import SwiftUI

struct PostDetailsView: View {
  @EnvironmentObject var settings: SettingsManager
  @State private var loadingStage: BooruPostLoadingState = .loadingPreview
  private var imageURL: URL? {
    guard let post = selectedPost.post else { return nil }

    switch settings.detailViewQuality {
    case .preview:
      return post.previewURL

    case .sample:
      return post.sampleURL

    case .original:
      return post.fileURL
    }
  }
  @State private var isTagsSheetPresented = false
  @Binding var selectedPost: (post: BooruPost?, manager: BooruManager?)

  var filteredPosts: [BooruPost] {
    selectedPost.manager!.posts
      .filter { settings.displayRatings.contains($0.rating) }
  }

  var body: some View {
    if let post = selectedPost.post {
      VStack(spacing: 0) {
#if os(macOS)
        PostDetailsImageView(
          url: imageURL,
          loadingStage: $loadingStage,
          selectedPost: $selectedPost,
          finalLoadingState: .loaded
        ) {
          PostDetailsImageView(
            url: post.previewURL,
            loadingStage: $loadingStage,
            selectedPost: $selectedPost
          )
          .id(post.previewURL)
        }
        .id(imageURL)
#else
        PostDetailsCarouselView(
          posts: filteredPosts,
          loadingStage: $loadingStage,
          focusedPost: post,
          selectedPost: $selectedPost
        )
        .frame(maxWidth: .infinity, maxHeight: .infinity, alignment: .center)
#endif

        if settings.displayDetailsInformationBar {
          VStack(spacing: 5) {
            HStack {
              Text(post.createdAt.formatted())
                .frame(maxWidth: .infinity, alignment: .leading)

              Group {
                switch loadingStage {
                case .loadingPreview:
                  Text("Loading Preview…")

                case .loadingFile:
                  Text("Loading \(settings.detailViewQuality.rawValue)…")

                case .loaded:
                  EmptyView()
                }
              }
              .padding(.trailing, 5)
            }
            .frame(maxWidth: .infinity, alignment: .leading)
            .foregroundStyle(.secondary)
          }
          .padding(.horizontal, 10)
          .padding(.vertical, 10 / 1.33)
          .textSelection(.enabled)
          .font(.footnote)
#if os(iOS)
          .background(.ultraThinMaterial)
#else
          .background(.opacity(0.1))
#endif
          .zIndex(1)
        }
      }
      .navigationTitle("Details")
#if os(iOS)
      .navigationBarTitleDisplayMode(.inline)
      .toolbarBackground(.visible, for: .navigationBar)
      .toolbarBackground(.ultraThinMaterial, for: .navigationBar)
#endif
      .toolbar {
#if !os(macOS)
        if selectedPost.manager?.isLoading != false || loadingStage != .loaded {
          ToolbarItem {
            ProgressView()
          }
        }
#endif

        ToolbarItem {
          Button(action: {
            isTagsSheetPresented.toggle()
          }) {
            Label("Tags", systemImage: "tag")
          }
        }

#if os(macOS)
        if settings.enableShareShortcut {
          ToolbarItem {
            ShareLink(item: imageURL!) {
              Label("Share", systemImage: "square.and.arrow.up")
            }
          }
        }
#endif
      }
      .sheet(isPresented: $isTagsSheetPresented) {
        PostDetailsTagsView(
          isPresented: $isTagsSheetPresented,
          tags: post.tags,
          selectedPost: $selectedPost
        )
        .frame(minHeight: 250)
      }
    }
  }
}