var Helpers = {
  error: function() {
    return Session.get('error');
  },

  toLowerCase: function(text) {
    return text && text.toLowerCase();
  },

  toUpperCase: function(text) {
    return text && text.toUpperCase();
  },

  firstChar: function(text) {
    return text && text[0].toUpperCase();
  },

  session: function(prop) {
    return Session.get(prop);
  },

  getUser: function(userId) {
    return Users.findOne(userId);
  }
};

// Register all Helpers
_.each(Helpers, function(fn, name) { Blaze.registerHelper(name, fn); });

// XXX I believe we should compute a HTML rendered field on the server that
// would handle markdown, emojies 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.
var at = HTML.CharRef({html: '@', str: '@'});
Blaze.Template.registerHelper('mentions', new Template('mentions', function() {
  var view = this;
  var content = Blaze.toHTML(view.templateContentBlock);
  var currentBoard = Session.get('currentBoard');
  var knowedUsers = _.map(currentBoard.members, function(member) {
    member.username = Users.findOne(member.userId).username;
    return member;
  });

  var mentionRegex = /\B@(\w*)/gi;
  var currentMention, knowedUser, href, linkClass, linkValue, link;
  while (!! (currentMention = mentionRegex.exec(content))) {

    knowedUser = _.findWhere(knowedUsers, { username: currentMention[1] });
    if (! knowedUser)
      continue;

    linkValue = [' ', at, knowedUser.username];
    href = Router.url('Profile', { username: knowedUser.username });
    linkClass = 'atMention';
    if (knowedUser.userId === Meteor.userId())
      linkClass += ' me';
    link = HTML.A({ href: href, 'class': linkClass }, linkValue);

    content = content.replace(currentMention[0], Blaze.toHTML(link));
  }

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