import SwiftUI

struct AuthView: View {
    @EnvironmentObject private var model: AppModel
    @State private var registering = false
    @State private var login = ""
    @State private var password = ""
    @State private var form = RegistrationForm()

    var body: some View {
        ScrollView {
            VStack(spacing: 14) {
                HStack {
                    Image("Logo")
                        .resizable()
                        .scaledToFit()
                        .frame(height: 58)
                    Spacer()
                    LanguageButton()
                }
                .padding(.bottom, 18)

                if registering { registrationForm }
                else { loginForm }
            }
            .padding(22)
        }
        .scrollDismissesKeyboard(.interactively)
        .background(KTheme.background)
    }

    private var loginForm: some View {
        VStack(alignment: .leading, spacing: 14) {
            Text(model.text("Zaloguj się", "Sign in")).font(.largeTitle.bold())
            Text(model.text("Twoja karta i punkty będą dostępne po zalogowaniu.", "Your card and points will be available after signing in."))
                .foregroundStyle(.secondary)
            KasztelanField(title: model.text("E-mail lub login", "Email or username"), text: $login, keyboard: .emailAddress, contentType: .username)
            KasztelanField(title: model.text("Hasło", "Password"), text: $password, secure: true, contentType: .password)
            Button(model.text("Zaloguj", "Sign in")) {
                guard !login.trimmingCharacters(in: .whitespaces).isEmpty, !password.isEmpty else {
                    model.errorMessage = model.text("Wpisz login i hasło.", "Enter your username and password.")
                    return
                }
                Task { await model.login(login: login, password: password) }
            }
            .buttonStyle(PrimaryButtonStyle())
            Link(destination: URL(string: "https://kasztelan.co.uk/forgot/")!) {
                HStack(spacing: 8) {
                    Image(systemName: "key.fill")
                    Text(model.text("Nie pamiętasz hasła?", "Forgot your password?"))
                }
                .font(.subheadline.bold())
                .foregroundStyle(KTheme.orange)
                .frame(maxWidth: .infinity, minHeight: 46)
            }
            .accessibilityLabel(model.text("Otwórz resetowanie hasła", "Open password reset"))
            Button(model.text("Załóż konto", "Create account")) { registering = true }
                .frame(maxWidth: .infinity, minHeight: 50)
                .background(KTheme.panel)
                .clipShape(RoundedRectangle(cornerRadius: 16))
        }
    }

    private var registrationForm: some View {
        VStack(alignment: .leading, spacing: 12) {
            Text(model.text("Załóż konto", "Create account")).font(.largeTitle.bold())
            KasztelanField(title: model.text("Imię", "First name"), text: $form.firstName, contentType: .givenName)
            KasztelanField(title: model.text("Nazwisko", "Last name"), text: $form.lastName, contentType: .familyName)
            KasztelanField(title: "E-mail", text: $form.email, keyboard: .emailAddress, contentType: .emailAddress)
            KasztelanField(title: model.text("Hasło", "Password"), text: $form.password, secure: true, contentType: .newPassword)
            KasztelanField(title: model.text("Telefon UK lub PL", "UK or Polish phone number"), text: $form.mobile, keyboard: .phonePad, contentType: .telephoneNumber)
            KasztelanField(title: model.text("Kod pocztowy UK", "UK postcode"), text: $form.postcode, contentType: .postalCode)
            KasztelanField(title: model.text("Data urodzenia: RRRR-MM-DD", "Date of birth: YYYY-MM-DD"), text: dateBinding, keyboard: .numberPad)
            KasztelanField(title: model.text("Numer karty (opcjonalnie)", "Card number (optional)"), text: $form.cardNumber, keyboard: .numberPad)
            Toggle(model.text("Akceptuję regulamin", "I accept the terms"), isOn: $form.acceptsTerms)
                .tint(KTheme.orange)
            HStack(spacing: 16) {
                Link(model.text("Regulamin", "Terms"), destination: URL(string: "https://kasztelan.co.uk/regulamin/")!)
                Link(model.text("Polityka prywatności", "Privacy policy"), destination: URL(string: "https://kasztelan.co.uk/privacy-policy/")!)
            }
            .font(.subheadline.bold())
            .foregroundStyle(KTheme.orange)
            Button(model.text("Utwórz konto", "Create account")) {
                Task { await model.register(form) }
            }
            .buttonStyle(PrimaryButtonStyle())
            Button(model.text("Mam już konto", "I already have an account")) { registering = false }
                .frame(maxWidth: .infinity, minHeight: 50)
                .background(KTheme.panel)
                .clipShape(RoundedRectangle(cornerRadius: 16))
        }
    }

    private var dateBinding: Binding<String> {
        Binding(
            get: { form.dob },
            set: { form.dob = Self.formatDateInput($0) }
        )
    }

    static func formatDateInput(_ input: String) -> String {
        let digits = String(input.filter(\.isNumber).prefix(8))
        var result = ""
        for (index, character) in digits.enumerated() {
            if index == 4 || index == 6 { result.append("-") }
            result.append(character)
        }
        return result
    }
}

struct LanguageButton: View {
    @EnvironmentObject private var model: AppModel

    var body: some View {
        Button {
            model.language = model.language == .pl ? .en : .pl
        } label: {
            Text(model.language == .pl ? "EN" : "PL")
                .font(.subheadline.bold())
                .foregroundStyle(KTheme.orange)
                .frame(width: 44, height: 44, alignment: .center)
                .background(KTheme.panel, in: Circle())
                .contentShape(Circle())
        }
        .buttonStyle(.plain)
        .accessibilityLabel(model.text("Zmień język na angielski", "Change language to Polish"))
    }
}