/*
 * Copyright (c) 2014 The Polymer Project Authors. All rights reserved.
 * This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
 * The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
 * The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
 * Code distributed by Google as part of the polymer project is also
 * subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
 */

(function(scope) {

  // imports

  var log = window.WebComponents ? WebComponents.flags.log : {};
  var api = scope.api.instance.events;
  var EVENT_PREFIX = api.EVENT_PREFIX;

  var mixedCaseEventTypes = {};
  [
    'webkitAnimationStart',
    'webkitAnimationEnd',
    'webkitTransitionEnd',
    'DOMFocusOut',
    'DOMFocusIn',
    'DOMMouseScroll'
  ].forEach(function(e) {
    mixedCaseEventTypes[e.toLowerCase()] = e;
  });

  // polymer-element declarative api: events feature
  var events = {
    parseHostEvents: function() {
      // our delegates map
      var delegates = this.prototype.eventDelegates;
      // extract data from attributes into delegates
      this.addAttributeDelegates(delegates);
    },
    addAttributeDelegates: function(delegates) {
      // for each attribute
      for (var i=0, a; a=this.attributes[i]; i++) {
        // does it have magic marker identifying it as an event delegate?
        if (this.hasEventPrefix(a.name)) {
          // if so, add the info to delegates
          delegates[this.removeEventPrefix(a.name)] = a.value.replace('{{', '')
              .replace('}}', '').trim();
        }
      }
    },
    // starts with 'on-'
    hasEventPrefix: function (n) {
      return n && (n[0] === 'o') && (n[1] === 'n') && (n[2] === '-');
    },
    removeEventPrefix: function(n) {
      return n.slice(prefixLength);
    },
    findController: function(node) {
      while (node.parentNode) {
        if (node.eventController) {
          return node.eventController;
        }
        node = node.parentNode;
      }
      return node.host;
    },
    getEventHandler: function(controller, target, method) {
      var events = this;
      return function(e) {
        if (!controller || !controller.PolymerBase) {
          controller = events.findController(target);
        }

        var args = [e, e.detail, e.currentTarget];
        controller.dispatchMethod(controller, method, args);
      };
    },
    prepareEventBinding: function(pathString, name, node) {
      if (!this.hasEventPrefix(name))
        return;

      var eventType = this.removeEventPrefix(name);
      eventType = mixedCaseEventTypes[eventType] || eventType;

      var events = this;

      return function(model, node, oneTime) {
        var handler = events.getEventHandler(undefined, node, pathString);
        PolymerGestures.addEventListener(node, eventType, handler);

        if (oneTime)
          return;

        // TODO(rafaelw): This is really pointless work. Aside from the cost
        // of these allocations, NodeBind is going to setAttribute back to its
        // current value. Fixing this would mean changing the TemplateBinding
        // binding delegate API.
        function bindingValue() {
          return '{{ ' + pathString + ' }}';
        }

        return {
          open: bindingValue,
          discardChanges: bindingValue,
          close: function() {
            PolymerGestures.removeEventListener(node, eventType, handler);
          }
        };
      };
    }
  };

  var prefixLength = EVENT_PREFIX.length;

  // exports
  scope.api.declaration.events = events;

})(Polymer);