// Copyright (c) Microsoft Corporation. All rights reserved.

// Licensed under the MIT License.

'use strict';

import { inject, injectable } from 'inversify';

import { IDisposableRegistry } from '../common/types';

import { IServiceContainer } from '../ioc/types';

import { IHistory, IHistoryProvider } from './types';

@injectable()

export class HistoryProvider implements IHistoryProvider {

private activeHistory : IHistory | undefined;

constructor(

@inject(IServiceContainer) private serviceContainer: IServiceContainer,

@inject(IDisposableRegistry) private disposables: IDisposableRegistry) {

}

public getActive() : IHistory | undefined {

return this.activeHistory;

}

public getOrCreateActive() : IHistory {

if (!this.activeHistory) {

this.activeHistory = this.create();

}

return this.activeHistory;

}

private create = () => {

const result = this.serviceContainer.get<IHistory>(IHistory);

const handler = result.closed(this.onHistoryClosed);

this.disposables.push(result);

this.disposables.push(handler);

return result;

}

private onHistoryClosed = (history: IHistory) => {

if (this.activeHistory === history) {

this.activeHistory = undefined;

}

}

}