import Combine
import Martin
import SwiftUI

struct LoginScreen: View {
    @EnvironmentObject var navigation: NavigationStore
    @EnvironmentObject var clientsStore: ClientsStore

    enum Field {
        case userJid
        case password
    }

    @FocusState private var focus: Field?

    @State private var isLoading = false
    @State private var isError = false

    #if DEBUG
        @State private var jidStr: String = "nartest1@conversations.im"
        @State private var pass: String = "nartest12345"
    // @State private var jidStr: String = "test1@test.anal.company"
    // @State private var pass: String = "12345"
    #else
        @State private var jidStr: String = ""
        @State private var pass: String = ""
    #endif

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

            // content
            VStack(spacing: 32) {
                // icon
                Image.logo
                    .resizable()
                    .aspectRatio(contentMode: .fit)
                    .frame(width: 120, height: 120)

                // texts
                VStack(spacing: 10) {
                    Text(L10n.Login.title)
                        .font(.head1l)
                        .foregroundColor(.Material.Text.main)
                        .fixedSize(horizontal: true, vertical: false)
                    Text(L10n.Login.subtitle)
                        .font(.body2)
                        .foregroundColor(.Material.Text.sub)
                        .multilineTextAlignment(.center)
                        .fixedSize(horizontal: false, vertical: true)
                }

                VStack(spacing: 16) {
                    UniversalInputCollection.TextField(
                        prompt: L10n.Login.Hint.jid,
                        text: $jidStr,
                        focus: $focus,
                        fieldType: .userJid,
                        contentType: .emailAddress,
                        keyboardType: .emailAddress,
                        submitLabel: .next,
                        action: {
                            focus = .password
                        }
                    )
                    UniversalInputCollection.SecureField(
                        prompt: L10n.Login.Hint.password,
                        text: $pass,
                        focus: $focus,
                        fieldType: .password,
                        submitLabel: .go,
                        action: {
                            focus = nil
                        }
                    )

                    Button {
                        Task {
                            await tryLogin()
                        }
                    } label: {
                        Text(L10n.Login.btn)
                    }
                    .buttonStyle(PrimaryButtonStyle())
                    .disabled(!loginInputValid)

                    Button {
                        withAnimation {
                            navigation.flow = .entering(.welcome)
                        }
                    } label: {
                        Text("\(Image(systemName: "chevron.left")) \(L10n.Global.back)")
                            .foregroundColor(.Material.Elements.active)
                            .font(.body2)
                    }
                }
            }
            .padding(.horizontal, 32)
        }
        .if(isLoading) {
            $0.loadingOverlay()
        }
        .alert(isPresented: $isError) {
            Alert(
                title: Text(L10n.Global.Error.title),
                message: Text(L10n.Login.error),
                dismissButton: .default(Text(L10n.Global.ok))
            )
        }
    }

    private var loginInputValid: Bool {
        !jidStr.isEmpty && !pass.isEmpty && UniversalInputCollection.Validators.isEmail(jidStr)
    }

    private func tryLogin() async {
        isLoading = true

        // login with fake timeout
        async let sleep: Void? = try? await Task.sleep(nanoseconds: 1 * NSEC_PER_SEC)
        async let request = await Client.tryLogin(with: .init(bareJid: jidStr, pass: pass, isActive: true))
        let result = await(request, sleep).0

        switch result {
        case .success(let client):
            clientsStore.addNewClient(client)
            isLoading = false
            isError = false
            if navigation.flow == .entering(.login) {
                navigation.flow = .main(.contacts)
            }

        case .failure:
            isLoading = false
            isError = true
        }
    }
}