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

import {
  FastDomNode,
  createFastDomNode,
} from '../../../../../vs/base/browser/fastDomNode';
import { ViewPart } from '../../../../../vs/editor/browser/view/viewPart';
import {
  RenderingContext,
  RestrictedRenderingContext,
} from '../../../../../vs/editor/common/view/renderingContext';
import { ViewContext } from '../../../../../vs/editor/common/view/viewContext';
import * as viewEvents from '../../../../../vs/editor/common/view/viewEvents';
import { EditorOption } from '../../../../../vs/editor/common/config/editorOptions';

export class Margin extends ViewPart {
  public static readonly CLASS_NAME = 'glyph-margin';
  public static readonly OUTER_CLASS_NAME = 'margin';

  private readonly _domNode: FastDomNode<HTMLElement>;
  private _canUseLayerHinting: boolean;
  private _contentLeft: number;
  private _glyphMarginLeft: number;
  private _glyphMarginWidth: number;
  private _glyphMarginBackgroundDomNode: FastDomNode<HTMLElement>;

  constructor(context: ViewContext) {
    super(context);
    const options = this._context.configuration.options;
    const layoutInfo = options.get(EditorOption.layoutInfo);

    this._canUseLayerHinting = !options.get(EditorOption.disableLayerHinting);
    this._contentLeft = layoutInfo.contentLeft;
    this._glyphMarginLeft = layoutInfo.glyphMarginLeft;
    this._glyphMarginWidth = layoutInfo.glyphMarginWidth;

    this._domNode = createFastDomNode(document.createElement('div'));
    this._domNode.setClassName(Margin.OUTER_CLASS_NAME);
    this._domNode.setPosition('absolute');
    this._domNode.setAttribute('role', 'presentation');
    this._domNode.setAttribute('aria-hidden', 'true');

    this._glyphMarginBackgroundDomNode = createFastDomNode(
      document.createElement('div')
    );
    this._glyphMarginBackgroundDomNode.setClassName(Margin.CLASS_NAME);

    this._domNode.appendChild(this._glyphMarginBackgroundDomNode);
  }

  public override dispose(): void {
    super.dispose();
  }

  public getDomNode(): FastDomNode<HTMLElement> {
    return this._domNode;
  }

  // --- begin event handlers

  public override onConfigurationChanged(
    e: viewEvents.ViewConfigurationChangedEvent
  ): boolean {
    const options = this._context.configuration.options;
    const layoutInfo = options.get(EditorOption.layoutInfo);

    this._canUseLayerHinting = !options.get(EditorOption.disableLayerHinting);
    this._contentLeft = layoutInfo.contentLeft;
    this._glyphMarginLeft = layoutInfo.glyphMarginLeft;
    this._glyphMarginWidth = layoutInfo.glyphMarginWidth;

    return true;
  }
  public override onScrollChanged(
    e: viewEvents.ViewScrollChangedEvent
  ): boolean {
    return super.onScrollChanged(e) || e.scrollTopChanged;
  }

  // --- end event handlers

  public prepareRender(ctx: RenderingContext): void {
    // Nothing to read
  }

  public render(ctx: RestrictedRenderingContext): void {
    this._domNode.setLayerHinting(this._canUseLayerHinting);
    this._domNode.setContain('strict');
    const adjustedScrollTop = ctx.scrollTop - ctx.bigNumbersDelta;
    this._domNode.setTop(-adjustedScrollTop);

    const height = Math.min(ctx.scrollHeight, 1000000);
    this._domNode.setHeight(height);
    this._domNode.setWidth(this._contentLeft);

    this._glyphMarginBackgroundDomNode.setLeft(this._glyphMarginLeft);
    this._glyphMarginBackgroundDomNode.setWidth(this._glyphMarginWidth);
    this._glyphMarginBackgroundDomNode.setHeight(height);
  }
}