Template.editor.onRendered(() => {
  const $textarea = this.$('textarea');

  autosize($textarea);

  $textarea.escapeableTextComplete([
    // User mentions
    {
      match: /\B@([\w.]*)$/,
      search(term, callback) {
        const currentBoard = Boards.findOne(Session.get('currentBoard'));
        callback(
          currentBoard
            .activeMembers()
            .map(member => {
              const username = Users.findOne(member.userId).username;
              return username.includes(term) ? username : null;
            })
            .filter(Boolean),
        );
      },
      template(value) {
        return value;
      },
      replace(username) {
        return `@${username} `;
      },
      index: 1,
    },
  ]);
});

import sanitizeXss from 'xss';

// XXX I believe we should compute a HTML rendered field on the server that
// would handle markdown and user mentions. We can simply have two
// fields, one source, and one compiled version (in HTML) and send only the
// compiled version to most users -- who don't need to edit.
// In the meantime, all the transformation are done on the client using the
// Blaze API.
const at = HTML.CharRef({ html: '@', str: '@' });
Blaze.Template.registerHelper(
  'mentions',
  new Template('mentions', function() {
    const view = this;
    let content = Blaze.toHTML(view.templateContentBlock);
    const currentBoard = Boards.findOne(Session.get('currentBoard'));
    if (!currentBoard) return HTML.Raw(sanitizeXss(content));
    const knowedUsers = currentBoard.members.map(member => {
      const u = Users.findOne(member.userId);
      if (u) {
        member.username = u.username;
      }
      return member;
    });
    const mentionRegex = /\B@([\w.]*)/gi;

    let currentMention;
    while ((currentMention = mentionRegex.exec(content)) !== null) {
      const [fullMention, username] = currentMention;
      const knowedUser = _.findWhere(knowedUsers, { username });
      if (!knowedUser) {
        continue;
      }

      const linkValue = [' ', at, knowedUser.username];
      let linkClass = 'atMention js-open-member';
      if (knowedUser.userId === Meteor.userId()) {
        linkClass += ' me';
      }
      const link = HTML.A(
        {
          class: linkClass,
          // XXX Hack. Since we stringify this render function result below with
          // `Blaze.toHTML` we can't rely on blaze data contexts to pass the
          // `userId` to the popup as usual, and we need to store it in the DOM
          // using a data attribute.
          'data-userId': knowedUser.userId,
        },
        linkValue,
      );

      content = content.replace(fullMention, Blaze.toHTML(link));
    }

    return HTML.Raw(sanitizeXss(content));
  }),
);

Template.viewer.events({
  // Viewer sometimes have click-able wrapper around them (for instance to edit
  // the corresponding text). Clicking a link shouldn't fire these actions, stop
  // we stop these event at the viewer component level.
  'click a'(event, templateInstance) {
    event.stopPropagation();

    // XXX We hijack the build-in browser action because we currently don't have
    // `_blank` attributes in viewer links, and the transformer function is
    // handled by a third party package that we can't configure easily. Fix that
    // by using directly `_blank` attribute in the rendered HTML.
    event.preventDefault();

    const userId = event.currentTarget.dataset.userid;
    if (userId) {
      Popup.open('member').call({ userId }, event, templateInstance);
    } else {
      const href = event.currentTarget.href;
      if (href) {
        window.open(href, '_blank');
      }
    }
  },
});