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

// import 'vs/css!./rulers';
import {
  FastDomNode,
  createFastDomNode,
} from '../../../../../vs/base/browser/fastDomNode';
import { ViewPart } from '../../../../../vs/editor/browser/view/viewPart';
import { editorRuler } from '../../../../../vs/editor/common/view/editorColorRegistry';
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 { registerThemingParticipant } from '../../../../../vs/platform/theme/common/themeService';
import {
  EditorOption,
  IRulerOption,
} from '../../../../../vs/editor/common/config/editorOptions';

export class Rulers extends ViewPart {
  public domNode: FastDomNode<HTMLElement>;
  private readonly _renderedRulers: FastDomNode<HTMLElement>[];
  private _rulers: IRulerOption[];
  private _typicalHalfwidthCharacterWidth: number;

  constructor(context: ViewContext) {
    super(context);
    this.domNode = createFastDomNode<HTMLElement>(
      document.createElement('div')
    );
    this.domNode.setAttribute('role', 'presentation');
    this.domNode.setAttribute('aria-hidden', 'true');
    this.domNode.setClassName('view-rulers');
    this._renderedRulers = [];
    const options = this._context.configuration.options;
    this._rulers = options.get(EditorOption.rulers);
    this._typicalHalfwidthCharacterWidth = options.get(
      EditorOption.fontInfo
    ).typicalHalfwidthCharacterWidth;
  }

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

  // --- begin event handlers

  public override onConfigurationChanged(
    e: viewEvents.ViewConfigurationChangedEvent
  ): boolean {
    const options = this._context.configuration.options;
    this._rulers = options.get(EditorOption.rulers);
    this._typicalHalfwidthCharacterWidth = options.get(
      EditorOption.fontInfo
    ).typicalHalfwidthCharacterWidth;
    return true;
  }
  public override onScrollChanged(
    e: viewEvents.ViewScrollChangedEvent
  ): boolean {
    return e.scrollHeightChanged;
  }

  // --- end event handlers

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

  private _ensureRulersCount(): void {
    const currentCount = this._renderedRulers.length;
    const desiredCount = this._rulers.length;

    if (currentCount === desiredCount) {
      // Nothing to do
      return;
    }

    if (currentCount < desiredCount) {
      const { tabSize } = this._context.model.getTextModelOptions();
      const rulerWidth = tabSize;
      let addCount = desiredCount - currentCount;
      while (addCount > 0) {
        const node = createFastDomNode(document.createElement('div'));
        node.setClassName('view-ruler');
        node.setWidth(rulerWidth);
        this.domNode.appendChild(node);
        this._renderedRulers.push(node);
        addCount--;
      }
      return;
    }

    let removeCount = currentCount - desiredCount;
    while (removeCount > 0) {
      const node = this._renderedRulers.pop()!;
      this.domNode.removeChild(node);
      removeCount--;
    }
  }

  public render(ctx: RestrictedRenderingContext): void {
    this._ensureRulersCount();

    for (let i = 0, len = this._rulers.length; i < len; i++) {
      const node = this._renderedRulers[i];
      const ruler = this._rulers[i];

      node.setBoxShadow(ruler.color ? `1px 0 0 0 ${ruler.color} inset` : ``);
      node.setHeight(Math.min(ctx.scrollHeight, 1000000));
      node.setLeft(ruler.column * this._typicalHalfwidthCharacterWidth);
    }
  }
}

registerThemingParticipant((theme, collector) => {
  const rulerColor = theme.getColor(editorRuler);
  if (rulerColor) {
    collector.addRule(
      `.monaco-editor .view-ruler { box-shadow: 1px 0 0 0 ${rulerColor} inset; }`
    );
  }
});