2 files changed, 63 insertions, 5 deletions

diff --git a/Sora/Views/Post/Details/Carousel/PostDetailsCarouselView.swift b/Sora/Views/Post/Details/Carousel/PostDetailsCarouselView.swift
index 94d258e..f733a89 100644
--- a/Sora/Views/Post/Details/Carousel/PostDetailsCarouselView.swift
+++ b/Sora/Views/Post/Details/Carousel/PostDetailsCarouselView.swift
@@ -5,6 +5,7 @@ struct PostDetailsCarouselView: View {
   @EnvironmentObject var settings: SettingsManager
   let posts: [BooruPost]
   let focusedPost: BooruPost?
+  let onFocusedPostChange: (BooruPost) -> Void
   @Binding var loadingStage: BooruPostLoadingState
   @State private var currentIndex: Int?
   private let cacheManager = ImageCacheManager.shared
@@ -12,10 +13,12 @@ struct PostDetailsCarouselView: View {
   init(
     posts: [BooruPost],
     loadingStage: Binding<BooruPostLoadingState>,
-    focusedPost: BooruPost? = nil
+    focusedPost: BooruPost? = nil,
+    onFocusedPostChange: @escaping (BooruPost) -> Void = { _ in }
   ) {
     self.posts = posts
     self.focusedPost = focusedPost
+    self.onFocusedPostChange = onFocusedPostChange
     _loadingStage = loadingStage
 
     if let focused = focusedPost,
@@ -61,7 +64,9 @@ struct PostDetailsCarouselView: View {
     .scrollIndicators(.hidden)
     .scrollTargetBehavior(.paging)
     .onChange(of: currentIndex) {
-      guard let currentIndex else { return }
+      guard let currentIndex, posts.indices.contains(currentIndex) else { return }
+
+      onFocusedPostChange(posts[currentIndex])
 
       Task(priority: .utility) {
         if currentIndex == posts.count - 1 { await manager.loadNextPage() }
@@ -69,7 +74,13 @@ struct PostDetailsCarouselView: View {
 
       preloadNearbyImages()
     }
-    .onAppear(perform: preloadNearbyImages)
+    .onChange(of: focusedPost?.id) {
+      syncCurrentIndexWithFocus()
+    }
+    .onAppear {
+      syncCurrentIndexWithFocus()
+      preloadNearbyImages()
+    }
   }
 
   private func preloadNearbyImages() {
@@ -92,4 +103,16 @@ struct PostDetailsCarouselView: View {
 
     cacheManager.preloadImages(urlsToPreload)
   }
+
+  private func syncCurrentIndexWithFocus() {
+    if let focusedPost,
+      let index = posts.firstIndex(where: { $0.id == focusedPost.id })
+    {
+      currentIndex = index
+      onFocusedPostChange(posts[index])
+    } else if !posts.isEmpty {
+      currentIndex = 0
+      onFocusedPostChange(posts[0])
+    }
+  }
 }
diff --git a/Sora/Views/Post/Details/PostDetailsView.swift b/Sora/Views/Post/Details/PostDetailsView.swift
index 9c55798..bb58c49 100644
--- a/Sora/Views/Post/Details/PostDetailsView.swift
+++ b/Sora/Views/Post/Details/PostDetailsView.swift
@@ -7,6 +7,7 @@ struct PostDetailsView: View {
   @Binding var navigationPath: NavigationPath
   @State private var loadingStage: BooruPostLoadingState = .loadingPreview
   @State private var isTagsSheetPresented = false
+  @State private var activePost: BooruPost
   // swiftlint:disable:next discouraged_optional_collection
   let posts: [BooruPost]?
   let baseSearchText: String?
@@ -33,6 +34,7 @@ struct PostDetailsView: View {
   ) {
     self.post = post
     self._navigationPath = navigationPath
+    self._activePost = State(initialValue: post)
     self.posts = posts
     self.baseSearchText = baseSearchText
   }
@@ -44,7 +46,7 @@ struct PostDetailsView: View {
   }
 
   private var currentPost: BooruPost {
-    manager.selectedPost ?? post
+    activePost
   }
 
   var body: some View {
@@ -67,7 +69,8 @@ struct PostDetailsView: View {
         PostDetailsCarouselView(
           posts: filteredPosts,
           loadingStage: $loadingStage,
-          focusedPost: currentPost
+          focusedPost: currentPost,
+          onFocusedPostChange: updateActivePost
         )
         .frame(maxWidth: .infinity, maxHeight: .infinity, alignment: .center)
       #endif
@@ -149,6 +152,16 @@ struct PostDetailsView: View {
         tagsSheetContent()
       }
     }
+    .onAppear {
+      syncActivePost()
+    }
+    .onChange(of: post.id) {
+      activePost = post
+      syncActivePost()
+    }
+    .onChange(of: manager.selectedPost?.id) {
+      syncActivePost()
+    }
   }
 
   @ViewBuilder
@@ -167,4 +180,26 @@ struct PostDetailsView: View {
       )
     #endif
   }
+
+  private func updateActivePost(_ post: BooruPost) {
+    guard activePost.id != post.id else { return }
+
+    activePost = post
+  }
+
+  private func syncActivePost() {
+    #if os(macOS)
+      if let selectedPost = manager.selectedPost {
+        updateActivePost(selectedPost)
+      } else {
+        updateActivePost(post)
+      }
+    #else
+      if let selectedPost = manager.selectedPost, posts == nil {
+        updateActivePost(selectedPost)
+      } else {
+        updateActivePost(post)
+      }
+    #endif
+  }
 }