///
/// 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 { Injectable, QueryList } from '@angular/core';
import { BehaviorSubject } from 'rxjs';
import { AnchorPlacement } from '../../common/overlay/index';
import { FloatingActionButtonComponent } from './floating-action-button.component';

export type FloatingActionButtonDirection = AnchorPlacement;

@Injectable()
export class FloatingActionButtonsService {
  open$ = new BehaviorSubject<boolean>(false);
  direction$ = new BehaviorSubject<FloatingActionButtonDirection>('top');

  private _buttons: QueryList<FloatingActionButtonComponent>;

  open(): void {
    this.open$.next(true);
  }

  toggle(): void {
    this.open$.next(!this.open$.getValue());
  }

  close(): void {
    this.open$.next(false);

    // make the first button tabbable again
    this.setPrimaryButtonFocusable();
  }

  isHorizontal(): boolean {
    return this.direction$.value === 'left' || this.direction$.value === 'right';
  }

  isVertical(): boolean {
    return this.direction$.value === 'top' || this.direction$.value === 'bottom';
  }

  setButtons(buttons: QueryList<FloatingActionButtonComponent>): void {
    this._buttons = buttons;

    // make the first button tabbable (after a delay to prevent expression changed error)
    requestAnimationFrame(() => this.setPrimaryButtonFocusable());
  }

  /** Make only the first button tabbable */
  setPrimaryButtonFocusable(): void {
    this._buttons.forEach(btn => btn.tabindex$.next(btn.primary ? 0 : -1));
  }

  focusPrimaryButton(): void {
    this.focus(this._buttons.find(btn => btn.primary));
  }

  focus(button: FloatingActionButtonComponent): void {
    // if the button is not defined then do nothing
    if (!button) {
      return;
    }

    // set the button tab index
    this._buttons.forEach(btn => btn.tabindex$.next(button === btn ? 0 : -1));

    // apply the focus
    button.focus();
  }

  focusSibling(next: boolean): void {
    // if the buttons are not visible then do nothing
    if (this.open$.value === false) {
      return;
    }

    // get the current focused item
    const button = this.getFocusedButton();

    if (next && button === this._buttons.last) {
      return this.focus(this._buttons.first);
    } else if (!next && button === this._buttons.first) {
      return this.focus(this._buttons.last);
    }

    // find the sibling button
    const sibling = this._buttons.toArray()[this.getButtonIndex(button) + (next ? 1 : -1)];

    // focus the next button
    this.focus(sibling);
  }

  private getFocusedButton(): FloatingActionButtonComponent {
    return this._buttons.find(btn => btn.tabindex$.value === 0);
  }

  private getButtonIndex(button: FloatingActionButtonComponent): number {
    return this._buttons.toArray().findIndex(btn => btn === button);
  }
}