import SwiftUI

/// "Registrieren" screen. On success this does NOT sign the user in — the
/// backend requires the emailed confirmation link to be opened first, exactly
/// like the web signup flow (see `AppState.signup(name:email:password:)`) —
/// so success routes to `VerificationPendingView` via `onSignupSucceeded`,
/// not into `AppState`.
struct SignupView: View {
    @EnvironmentObject private var appState: AppState

    var onSignupSucceeded: (_ email: String) -> Void
    var onSwitchToLogin: () -> Void

    @State private var name = ""
    @State private var email = ""
    @State private var password = ""
    @State private var isSubmitting = false

    private var canSubmit: Bool {
        !email.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty
            && !password.isEmpty
            && !isSubmitting
    }

    var body: some View {
        ScrollView {
            VStack(spacing: ZenithSpacing.md) {
                Text("Konto erstellen")
                    .zenithHeadlineLgStyle()
                    .padding(.top, ZenithSpacing.lg)

                VStack(spacing: ZenithSpacing.sm) {
                    ZenithTextField(
                        label: "Name (optional)",
                        text: $name,
                        textContentType: .name,
                        autocapitalization: .words
                    )

                    ZenithTextField(
                        label: "E-Mail",
                        text: $email,
                        keyboardType: .emailAddress,
                        textContentType: .username,
                        autocapitalization: .never,
                        autocorrectionDisabled: true
                    )

                    ZenithTextField(
                        label: "Passwort",
                        text: $password,
                        isSecure: true,
                        textContentType: .newPassword
                    )
                }

                if let error = appState.lastError {
                    Text(error)
                        .zenithBodySmStyle(color: .zenithError)
                        .multilineTextAlignment(.center)
                }

                Button {
                    Task { await submit() }
                } label: {
                    Group {
                        if isSubmitting {
                            ProgressView()
                                .tint(.white)
                        } else {
                            Text("Konto erstellen")
                        }
                    }
                    .frame(maxWidth: .infinity)
                }
                .buttonStyle(.zenithPrimary)
                .disabled(!canSubmit)

                Button("Schon ein Konto? Anmelden") {
                    appState.lastError = nil
                    onSwitchToLogin()
                }
                .buttonStyle(.zenithPlain)
                .padding(.top, ZenithSpacing.xs)
            }
            .padding(.horizontal, ZenithSpacing.md)
            .padding(.bottom, ZenithSpacing.lg)
        }
        .scrollDismissesKeyboard(.interactively)
        .background(Color.zenithBg)
    }

    private func submit() async {
        guard canSubmit else { return }
        isSubmitting = true
        defer { isSubmitting = false }

        let trimmedEmail = email.trimmingCharacters(in: .whitespacesAndNewlines)
        let trimmedName = name.trimmingCharacters(in: .whitespacesAndNewlines)

        let succeeded = await appState.signup(
            name: trimmedName.isEmpty ? nil : trimmedName,
            email: trimmedEmail,
            password: password
        )
        if succeeded {
            onSignupSucceeded(trimmedEmail)
        }
    }
}