Add updating logic to text message (#178)

* Add updating logic to text message

* Change Observable to class

* Fix avatar hiding

* Move willBeShown/wasHidden declarations to common protocol

ChattoAdditions/Source/Chat Items/BaseMessage/BaseMessagePresenter.swift

@@ -97,9 +97,7 @@ public class BaseMessagePresenter<BubbleViewT, ViewModelBuilderT, InteractionHan
     public func configureCell(cell: CellT, decorationAttributes: ChatItemDecorationAttributes, animated: Bool, additionalConfiguration: (() -> Void)?) {
         cell.performBatchUpdates({ () -> Void in
             self.messageViewModel.showsTail = decorationAttributes.showsTail
-            if !decorationAttributes.canShowAvatar {
-                self.messageViewModel.avatarImage.value = nil
-            }
+            cell.avatarView.hidden = !decorationAttributes.canShowAvatar
             cell.bubbleView.userInteractionEnabled = true // just in case something went wrong while showing UIMenuController
             cell.baseStyle = self.cellStyle
             cell.messageViewModel = self.messageViewModel

ChattoAdditions/Source/Chat Items/BaseMessage/BaseMessageViewModel.swift

@@ -54,6 +54,8 @@ public protocol MessageViewModelProtocol: class { // why class? https://gist.git
 
 public protocol DecoratedMessageViewModelProtocol: MessageViewModelProtocol {
     var messageViewModel: MessageViewModelProtocol { get }
+    func willBeShown()
+    func wasHidden()
 }
 
 extension DecoratedMessageViewModelProtocol {

ChattoAdditions/Source/Chat Items/PhotoMessages/PhotoMessagePresenter.swift

@@ -65,6 +65,7 @@ public class PhotoMessagePresenter<ViewModelBuilderT, InteractionHandlerT where
         let updateClosure = { [weak self] (old: Any, new: Any) -> () in
             self?.updateCurrentCell()
         }
+        viewModel.avatarImage.observe(self, closure: updateClosure)
         viewModel.image.observe(self, closure: updateClosure)
         viewModel.transferDirection.observe(self, closure: updateClosure)
         viewModel.transferProgress.observe(self, closure: updateClosure)

ChattoAdditions/Source/Chat Items/PhotoMessages/PhotoMessageViewModel.swift

@@ -42,13 +42,6 @@ public protocol PhotoMessageViewModelProtocol: DecoratedMessageViewModelProtocol
     var transferStatus: Observable<TransferStatus> { get set }
     var image: Observable<UIImage?> { get set }
     var imageSize: CGSize { get }
-    func willBeShown() // Optional
-    func wasHidden() // Optional
-}
-
-public extension PhotoMessageViewModelProtocol {
-    func willBeShown() {}
-    func wasHidden() {}
 }
 
 public class PhotoMessageViewModel<PhotoMessageModelT: PhotoMessageModelProtocol>: PhotoMessageViewModelProtocol {

ChattoAdditions/Source/Chat Items/TextMessages/TextMessagePresenter.swift

@@ -64,6 +64,26 @@ public class TextMessagePresenter<ViewModelBuilderT, InteractionHandlerT where
         let identifier = self.messageViewModel.isIncoming ? "text-message-incoming" : "text-message-outcoming"
         return collectionView.dequeueReusableCellWithReuseIdentifier(identifier, forIndexPath: indexPath)
     }
+    
+    public override func createViewModel() -> ViewModelBuilderT.ViewModelT {
+        let viewModel = self.viewModelBuilder.createViewModel(self.messageModel)
+        let updateClosure = { [weak self] (old: Any, new: Any) -> () in
+            self?.updateCurrentCell()
+        }
+        viewModel.avatarImage.observe(self, closure: updateClosure)
+        return viewModel
+    }
+    
+    public var textCell: TextMessageCollectionViewCell? {
+        if let cell = self.cell {
+            if let textCell = cell as? TextMessageCollectionViewCell {
+                return textCell
+            } else {
+                assert(false, "Invalid cell was given to presenter!")
+            }
+        }
+        return nil
+    }
 
     public override func configureCell(cell: BaseMessageCollectionViewCell<TextBubbleView>, decorationAttributes: ChatItemDecorationAttributes, animated: Bool, additionalConfiguration: (() -> Void)?) {
         guard let cell = cell as? TextMessageCollectionViewCell else {
@@ -78,6 +98,20 @@ public class TextMessagePresenter<ViewModelBuilderT, InteractionHandlerT where
             additionalConfiguration?()
         }
     }
+    
+    public override func cellWillBeShown() {
+        self.messageViewModel.willBeShown()
+    }
+    
+    public override func cellWasHidden() {
+        self.messageViewModel.wasHidden()
+    }
+    
+    public func updateCurrentCell() {
+        if let cell = self.textCell, decorationAttributes = self.decorationAttributes {
+            self.configureCell(cell, decorationAttributes: decorationAttributes, animated: self.itemVisibility != .Appearing, additionalConfiguration: nil)
+        }
+    }
 
     public override func canShowMenu() -> Bool {
         return true

ChattoAdditions/Source/Chat Items/TextMessages/TextMessageViewModel.swift

@@ -39,6 +39,14 @@ public class TextMessageViewModel<TextMessageModelT: TextMessageModelProtocol>:
         self.textMessage = textMessage
         self.messageViewModel = messageViewModel
     }
+    
+    public func willBeShown() {
+        // Need to declare empty. Otherwise subclass code won't execute (as of Xcode 7.2)
+    }
+    
+    public func wasHidden() {
+        // Need to declare empty. Otherwise subclass code won't execute (as of Xcode 7.2)
+    }
 }
 
 public class TextMessageViewModelDefaultBuilder<TextMessageModelT: TextMessageModelProtocol>: ViewModelBuilderProtocol {

ChattoAdditions/Source/Observable.swift

@@ -25,7 +25,8 @@
 import Foundation
 
 // Be aware this is not thread safe!
-public struct Observable<T> {
+// Why class? https://lists.swift.org/pipermail/swift-users/Week-of-Mon-20160711/002580.html
+public class Observable<T> {
 
     public init(_ value: T) {
         self.value = value
@@ -40,12 +41,12 @@ public struct Observable<T> {
         }
     }
 
-    public mutating func observe(observer: AnyObject, closure: (old: T, new: T) -> ()) {
+    public func observe(observer: AnyObject, closure: (old: T, new: T) -> ()) {
         self.observers.append(Observer(owner: observer, closure: closure))
         self.cleanDeadObservers()
     }
 
-    private mutating func cleanDeadObservers() {
+    private func cleanDeadObservers() {
         self.observers = self.observers.filter { $0.owner != nil }
     }