import SwiftUI

struct PostDetailsView: View {
    @EnvironmentObject var settings: Settings
    let post: MoebooruPost
    @State var loadingStage: PostLoadingState = .loadingPreview
    private var imageURL: URL? {
        switch settings.detailViewType {
        case .preview:
            return post.previewURL
        case .sample:
            return post.sampleURL
        case .original:
            return post.fileURL
        case .compressed:
            return post.jpegURL
        }
    }

    var body: some View {
        VStack(spacing: 0) {
            AsyncImageWithPreview(
                url: imageURL,
                loadingStage: $loadingStage,
                finalLoadingState: .loaded,
                postURL: URL(string: "https://yande.re/post/show/\(post.id)")!
            ) {
                AsyncImageWithPreview(
                    url: post.previewURL,
                    loadingStage: $loadingStage
                )
                .frame(maxWidth: .infinity, maxHeight: .infinity, alignment: .center)
                .id(post.previewURL)
            }
            .frame(maxWidth: .infinity, maxHeight: .infinity, alignment: .center)
            .id(imageURL)
            .padding(0)
            .zIndex(0)

            VStack(spacing: 5) {
                HStack {
                    Text(post.tags.joined(separator: ", "))
                }
                .frame(maxWidth: .infinity, alignment: .leading)

                HStack {
                    Text(
                        Date(
                            timeIntervalSince1970: TimeInterval(post.createdAt)
                        ).formatted()
                    )
                    .frame(maxWidth: .infinity, alignment: .leading)

                    Group {
                        switch loadingStage {
                        case .loadingPreview:
                            Text("Loading preview …")
                        case .loadingFile:
                            Text("Loading \(settings.detailViewType.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
    }
}