import { Injectable } from '@angular/core';

import { App } from '../app/app';
import { Config } from '../../config/config';
import { Loading } from './loading';
import { LoadingOptions } from './loading-options';

/**
 * @name LoadingController
 * @description
 * An overlay that can be used to indicate activity while blocking user
 * interaction. The loading indicator appears on top of the app's content,
 * and can be dismissed by the app to resume user interaction with
 * the app. It includes an optional backdrop, which can be disabled
 * by setting `showBackdrop: false` upon creation.
 *
 * ### Creating
 * You can pass all of the loading options in the first argument of
 * the create method: `create(opts)`. The spinner name should be
 * passed in the `spinner` property, and any optional HTML can be passed
 * in the `content` property. If you do not pass a value to `spinner`
 * the loading indicator will use the spinner specified by the mode. To
 * set the spinner name across the app, set the value of `loadingSpinner`
 * in your app's config. To hide the spinner, set `loadingSpinner: 'hide'`
 * in the app's config or pass `spinner: 'hide'` in the loading
 * options. See the [create](#create) method below for all available options.
 *
 * ### Dismissing
 * The loading indicator can be dismissed automatically after a specific
 * amount of time by passing the number of milliseconds to display it in
 * the `duration` of the loading options. By default the loading indicator
 * will show even during page changes, but this can be disabled by setting
 * `dismissOnPageChange` to `true`. To dismiss the loading indicator after
 * creation, call the `dismiss()` method on the Loading instance. The
 * `onDidDismiss` function can be called to perform an action after the loading
 * indicator is dismissed.
 *
 * >Note that after the component is dismissed, it will not be usable anymore
 * and another one must be created. This can be avoided by wrapping the
 * creation and presentation of the component in a reusable function as shown
 * in the `usage` section below.
 *
 * ### Limitations
 * The element is styled to appear on top of other content by setting its
 * `z-index` property. You must ensure no element has a stacking context with
 * a higher `z-index` than this element.
 *
 * @usage
 * ```ts
 * import { LoadingController } from 'ionic-angular';
 *
 * constructor(public loadingCtrl: LoadingController) { }
 *
 * presentLoadingDefault() {
 *   const loading = this.loadingCtrl.create({
 *     content: 'Please wait...'
 *   });
 *
 *   loading.present();
 *
 *   setTimeout(() => {
 *     loading.dismiss();
 *   }, 5000);
 * }
 *
 * presentLoadingCustom() {
 *   const loading = this.loadingCtrl.create({
 *     spinner: 'hide',
 *     content: `
 *       <div class="custom-spinner-container">
 *         <div class="custom-spinner-box"></div>
 *       </div>`,
 *     duration: 5000
 *   });
 *
 *   loading.onDidDismiss(() => {
 *     console.log('Dismissed loading');
 *   });
 *
 *   loading.present();
 * }
 *
 * presentLoadingText() {
 *   const loading = this.loadingCtrl.create({
 *     spinner: 'hide',
 *     content: 'Loading Please Wait...'
 *   });
 *
 *   loading.present();
 *
 *   setTimeout(() => {
 *     this.nav.push(Page2);
 *   }, 1000);
 *
 *   setTimeout(() => {
 *     loading.dismiss();
 *   }, 5000);
 * }
 * ```
 * @advanced
 *
 * Loading options
 *
 * | Option                | Type       | Description                                                                                                      |
 * |-----------------------|------------|------------------------------------------------------------------------------------------------------------------|
 * | spinner               |`string`    | The name of the SVG spinner for the loading indicator.                                                           |
 * | content               |`string`    | The html content for the loading indicator.                                                                      |
 * | cssClass              |`string`    | Additional classes for custom styles, separated by spaces.                                                       |
 * | showBackdrop          |`boolean`   | Whether to show the backdrop. Default true.                                                                      |
 * | enableBackdropDismiss | `boolean`  | Whether the loading indicator should be dismissed by tapping the backdrop. Default false.                        |
 * | dismissOnPageChange   |`boolean`   | Whether to dismiss the indicator when navigating to a new page. Default false.                                   |
 * | duration              |`number`    | How many milliseconds to wait before hiding the indicator. By default, it will show until `dismiss()` is called. |
 *
 * @demo /docs/demos/src/loading/
 * @see {@link /docs/api/components/spinner/Spinner Spinner API Docs}
 */
@Injectable()
export class LoadingController {

  constructor(private _app: App, public config: Config) { }

  /**
   * Create a loading indicator. See below for options.
   * @param {LoadingOptions} [opts] Loading options
   * @returns {Loading} Returns a Loading Instance
   */
  create(opts: LoadingOptions = {}) {
    return new Loading(this._app, opts, this.config);
  }

}
