Executing Angular App from non-root URL, doing all the operations and loading the required route (external social networks login is one of the use cases)

app.js

angular.module('simplified', ['ng-route'])
.config([
  '$routeProvider',
  function ($router) {
    $router.when('/', {
      templateUrl: '/views/main.html',
      controller: 'MainCtrl'
    });
  }
])
.run([
  '$location',
  'routeTracker', 
  function ($location, routeTracker) {
    // Check if SPA has been requested from a diffent
    // main URL
    if ($location.path() !== '/') {
      // Track the current URL to redirect to it
      // after the application state restore (MaintCtrl)
      routeTracker.track($location.url());
      
      // Change the URL to execute (MainCtrl)
      // Because it is changed here, previous
      // URL never has been executed, `run`
      // execute before to execute the controller
      // associated with the route
      $location.url('/');
    }
  }
]);

main-ctrl.js

angular.module('simplified')
.controller('MainCtrl', [
  '$location',
  'routeTracker',
  // The other services which are required
  // to inject to use in the controller
  function ($location, routeTracker /*the rest of services*/) {
    // Make all the operations that you require, 
    // e.g. load data from local store, make request to the server
    // to pull last status, etc.
    
    // If tracker has a tracked route
    if (routeTracker.isRouteTracked()) {
      // Get the route and load the tracked local route
      $location.url(routeTracker.pop());
    }
  }
]);

router-tracker-service.js

// Very simple service
anguar.module('simplified')
.factory('routeTracker', function () {
  var trackedUrl = null;
  
  return {
    isRouteTracked: function () {
      return (trackedUrl === null) ? false : true;
    },
    track: function (url) {
      trackedUrl = url;
    },
    pop: function () {
      var url = trackedUrl;
      
      trackedUrl = null;
      return url;
    }
  };
});