import Foundation

public struct ExpiringUserId: LosslessStringConvertible, Codable, Sendable {

    static let expirationInterval: TimeInterval = 60.0 * 60.0
    let id: UUID
    let expiration: Date

    init (user: any ManagedUser) {
        id = user.id
        expiration = Date (timeIntervalSinceNow: ExpiringUserId.expirationInterval)
    }

    public init? (_ description: String) {
        if let data = Data (base64Encoded: description) {
            do {
                self = try JSONDecoder().decode (ExpiringUserId.self, from: data)
                if expiration.timeIntervalSinceNow < 0.0 {
                    return nil
                }
            } catch {
                return nil
            }
        } else {
            return nil
        }
    }

    public var description: String {
        do {
            return try JSONEncoder().encode (self).base64EncodedString()
        } catch {
            return error.localizedDescription
        }
    }
}