import SwiftUI

struct AddContactOrChannelScreen: View {
    @Environment(\.router) var router
    @EnvironmentObject var clientsStore: ClientsStore
    @EnvironmentObject var rostersStore: RostersStore

    enum Field {
        case account
        case contact
    }

    @FocusState private var focus: Field?

    @State private var ownerCredentials: Credentials?
    @State private var contactJID: String = ""

    var body: some View {
        ZStack {
            // Background color
            Color.Material.Background.light
                .ignoresSafeArea()

            // Content
            VStack(spacing: 0) {
                // Header
                SharedNavigationBar(
                    leftButton: .init(
                        image: Image(systemName: "xmark"),
                        action: {
                            router.dismissScreen()
                        }
                    ),
                    centerText: .init(text: L10n.Contacts.Add.title),
                    rightButton: .init(
                        image: Image(systemName: "plus.viewfinder"),
                        action: {
                            print("Scan QR-code")
                        }
                    )
                )

                // Content
                VStack(spacing: 16) {
                    // Explanation text
                    Text(L10n.Contacts.Add.explanation)
                        .font(.body3)
                        .foregroundColor(.Material.Shape.separator)
                        .multilineTextAlignment(.center)
                        .padding(.top, 16)

                    // Account selector
                    HStack(spacing: 0) {
                        Text("Use account:")
                            .font(.body2)
                            .foregroundColor(.Material.Text.main)
                            .frame(alignment: .leading)
                        Spacer()
                    }
                    UniversalInputCollection.DropDownMenu(
                        prompt: "Use account",
                        elements: activeClientsCredentials,
                        selected: $ownerCredentials,
                        focus: $focus,
                        fieldType: .account
                    )

                    // Contact text input
                    HStack(spacing: 0) {
                        Text("Contact JID:")
                            .font(.body2)
                            .foregroundColor(.Material.Text.main)
                            .frame(alignment: .leading)
                        Spacer()
                    }
                    UniversalInputCollection.TextField(
                        prompt: "Contact or channel JID",
                        text: $contactJID,
                        focus: $focus,
                        fieldType: .contact,
                        contentType: .emailAddress,
                        keyboardType: .emailAddress,
                        submitLabel: .done,
                        action: {
                            focus = .account
                        }
                    )

                    // Save button
                    Button {
                        Task {
                            await save()
                        }
                    } label: {
                        Text(L10n.Global.save)
                    }
                    .buttonStyle(PrimaryButtonStyle())
                    .disabled(!inputValid)
                    .padding(.top)
                    Spacer()
                }
                .padding(.horizontal, 32)
            }
        }
        .onAppear {
            if let exists = activeClientsCredentials.first {
                ownerCredentials = exists
            }
        }
    }

    private var activeClientsCredentials: [Credentials] {
        clientsStore.clients
            .filter { $0.state != .disabled }
            .map { $0.credentials }
    }

    private var inputValid: Bool {
        ownerCredentials != nil && !contactJID.isEmpty && UniversalInputCollection.Validators.isEmail(contactJID)
    }

    private func save() async {
        guard let ownerCredentials = ownerCredentials else { return }

        router.showModal {
            LoadingScreen()
        }

        defer {
            router.dismissModal()
        }

        let result = await rostersStore.addRoster(ownerCredentials, contactJID: contactJID, name: nil, groups: [])

        switch result {
        case .success:
            router.dismissScreen()

        case .connectionError:
            showErrorAlert(subtitle: L10n.Contacts.Add.connectionError)

        case .serverError:
            showErrorAlert(subtitle: L10n.Contacts.Add.serverError)
        }
    }

    private func showErrorAlert(subtitle: String) {
        router.showAlert(
            .alert,
            title: L10n.Global.Error.title,
            subtitle: subtitle
        ) {
            Button(L10n.Global.ok, role: .cancel) {}
        }
    }
}