From a112a485e891a98ca3c3f5d9e08bdd3ea2e6f664 Mon Sep 17 00:00:00 2001
From: Fuwn <contact@fuwn.me>
Date: Thu, 24 Jul 2025 18:15:50 +0200
Subject: feat: Development commit

---
 Sora/Data/ColumnsDataCache.swift        |  5 ++++
 Sora/Views/Post/Grid/PostGridView.swift | 45 ++++++++++++++++++++++++++++-----
 2 files changed, 43 insertions(+), 7 deletions(-)
 create mode 100644 Sora/Data/ColumnsDataCache.swift

(limited to 'Sora')

diff --git a/Sora/Data/ColumnsDataCache.swift b/Sora/Data/ColumnsDataCache.swift
new file mode 100644
index 0000000..4858e80
--- /dev/null
+++ b/Sora/Data/ColumnsDataCache.swift
@@ -0,0 +1,5 @@
+struct ColumnsDataCache {
+  let data: [[BooruPost]]
+  let columnCount: Int
+  let posts: [BooruPost]
+}
diff --git a/Sora/Views/Post/Grid/PostGridView.swift b/Sora/Views/Post/Grid/PostGridView.swift
index 99c7966..a63bf97 100644
--- a/Sora/Views/Post/Grid/PostGridView.swift
+++ b/Sora/Views/Post/Grid/PostGridView.swift
@@ -17,6 +17,8 @@ struct PostGridView: View {  // swiftlint:disable:this type_body_length
   @State private var suggestions: [BooruTag] = []
   private static let topID = "PostGridScrollTop"
   @State private var scrollID: String?
+  @State private var cachedColumnsData: ColumnsDataCache?
+  @State private var scrollDebounceTask: Task<Void, Never>?
 
   @Environment(\.isSearching)
   private var isSearching
@@ -72,7 +74,7 @@ struct PostGridView: View {  // swiftlint:disable:this type_body_length
   @ViewBuilder
   private func gridView(columnCount: Int) -> some View {
     if settings.alternativeThumbnailGrid {
-      let columnsData = computeColumnsData(columnCount: columnCount)
+      let columnsData = getColumnsData(columnCount: columnCount)
 
       HStack(alignment: .top) {
         ForEach(0..<columnCount, id: \.self) { columnIndex in
@@ -109,12 +111,27 @@ struct PostGridView: View {  // swiftlint:disable:this type_body_length
     }
   }
 
-  private func computeColumnsData(columnCount: Int) -> [[BooruPost]] {
-    (0..<columnCount).map { columnIndex in
+  private func getColumnsData(columnCount: Int) -> [[BooruPost]] {
+    if let cached = cachedColumnsData,
+      cached.columnCount == columnCount,
+      cached.posts == activePosts
+    {
+      return cached.data
+    }
+
+    let computedData = (0..<columnCount).map { columnIndex in
       activePosts.enumerated().compactMap { index, post in
         index % columnCount == columnIndex ? post : nil
       }
     }
+
+    cachedColumnsData = ColumnsDataCache(
+      data: computedData,
+      columnCount: columnCount,
+      posts: activePosts
+    )
+
+    return computedData
   }
 
   var body: some View {
@@ -213,9 +230,17 @@ struct PostGridView: View {  // swiftlint:disable:this type_body_length
         return
       }
 
-      let queryID = manager.searchHistory[manager.historyIndex].id
+      scrollDebounceTask?.cancel()
+
+      scrollDebounceTask = Task {
+        try? await Task.sleep(nanoseconds: 200_000_000)
 
-      updateViewState(for: queryID, scrollPostID: newValue)
+        guard !Task.isCancelled else { return }
+
+        let queryID = manager.searchHistory[manager.historyIndex].id
+
+        updateViewState(for: queryID, scrollPostID: newValue)
+      }
     }
     .onChange(of: manager.historyIndex) { _, newIndex in
       guard newIndex >= 0 && newIndex < manager.searchHistory.count else { return }
@@ -359,7 +384,11 @@ struct PostGridView: View {  // swiftlint:disable:this type_body_length
       )
     }
     .onAppear {
-      scrollID = viewStates[queryID]?.scrollPostID ?? Self.topID
+      let targetScrollID = viewStates[queryID]?.scrollPostID ?? Self.topID
+
+      if scrollID == nil || scrollID != targetScrollID {
+        scrollID = targetScrollID
+      }
     }
     .onDisappear {
       guard manager.historyIndex >= 0 && manager.historyIndex < manager.searchHistory.count else {
@@ -368,7 +397,9 @@ struct PostGridView: View {  // swiftlint:disable:this type_body_length
 
       let queryID = manager.searchHistory[manager.historyIndex].id
 
-      updateViewState(for: queryID, scrollPostID: scrollID)
+      if viewStates[queryID]?.scrollPostID != scrollID {
+        updateViewState(for: queryID, scrollPostID: scrollID)
+      }
     }
     #if os(iOS)
       .gesture(
-- 
cgit v1.2.3