Core_Be/Models/SubscriptionMember.cs

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

namespace Fitness_core_BE.Models
{
    /// <summary>
    /// Links a customer to a subscription. Every subscription has one IsPrimary row
    /// (mirroring CustomerSubscription.FKCustomerId); group plans add more rows up to
    /// the plan's MemberLimit. The primary row is never removed.
    /// </summary>
    public class SubscriptionMember
    {
        [Key]
        public Guid SubscriptionMemberId { get; set; }

        public Guid FKSubscriptionId { get; set; }
        [ForeignKey("FKSubscriptionId")]
        public virtual CustomerSubscription Subscription { get; set; }

        // Tenant-bucket entity: this FK holds a TenantCustomerLinkId (not the central
        // Customer.CusId directly) -- see Models/TenantCustomerLink.cs.
        public Guid FKCustomerId { get; set; }
        [ForeignKey("FKCustomerId")]
        public virtual TenantCustomerLink TenantCustomerLink { get; set; }

        public bool IsPrimary { get; set; }
        public DateTime JoinedAt { get; set; } = DateTime.UtcNow;
        public bool IsActive { get; set; } = true;

        /// <summary>
        /// Whether the member is currently *using* this plan. Unassigning clears this and
        /// leaves IsActive alone, so the member keeps their row in the gym's member list
        /// (and their access/device enrollment) and the same button can re-assign them.
        /// IsActive stays reserved for a real removal, which does hide the row.
        /// </summary>
        public bool IsPlanAssigned { get; set; } = true;
    }
}