import SwiftUI

struct RegistrationView: View {
    @Binding var root: RootFlow
    @Binding var selectedTab: MainTab
    let tokenStore: TokenStore
    @Binding var appState: AppState
    @State var name = ""
    @State var email = ""
    @State var phone = ""
    @State var acceptedTerms = false
    @State var isLoading = false
    @State var errorMessage: String?
    @Environment(\.dismiss) var dismiss
    @Environment(\.colorScheme) var colorScheme
    let navigate: (Route) -> Void

    private var isFormValid: Bool { !name.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty && !email.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty && !phone.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty && acceptedTerms }

    @ViewBuilder private var logoImage: some View {
#if os(Android)
        SwiftUI.Image("pedifoods", bundle: .module)
            .resizable()
#else
        SwiftUI.Image("pedifoods")
            .resizable()
#endif
    }

    var body: some View {
        ZStack {
            (colorScheme == .dark ? Color.black : AppColors.backgroundLight).ignoresSafeArea()

            ScrollView {
                VStack(spacing: 0) {
                    logoImage
                        .scaledToFit()
                        .frame(width: 120, height: 120)

                    Text("Crie sua conta")
                        .font(AppTypography.heading1)
                        .foregroundStyle(colorScheme == .dark ? Color.white : AppColors.textPrimary)

                    Text("Preencha os dados abaixo para começar.")
                        .font(AppTypography.body)
                        .foregroundStyle(colorScheme == .dark ? Color.white : AppColors.textPrimary)
                        .padding(.top, 8)
                        .padding(.bottom, 20)

                    VStack(spacing: 16) {
                        VStack(alignment: .leading, spacing: 16) {
                            LoginField(icon: "person", placeholder: "Ex: Maria Silva", text: $name)
                            LoginField(icon: "envelope", placeholder: "seu@email.com", text: $email)
                            LoginField(icon: "phone", placeholder: "(00) 00000-0000", text: $phone)
                                .onChange(of: phone) { _, newValue in
                                    let masked = formatPhoneBR(newValue)
                                    if masked != newValue {
                                        phone = masked
                                    }
                                }
                        }
                    }
                    .padding(.horizontal, 24)

                    HStack(alignment: .top, spacing: 12) {
                        Toggle("", isOn: $acceptedTerms)
                            .labelsHidden()
                            .tint(AppColors.primary)

                        Group {
                            Text("Ao se cadastrar, você concorda com nossos [Termos de Uso](app://terms) e [Política de Privacidade](app://policy)")
                                .foregroundStyle(colorScheme == .dark ? Color.white : AppColors.textPrimary)
                                .tint(AppColors.primary)
                                .environment(\.openURL, OpenURLAction { url in
                                    guard url.scheme == "app" else { return .handled }

                                    switch url.host {
                                    case "terms":
                                        navigate(.terms)
                                        return .handled
                                    case "policy":
                                        navigate(.policy)
                                        return .handled
                                    default:
                                        return .handled
                                    }
                                })
                        }
                        .multilineTextAlignment(.leading)
                    }
                    .padding(.horizontal, 24)
                    .padding(.top, 16)
                    .padding(.bottom, 16)

                    PrimaryButton(title: "Cadastrar e Receber Código", image: Image(systemName: "arrow.right")) {
                        registerAndRequestOtp()
                    }
                    .padding(.horizontal, 24)
                    .padding(.top, 6)
                    .disabled(!isFormValid || isLoading)
                    .opacity((!isFormValid || isLoading) ? 0.5 : 1.0)
                    .tint(AppColors.tertiary)

                    HStack(spacing: 6) {
                        Text("Já tem uma conta?")
                            .foregroundStyle(colorScheme == .dark ? Color.white.opacity(0.8) : AppColors.textPrimary)
                        NavigationLink("Entrar") {
                            LoginEmailView(root: $root, selectedTab: $selectedTab, tokenStore: tokenStore, appState: $appState, navigate: navigate)
                        }
                        .foregroundStyle(AppColors.primary)
                    }
                    .font(AppTypography.body)
                    .padding(.top, 16)

                    Spacer().frame(height: 12)
                }
            }
            .padding(.top, -40)
        }
    }

    private func registerAndRequestOtp() {
        let sanitizedName = name.trimmingCharacters(in: .whitespacesAndNewlines)
        let sanitizedEmail = email.trimmingCharacters(in: .whitespacesAndNewlines)
        let normalizedPhone = normalizePhoneNumberForAPI(phone)
        guard !sanitizedName.isEmpty, !sanitizedEmail.isEmpty, !normalizedPhone.isEmpty else { return }

        isLoading = true
        errorMessage = nil

        Task {
            do {
                let service = ApiService()
                let registration = try await service.registerCustomer(
                    name: sanitizedName,
                    email: sanitizedEmail,
                    phoneNumber: normalizedPhone
                )
                if registration.error {
                    await MainActor.run {
                        isLoading = false
                        let message = registration.message ?? "Nao foi possivel concluir o cadastro."
                        errorMessage = message
                        SnackbarCenter.shared.show(title: message, style: .error, icon: "xmark.octagon.fill", duration: 4.0)
                    }
                    return
                }

                let otp = try await service.requestOtp(email: sanitizedEmail, phoneNumber: normalizedPhone)
                await MainActor.run {
                    isLoading = false
                    if otp.error {
                        let message = otp.message ?? "Cadastro concluido, mas nao foi possivel enviar o codigo."
                        errorMessage = message
                        SnackbarCenter.shared.show(title: message, style: .warning, icon: "exclamationmark.triangle.fill", duration: 4.0)
                        return
                    }
                    SnackbarCenter.shared.show(title: "Cadastro concluido. Codigo enviado.", style: .success, icon: "checkmark.seal.fill", duration: 3.0)
                    appState.profile.email = sanitizedEmail
                    appState.profile.phone = phone
                    navigate(.otp(email: sanitizedEmail, phoneNumber: normalizedPhone))
                }
            } catch {
                await MainActor.run {
                    isLoading = false
                    let message = userFacingAuthErrorMessage(error)
                    errorMessage = message
                    SnackbarCenter.shared.show(title: message, style: .error, icon: "xmark.octagon.fill", duration: 4.0)
                }
            }
        }
    }
}