import type { Getter } from "./Getter.ts";
/** Lifecycle status constants for resources. */
export declare const ResourceStatus: {
    /** No load is currently running. */
    readonly Idle: "idle";
    /** A load is currently running. */
    readonly Loading: "loading";
    /** The last load completed successfully. */
    readonly Ready: "ready";
    /** The last load failed. */
    readonly Failed: "failed";
    /** The resource has been disposed. */
    readonly Disposed: "disposed";
};
/** Lifecycle status of a resource. */
export type ResourceStatus = typeof ResourceStatus[keyof typeof ResourceStatus];
/** Loads a resource value from the current source state. */
export type ResourceLoader<S, T> = (source: S, abortSignal: AbortSignal) => T | Promise<T>;
/** Options for creating a resource. */
export interface CreateResourceOptions<T, Init = never, S = unknown> {
    /**
     * Compares the previous and next resource value.
     *
     * Returning true suppresses the value update and keeps dependent computations clean. Set this to false to force a value update for every
     * successful load.
     *
     * @param previous - The previous resource value.
     * @param next     - The next resource value.
     * @returns True when both values should be treated as equal.
     */
    equals?: false | ((previous: T | Init, next: T | Init) => boolean);
    /** The initial resource value visible before the first successful load. */
    initialValue?: Init;
    /**
     * Returns true when the current source value should skip loading.
     *
     * When loading is skipped, the loader is not called, the current resource value stays unchanged, the resource enters `Idle` state, and
     * any previous resource error is cleared.
     *
     * @param source - The current source value.
     * @returns True when loading should be skipped for the current source value.
     */
    skip?: (source: S) => boolean;
}
/** Controls and status accessors returned together with a resource value getter. */
export interface Resource extends Disposable {
    /**
     * Returns the last resource error, if any.
     *
     * @returns The last resource error or undefined.
     */
    error(): Error | undefined;
    /**
     * Returns the current resource status.
     *
     * @returns The current resource status.
     */
    status(): ResourceStatus;
    /**
     * Reloads the resource for the current source value.
     */
    reload(): void;
}
/**
 * Creates a reactive async resource and returns a value getter together with status and control methods.
 *
 * The resource eagerly loads from the current source value and reloads whenever the source changes or `resource.reload()` is called.
 * Concurrent loads are cancelled through an abort signal and stale results are ignored. The returned resource object can be manually
 * disposed manually.
 *
 * @param source  - Getter providing the current load source.
 * @param load    - Loads the resource value for the current source.
 * @param options - Optional resource behavior overrides without an explicit initial value.
 * @returns A resource value getter and a resource controller object.
 */
export declare function createResource<S, T>(source: Getter<S>, load: ResourceLoader<S, T>, options?: CreateResourceOptions<T, never, S> & {
    initialValue?: never;
}): [Getter<T | undefined>, Resource];
/**
 * Creates a reactive async resource and returns a value getter together with status and control methods.
 *
 * The resource eagerly loads from the current source value and reloads whenever the source changes or `resource.reload()` is called.
 * Concurrent loads are cancelled through an abort signal and stale results are ignored. The returned resource object can be manually
 * disposed manually.
 *
 * @param source  - Getter providing the current load source.
 * @param load    - Loads the resource value for the current source.
 * @param options - Optional resource behavior overrides with an explicit initial value.
 * @returns A resource value getter and a resource controller object.
 */
export declare function createResource<S, T, Init>(source: Getter<S>, load: ResourceLoader<S, T>, options: CreateResourceOptions<T, Init, S> & {
    initialValue: Init;
}): [Getter<T | Init>, Resource];