import type { Context, EggCore } from '@eggjs/core';
import type { ViewConfig } from '../config/config.default.js';
export interface ViewManagerConfig extends Omit<ViewConfig, 'root'> {
    root: string[];
}
export type PlainObject<T = any> = {
    [key: string]: T;
};
export interface RenderOptions extends PlainObject {
    name?: string;
    root?: string;
    locals?: PlainObject;
    viewEngine?: string;
}
export interface ViewEngine {
    render: (name: string, locals?: Record<string, any>, options?: RenderOptions) => Promise<string>;
    renderString: (tpl: string, locals?: Record<string, any>, options?: RenderOptions) => Promise<string>;
}
export type ViewEngineClass = new (app: Context) => ViewEngine;
/**
 * ViewManager will manage all view engine that is registered.
 *
 * It can find the real file, then retrieve the view engine based on extension.
 * The plugin just register view engine using {@link ViewManager#use}
 */
export declare class ViewManager extends Map<string, ViewEngineClass> {
    config: ViewManagerConfig;
    extMap: Map<string, string>;
    fileMap: Map<string, string>;
    /**
     * @param {Application} app - application instance
     */
    constructor(app: EggCore);
    /**
     * This method can register view engine.
     *
     * You can define a view engine class contains two method, `render` and `renderString`
     *
     * ```js
     * class View {
     *   render() {}
     *   renderString() {}
     * }
     * ```
     * @param {String} name - the name of view engine
     * @param {Object} viewEngine - the class of view engine
     */
    use(name: string, viewEngine: ViewEngineClass): void;
    /**
     * Resolve the path based on the given name,
     * if the name is `user.html` and root is `app/view` (by default),
     * it will return `app/view/user.html`
     * @param {String} name - the given path name, it's relative to config.root
     * @return {String} filename - the full path
     */
    resolve(name: string): Promise<string>;
}