import SwiftUI

struct CapImagesView: View {
    
    private let imageSize: CGFloat = 70
    
    @Binding
    var cap: Cap?
    
    @Binding
    var isPresented: Bool

    @State
    private var selectedCap: CapImage?

    
    init(cap: Binding<Cap?>, database: Database, isPresented: Binding<Bool>) {
        self.database = database
        self._cap = cap
        self._isPresented = isPresented
    }
    
    let database: Database
    
    var images: [CapImage] {
        guard let cap else {
            return []
        }
        return (0..<cap.imageCount).map {
            cap.image(version: $0)
        }
    }
    
    var title: String {
        guard let cap else {
            return "Images"
        }
        return "Cap \(cap.id)"
    }
    
    var body: some View {
        GeometryReader { geo in
            VStack {
                HStack {
                    Text(title).font(.title2).bold()
                    Spacer()
                    Button(action: { isPresented = false }) {
                        Image(systemSymbol: .xmarkCircleFill)
                            .foregroundColor(.gray)
                            .font(.system(size: 26))
                    }
                }
                let gridItem = GridItem(.flexible(), spacing: 10, alignment: .leading)
                ScrollView(.vertical) {
                    LazyVGrid(columns: [gridItem, gridItem, gridItem, gridItem]) {
                        ForEach(images) { item in
                            ZStack(alignment: .topLeading) {
                                CachedCapImage(
                                    item,
                                    check: { database.images.cachedImage(item) },
                                    fetch: { await database.images.image(item) },
                                    content: { $0.resizable() },
                                    placeholder: { ProgressView() })
                                .frame(width: imageSize,
                                       height: imageSize)
                                .clipShape(Circle())
                                .onLongPressGesture { selectedCap = item }
                                if item.version == cap?.mainImage {
                                    Image(systemSymbol: .checkmarkCircleFill)
                                        .foregroundColor(.green)
                                        .background(Color.white)
                                        .clipShape(Circle())
                                }
                            }

                        }
                    }
                }
            }
            .padding(.horizontal)
        }
        .actionSheet(item: $selectedCap) { item in
            ActionSheet(title: Text("Image \(item.version)"), buttons: [
                .default(Text("Set as main image")) { setMainImage(item) },
                .destructive(Text("Delete image")) { delete(image: item) },
                .cancel()
            ])
        }
    }

    private func delete(image: CapImage) {
        Task {
            guard let cap = await database.setMainImage(image.version, for: image.cap) else {
                return
            }
            DispatchQueue.main.async {
                self.cap = cap
            }
        }
        selectedCap = nil
    }

    private func setMainImage(_ image: CapImage) {
        Task {
            guard let cap = await database.setMainImage(image.version, for: image.cap) else {
                return
            }
            DispatchQueue.main.async {
                self.cap = cap
                #warning("Update all images and rows with the cap")
            }
        }
        self.selectedCap = nil
    }
}

struct CapImagesView_Previews: PreviewProvider {
    static var previews: some View {
        CapImagesView(cap: .constant(.init(id: 123, name: "Some")), database: .mock, isPresented: .constant(true))
    }
}