import { Event, Emitter } from './event';

export interface Disposable {
    /**
     * Dispose this object.
     */
    dispose(): void;
}

export namespace Disposable {
    // eslint-disable-next-line @typescript-eslint/no-explicit-any
    export function is(arg: any): arg is Disposable {
        return !!arg && typeof arg === 'object' && 'dispose' in arg && typeof arg['dispose'] === 'function';
    }
    export function create(func: () => void): Disposable {
        return {
            dispose: func
        };
    }
    export const NULL = create(() => { });
}

export class DisposableCollection implements Disposable {

    protected readonly disposables: Disposable[] = [];
    protected readonly onDisposeEmitter = new Emitter<void>();

    constructor(...toDispose: Disposable[]) {
        toDispose.forEach(d => this.push(d));
    }

    /**
     * This event is fired only once
     * on first dispose of not empty collection.
     */
    get onDispose(): Event<void> {
        return this.onDisposeEmitter.event;
    }

    protected checkDisposed(): void {
        if (this.disposed && !this.disposingElements) {
            this.onDisposeEmitter.fire(undefined);
            this.onDisposeEmitter.dispose();
        }
    }

    get disposed(): boolean {
        return this.disposables.length === 0;
    }

    private disposingElements = false;
    dispose(): void {
        if (this.disposed || this.disposingElements) {
            return;
        }
        this.disposingElements = true;
        while (!this.disposed) {
            try {
                this.disposables.pop()!.dispose();
            } catch (e) {
                console.error(e);
            }
        }
        this.disposingElements = false;
        this.checkDisposed();
    }

    push(disposable: Disposable): Disposable {
        const disposables = this.disposables;
        disposables.push(disposable);
        const originalDispose = disposable.dispose.bind(disposable);
        const toRemove = Disposable.create(() => {
            const index = disposables.indexOf(disposable);
            if (index !== -1) {
                disposables.splice(index, 1);
            }
            this.checkDisposed();
        });
        disposable.dispose = () => {
            toRemove.dispose();
            disposable.dispose = originalDispose;
            originalDispose();
        };
        return toRemove;
    }

    pushAll(disposables: Disposable[]): Disposable[] {
        return disposables.map(disposable =>
            this.push(disposable)
        );
    }

}