/**
 * @ngdoc directive
 * @name ionTab
 * @module ionic
 * @restrict E
 * @parent ionic.directive:ionTabs
 *
 * @description
 * Contains a tab's content.  The content only exists while the given tab is selected.
 *
 * Each ionTab has its own view history.
 *
 * @usage
 * ```html
 * <ion-tab
 *   title="Tab!"
 *   icon="my-icon"
 *   href="#/tab/tab-link"
 *   on-select="onTabSelected()"
 *   on-deselect="onTabDeselected()">
 * </ion-tab>
 * ```
 * For a complete, working tab bar example, see the {@link ionic.directive:ionTabs} documentation.
 *
 * @param {string} title The title of the tab.
 * @param {string=} href The link that this tab will navigate to when tapped.
 * @param {string=} icon The icon of the tab. If given, this will become the default for icon-on and icon-off.
 * @param {string=} icon-on The icon of the tab while it is selected.
 * @param {string=} icon-off The icon of the tab while it is not selected.
 * @param {expression=} badge The badge to put on this tab (usually a number).
 * @param {expression=} badge-style The style of badge to put on this tab (eg tabs-positive).
 * @param {expression=} on-select Called when this tab is selected.
 * @param {expression=} on-deselect Called when this tab is deselected.
 * @param {expression=} ng-click By default, the tab will be selected on click. If ngClick is set, it will not.  You can explicitly switch tabs using {@link ionic.service:$ionicTabsDelegate#select $ionicTabsDelegate.select()}.
 */
IonicModule
.directive('ionTab', [
  '$rootScope',
  '$animate',
  '$ionicBind',
  '$compile',
function($rootScope, $animate, $ionicBind, $compile) {

  //Returns ' key="value"' if value exists
  function attrStr(k,v) {
    return angular.isDefined(v) ? ' ' + k + '="' + v + '"' : '';
  }
  return {
    restrict: 'E',
    require: ['^ionTabs', 'ionTab'],
    replace: true,
    controller: '$ionicTab',
    scope: true,
    compile: function(element, attr) {

      //We create the tabNavTemplate in the compile phase so that the
      //attributes we pass down won't be interpolated yet - we want
      //to pass down the 'raw' versions of the attributes
      var tabNavTemplate = '<ion-tab-nav' +
        attrStr('ng-click', attr.ngClick) +
        attrStr('title', attr.title) +
        attrStr('icon', attr.icon) +
        attrStr('icon-on', attr.iconOn) +
        attrStr('icon-off', attr.iconOff) +
        attrStr('badge', attr.badge) +
        attrStr('badge-style', attr.badgeStyle) +
        '></ion-tab-nav>';

      //Remove the contents of the element so we can compile them later, if tab is selected
      //We don't use regular transclusion because it breaks element inheritance
      var tabContent = angular.element('<div class="pane">')
        .append( element.contents().remove() );

      return function link($scope, $element, $attr, ctrls) {
        var childScope;
        var childElement;
        var tabsCtrl = ctrls[0];
        var tabCtrl = ctrls[1];

        var navView = tabContent[0].querySelector('ion-nav-view') ||
          tabContent[0].querySelector('data-ion-nav-view');
        var navViewName = navView && navView.getAttribute('name');

        $ionicBind($scope, $attr, {
          animate: '=',
          onSelect: '&',
          onDeselect: '&',
          title: '@',
          uiSref: '@',
          href: '@',
        });

        tabsCtrl.add($scope);
        $scope.$on('$destroy', function() {
          tabsCtrl.remove($scope);
          tabNavElement.isolateScope().$destroy();
          tabNavElement.remove();
        });

        //Remove title attribute so browser-tooltip does not apear
        $element[0].removeAttribute('title');

        if (navViewName) {
          tabCtrl.navViewName = navViewName;
        }
        $scope.$on('$stateChangeSuccess', selectIfMatchesState);
        selectIfMatchesState();
        function selectIfMatchesState() {
          if (tabCtrl.tabMatchesState()) {
            tabsCtrl.select($scope);
          }
        }

        var tabNavElement = angular.element(tabNavTemplate);
        tabNavElement.data('$ionTabsController', tabsCtrl);
        tabNavElement.data('$ionTabController', tabCtrl);
        tabsCtrl.$tabsElement.append($compile(tabNavElement)($scope));

        $scope.$watch('$tabSelected', function(value) {
          childScope && childScope.$destroy();
          childScope = null;
          childElement && $animate.leave(childElement);
          childElement = null;
          if (value) {
            childScope = $scope.$new();
            childElement = tabContent.clone();
            $animate.enter(childElement, tabsCtrl.$element);
            $compile(childElement)(childScope);
          }
        });

      };
    }
  };
}]);