provided promise settles.
 */
export declare function defer<T>(host: DeferredContentHost, promise: Promise<T>): void;
/**
 * Signals a parent `DeferredContent` element to delay revealing its
 * content while any of the promises of the given references are unresolved.
 *
 * @remarks
 *
 * The returned `DeferredContentRenderer` instance can be used to create
 * a render function that receives the resolved values of the promises.
 * This allows rendering the content with the resolved data once all
 * promises have settled.
 */
export declare function defer<T extends PromiseReference.Collection<any>>(host: DeferredContentHost, ...references: T): DeferredContentRenderer<T>;
export declare namespace defer {
    /**
     * @internal scope: workspace
     */
    type Renderer<T extends PromiseReference.Collection<any>> = DeferredContentRenderer<T>;
}
export {};
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