/**
 * @license
 * Copyright 2019 Google LLC
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import {
  FirebaseApp,
  FirebaseOptions,
  FirebaseAppConfig
} from '@firebase/app-types';
import {
  _FirebaseNamespace,
  FirebaseService
} from '@firebase/app-types/private';
import { deepCopy } from '@firebase/util';
import { ERROR_FACTORY, AppError } from '../errors';
import { DEFAULT_ENTRY_NAME } from '../constants';
import {
  ComponentContainer,
  Component,
  ComponentType,
  Name
} from '@firebase/component';

/**
 * Global context object for a collection of services using
 * a shared authentication state.
 */
export class FirebaseAppLiteImpl implements FirebaseApp {
  private readonly options_: FirebaseOptions;
  private readonly name_: string;
  private isDeleted_ = false;
  private automaticDataCollectionEnabled_: boolean;
  private container: ComponentContainer;

  // lite version has an empty INTERNAL namespace
  readonly INTERNAL = {};

  constructor(
    options: FirebaseOptions,
    config: FirebaseAppConfig,
    private readonly firebase_: _FirebaseNamespace
  ) {
    this.name_ = config.name!;
    this.automaticDataCollectionEnabled_ =
      config.automaticDataCollectionEnabled || false;
    this.options_ = deepCopy<FirebaseOptions>(options);
    this.container = new ComponentContainer(config.name!);

    // add itself to container
    this.container.addComponent(
      new Component('app', () => this, ComponentType.PUBLIC)
    );
    // populate ComponentContainer with existing components
    this.firebase_.INTERNAL.components.forEach(component =>
      this.container.addComponent(component)
    );
  }

  get automaticDataCollectionEnabled(): boolean {
    this.checkDestroyed_();
    return this.automaticDataCollectionEnabled_;
  }

  set automaticDataCollectionEnabled(val) {
    this.checkDestroyed_();
    this.automaticDataCollectionEnabled_ = val;
  }

  get name(): string {
    this.checkDestroyed_();
    return this.name_;
  }

  get options(): FirebaseOptions {
    this.checkDestroyed_();
    return this.options_;
  }

  delete(): Promise<void> {
    return new Promise<void>(resolve => {
      this.checkDestroyed_();
      resolve();
    })
      .then(() => {
        this.firebase_.INTERNAL.removeApp(this.name_);

        return Promise.all(
          this.container.getProviders().map(provider => provider.delete())
        );
      })
      .then((): void => {
        this.isDeleted_ = true;
      });
  }

  /**
   * Return a service instance associated with this app (creating it
   * on demand), identified by the passed instanceIdentifier.
   *
   * NOTE: Currently storage is the only one that is leveraging this
   * functionality. They invoke it by calling:
   *
   * ```javascript
   * firebase.app().storage('STORAGE BUCKET ID')
   * ```
   *
   * The service name is passed to this already
   * @internal
   */
  _getService(
    name: string,
    instanceIdentifier: string = DEFAULT_ENTRY_NAME
  ): FirebaseService {
    this.checkDestroyed_();

    // getImmediate will always succeed because _getService is only called for registered components.
    return (this.container.getProvider(name as Name).getImmediate({
      identifier: instanceIdentifier
    }) as unknown) as FirebaseService;
  }

  /**
   * This function will throw an Error if the App has already been deleted -
   * use before performing API actions on the App.
   */
  private checkDestroyed_(): void {
    if (this.isDeleted_) {
      throw ERROR_FACTORY.create(AppError.APP_DELETED, { appName: this.name_ });
    }
  }

  toJSON(): object {
    return {
      name: this.name,
      automaticDataCollectionEnabled: this.automaticDataCollectionEnabled,
      options: this.options
    };
  }
}