import SwiftUI

struct LoginView: View {
    @EnvironmentObject private var session: Session

    @State private var server: String = ""
    @State private var username = ""
    @State private var password = ""
    @State private var error: String?
    @State private var busy = false
    @State private var stayLoggedIn = Session.shared.stayLoggedIn
    @State private var manageShown = false

    var body: some View {
        NavigationStack {
            Form {
                Section("Server") {
                    TextField("http://192.168.1.10:8080", text: $server)
                        .textInputAutocapitalization(.never)
                        .autocorrectionDisabled()
                        .keyboardType(.URL)
                    // Mit mehreren Servern ist das hier der Weg zurueck, wenn man
                    // am falschen gelandet ist.
                    if session.profiles.count > 1 {
                        Picker("Ausgewählt", selection: profileSelection) {
                            ForEach(session.profiles) { profile in
                                Text(profile.name).tag(profile.id)
                            }
                        }
                    }
                }
                Section("Anmeldung") {
                    TextField("Benutzername", text: $username)
                        .textInputAutocapitalization(.never)
                        .autocorrectionDisabled()
                    SecureField("Passwort", text: $password)
                    Toggle("Angemeldet bleiben", isOn: $stayLoggedIn)
                }
                if !stayLoggedIn {
                    Section {
                        Text("Die Anmeldung gilt nur, solange die App geoeffnet ist.")
                            .font(.caption).foregroundStyle(.secondary)
                    }
                }
                if let error {
                    Section { Text(error).foregroundStyle(.red).font(.callout) }
                }
                Section {
                    Button(busy ? "Anmelden…" : "Anmelden") { Task { await login() } }
                        .disabled(busy || server.isEmpty || username.isEmpty)
                }
            }
            .navigationTitle(session.activeProfile?.name ?? "Vorrania")
            .toolbar {
                ToolbarItem(placement: .topBarTrailing) {
                    Button("Server verwalten", systemImage: "server.rack") { manageShown = true }
                }
            }
            .sheet(isPresented: $manageShown) { ServerListView() }
        }
        // Beim Start und bei jedem Serverwechsel die Felder auf das aktive
        // Profil setzen - sonst steht die Adresse des vorigen Servers da.
        .task(id: session.activeProfileID) { syncFromProfile() }
    }

    private var profileSelection: Binding<UUID> {
        Binding(
            get: { session.activeProfileID ?? session.profiles.first?.id ?? UUID() },
            set: { session.switchTo($0) }
        )
    }

    private func syncFromProfile() {
        server = session.activeProfile?.urlString ?? ""
        username = session.activeProfile?.username ?? ""
        password = ""
        error = nil
    }

    private func login() async {
        error = nil
        busy = true
        defer { busy = false }
        session.setServer(server)
        do {
            let token = try await APIClient.shared.login(username: username, password: password)
            session.store(token: token.accessToken, username: token.username,
                          isAdmin: token.role == "admin", persist: stayLoggedIn)
        } catch {
            self.error = error.localizedDescription
        }
    }
}