import { PluginContext } from './context';
import { PluginEvent } from './event';
import { PluginHost } from './host';
import { PluginExtensionManager } from './manager';
import { Plugin, PluginBase } from './plugin';
import { PluginRuntime } from './runtime';
/**
 * Enumeration which holds the plugin extension constraints.
 */
export declare enum PluginExtensionConstraint {
    /**
     * Internal plugin extension.
     *
     * @var {string}
     */
    Internal = "internal",
    /**
     * Required plugin extension.
     *
     * @var {string}
     */
    Required = "required",
    /**
     * Optional plugin extension.
     *
     * @var {string}
     */
    Optional = "optional"
}
/**
 * Enumeration which holds the plugin extension resolve methods.
 */
export declare enum PluginExtensionResolveMethod {
    UnSafe = "unsafe",
    Safe = "safe"
}
/**
 * Interface which describes the plugin extension promise cache.
 */
export interface PluginExtensionPromiseCache<PluginType> {
    /**
     * Holds the extension identifier for which a resolve is being
     * perform or has been performed.
     */
    [key: string]: {
        /**
         * Holds the promise which is resolving the extension.
         *
         * @var {Promise<Plugin>}
         */
        promise: Promise<PluginType> | null;
        /**
         * Holds the resolve function to the promise.
         *
         * @var {function}
         */
        resolve: ((extension: PluginType) => void) | null;
    };
}
/**
 * Host type alias for extensible plugins.
 */
export declare type PluginExtensionHost<PluginRuntimeType extends PluginRuntime> = ExtensiblePlugin<PluginHost, PluginContext, PluginRuntimeType>;
/**
 * Interface which describes a plugin which functionality can be extended.
 */
export interface ExtensiblePlugin<PluginHostType extends PluginHost = PluginHost, PluginContextType extends PluginContext = PluginContext, PluginRuntimeType extends PluginRuntime = PluginRuntime> extends Plugin<PluginHostType, PluginContextType, PluginRuntimeType>, PluginHost {
    /**
     * Get the extension manager.
     *
     * @return {PluginExtensionManager}
     *   An object which represents the extension manager.
     */
    getExtensionManager(): PluginExtensionManager<Plugin<PluginExtensionHost<PluginRuntimeType>, PluginContext, PluginRuntimeType>>;
    /**
     * Get the extension with specified identifier using safe resolving method.
     *
     * @param {string} id
     *   An extension identifier. A nested extension can be retrieved using the '.' as delimiter.
     * @param {PluginExtensionResolveMethod} [resolveMethod=PluginExtensionResolvingMethod.Safe]
     *   Method which should be used for resolving an extension.
     *
     * @return {Promise<T>}
     *   A promise to resolve the extension.
     */
    getExtension<T extends Plugin<PluginExtensionHost<PluginRuntimeType>, PluginContext, PluginRuntimeType> = Plugin<PluginExtensionHost<PluginRuntimeType>, PluginContext, PluginRuntimeType>>(id: string, resolveMethod?: PluginExtensionResolveMethod.Safe): Promise<T>;
    /**
     * Get the extension with specified identifier using unsafe resolving method.
     *
     * @param {string} id
     *   An extension identifier.
     * @param {PluginExtensionResolveMethod} resolveMethod
     *   Method which should be used for resolving an extension.
     *
     * @return {T}
     *   The resolved extension.
     */
    getExtension<T extends Plugin<PluginExtensionHost<PluginRuntimeType>, PluginContext, PluginRuntimeType> = Plugin<PluginExtensionHost<PluginRuntimeType>, PluginContext, PluginRuntimeType>>(id: string, resolveMethod: PluginExtensionResolveMethod.UnSafe): T;
    /**
     * Get a extension with specified identifier.
     *
     * @param {string} id
     *   An extension identifier.
     * @param {PluginExtensionResolveMethod} [resolveMethod=PluginExtensionResolveMethod.Safe]
     *   Method which should be used for resolving an extension.
     *
     * @return {Promise<T>|T}
     *   A promise to resolve the extension or the extension itself.
     */
    getExtension<T extends Plugin<PluginExtensionHost<PluginRuntimeType>, PluginContext, PluginRuntimeType> = Plugin<PluginExtensionHost<PluginRuntimeType>, PluginContext, PluginRuntimeType>>(id: string, resolveMethod?: PluginExtensionResolveMethod): Promise<T> | T;
}
/**
 * Base implementation for an extensible plugin.
 */
export declare abstract class ExtensiblePluginBase<PluginHostType extends PluginHost, PluginContextType extends PluginContext, PluginRuntimeType extends PluginRuntime> extends PluginBase<PluginHostType, PluginContextType, PluginRuntimeType> implements PluginExtensionHost<PluginRuntimeType> {
    /**
     * Holds the extension manager.
     *
     * @var {PluginExtensionManager}
     */
    protected extensionManager: PluginExtensionManager<Plugin<PluginExtensionHost<PluginRuntimeType>, PluginContext, PluginRuntimeType>> | undefined;
    /**
     * Holds the extension promise cache.
     *
     * @var {PluginExtensionPromiseCache}
     */
    protected extensionPromiseCache: PluginExtensionPromiseCache<Plugin<PluginExtensionHost<PluginRuntimeType>, PluginContext, PluginRuntimeType>>;
    /**
     * Create an ExtensiblePluginBase object.
     *
     * @param {PluginHost} pluginHost
     *   An object which represents the plugin host.
     * @param {PluginContext} pluginContext
     *   An object which represents the widget context.
     */
    constructor(pluginHost: PluginHostType, pluginContext: PluginContextType);
    /**
     * {@inheritdoc}
     */
    protected createHookEvent(hook: string, ...args: any[]): PluginEvent;
    /**
     * {@inheritdoc}
     */
    protected onBeforeReady(): Promise<void>;
    /**
     * {@inheritdoc}
     */
    protected onReady(): Promise<void>;
    /**
     * Handle tasks after a extension was created.
     *
     * @param {Plugin} extension
     *   An object which represents an extension.
     */
    protected onExtension(extension: Plugin<PluginExtensionHost<PluginRuntimeType>, PluginContext, PluginRuntimeType>): Promise<void>;
    /**
     * Resolve the extension contexts.
     *
     * @param {PluginExtensionConstraint} extensionConstraint
     *   Constraint of which plugin extension contexts should be resolved.
     *
     * @return {Promise<PluginContext[]>}
     *   A promise to resolve the extension contexts.
     */
    protected abstract resolveExtensionContexts(extensionConstraint: PluginExtensionConstraint): Promise<PluginContext[]>;
    /**
     * Create extensions for given constraint.
     *
     * @param {PluginExtensionConstraint} extensionConstraint
     *   Constraint of which plugin extension contexts should be created.
     *
     * @return {Promise<Plugin[]>}
     *   A promise to create extensions based on the constraint.
     */
    protected createExtensionsByConstraint(extensionConstraint: PluginExtensionConstraint): Promise<Plugin[]>;
    /**
     * Create extensions for given contexts.
     *
     * @param {PluginContext[]} extensionContexts
     *   An list of plugin contexts which should be created.
     *
     * @return {Promise<Plugin[]>}
     *   A promise to create extensions based on the contexts.
     */
    protected createExtensionsByContexts(extensionContexts: PluginContext[]): Promise<Plugin[]>;
    /**
     * Create an extension manager.
     *
     * @return {PluginExtensionManager}
     *   An object which represents the plugin extension manager.
     */
    protected abstract createExtensionManager(): PluginExtensionManager<Plugin<PluginExtensionHost<PluginRuntimeType>, PluginContext, PluginRuntimeType>>;
    /**
     * {@inheritdoc}
     */
    getExtensionManager(): PluginExtensionManager<Plugin<PluginExtensionHost<PluginRuntimeType>, PluginContext, PluginRuntimeType>>;
    /**
     * Get an extension using safe resolving method.
     *
     * @param {string} id
     *   Plugin extension identifier.
     *
     * @return {Promise<T>}
     *   A promise to resolve the extension.
     */
    protected getExtensionSafe<T extends Plugin<PluginExtensionHost<PluginRuntimeType>, PluginContext, PluginRuntimeType> = Plugin<PluginExtensionHost<PluginRuntimeType>, PluginContext, PluginRuntimeType>>(id: string): Promise<T>;
    /**
     * Try to get an extension using unsafe resolving method.
     *
     * @param {string} id
     *   Plugin extension identifier.
     *
     * @return {T|null}
     *   The resolved extension if available, otherwise null.
     */
    protected tryGetExtensionUnsafe<T extends Plugin<PluginExtensionHost<PluginRuntimeType>, PluginContext, PluginRuntimeType> = Plugin<PluginExtensionHost<PluginRuntimeType>, PluginContext, PluginRuntimeType>>(id: string): T | null;
    /**
     * Get an extension using unsafe resolving method.
     *
     * @param {string} id
     *   Plugin extension identifier.
     *
     * @return {T}
     *   The resolved extension.
     */
    protected getExtensionUnsafe<T extends Plugin<PluginExtensionHost<PluginRuntimeType>, PluginContext, PluginRuntimeType> = Plugin<PluginExtensionHost<PluginRuntimeType>, PluginContext, PluginRuntimeType>>(id: string): T;
    /**
     * {@inheritdoc}
     */
    getExtension<T extends Plugin<PluginExtensionHost<PluginRuntimeType>, PluginContext, PluginRuntimeType> = Plugin<PluginExtensionHost<PluginRuntimeType>, PluginContext, PluginRuntimeType>>(id: string, resolveMethod?: PluginExtensionResolveMethod.Safe): Promise<T>;
    /**
     * {@inheritdoc}
     */
    getExtension<T extends Plugin<PluginExtensionHost<PluginRuntimeType>, PluginContext, PluginRuntimeType> = Plugin<PluginExtensionHost<PluginRuntimeType>, PluginContext, PluginRuntimeType>>(id: string, resolveMethod: PluginExtensionResolveMethod.UnSafe): T;
}