Vim-Vixen/src/content/presenters/Hint.ts

import * as doms from '../../shared/utils/dom';

interface Point {
  x: number;
  y: number;
}

const hintPosition = (element: Element): Point => {
  let { left, top, right, bottom } = doms.viewportRect(element);

  if (element.tagName !== 'AREA') {
    return { x: left, y: top };
  }

  return {
    x: (left + right) / 2,
    y: (top + bottom) / 2,
  };
};

export default abstract class Hint {
  private hint: HTMLElement;

  private tag: string;

  constructor(target: HTMLElement, tag: string) {
    this.tag = tag;

    let doc = target.ownerDocument;
    if (doc === null) {
      throw new TypeError('ownerDocument is null');
    }

    let { x, y } = hintPosition(target);
    let { scrollX, scrollY } = window;

    let hint = doc.createElement('span');
    hint.className = 'vimvixen-hint';
    hint.textContent = tag;
    hint.style.left = x + scrollX + 'px';
    hint.style.top = y + scrollY + 'px';

    doc.body.append(hint);

    this.hint = hint;
    this.show();
  }

  show(): void {
    this.hint.style.display = 'inline';
  }

  hide(): void {
    this.hint.style.display = 'none';
  }

  remove(): void {
    this.hint.remove();
  }

  getTag(): string {
    return this.tag;
  }
}

export class LinkHint extends Hint {
  private target: HTMLAnchorElement | HTMLAreaElement;

  constructor(target: HTMLAnchorElement | HTMLAreaElement, tag: string) {
    super(target, tag);

    this.target = target;
  }

  getLink(): string {
    return this.target.href;
  }

  getLinkTarget(): string | null {
    return this.target.getAttribute('target');
  }

  click(): void {
    this.target.click();
  }
}

export class InputHint extends Hint {
  private target: HTMLElement;

  constructor(target: HTMLElement, tag: string) {
    super(target, tag);

    this.target = target;
  }

  activate(): void {
    let target = this.target;
    switch (target.tagName.toLowerCase()) {
    case 'input':
      switch ((target as HTMLInputElement).type) {
      case 'file':
      case 'checkbox':
      case 'radio':
      case 'submit':
      case 'reset':
      case 'button':
      case 'image':
      case 'color':
        return target.click();
      default:
        return target.focus();
      }
    case 'textarea':
      return target.focus();
    case 'button':
    case 'summary':
      return target.click();
    default:
      if (doms.isContentEditable(target)) {
        return target.focus();
      } else if (target.hasAttribute('tabindex')) {
        return target.click();
      }
    }
  }
}