From 2958d2b1acca776f64d8ccc5e36d17c077edcfdd Mon Sep 17 00:00:00 2001
From: Shadowfacts <me@shadowfacts.net>
Date: Sun, 22 Jan 2023 18:07:16 -0500
Subject: [PATCH] Change TrendingLinkCardCollectionViewCell to use
 CachedImageView

---
 .../TrendingLinkCardCollectionViewCell.swift  | 39 ++-------------
 .../TrendingLinkCardCollectionViewCell.xib    |  6 +--
 Tusker/Views/CachedImageView.swift            | 48 ++++++++++++++-----
 3 files changed, 45 insertions(+), 48 deletions(-)

diff --git a/Tusker/Screens/Explore/TrendingLinkCardCollectionViewCell.swift b/Tusker/Screens/Explore/TrendingLinkCardCollectionViewCell.swift
index f9fdad85..55de1361 100644
--- a/Tusker/Screens/Explore/TrendingLinkCardCollectionViewCell.swift
+++ b/Tusker/Screens/Explore/TrendingLinkCardCollectionViewCell.swift
@@ -8,14 +8,13 @@
 
 import UIKit
 import Pachyderm
+import WebURLFoundationExtras
 
 class TrendingLinkCardCollectionViewCell: UICollectionViewCell {
     
     private var card: Card?
-    private var isGrayscale = false
-    private var thumbnailRequest: ImageCache.Request?
     
-    @IBOutlet weak var thumbnailView: UIImageView!
+    @IBOutlet weak var thumbnailView: CachedImageView!
     @IBOutlet weak var titleLabel: UILabel!
     @IBOutlet weak var descriptionLabel: UILabel!
     @IBOutlet weak var providerLabel: UILabel!
@@ -27,14 +26,14 @@ class TrendingLinkCardCollectionViewCell: UICollectionViewCell {
     override func awakeFromNib() {
         super.awakeFromNib()
         
+        thumbnailView.cache = .attachments
+        
         layer.shadowOpacity = 0.2
         layer.shadowRadius = 8
         layer.shadowOffset = .zero
         layer.masksToBounds = false
         updateLayerColors()
         
-        NotificationCenter.default.addObserver(self, selector: #selector(updateUIForPreferences), name: .preferencesChanged, object: nil)
-        
         addGestureRecognizer(UIHoverGestureRecognizer(target: self, action: #selector(hoverRecognized)))
     }
     
@@ -48,8 +47,7 @@ class TrendingLinkCardCollectionViewCell: UICollectionViewCell {
         self.card = card
         self.thumbnailView.image = nil
         
-        updateGrayscaleableUI(card: card)
-        updateUIForPreferences()
+        thumbnailView.update(for: card.image.flatMap { URL($0) }, blurhash: card.blurhash)
         
         let title = card.title.trimmingCharacters(in: .whitespacesAndNewlines)
         titleLabel.text = title
@@ -77,33 +75,6 @@ class TrendingLinkCardCollectionViewCell: UICollectionViewCell {
         historyView.isHidden = card.history == nil || card.history!.count < 2
     }
     
-    @objc private func updateUIForPreferences() {
-        if isGrayscale != Preferences.shared.grayscaleImages,
-           let card {
-            updateGrayscaleableUI(card: card)
-        }
-    }
-    
-    private func updateGrayscaleableUI(card: Card) {
-        isGrayscale = Preferences.shared.grayscaleImages
-        
-        if let imageURL = card.image,
-           let url = URL(imageURL) {
-            thumbnailRequest = ImageCache.attachments.get(url, completion: { _, image in
-                guard let image,
-                      let transformedImage = ImageGrayscalifier.convertIfNecessary(url: url, image: image) else {
-                    return
-                }
-                DispatchQueue.main.async {
-                    self.thumbnailView.image = transformedImage
-                }
-            })
-            if thumbnailRequest != nil {
-                loadBlurHash(card: card)
-            }
-        }
-    }
-    
     private func loadBlurHash(card: Card) {
         guard let hash = card.blurhash else {
             return
diff --git a/Tusker/Screens/Explore/TrendingLinkCardCollectionViewCell.xib b/Tusker/Screens/Explore/TrendingLinkCardCollectionViewCell.xib
index 53111e9b..6480291d 100644
--- a/Tusker/Screens/Explore/TrendingLinkCardCollectionViewCell.xib
+++ b/Tusker/Screens/Explore/TrendingLinkCardCollectionViewCell.xib
@@ -18,7 +18,7 @@
                 <rect key="frame" x="0.0" y="0.0" width="300" height="406"/>
                 <autoresizingMask key="autoresizingMask"/>
                 <subviews>
-                    <imageView clipsSubviews="YES" userInteractionEnabled="NO" contentMode="scaleAspectFill" horizontalHuggingPriority="251" verticalHuggingPriority="251" translatesAutoresizingMaskIntoConstraints="NO" id="h3b-Mf-lD6">
+                    <imageView clipsSubviews="YES" userInteractionEnabled="NO" contentMode="scaleAspectFill" horizontalHuggingPriority="251" verticalHuggingPriority="251" translatesAutoresizingMaskIntoConstraints="NO" id="h3b-Mf-lD6" customClass="CachedImageView" customModule="Tusker" customModuleProvider="target">
                         <rect key="frame" x="0.0" y="0.0" width="300" height="225"/>
                         <constraints>
                             <constraint firstAttribute="width" secondItem="h3b-Mf-lD6" secondAttribute="height" multiplier="4:3" id="QDY-8a-LYC"/>
@@ -56,9 +56,9 @@
                         </constraints>
                     </view>
                     <visualEffectView opaque="NO" contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="cWo-9n-z42">
-                        <rect key="frame" x="0.0" y="196.33333333333334" width="300" height="28.666666666666657"/>
+                        <rect key="frame" x="0.0" y="196.66666666666666" width="300" height="28.333333333333343"/>
                         <view key="contentView" opaque="NO" clipsSubviews="YES" multipleTouchEnabled="YES" contentMode="center" insetsLayoutMarginsFromSafeArea="NO" id="ktv-3s-cp9">
-                            <rect key="frame" x="0.0" y="0.0" width="300" height="29"/>
+                            <rect key="frame" x="0.0" y="0.0" width="300" height="28"/>
                             <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                             <subviews>
                                 <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="Title" textAlignment="natural" lineBreakMode="tailTruncation" numberOfLines="2" baselineAdjustment="alignBaselines" adjustsLetterSpacingToFitWidth="YES" showsExpansionTextWhenTruncated="YES" adjustsFontForContentSizeCategory="YES" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="Ho3-cU-IGi">
diff --git a/Tusker/Views/CachedImageView.swift b/Tusker/Views/CachedImageView.swift
index 50051d6b..617a301d 100644
--- a/Tusker/Views/CachedImageView.swift
+++ b/Tusker/Views/CachedImageView.swift
@@ -10,26 +10,32 @@ import UIKit
 
 class CachedImageView: UIImageView {
     
-    private let cache: ImageCache
+    var cache: ImageCache!
     private var url: URL?
     private var isGrayscale = false
     private var fetchTask: Task<Void, Error>?
+    private var blurHashTask: DispatchWorkItem?
     
     init(cache: ImageCache) {
         self.cache = cache
-        
         super.init(frame: .zero)
-        
-        NotificationCenter.default.addObserver(self, selector: #selector(preferencesChanged), name: .preferencesChanged, object: nil)
+        commonInit()
     }
     
     required init?(coder: NSCoder) {
-        fatalError("init(coder:) has not been implemented")
+        super.init(coder: coder)
+        commonInit()
     }
     
-    func update(for url: URL?) {
-        if url != self.url {
+    private func commonInit() {
+        NotificationCenter.default.addObserver(self, selector: #selector(preferencesChanged), name: .preferencesChanged, object: nil)
+    }
+    
+    func update(for url: URL?, blurhash: String? = nil) {
+        if url != self.url || (url != nil && self.image == nil) {
             self.url = url
+            self.image = nil
+            updateBlurhash(blurhash, for: url)
             updateImage()
         }
     }
@@ -40,13 +46,32 @@ class CachedImageView: UIImageView {
         }
     }
     
+    private func updateBlurhash(_ blurhash: String?, for url: URL?) {
+        blurHashTask?.cancel()
+        
+        if let blurhash {
+            let aspectRatio = self.bounds.width > 0 ? self.bounds.height / self.bounds.width : 1
+            blurHashTask = DispatchWorkItem {
+                let size = CGSize(width: 60, height: aspectRatio * 60)
+                let image = UIImage(blurHash: blurhash, size: size)
+                DispatchQueue.main.async {
+                    if self.image == nil && self.url == url && self.blurHashTask?.isCancelled == false {
+                        self.image = image
+                    }
+                }
+            }
+            AttachmentView.queue.async(execute: blurHashTask!)
+        }
+    }
+    
     private func updateImage() {
         fetchTask?.cancel()
+        
+        guard let url else {
+            return
+        }
+        
         fetchTask = Task(priority: .high) {
-            self.image = nil
-            guard let url else {
-                return
-            }
             let (_, image) = await cache.get(url)
             guard let image else {
                 return
@@ -59,6 +84,7 @@ class CachedImageView: UIImageView {
             try Task.checkCancellation()
             self.image = transformedImage
             self.isGrayscale = Preferences.shared.grayscaleImages
+            self.blurHashTask?.cancel()
         }
     }