(function() {

var $frm = $('form'),
    $cmp = $('#cmp'),
    $cls = $('#cls'),
    $url = $('#url'),
    lastUrl;

var resize = function() {
  var rect = $frm.get(0).getBoundingClientRect();
  $frm.css('margin-top', window.innerHeight/3 - rect.height/2);
};

var nameFrom = function(uri) {
  var parts = uri.substring(1).split('/');
  return parts[1];
};

var load = function() {
  var name = nameFrom(location.pathname);
  $.ajax({
    url: '/api/url/' + name,
    dataType: 'json'
  }).always(function(data) {
    if (!data.ok) {
      // TODO(knorton): Error
      return;
    }

    var route = data.route,
        url = route && route.url || '';
    $url.val(url).focus();
    urlDidChange();
  });
}

var showLink = function(name) {
  var lnk = location.origin + '/' + name;

  $cmp.find('a').remove();

  var a = $(document.createElement('a'))
    .attr('href', lnk)
    .text(lnk)
    .appendTo($cmp.text(''));

  $cmp.css('transform', 'scaleY(1)');

  getSelection().setBaseAndExtent(a.get(0), 0, a.get(0), 1);
};

var hideLink = function() {
  $cmp.css('transform', 'scaleY(0)');
};

var urlDidChange = function() {
  var url = $url.val().trim();
  if (url == lastUrl) {
    return;
  }

  lastUrl = url;

  if (url) {
    $cls.fadeIn(200);
  } else {
    $cls.fadeOut(200);
  }
};

$frm.on('submit', function(e) {
  e.preventDefault();
  var name = nameFrom(location.pathname),
      url = $url.val().trim();

  $.ajax({
    type: 'POST',
    url : '/api/url/' + name,
    data : JSON.stringify({ url : url }),
    dataType : 'json'
  }).always(function(data) {
    if (!data.ok) {
      hideLink();
      return;
    }

    var route = data.route;
    if (!route) {
      hideLink();
      return;
    }

    var url = route.url || '',
        name = route.name || '';
    if (url) {
      history.replaceState({}, null, '/edit/' + name);
      showLink(name);
    }
  });
});

$url.on('keydown', urlDidChange)
    .on('paste', urlDidChange)
    .on('change', urlDidChange);

$cls.on('click', function(e) {
  $url.val('');
  $frm.submit();
  urlDidChange();
});

window.addEventListener('resize', resize);
resize();
urlDidChange();
load();

})();