import SwiftUI

struct PostDetailsView: View {
  @EnvironmentObject var manager: BooruManager
  @EnvironmentObject var settings: SettingsManager
  let post: BooruPost
  @Binding var navigationPath: NavigationPath
  @State private var loadingStage: BooruPostLoadingState = .loadingPreview
  @State private var isTagsSheetPresented = false
  // swiftlint:disable:next discouraged_optional_collection
  let posts: [BooruPost]?
  let baseSearchText: String?

  private var imageURL: URL? {
    switch settings.detailViewQuality {
    case .preview:
      currentPost.previewURL

    case .sample:
      currentPost.sampleURL

    case .original:
      currentPost.fileURL
    }
  }

  init(
    post: BooruPost,
    navigationPath: Binding<NavigationPath>,
    // swiftlint:disable:next discouraged_optional_collection
    posts: [BooruPost]? = nil,
    baseSearchText: String? = nil
  ) {
    self.post = post
    self._navigationPath = navigationPath
    self.posts = posts
    self.baseSearchText = baseSearchText
  }

  var filteredPosts: [BooruPost] {
    let sourcePosts = posts ?? manager.posts

    return sourcePosts.filter { settings.displayRatings.contains($0.rating) }
  }

  private var currentPost: BooruPost {
    manager.selectedPost ?? post
  }

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

      if settings.displayDetailsInformationBar {
        VStack(spacing: 5) {
          HStack {
            Text(currentPost.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)
      }
    }
    .ifiOS26Unavailable { view in
      view
        .navigationTitle("Details")
        #if os(iOS)
          .navigationBarTitleDisplayMode(.inline)
        #endif
    }
    .toolbar {
      ToolbarItem {
        PostGridFavoriteButtonView(post: currentPost)
      }

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

      #if os(macOS)
        if settings.enableShareShortcut {
          if let imageURL {
            ToolbarItem {
              ShareLink(item: imageURL) {
                Label("Share", systemImage: "square.and.arrow.up")
              }
            }
          }
        }
      #endif
    }
    .sheet(isPresented: $isTagsSheetPresented) {
      if #available(macOS 15.0, *) {
        tagsSheetContent()
          #if os(macOS)
            .presentationSizing(.page)
          #endif
      } else {
        tagsSheetContent()
      }
    }
  }

  @ViewBuilder
  private func tagsSheetContent() -> some View {
    PostDetailsTagsView(
      isPresented: $isTagsSheetPresented,
      navigationPath: $navigationPath,
      tags: currentPost.tags,
      isNestedContext: posts != nil,
      baseSearchText: baseSearchText
    )
    #if os(macOS)
      .frame(
        minHeight: (NSScreen.main?.frame.height ?? 1_080) / 2,
        maxHeight: .infinity
      )
    #endif
  }
}