From ef3e2c02974e49724cfa6c5347ee070edbf7f97f Mon Sep 17 00:00:00 2001
From: Steven Deutsch <stevensdeutsch@yahoo.com>
Date: Tue, 3 Oct 2017 22:06:50 -0500
Subject: [PATCH] Add generic method for header/footer dequeueing and change
 extension to MessagesCollectionView

---
 Sources/UICollectionView+Extensions.swift | 52 +++++++++++++++++++----
 1 file changed, 43 insertions(+), 9 deletions(-)

diff --git a/Sources/UICollectionView+Extensions.swift b/Sources/UICollectionView+Extensions.swift
index 3d2b7c3d..dc5d1ff1 100644
--- a/Sources/UICollectionView+Extensions.swift
+++ b/Sources/UICollectionView+Extensions.swift
@@ -1,19 +1,35 @@
-//
-//  UICollectionView+Extensions.swift
-//  MessageKit
-//
-//  Created by Frederic Barthelemy on 10/3/17.
-//  Copyright © 2017 MessageKit. All rights reserved.
-//
+/*
+ MIT License
+
+ Copyright (c) 2017 MessageKit
+
+ Permission is hereby granted, free of charge, to any person obtaining a copy
+ of this software and associated documentation files (the "Software"), to deal
+ in the Software without restriction, including without limitation the rights
+ to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ copies of the Software, and to permit persons to whom the Software is
+ furnished to do so, subject to the following conditions:
+
+ The above copyright notice and this permission notice shall be included in all
+ copies or substantial portions of the Software.
+
+ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ SOFTWARE.
+ */
 
 import Foundation
 
 /// Optional Cell Protocol to Simplify registration/cell type loading in a generic way
-protocol CollectionViewReusable: class {
+public protocol CollectionViewReusable: class {
     static func reuseIdentifier() -> String
 }
 
-extension UICollectionView {
+public extension MessagesCollectionView {
     /// Registers a particular cell using its reuse-identifier
     func register<CellType: UICollectionViewCell & CollectionViewReusable>(_ cellClass: CellType.Type) {
 	    register(cellClass, forCellWithReuseIdentifier: CellType.reuseIdentifier())
@@ -33,4 +49,22 @@ extension UICollectionView {
 	    }
 	    return cell
     }
+
+    /// Generically dequeues a header of the correct type allowing you to avoid scattering your code with guard-let-else-fatal
+    func dequeueReusableHeaderView<ViewType: UICollectionReusableView & CollectionViewReusable>(_ viewClass: ViewType.Type, for indexPath: IndexPath) -> ViewType {
+        let view = dequeueReusableSupplementaryView(ofKind: UICollectionElementKindSectionHeader, withReuseIdentifier: viewClass.reuseIdentifier(), for: indexPath)
+        guard let viewType = view as? ViewType else {
+            fatalError("Unable to dequeue \(String(describing: viewClass)) with reuseId of \(viewClass.reuseIdentifier())")
+        }
+        return viewType
+    }
+
+    /// Generically dequeues a footer of the correct type allowing you to avoid scattering your code with guard-let-else-fatal
+    func dequeueReusableFooterView<ViewType: UICollectionReusableView & CollectionViewReusable>(_ viewClass: ViewType.Type, for indexPath: IndexPath) -> ViewType {
+        let view = dequeueReusableSupplementaryView(ofKind: UICollectionElementKindSectionFooter, withReuseIdentifier: viewClass.reuseIdentifier(), for: indexPath)
+        guard let viewType = view as? ViewType else {
+            fatalError("Unable to dequeue \(String(describing: viewClass)) with reuseId of \(viewClass.reuseIdentifier())")
+        }
+        return viewType
+    }
 }