(function () {
  var ns = $.namespace('pskl.widgets');

  var OPTION_CLASSNAME = 'anchor-option';
  // Maybe move to HTML ...
  var WIDGET_TEMPLATE =
    '<div class="anchor-option"  title="top left"      data-origin="TOPLEFT"></div>' +
    '<div class="anchor-option"  title="top"           data-origin="TOP"></div>' +
    '<div class="anchor-option"  title="top right"     data-origin="TOPRIGHT"></div>' +
    '<div class="anchor-option"  title="middle left"   data-origin="MIDDLELEFT"></div>' +
    '<div class="anchor-option"  title="middle"        data-origin="MIDDLE"></div>' +
    '<div class="anchor-option"  title="middle right"  data-origin="MIDDLERIGHT"></div>' +
    '<div class="anchor-option"  title="bottom left"   data-origin="BOTTOMLEFT"></div>' +
    '<div class="anchor-option"  title="bottom"        data-origin="BOTTOM"></div>' +
    '<div class="anchor-option"  title="bottom right"  data-origin="BOTTOMRIGHT"></div>';

  ns.AnchorWidget = function (container, onChangeCallback) {
    this.onChangeCallback = onChangeCallback;

    this.wrapper = document.createElement('div');
    this.wrapper.classList.add('anchor-wrapper');
    this.wrapper.innerHTML = WIDGET_TEMPLATE;

    container.innerHTML = '';
    container.appendChild(this.wrapper);

    this.disabled = false;
    pskl.utils.Event.addEventListener(this.wrapper, 'click', this.onResizeOriginClick_, this);
  };

  ns.AnchorWidget.ORIGIN = {
    TOPLEFT : 'TOPLEFT',
    TOP : 'TOP',
    TOPRIGHT : 'TOPRIGHT',
    MIDDLELEFT : 'MIDDLELEFT',
    MIDDLE : 'MIDDLE',
    MIDDLERIGHT : 'MIDDLERIGHT',
    BOTTOMLEFT : 'BOTTOMLEFT',
    BOTTOM : 'BOTTOM',
    BOTTOMRIGHT : 'BOTTOMRIGHT'
  };

  ns.AnchorWidget.prototype.destroy = function (evt) {
    pskl.utils.Event.removeAllEventListeners(this);
    this.wrapper = null;
  };

  ns.AnchorWidget.prototype.onResizeOriginClick_ = function (evt) {
    var origin = evt.target.dataset.origin;
    if (origin && ns.AnchorWidget.ORIGIN[origin] && !this.disabled) {
      this.setOrigin(origin);
    }
  };

  ns.AnchorWidget.prototype.setOrigin = function (origin) {
    this.origin = origin;
    var previous = this.wrapper.querySelector('.' + OPTION_CLASSNAME + '.selected');
    if (previous) {
      previous.classList.remove('selected');
    }

    var selected = this.wrapper.querySelector('.' + OPTION_CLASSNAME + '[data-origin="' + origin + '"]');
    if (selected) {
      selected.classList.add('selected');
      this.refreshNeighbors_(selected);
    }

    if (typeof this.onChangeCallback === 'function') {
      this.onChangeCallback(origin);
    }
  };

  ns.AnchorWidget.prototype.getOrigin = function () {
    return this.origin;
  };

  ns.AnchorWidget.prototype.disable = function () {
    this.disabled = true;
    this.wrapper.classList.add('transition');
    this.wrapper.classList.add('disabled');
  };

  ns.AnchorWidget.prototype.enable = function () {
    this.disabled = false;
    this.wrapper.classList.remove('disabled');
    window.setTimeout(this.wrapper.classList.remove.bind(this.wrapper.classList, 'transition'), 250);
  };

  ns.AnchorWidget.prototype.refreshNeighbors_ = function (selected) {
    var options = this.wrapper.querySelectorAll('.' + OPTION_CLASSNAME);
    for (var i = 0 ; i < options.length ; i++) {
      options[i].removeAttribute('data-neighbor');
    }

    var selectedIndex = Array.prototype.indexOf.call(options, selected);

    this.setNeighborhood_(options[selectedIndex - 1], 'left');
    this.setNeighborhood_(options[selectedIndex + 1], 'right');
    this.setNeighborhood_(options[selectedIndex - 3], 'top');
    this.setNeighborhood_(options[selectedIndex + 3], 'bottom');
  };

  ns.AnchorWidget.prototype.setNeighborhood_ = function (el, neighborhood) {
    var origin = this.origin.toLowerCase();
    var isNeighborhoodValid = origin.indexOf(neighborhood) === -1;
    if (isNeighborhoodValid) {
      el.setAttribute('data-neighbor', neighborhood);
    }
  };
})();