import Foundation
import ManaCore
import Observation

/// State-Maschine für ``ManaForgotPasswordView``. Wraps
/// `AuthClient.forgotPassword`.
///
/// **User-Enumeration-Schutz:** Server antwortet immer 200,
/// unabhängig davon ob die Email existiert. Die UI meldet daher
/// generisch ("Wenn dein Account existiert, ist eine Mail unterwegs").
@MainActor
@Observable
public final class ForgotPasswordViewModel {
    public enum Status: Equatable, Sendable {
        case idle
        case sending
        case sent
        case error(String)
    }

    public var email: String = ""
    public private(set) var status: Status = .idle

    private let auth: AuthClient
    private let resetUniversalLink: URL

    /// - Parameter resetUniversalLink: Universal-Link der App für den
    ///   Reset-Klick aus der Email. Z.B.
    ///   `URL(string: "https://cardecky.mana.how/auth/reset")!`.
    public init(auth: AuthClient, resetUniversalLink: URL) {
        self.auth = auth
        self.resetUniversalLink = resetUniversalLink
    }

    public var canSubmit: Bool {
        guard !email.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty else { return false }
        if case .sending = status { return false }
        return true
    }

    public var isSending: Bool {
        if case .sending = status { return true }
        return false
    }

    public func submit() async {
        let trimmed = email.trimmingCharacters(in: .whitespacesAndNewlines)
        guard !trimmed.isEmpty else { return }

        status = .sending
        do {
            try await auth.forgotPassword(email: trimmed, resetUniversalLink: resetUniversalLink)
            status = .sent
        } catch let error as AuthError {
            status = .error(error.errorDescription ?? "Senden fehlgeschlagen")
        } catch {
            status = .error(String(describing: error))
        }
    }
}