import { Disposable } from './Disposable'

/**
 * Represents a group of disposable resources that are disposed together.
 * @constructor
 */
export class CompositeDisposable {
	private isDisposed = false
	private disposables: Disposable[]

	constructor(...disposables: Disposable[]) {
		this.disposables = disposables
	}

	/**
	 * Adds a disposable to the CompositeDisposable or disposes the disposable if the CompositeDisposable is disposed.
	 * @param {Any} item Disposable to add.
	 */
	public add(item: Disposable) {
		if (this.isDisposed) {
			item.dispose()
		} else {
			this.disposables.push(item)
		}
	}

	/**
	 * Removes and disposes the first occurrence of a disposable from the CompositeDisposable.
	 * @param {Any} item Disposable to remove.
	 * @returns {Boolean} true if found; false otherwise.
	 */
	public remove(item: Disposable) {
		let shouldDispose = false
		if (!this.isDisposed) {
			const idx = this.disposables.indexOf(item)
			if (idx !== -1) {
				shouldDispose = true
				this.disposables.splice(idx, 1)
				item.dispose()
			}
		}
		return shouldDispose
	}

	/**
	 *  Disposes all disposables in the group and removes them from the group but
	 *  does not dispose the CompositeDisposable.
	 */
	public clear() {
		if (!this.isDisposed) {
			const len = this.disposables.length
			const currentDisposables = new Array(len)
			for (let i = 0; i < len; i++) {
				currentDisposables[i] = this.disposables[i]
			}
			this.disposables = []

			for (let i = 0; i < len; i++) {
				currentDisposables[i].dispose()
			}
		}
	}

	/**
	 *  Disposes all disposables in the group and removes them from the group.
	 */
	public dispose() {
		if (!this.isDisposed) {
			this.isDisposed = true
			const len = this.disposables.length
			const currentDisposables = new Array(len)
			for (let i = 0; i < len; i++) {
				currentDisposables[i] = this.disposables[i]
			}
			this.disposables = []

			for (let i = 0; i < len; i++) {
				currentDisposables[i].dispose()
			}
		}
	}
}