From 592c8ee142c17e5cdd1f4d698aeae5707cc549bc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Diego=20S=C3=A1nchez?= <diego.sanchezr@gmail.com>
Date: Wed, 1 Jun 2016 12:30:53 +0100
Subject: [PATCH] Allows the decorator to override item ids (#143)

---
 Chatto/Source/Chat Items/ChatItemCompanion.swift    | 13 +++++++++----
 .../BaseChatViewController+Changes.swift            |  6 +++---
 2 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/Chatto/Source/Chat Items/ChatItemCompanion.swift b/Chatto/Source/Chat Items/ChatItemCompanion.swift
index c5c903c..c47c341 100644
--- a/Chatto/Source/Chat Items/ChatItemCompanion.swift	
+++ b/Chatto/Source/Chat Items/ChatItemCompanion.swift	
@@ -28,20 +28,25 @@ public protocol ChatItemsDecoratorProtocol {
     func decorateItems(chatItems: [ChatItemProtocol]) -> [DecoratedChatItem]
 }
 
-public struct DecoratedChatItem {
+public struct DecoratedChatItem: UniqueIdentificable {
+    public let uid: String
     public let chatItem: ChatItemProtocol
     public let decorationAttributes: ChatItemDecorationAttributesProtocol?
+
     public init(chatItem: ChatItemProtocol, decorationAttributes: ChatItemDecorationAttributesProtocol?) {
+        self.init(uid: chatItem.uid, chatItem: chatItem, decorationAttributes: decorationAttributes)
+    }
+
+    public init(uid: String, chatItem: ChatItemProtocol, decorationAttributes: ChatItemDecorationAttributesProtocol?) {
+        self.uid = uid
         self.chatItem = chatItem
         self.decorationAttributes = decorationAttributes
     }
 }
 
 public struct ChatItemCompanion: UniqueIdentificable {
+    public let uid: String
     public let chatItem: ChatItemProtocol
     public let presenter: ChatItemPresenterProtocol
     public var decorationAttributes: ChatItemDecorationAttributesProtocol?
-    public var uid: String {
-        return self.chatItem.uid
-    }
 }
diff --git a/Chatto/Source/ChatController/BaseChatViewController+Changes.swift b/Chatto/Source/ChatController/BaseChatViewController+Changes.swift
index c8666c2..457d166 100644
--- a/Chatto/Source/ChatController/BaseChatViewController+Changes.swift
+++ b/Chatto/Source/ChatController/BaseChatViewController+Changes.swift
@@ -201,7 +201,7 @@ extension BaseChatViewController: ChatDataSourceDelegateProtocol {
 
     private func createModelUpdates(newItems newItems: [ChatItemProtocol], oldItems: ChatItemCompanionCollection, collectionViewWidth: CGFloat) -> (changes: CollectionChanges, updateModelClosure: () -> Void) {
         let newDecoratedItems = self.chatItemsDecorator?.decorateItems(newItems) ?? newItems.map { DecoratedChatItem(chatItem: $0, decorationAttributes: nil) }
-        let changes = Chatto.generateChanges(oldCollection: oldItems.map { $0.chatItem }, newCollection: newDecoratedItems.map { $0.chatItem })
+        let changes = Chatto.generateChanges(oldCollection: oldItems.lazy.map { $0 }, newCollection: newDecoratedItems.lazy.map { $0 })
         let itemCompanionCollection = self.createCompanionCollection(fromChatItems: newDecoratedItems, previousCompanionCollection: oldItems)
         let layoutModel = self.createLayoutModel(itemCompanionCollection, collectionViewWidth: collectionViewWidth)
         let updateModelClosure : () -> Void = { [weak self] in
@@ -220,12 +220,12 @@ extension BaseChatViewController: ChatDataSourceDelegateProtocol {
             // Oherwise updateVisibleCells may try to update existing cell with a new presenter which is working with a different type of cell
 
             // Optimization: reuse presenter if it's the same instance.
-            if let oldChatItemCompanion = oldItems[chatItem.uid] where oldChatItemCompanion.chatItem === chatItem {
+            if let oldChatItemCompanion = oldItems[decoratedChatItem.uid] where oldChatItemCompanion.chatItem === chatItem {
                 presenter = oldChatItemCompanion.presenter
             } else {
                 presenter = self.createPresenterForChatItem(decoratedChatItem.chatItem)
             }
-            return ChatItemCompanion(chatItem: decoratedChatItem.chatItem, presenter: presenter, decorationAttributes: decoratedChatItem.decorationAttributes)
+            return ChatItemCompanion(uid: decoratedChatItem.uid, chatItem: decoratedChatItem.chatItem, presenter: presenter, decorationAttributes: decoratedChatItem.decorationAttributes)
         })
     }