From b79d3610162cd4a0dbed22f7df8963ef487f45dd Mon Sep 17 00:00:00 2001
From: William Casarin <jb55@jb55.com>
Date: Tue, 2 May 2023 07:33:54 -0700
Subject: [PATCH] Preload profile pictures while scrolling

Changelog-Added: Preload profile pictures while scrolling
---
 damus/Components/ImageCarousel.swift |  3 +++
 damus/Util/EventCache.swift          | 26 ++++++++++++++++++++++----
 2 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/damus/Components/ImageCarousel.swift b/damus/Components/ImageCarousel.swift
index 88d587d7..caff10b8 100644
--- a/damus/Components/ImageCarousel.swift
+++ b/damus/Components/ImageCarousel.swift
@@ -132,6 +132,9 @@ struct ImageCarousel: View {
                         .imageFill(for: geo.size, max: maxHeight, fill: fillHeight) { fill in
                             state.previews.cache_image_meta(evid: evid, image_fill: fill)
                             // blur hash can be discarded when we have the url
+                            // NOTE: this is the wrong place for this... we need to remove
+                            //       it when the image is loaded in memory. This may happen
+                            //       earlier than this (by the preloader, etc)
                             DispatchQueue.main.asyncAfter(deadline: .now() + 1.0) {
                                 state.events.lookup_img_metadata(url: url)?.state = .not_needed
                             }
diff --git a/damus/Util/EventCache.swift b/damus/Util/EventCache.swift
index 4c35b234..3766c7c0 100644
--- a/damus/Util/EventCache.swift
+++ b/damus/Util/EventCache.swift
@@ -337,11 +337,32 @@ func get_preload_plan(cache: EventData, ev: NostrEvent, our_keypair: Keypair, se
     return PreloadPlan(data: cache, event: ev, load_artifacts: load_artifacts, load_translations: load_translations, load_preview: load_preview)
 }
 
+func preload_image(url: URL) {
+    if ImageCache.default.isCached(forKey: url.absoluteString) {
+        print("Preloaded image \(url.absoluteString) found in cache")
+        // looks like we already have it cached. no download needed
+        return
+    }
+    
+    print("Preloading image \(url.absoluteString)")
+    
+    KingfisherManager.shared.retrieveImage(with: ImageResource(downloadURL: url)) { val in
+        print("Preloaded image \(url.absoluteString)")
+    }
+}
+
 func preload_event(plan: PreloadPlan, profiles: Profiles, our_keypair: Keypair, settings: UserSettingsStore) async {
     var artifacts: NoteArtifacts? = plan.data.artifacts.artifacts
     
     print("Preloading event \(plan.event.content)")
     
+    // preload pfp
+    if let profile = profiles.lookup(id: plan.event.pubkey),
+       let picture = profile.picture,
+       let url = URL(string: picture) {
+        preload_image(url: url)
+    }
+    
     if artifacts == nil && plan.load_artifacts {
         let arts = render_note_content(ev: plan.event, profiles: profiles, privkey: our_keypair.privkey)
         artifacts = arts
@@ -352,10 +373,7 @@ func preload_event(plan: PreloadPlan, profiles: Profiles, our_keypair: Keypair,
         }
         
         for url in arts.images {
-            print("Preloading image \(url.absoluteString)")
-            KingfisherManager.shared.retrieveImage(with: ImageResource(downloadURL: url)) { val in
-                print("Finished preloading image \(url.absoluteString)")
-            }
+            preload_image(url: url)
         }
     }