perf: memoize post grid derived collections and remove columns cache

2 files changed, 59 insertions, 88 deletions

diff --git a/Sora/Data/ColumnsDataCache.swift b/Sora/Data/ColumnsDataCache.swift
deleted file mode 100644
index bec37fb..0000000
--- a/Sora/Data/ColumnsDataCache.swift
+++ /dev/null
@@ -1,17 +0,0 @@
-struct ColumnsDataCache: Equatable {
-  let data: [[BooruPost]]
-  let columnCount: Int
-  let posts: [BooruPost]
-
-  static func == (lhs: Self, rhs: Self) -> Bool {
-    guard lhs.columnCount == rhs.columnCount else { return false }
-    guard lhs.posts.count == rhs.posts.count else { return false }
-    guard !lhs.posts.isEmpty, !rhs.posts.isEmpty else {
-      return lhs.posts.isEmpty == rhs.posts.isEmpty
-    }
-    guard lhs.posts.first?.id == rhs.posts.first?.id else { return false }
-    guard lhs.posts.last?.id == rhs.posts.last?.id else { return false }
-
-    return true
-  }
-}
diff --git a/Sora/Views/Post/Grid/PostGridView.swift b/Sora/Views/Post/Grid/PostGridView.swift
index 9c24932..03e5575 100644
--- a/Sora/Views/Post/Grid/PostGridView.swift
+++ b/Sora/Views/Post/Grid/PostGridView.swift
@@ -1,7 +1,6 @@
 // swiftlint:disable file_length
 
 import SwiftUI
-import WaterfallGrid
 
 struct PostGridView: View {  // swiftlint:disable:this type_body_length
   @EnvironmentObject var settings: SettingsManager
@@ -9,11 +8,9 @@ struct PostGridView: View {  // swiftlint:disable:this type_body_length
   @State private var isSearchHistoryPresented = false
   @Binding var selectedTab: Int
   @State private var isSearchablePresented = false
-  @State private var cachedSuggestions: [Either<BooruTag, BooruSearchQuery>] = []
   @State private var suppressNextSearchSubmit = false
   @State private var searchTask: Task<Void, Never>?
   @State private var suggestions: [BooruTag] = []
-  @State private var cachedColumnsData: ColumnsDataCache?
   let initialTag: String?
   @Binding var navigationPath: NavigationPath
   @State private var localPosts: [BooruPost] = []
@@ -25,6 +22,9 @@ struct PostGridView: View {  // swiftlint:disable:this type_body_length
   @State private var hasAppearedBefore = false
   @State private var currentLocalTask: Task<Void, Never>?
   @State private var previousNavigationPathCount = 0
+  @State private var displayedPosts: [BooruPost] = []
+  @State private var displayedColumnsData: [[BooruPost]] = []
+  @State private var folderHierarchy = FolderHierarchy(folders: [])
 
   init(
     selectedTab: Binding<Int>, navigationPath: Binding<NavigationPath>, initialTag: String? = nil
@@ -37,14 +37,38 @@ struct PostGridView: View {  // swiftlint:disable:this type_body_length
   @Environment(\.isSearching)
   private var isSearching
 
-  private var activePosts: [BooruPost] {
-    let posts = initialTag != nil ? localPosts : manager.posts
+  private var isLoading: Bool {
+    initialTag != nil ? localIsLoading : manager.isLoading
+  }
 
-    return posts.filter { settings.displayRatings.contains($0.rating) }
+  private func currentPostsSource() -> [BooruPost] {
+    initialTag != nil ? localPosts : manager.posts
   }
 
-  private var isLoading: Bool {
-    initialTag != nil ? localIsLoading : manager.isLoading
+  private func refreshFolderHierarchy() {
+    folderHierarchy = FolderHierarchy(folders: settings.folders)
+  }
+
+  private func columnsData(
+    for posts: [BooruPost], columnCount: Int
+  ) -> [[BooruPost]] {
+    (0..<columnCount).map { columnIndex in
+      posts.enumerated().compactMap { postIndex, post in
+        postIndex % columnCount == columnIndex ? post : nil
+      }
+    }
+  }
+
+  private func refreshDisplayedPosts() {
+    let filteredPosts = currentPostsSource().filter { post in
+      settings.displayRatings.contains(post.rating)
+    }
+
+    displayedPosts = filteredPosts
+    displayedColumnsData = columnsData(
+      for: filteredPosts,
+      columnCount: settings.thumbnailGridColumns
+    )
   }
 
   private var searchText: Binding<String> {
@@ -70,7 +94,7 @@ struct PostGridView: View {  // swiftlint:disable:this type_body_length
       )
     }
 
-    if activePosts.isEmpty, isLoading {
+    if displayedPosts.isEmpty, isLoading {
       placeholderGrid
     } else {
       gridView(columnCount: settings.thumbnailGridColumns)
@@ -98,67 +122,14 @@ struct PostGridView: View {  // swiftlint:disable:this type_body_length
 
   @ViewBuilder
   private func gridView(columnCount: Int) -> some View {
-    if settings.alternativeThumbnailGrid {
-      let columnsData = getColumnsData(columnCount: columnCount)
-
-      HStack(alignment: .top) {
-        ForEach(0..<columnCount, id: \.self) { columnIndex in
-          LazyVStack {
-            ForEach(columnsData[columnIndex], id: \.id) { post in
-              waterfallGridContent(post: post)
-                .id(post.id)
-            }
-          }
-          .transaction { $0.animation = nil }
-        }
-      }
-      #if os(macOS)
-        .padding(8)
-      #else
-        .padding(.horizontal)
-      #endif
-      .transition(.opacity)
-    } else {
-      WaterfallGrid(activePosts, id: \.id) { post in
-        waterfallGridContent(post: post)
-          .id(post.id)
-      }
-      .gridStyle(columns: columnCount)
-      .transaction { $0.animation = nil }
-      #if os(macOS)
-        .padding(8)
-      #else
-        .padding(.horizontal)
-      #endif
-      .transition(.opacity)
-    }
-  }
-
-  private func getColumnsData(columnCount: Int) -> [[BooruPost]] {
-    if let cached = cachedColumnsData,
-      cached
-        == ColumnsDataCache(
-          data: cached.data,
-          columnCount: columnCount,
-          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,
+    ThumbnailGridView(
+      items: displayedPosts,
       columnCount: columnCount,
-      posts: activePosts
-    )
-
-    return computedData
+      useAlternativeGrid: settings.alternativeThumbnailGrid,
+      columnsData: displayedColumnsData
+    ) { post in
+      waterfallGridContent(post: post)
+    }
   }
 
   var body: some View {
@@ -238,7 +209,24 @@ struct PostGridView: View {  // swiftlint:disable:this type_body_length
 
       previousNavigationPathCount = currentPathCount
     }
+    .onChange(of: localPosts) {
+      refreshDisplayedPosts()
+    }
+    .onChange(of: manager.posts) {
+      refreshDisplayedPosts()
+    }
+    .onChange(of: settings.displayRatings) {
+      refreshDisplayedPosts()
+    }
+    .onChange(of: settings.thumbnailGridColumns) {
+      refreshDisplayedPosts()
+    }
+    .onChange(of: settings.folders) {
+      refreshFolderHierarchy()
+    }
     .onAppear {
+      refreshFolderHierarchy()
+      refreshDisplayedPosts()
       previousNavigationPathCount = navigationPath.count
 
       if let initialTag {
@@ -480,7 +468,7 @@ struct PostGridView: View {  // swiftlint:disable:this type_body_length
     }) {
       PostGridThumbnailView(
         post: post,
-        posts: activePosts,
+        posts: displayedPosts,
         isNestedView: initialTag != nil,
         endOfData: initialTag != nil ? localEndOfData : manager.endOfData,
         onLoadNextPage: {
@@ -513,7 +501,7 @@ struct PostGridView: View {  // swiftlint:disable:this type_body_length
 
       Menu {
         FolderMenuView(
-          folderHierarchy: FolderHierarchy(folders: settings.folders),
+          folderHierarchy: folderHierarchy,
           showsTopLevelUncategorized: false,
           onSelectFolder: { folderIdentifier in
             settings.addFavorite(post: post, provider: manager.provider, folder: folderIdentifier)