import { ProtectedEventEmitter } from './utils/ProtectedEventEmitter';
import { Debugger } from './utils/Debugger';
import type { CrossOrigin } from './Def';
export declare enum ResourceType {
    JS = "JS",
    CSS = "CSS"
}
export declare enum ResourceState {
    NOT_LOADED = "NOT_LOADED",
    LOADING = "LOADING",
    UNLOADING = "UNLOADING",
    LOADED = "LOADED",
    LOAD_ERROR = "LOAD_ERROR"
}
export interface ResourceEvent {
    statechange: {
        state: ResourceState;
    };
    refcountchange: {
        refCount: number;
    };
}
export declare abstract class Resource extends Debugger implements ProtectedEventEmitter<ResourceEvent> {
    #private;
    off<T extends keyof ResourceEvent>(event: T, listener: (ev: ResourceEvent[T]) => unknown, context?: unknown): this;
    on<T extends keyof ResourceEvent>(event: T, listener: (ev: ResourceEvent[T]) => unknown, context?: unknown): this;
    once<T extends keyof ResourceEvent>(event: T, listener: (ev: ResourceEvent[T]) => unknown, context?: unknown): this;
    protected constructor(src: string, type: ResourceType, crossOrigin?: CrossOrigin);
    abstract get [Symbol.toStringTag](): string;
    protected get debugName(): string;
    toString(): string;
    protected get crossOrigin(): CrossOrigin;
    /**
     * Create a new resource by src and optional type.
     * @param src Source url of the resource.
     * @param type Type of resource, only CSS and JS are supported.
     * @returns Resource
     */
    static create(src: string, type?: ResourceType, crossOrigin?: CrossOrigin): Resource;
    get src(): string;
    get refCount(): number;
    get state(): ResourceState;
    get type(): ResourceType;
    ref(obj: unknown): Promise<void>;
    deref(obj: unknown): Promise<void>;
    abstract get element(): HTMLScriptElement | HTMLLinkElement | null;
    protected load(): Promise<void>;
    protected unload(): Promise<void>;
    protected abstract fetchInBrowser(): Promise<void>;
    protected abstract promiseUnload(): Promise<void>;
}