Core_Be/Models/ClientDeviceBilling.cs

using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;

namespace Fitness_core_BE.Models
{
    // Records what an admin actually agreed with a client for their fingerprint/access
    // device at assignment time (full purchase vs. rental + one-time setup fee).
    // DevicePricingConfig stays as the admin's reference/default rates; this is per-client.
    public class ClientDeviceBilling
    {
        [Key]
        public Guid Id { get; set; }

        public Guid FKClientId { get; set; }
        [ForeignKey("FKClientId")]
        public virtual Client Client { get; set; }

        public string Mode { get; set; } = "Rental"; // "FullPurchase" | "Rental"
        public decimal AgreedAmount { get; set; } // full price if FullPurchase, monthly fee if Rental
        public decimal SetupFee { get; set; } = 0;

        public bool IsActive { get; set; } = true;
        public DateTime AssignedAt { get; set; } = DateTime.UtcNow;
        public Guid? AssignedByAdminId { get; set; }
    }
}