import Foundation
import ManaCore
import Observation

/// State-Maschine für ``ManaResetPasswordView``. Wraps
/// `AuthClient.resetPassword`. Wird aus dem Universal-Link-Handler
/// der App aufgerufen mit dem Token aus dem `?token=…`-Query-Param.
@MainActor
@Observable
public final class ResetPasswordViewModel {
    public enum Status: Equatable, Sendable {
        case idle
        case submitting
        case done
        case error(String)
    }

    public let token: String
    public var newPassword: String = ""
    public var confirmPassword: String = ""
    public private(set) var status: Status = .idle

    private let auth: AuthClient

    public init(token: String, auth: AuthClient) {
        self.token = token
        self.auth = auth
    }

    public var canSubmit: Bool {
        guard !newPassword.isEmpty, !confirmPassword.isEmpty else { return false }
        guard newPassword == confirmPassword else { return false }
        guard newPassword.count >= 8 else { return false }
        if case .submitting = status { return false }
        return true
    }

    public var isSubmitting: Bool {
        if case .submitting = status { return true }
        return false
    }

    /// UI-Hint je nach Eingabe-Status. Nil = alles ok oder noch leer.
    public var validationHint: String? {
        if !newPassword.isEmpty, newPassword.count < 8 {
            return "Passwort muss mindestens 8 Zeichen lang sein."
        }
        if !confirmPassword.isEmpty, newPassword != confirmPassword {
            return "Die Passwörter stimmen nicht überein."
        }
        return nil
    }

    public func submit() async {
        guard canSubmit else { return }

        status = .submitting
        do {
            try await auth.resetPassword(token: token, newPassword: newPassword)
            newPassword = ""
            confirmPassword = ""
            status = .done
        } catch let error as AuthError {
            status = .error(error.errorDescription ?? "Reset fehlgeschlagen")
        } catch {
            status = .error(String(describing: error))
        }
    }
}