How to trigger an angularjs animation from a controller method?

Question

I would like to trigger an angular animation from a controller method.

I have come up with something that I am not satisfied with (see code below).

The issu

Answer 1

Here is the solution I ended up using (see code below). It is an adaptation of Liamnes's proposed solution.

angular.module('signin')
    .controller('SigninCtrl', ['$scope', '$rootScope', '$cookies', '$state', '$animate', 'signinService', function ($scope, $rootScope, $cookies, $state, $animate, signinService) {

        var setPersonalInfo = function (param) {
            return signinService.setPersonalInfo(param.headers, $rootScope);
        };
        var goToDashboard = function (memberType) {
            $state.go('dashboard', {memberType: memberType});
        };
        var reportProblem = function () {
            $scope.formCtrl.username.$setValidity('username.wrong', false);
            $scope.formCtrl.password.$setValidity('password.wrong', false);
            $scope.$broadcast('SIGNIN_ERROR');
        };
        var resetForm = function(formCtrl){
            formCtrl.username.$setValidity('username.wrong', true);
            formCtrl.password.$setValidity('password.wrong', true);
        };

        $scope.signin = function (formCtrl) {

            resetForm(formCtrl);

            if (formCtrl.$valid) {
                signinService.signin($scope.credentials).then(setPersonalInfo).then(goToDashboard).catch(reportProblem);
            }
            else {
                $scope.$broadcast('SIGNIN_ERROR');
            }
        }
    }])
    .directive('shakeThat', ['$animate', function ($animate) {
        return {
            require: '^form',
            scope: {
                signin: '&'
            },
            link: function (scope, element, attrs, form) {
                scope.$on('SIGNIN_ERROR', function () {
                    $animate.addClass(element, 'shake').then(function () {
                        $animate.removeClass(element, 'shake');
                    });
                });
            }
        };
    }]);

HTML: