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

import * as objects from '../../../../../vs/base/common/objects';
import * as dom from '../../../../../vs/base/browser/dom';
import { renderLabelWithIcons } from '../../../../../vs/base/browser/ui/iconLabel/iconLabels';

export interface IHighlight {
  start: number;
  end: number;
  extraClasses?: string;
}

export class HighlightedLabel {
  private readonly domNode: HTMLElement;
  private text: string = '';
  private title: string = '';
  private highlights: IHighlight[] = [];
  private didEverRender: boolean = false;

  constructor(container: HTMLElement, private supportIcons: boolean) {
    this.domNode = document.createElement('span');
    this.domNode.className = 'monaco-highlighted-label';

    container.appendChild(this.domNode);
  }

  get element(): HTMLElement {
    return this.domNode;
  }

  set(
    text: string | undefined,
    highlights: IHighlight[] = [],
    title: string = '',
    escapeNewLines?: boolean
  ) {
    if (!text) {
      text = '';
    }
    if (escapeNewLines) {
      // adjusts highlights inplace
      text = HighlightedLabel.escapeNewLines(text, highlights);
    }
    if (
      this.didEverRender &&
      this.text === text &&
      this.title === title &&
      objects.equals(this.highlights, highlights)
    ) {
      return;
    }

    this.text = text;
    this.title = title;
    this.highlights = highlights;
    this.render();
  }

  private render(): void {
    const children: HTMLSpanElement[] = [];
    let pos = 0;

    for (const highlight of this.highlights) {
      if (highlight.end === highlight.start) {
        continue;
      }
      if (pos < highlight.start) {
        const substring = this.text.substring(pos, highlight.start);
        children.push(
          dom.$(
            'span',
            undefined,
            ...(this.supportIcons
              ? renderLabelWithIcons(substring)
              : [substring])
          )
        );
        pos = highlight.end;
      }

      const substring = this.text.substring(highlight.start, highlight.end);
      const element = dom.$(
        'span.highlight',
        undefined,
        ...(this.supportIcons ? renderLabelWithIcons(substring) : [substring])
      );
      if (highlight.extraClasses) {
        element.classList.add(highlight.extraClasses);
      }
      children.push(element);
      pos = highlight.end;
    }

    if (pos < this.text.length) {
      const substring = this.text.substring(pos);
      children.push(
        dom.$(
          'span',
          undefined,
          ...(this.supportIcons ? renderLabelWithIcons(substring) : [substring])
        )
      );
    }

    dom.reset(this.domNode, ...children);
    if (this.title) {
      this.domNode.title = this.title;
    } else {
      this.domNode.removeAttribute('title');
    }
    this.didEverRender = true;
  }

  static escapeNewLines(text: string, highlights: IHighlight[]): string {
    let total = 0;
    let extra = 0;

    return text.replace(/\r\n|\r|\n/g, (match, offset) => {
      extra = match === '\r\n' ? -1 : 0;
      offset += total;

      for (const highlight of highlights) {
        if (highlight.end <= offset) {
          continue;
        }
        if (highlight.start >= offset) {
          highlight.start += extra;
        }
        if (highlight.end >= offset) {
          highlight.end += extra;
        }
      }

      total += extra;
      return '\u23CE';
    });
  }
}