/**
 *
 */
import { IDisposable, ISubscription } from './Disposable';

export class SerialDisposable implements IDisposable {
    private _currentDisposable?: IDisposable | null;
    private _isDisposed = false;

    public get isDisposed() {
        return this._isDisposed;
    }

    public get disposable() {
        return this._currentDisposable;
    }

    public set disposable(value) {
        const shouldDispose = this.isDisposed;
        if (!shouldDispose) {
            this._currentDisposable = value;
        }
        if (!this.isDisposed) {
            this._currentDisposable = value;
        }
        if (this.isDisposed && value) {
            value.dispose();
        }
    }

    public unsubscribe(): void {
        this.dispose();
    }

    public dispose() {
        if (this.isDisposed) return;
        this._isDisposed = true;
        const old = this._currentDisposable;
        this._currentDisposable = null;
        if (old) {
            old.dispose();
        }
    }
}