/**
 * A replacement for `Array.from` until it becomes widely implemented.
 */
function arrayFrom(obj: any): any[] {
  return Array.prototype.slice.call(obj);
}

/**
 * A replacement for `String.repeat` until it becomes widely available.
 */
export function stringRepeat(text: string, length: number): string {
  let result = '';
  for (let x = 0; x < length; x++) {
    result += text;
  }
  return result;
}

/**
 * This function escapes all plain-text sequences that might get converted into markdown
 * formatting by Bitbucket server (via python-markdown).
 * @see MarkdownSerializerState.esc()
 */
export function escapeMarkdown(str: string, startOfLine?: boolean): string {
  let strToEscape = str || '';
  strToEscape = strToEscape.replace(/[`*\\+_|()\[\]{}]/g, '\\$&');
  if (startOfLine) {
    strToEscape = strToEscape.replace(/^[#-*]/, '\\$&').replace(/^(\d+)\./, '$1\\.');
  }
  return strToEscape;
}

/**
 * This function gets markup rendered by Bitbucket server and transforms it into markup that
 * can be consumed by Prosemirror HTML parser, conforming to our schema.
 */
export function transformHtml(html: string): HTMLElement {
  const el = document.createElement('div');
  el.innerHTML = html;

  // Remove zero-width-non-joiner
  arrayFrom(el.querySelectorAll('p')).forEach((p: HTMLParagraphElement) => {
    const zwnj = /\u200c/g;
    if (p.textContent && zwnj.test(p.textContent)) {
      p.textContent = p.textContent.replace(zwnj, '');
    }
  });

  // Convert mention containers, i.e.:
  //   <a href="/abodera/" rel="nofollow" title="@abodera" class="mention mention-me">Artur Bodera</a>
  arrayFrom(el.querySelectorAll('a.mention')).forEach((a: HTMLLinkElement) => {
    const span = document.createElement('span');
    span.setAttribute('class', 'editor-entity-mention');
    span.setAttribute('contenteditable', 'false');

    const title = a.getAttribute('title') || '';
    if (title) {
      const usernameMatch = title.match(/^@(.*?)$/);
      if (usernameMatch) {
        const username = usernameMatch[1];
        span.setAttribute('data-mention-id', username);
      }
    }

    const text = a.textContent || '';
    if (text.indexOf('@') === 0) {
      span.textContent = a.textContent;
    } else {
      span.textContent = `@${a.textContent}`;
    }

    a.parentNode!.insertBefore(span, a);
    a.parentNode!.removeChild(a);
  });

  // Parse emojis i.e.
  //     <img src="https://d301sr5gafysq2.cloudfront.net/207268dc597d/emoji/img/diamond_shape_with_a_dot_inside.svg" alt="diamond shape with a dot inside" title="diamond shape with a dot inside" class="emoji">
  arrayFrom(el.querySelectorAll('img.emoji')).forEach((img: HTMLImageElement) => {
    const span = document.createElement('span');
    let shortName = img.getAttribute('data-emoji-short-name') || '';

    if (!shortName) {
      // Fallback to parsing Bitbucket's src attributes to find the
      // short name
      const src = img.getAttribute('src');
      const idMatch = !src ? false : src.match(/([^\/]+)\.[^\/]+$/);

      if (idMatch) {
        shortName = `:${decodeURIComponent(idMatch[1])}:`;
      }
    }

    if (shortName) {
      span.setAttribute('data-emoji-short-name', shortName);
    }

    img.parentNode!.insertBefore(span, img);
    img.parentNode!.removeChild(img);
  });

  // Convert all automatic links to plain text, because they will be re-created on render by the server
  arrayFrom(el.querySelectorAll('a[rel="nofollow"]')).forEach((a: HTMLLinkElement) => {
    const text = document.createTextNode(a.innerText);
    a.parentNode!.insertBefore(text, a);
    a.parentNode!.removeChild(a);
  });

  return el;
}