import {Directive, Attribute, NgZone} from '@angular/core';

import {Platform} from '../../platform/platform';


/**
 * @private
 */
export class DisplayWhen {
  protected isMatch: boolean = false;
  private platform: Platform;
  private conditions: string[];

  constructor(conditions: string, platform: Platform, ngZone: NgZone) {
    this.platform = platform;

    if (!conditions) return;

    this.conditions = conditions.split(',');

    // check if its one of the matching platforms first
    // a platform does not change during the life of an app
    for (let i = 0; i < this.conditions.length; i++) {
      if (this.conditions[i] && platform.is(this.conditions[i])) {
        this.isMatch = true;
        return;
      }
    }

    if ( this.orientation() ) {
      // add window resize listener
      platform.onResize(() => {
        ngZone.run(() => {
          this.orientation();
        });
      });
      return;
    }

  }

  orientation(): boolean {
    for (let i = 0; i < this.conditions.length; i++) {

      if (this.conditions[i] === 'portrait') {
        this.isMatch = this.platform.isPortrait();
        return true;
      }

      if (this.conditions[i] === 'landscape') {
        this.isMatch = this.platform.isLandscape();
        return true;
      }
    }
  }

}

/**
 *
 * @name ShowWhen
 * @description
 * The `showWhen` attribute takes a string that represents a platform or screen orientation.
 * The element the attribute is added to will only be shown when that platform or screen orientation is active.
 *
 * Complements the [hideWhen attribute](../HideWhen). If the `showWhen` attribute is used on an
 * element that also has the `hideWhen` attribute, the element will not show if `hideWhen` evaluates
 * to `true` or `showWhen` evaluates to `false`. If the `hidden` attribute is also added, the element
 * will not show if `hidden` evaluates to `true`.
 *
 * View the [Platform API docs](../../../platform/Platform) for more information on the different
 * platforms you can use.
 *
 * @usage
 * ```html
 * <div showWhen="android">
 *  I am visible on Android!
 * </div>
 *
 * <div showWhen="ios">
 *  I am visible on iOS!
 * </div>
 *
 * <div showWhen="android,ios">
 *  I am visible on Android and iOS!
 * </div>
 *
 * <div showWhen="portrait">
 *  I am visible on Portrait!
 * </div>
 *
 * <div showWhen="landscape">
 *  I am visible on Landscape!
 * </div>
 * ```
 * @demo /docs/v2/demos/show-when/
 * @see {@link ../HideWhen HideWhen API Docs}
 * @see {@link ../../../platform/Platform Platform API Docs}
 */
@Directive({
  selector: '[showWhen]',
  host: {
    '[class.hidden-show-when]': '!isMatch'
  }
})
export class ShowWhen extends DisplayWhen {

  constructor(
    @Attribute('showWhen') showWhen: string,
    platform: Platform,
    ngZone: NgZone
  ) {
    super(showWhen, platform, ngZone);
  }

}

/**
 * @name HideWhen
 * @description
 * The `hideWhen` attribute takes a string that represents a plaform or screen orientation.
 * The element the attribute is added to will only be hidden when that platform or screen orientation is active.
 *
 * Complements the [showWhen attribute](../ShowWhen). If the `hideWhen` attribute is used on an
 * element that also has the `showWhen` attribute, the element will not show if `hideWhen` evaluates
 * to `true` or `showWhen` evaluates to `false`. If the `hidden` attribute is also added, the element
 * will not show if `hidden` evaluates to `true`.
 *
 * View the [Platform API docs](../../../platform/Platform) for more information on the different
 * platforms you can use.
 *
 * @usage
 * ```html
 * <div hideWhen="android">
 *  I am hidden on Android!
 * </div>
 *
 * <div hideWhen="ios">
 *  I am hidden on iOS!
 * </div>
 *
 * <div hideWhen="android,ios">
 *  I am hidden on Android and iOS!
 * </div>
 *
 * <div hideWhen="portrait">
 *  I am hidden on Portrait!
 * </div>
 *
 * <div hideWhen="landscape">
 *  I am hidden on Landscape!
 * </div>
 * ```
 *
 * @demo /docs/v2/demos/hide-when/
 * @see {@link ../ShowWhen ShowWhen API Docs}
 * @see {@link ../../../platform/Platform Platform API Docs}
*/
@Directive({
  selector: '[hideWhen]',
  host: {
    '[class.hidden-hide-when]': 'isMatch'
  }
})
export class HideWhen extends DisplayWhen {

  constructor(
    @Attribute('hideWhen') hideWhen: string,
    platform: Platform,
    ngZone: NgZone
  ) {
    super(hideWhen, platform, ngZone);
  }

}