///
/// Copyright 2015-2026 Micro Focus or one of its affiliates.
///
/// 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 { inject, Injectable, TemplateRef } from '@angular/core';
import { BehaviorSubject } from 'rxjs';
import { ColorService } from '../../services/color/index';

@Injectable({
  providedIn: 'root',
})
export class NotificationService {
  private readonly _colorService = inject(ColorService);

  /**
     *  Sets the order in which notifications are displayed:
        `above` - newer notifications will appear above older ones.
        `below` - newer notifications will appear below older ones.
     */
  direction: NotificationListDirection = 'above';

  /**
   * The list of notifications including notifications that have been dismissed
   */
  notifications$: BehaviorSubject<NotificationRef[]> = new BehaviorSubject<NotificationRef[]>([]);

  /**
   * Access the list of notifications as an array
   */
  get notifications(): NotificationRef[] {
    return this.notifications$.value;
  }

  /**
   * Define the default set of notification options
   */
  options: NotificationOptions = {
    duration: 4,
    backgroundColor: this._colorService.getColor('accent').toHex(),
    iconColor: this._colorService.getColor('accent').toHex(),
  };

  /**
   * This function should be called to show a notification.
   * It should be given a TemplateRef containing the content to be displayed.
   * @param templateRef - A TemplateRef containing the content to be displayed
   * @param options - The properties to configure the notification.
   * @param context - The context passed to the notification TemplateRef. This can be accessed by adding a let-data="data" to the ng-template element.
   */
  show(
    templateRef: TemplateRef<void>,
    options: NotificationOptions = this.options,
    context: { [key: string]: unknown } = {}
  ): NotificationRef {
    // populate the specified options with the default values for any missing properties
    options = { ...this.options, ...options };

    // create the notificationRef based on the options and context specified
    const notificationRef: NotificationRef = {
      templateRef,
      duration: options.duration,
      date: new Date(),
      visible: true,
      height: options.height,
      spacing: options.spacing,
      backgroundColor: options.backgroundColor,
      iconColor: options.iconColor,
      data: context,
    };

    // add the new notification to the list (either above or below based on direction)
    this.direction === 'above'
      ? this.notifications.unshift(notificationRef)
      : this.notifications.push(notificationRef);

    // update the notifications list
    this.notifications$.next(this.notifications);

    // remove notification after delay
    if (options.duration !== 0) {
      setTimeout(() => this.dismiss(notificationRef), options.duration * 1000);
    }

    return notificationRef;
  }

  /**
   * This function will return a list of all the notifications that have been shown.
   */
  getHistory(): NotificationRef[] {
    return this.notifications;
  }

  /**
   * This function can be called to dismiss a notification. It should be passed the object to dismiss.
   * @param notificationRef - The notification that should be dismissed
   */
  dismiss(notificationRef: NotificationRef): void {
    notificationRef.visible = false;
    this.notifications$.next(this.notifications);
  }

  /**
   * This function will dismiss any currently visible notifications.
   */
  dismissAll(): void {
    this.notifications.forEach(notificationRef => (notificationRef.visible = false));
    this.notifications$.next(this.notifications);
  }

  /** Remove the notification from the screen and from the notification history */
  remove(notificationRef: NotificationRef): void {
    this.notifications$.next(
      this.notifications.filter(_notificationRef => _notificationRef !== notificationRef)
    );
  }

  /** Remove all notifications from the screen and from the notification history */
  removeAll(): void {
    this.notifications$.next([]);
  }
}

export interface NotificationRef extends NotificationOptions {
  /** The content to display in the notification */
  templateRef: TemplateRef<void>;
  /** The datestamp to display in the notification */
  date: Date;
  /** Indicated whether or not the notification has been dismissed or not */
  visible?: boolean;
  /** Additional data passed as template context to the notification */
  data: { [key: string]: unknown };
}

export interface NotificationOptions {
  /** The duration the notification should display for before it is automatically dismissed */
  duration: number;
  /** The height of the notification */
  height?: number;
  /** The spacing between each notification */
  spacing?: number;
  /** The background color of the notification */
  backgroundColor?: string;
  /** The color of the notification icon */
  iconColor?: string;
}

export type NotificationListDirection = 'above' | 'below';