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

namespace Fitness_core_BE.Models
{
    public class CustomerSubscription
    {
        [Key]
        public Guid SubscriptionId { get; set; }

        public Guid FKCustomerPlanId { get; set; }
        [ForeignKey("FKCustomerPlanId")]
        public virtual CustomerPlan CustomerPlan { 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 DateTime OnboardDate { get; set; } = DateTime.UtcNow;

        // Set once, at creation, and never touched again -- see RenewalDate for the field that
        // actually reflects the subscription's current cycle end / renewal-eligibility date.
        public DateTime? ExpiryDate { get; set; }

        // Advances on every approved renewal cycle; every "is this due/expiring/current" query,
        // filter, sort or status display should read this instead of ExpiryDate.
        public DateTime? RenewalDate { get; set; }

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

        // Set together at assignment time; "was a discount given" is DiscountValue.HasValue.
        public string? DiscountType { get; set; }   // "Percentage" | "Flat"
        public decimal? DiscountValue { get; set; }

        /// <summary>Member has consented to auto-deduct renewals from FKAutoChargeCardId.</summary>
        public bool AutoChargeEnabled { get; set; } = false;
        public Guid? FKAutoChargeCardId { get; set; }
        [ForeignKey("FKAutoChargeCardId")]
        public virtual CustomerCards? AutoChargeCard { get; set; }

        // Session-count tracking for CustomerPlan.SessionsPerCycle plans (null for unlimited
        // gym-access plans). SessionsUsedThisCycle resets on renewal; SessionsCarriedOver holds
        // unused sessions brought forward when CustomerPlan.SessionRolloverPolicy == "GracePeriod"
        // and is cleared once RolloverGraceDays elapses. Booking creation increments
        // SessionsUsedThisCycle instead of duplicating this counter per facility.
        public int SessionsUsedThisCycle { get; set; } = 0;
        public int SessionsCarriedOver { get; set; } = 0;

        // Set at renewal approval time when CustomerPlan.SessionRolloverPolicy == "GracePeriod"
        // (now + RolloverGraceDays); null when there's nothing carried over. Booking creation
        // treats SessionsCarriedOver as spent/expired once this passes, even though the column
        // itself isn't zeroed until the next renewal -- see BookingService.CreateMemberBooking.
        public DateTime? SessionsCarriedOverExpiresAt { get; set; }

        public virtual ICollection<SubscriptionMember> SubscriptionMembers { get; set; }
        public virtual ICollection<SubscriptionInstallment> SubscriptionInstallments { get; set; }
    }
}