From 20dd53a714c25430b123c7133a94f026fdf77a26 Mon Sep 17 00:00:00 2001
From: Ben Scheirman <ben@scheirman.com>
Date: Sat, 11 Feb 2017 14:14:34 -0600
Subject: [PATCH] Add internal shared image cache to remote image view

---
 .../FiveCalls/IssueDetailViewController.swift |  6 ++---
 FiveCalls/FiveCalls/RemoteImageView.swift     | 27 ++++++++++++++++++-
 2 files changed, 28 insertions(+), 5 deletions(-)

diff --git a/FiveCalls/FiveCalls/IssueDetailViewController.swift b/FiveCalls/FiveCalls/IssueDetailViewController.swift
index 6cfbdaa1..1cff21a4 100644
--- a/FiveCalls/FiveCalls/IssueDetailViewController.swift
+++ b/FiveCalls/FiveCalls/IssueDetailViewController.swift
@@ -15,8 +15,7 @@ class IssueDetailViewController : UIViewController, IssueShareable {
     var issuesManager: IssuesManager!
     var issue: Issue!
     var logs: ContactLogs?
-    internal var images = [String: UIImage]()
-
+    
     @IBOutlet weak var tableView: UITableView!
     
     override var preferredStatusBarStyle: UIStatusBarStyle {
@@ -112,8 +111,7 @@ extension IssueDetailViewController : UITableViewDataSource {
                 cell.nameLabel.text = contact.name
                 cell.subtitleLabel.text = contact.area
                 if let photoURL = contact.photoURL {
-                    let imageKey = photoURL.absoluteString
-                    cell.avatarImageView.setRemoteImage(preferred: images[imageKey], url: photoURL, completion:  { self.images[imageKey] = $0 })
+                    cell.avatarImageView.setRemoteImage(url: photoURL)
                 } else {
                     cell.avatarImageView.image = cell.avatarImageView.defaultImage
                 }
diff --git a/FiveCalls/FiveCalls/RemoteImageView.swift b/FiveCalls/FiveCalls/RemoteImageView.swift
index 6cce4c12..cf293405 100644
--- a/FiveCalls/FiveCalls/RemoteImageView.swift
+++ b/FiveCalls/FiveCalls/RemoteImageView.swift
@@ -31,11 +31,15 @@ class RemoteImageView : UIImageView {
     }
     
     func setRemoteImage(url: URL, completion: @escaping RemoteImageCallback) {
-        image = defaultImage
         setRemoteImage(preferred: defaultImage, url: url, completion: completion)
     }
 
     func setRemoteImage(preferred preferredImage: UIImage?, url: URL, completion: @escaping RemoteImageCallback) {
+        if let cachedImage = ImageCache.shared.image(forKey: url) {
+            image = cachedImage
+            return
+        }
+        
         image = preferredImage
         guard preferredImage == nil || preferredImage == defaultImage else {
             return completion(preferredImage!)
@@ -56,6 +60,7 @@ class RemoteImageView : UIImageView {
                 if http.statusCode == 200 {
                     if let data = data, let image = UIImage(data: data) {
                         self.currentImageURL = url
+                        ImageCache.shared.set(image: image, forKey: url)
                         DispatchQueue.main.async {
                             completion(image)
                         }
@@ -68,3 +73,23 @@ class RemoteImageView : UIImageView {
         currentTask?.resume()
     }
 }
+
+private struct ImageCache {
+    static var shared = ImageCache()
+    
+    private let cache: NSCache<NSString, UIImage>
+    
+    init() {
+        cache = NSCache()
+    }
+    
+    func image(forKey key:URL) -> UIImage? {
+        return cache.object(forKey: key.absoluteString as NSString)
+    }
+    
+    func set(image: UIImage, forKey key: URL) {
+        cache.setObject(image, forKey: key.absoluteString as NSString)
+    }
+    
+    
+}