import SwiftUI

struct FileDetailView: View {

    @ObservedObject
    var file: FileResource

    @State
    private var newId: String

    init(file: FileResource) {
        self.file = file
        self.newId = file.id
    }

    private let allowedCharactersInPostId = CharacterSet.alphanumerics.union(CharacterSet(charactersIn: "-.")).inverted

    private var idExists: Bool {
        file.content.files.contains { $0.id == newId }
    }

    private var containsInvalidCharacters: Bool {
        newId.rangeOfCharacter(from: allowedCharactersInPostId) != nil
    }

    var body: some View {
        VStack(alignment: .leading) {
            Text("File Name")
                .font(.headline)
            HStack {
                TextField("", text: $newId)
                    .textFieldStyle(.roundedBorder)
                Button(action: setNewId) {
                    Text("Update")
                }
                .disabled(newId.isEmpty || containsInvalidCharacters || idExists)
            }
            Text("German Description")
                .font(.headline)
            TextField("", text: $file.germanDescription)
                .textFieldStyle(.roundedBorder)
            Text("English Description")
                .font(.headline)
            TextField("", text: $file.englishDescription)
                .textFieldStyle(.roundedBorder)
            if file.type.isImage {
                Text("Image size")
                    .font(.headline)
                Text("\(Int(file.size.width)) x \(Int(file.size.height)) (\(file.aspectRatio))")
                    .foregroundStyle(.secondary)
                #warning("Add button to show image versions")
            }
            Spacer()
        }.padding()
    }

    private func setNewId() {
        if !file.update(id: newId) {
            newId = file.id
        }
    }
}

extension FileDetailView: MainContentView {

    init(item: FileResource) {
        self.init(file: item)
    }

    static let itemDescription = "a file"
}


#Preview {
    FileDetailView(file: .mock)
}