     
     let CardUserIdentifier = "DiscoverCardUserCell"
     
-    var userMode: DiscoverUserMode? {
+    var userMode: DiscoverUserMode = .Card {
         didSet {
             layout.userMode = userMode
             
-            switch userMode! {
+            switch userMode {
+
             case .Card:
                 view.backgroundColor = UIColor.yepBackgroundColor()
                 modeButtonItem.image = UIImage(named: "icon_list")
+
             case .Normal:
                 view.backgroundColor = UIColor.whiteColor()
                 modeButtonItem.image = UIImage(named: "icon_minicard")


extension DiscoverViewController: UICollectionViewDelegate, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout {
    
    
    func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return discoveredUsers.count
    }
    
    func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
//        let discoveredUser = discoveredUsers[indexPath.row]
        
        switch userMode! {
        case .Normal:
            let cell = collectionView.dequeueReusableCellWithReuseIdentifier(NormalUserIdentifier, forIndexPath: indexPath) as! DiscoverNormalUserCell
            
//            cell.configureWithDiscoveredUser(discoveredUser, collectionView: collectionView, indexPath: indexPath)
            return cell
            
        case .Card:
           let cell = collectionView.dequeueReusableCellWithReuseIdentifier(CardUserIdentifier, forIndexPath: indexPath) as! DiscoverCardUserCell
//            cell.configureWithDiscoveredUser(discoveredUser, collectionView: collectionView, indexPath: indexPath)
            return cell
        }
    }

    func collectionView(collectionView: UICollectionView, willDisplayCell cell: UICollectionViewCell, forItemAtIndexPath indexPath: NSIndexPath) {
        let discoveredUser = discoveredUsers[indexPath.row]
        
        switch userMode {

        case .Normal:
            let cell = cell as! DiscoverNormalUserCell
            cell.configureWithDiscoveredUser(discoveredUser, collectionView: collectionView, indexPath: indexPath)
            
        case .Card:
