import SwiftUI
import PushAPI
import Push

extension String {

    var nonEmpty: String? {
        isEmpty ? nil : self
    }
}

struct DeviceList: View {

    let pushToken: PushToken

    let authToken: AuthenticationToken

    let api: PushClient
    
    @Binding
    var isPresented: Bool
    
    @State
    var devices: [DeviceRegistration]
    
    var body: some View {
        NavigationView {
            VStack(spacing: 0) {
                List(devices) { device in
                    HStack {
                        Text(device.name.nonEmpty ?? "Device")
                            .font(.headline)
                        Spacer()
                        VStack(alignment: .leading) {
                            Text(device.application)
                                .font(.footnote)
                                .fontWeight(.bold)
                                .padding(.bottom, 2)
                            Text(device.pushToken.prefix(5).hexEncoded + "...")
                                .font(.caption)
                        }
                    }
                }.refreshable {
                    await updateList()
                }
            }.toolbar {
                ToolbarItem(placement: .navigationBarTrailing) {
                    Button(action: dismiss) {
                        Text("Cancel")
                    }
                }
            }.navigationBarTitle("device-list-title")
        }.onAppear() {
            Task {
                await updateList()
            }
        }
    }
    
    private func updateList() async {
        let devices = await api.getDeviceList(pushToken: pushToken, authToken: authToken)
        print("Updated device list: \(devices?.count ?? -1)")
        DispatchQueue.main.async {
            self.devices = devices ?? []
        }
    }
    
    private func dismiss() {
        isPresented = false
    }
}

struct DeviceList_Previews: PreviewProvider {
    static var previews: some View {
        DeviceList(pushToken: Data(repeating: 42, count: 32),
                   authToken: Data(repeating: 42, count: 16),
                   api: .init(server: URL(string: "https://christophhagen.de/push")!, application: "some"),
                   isPresented: .constant(true),
                   devices: [DeviceRegistration(
                    pushToken: Data([1,2,3,4,5]),
                    application: "CC Messenger",
                    name: "Some")])
    }
}

extension DeviceRegistration: Identifiable {
    
    public var id: String {
        pushToken.prefix(5).hexEncoded
    }
}