/*---------------------------------------------------------------------------------------------
 *  Copyright (c) Microsoft Corporation. All rights reserved.
 *  Licensed under the MIT License. See License.txt in the project root for license information.
 *--------------------------------------------------------------------------------------------*/

import { Disposable } from '../../../../vs/base/common/lifecycle';
import {
  IAccessibilityService,
  AccessibilitySupport,
  CONTEXT_ACCESSIBILITY_MODE_ENABLED,
} from '../../../../vs/platform/accessibility/common/accessibility';
import { Event, Emitter } from '../../../../vs/base/common/event';
import {
  IContextKey,
  IContextKeyService,
} from '../../../../vs/platform/contextkey/common/contextkey';
import { IConfigurationService } from '../../../../vs/platform/configuration/common/configuration';

export class AccessibilityService
  extends Disposable
  implements IAccessibilityService
{
  declare readonly _serviceBrand: undefined;

  private _accessibilityModeEnabledContext: IContextKey<boolean>;
  protected _accessibilitySupport = AccessibilitySupport.Unknown;
  protected readonly _onDidChangeScreenReaderOptimized = new Emitter<void>();

  constructor(
    @IContextKeyService private readonly _contextKeyService: IContextKeyService,
    @IConfigurationService
    protected readonly _configurationService: IConfigurationService
  ) {
    super();
    this._accessibilityModeEnabledContext =
      CONTEXT_ACCESSIBILITY_MODE_ENABLED.bindTo(this._contextKeyService);
    const updateContextKey = () =>
      this._accessibilityModeEnabledContext.set(this.isScreenReaderOptimized());
    this._register(
      this._configurationService.onDidChangeConfiguration((e) => {
        if (e.affectsConfiguration('editor.accessibilitySupport')) {
          updateContextKey();
          this._onDidChangeScreenReaderOptimized.fire();
        }
      })
    );
    updateContextKey();
    this.onDidChangeScreenReaderOptimized(() => updateContextKey());
  }

  get onDidChangeScreenReaderOptimized(): Event<void> {
    return this._onDidChangeScreenReaderOptimized.event;
  }

  isScreenReaderOptimized(): boolean {
    const config = this._configurationService.getValue(
      'editor.accessibilitySupport'
    );
    return (
      config === 'on' ||
      (config === 'auto' &&
        this._accessibilitySupport === AccessibilitySupport.Enabled)
    );
  }

  getAccessibilitySupport(): AccessibilitySupport {
    return this._accessibilitySupport;
  }
}