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

namespace Fitness_core_BE.Models
{
    /// <summary>One reservation against a Facility — either a Scheduled-mode booking against a
    /// pre-created FacilitySession (many bookings share one capacity pool), or an AdHoc-mode
    /// booking that claims one of the Facility's NumberOfUnits directly for an arbitrary time
    /// window, no session needed. Either an existing member using a CustomerPlan session
    /// allowance (FKCustomerId set, IsGuest = false) or a non-member who booked online and pays
    /// per-session (IsGuest = true, no membership at all). The guest's identity proof for
    /// check-in is the OTP issued at booking time, verified at the door instead of a
    /// fingerprint/face profile a non-member will never have.</summary>
    public class Booking
    {
        [Key]
        public Guid BookingId { get; set; }

        /// <summary>Null for an AdHoc booking (no pre-created session).</summary>
        public Guid? FKFacilitySessionId { get; set; }
        [ForeignKey(nameof(FKFacilitySessionId))]
        public FacilitySession? FacilitySession { get; set; }

        /// <summary>Always set, for both modes -- copied from FacilitySession.FKFacilityId at
        /// creation (Scheduled) or the booked facility directly (AdHoc). Every place that needs
        /// "which facility / what time window" reads these (and StartTime/EndTime below)
        /// uniformly instead of reaching through FacilitySession, which doesn't exist for AdHoc
        /// bookings.</summary>
        public Guid FKFacilityId { get; set; }
        [ForeignKey(nameof(FKFacilityId))]
        public Facility Facility { get; set; }

        /// <summary>Copied from FacilitySession.StartTime (Scheduled) or the requested start
        /// (AdHoc) at creation; updated in place by Reschedule.</summary>
        public DateTime StartTime { get; set; }
        /// <summary>Same pattern as StartTime.</summary>
        public DateTime EndTime { get; set; }

        /// <summary>Informational headcount for an AdHoc booking (e.g. "how many will come") --
        /// never enforced as a capacity mechanic; each AdHoc booking claims one whole unit
        /// regardless of party size. Null for Scheduled bookings.</summary>
        public int? PartySize { get; set; }

        /// <summary>The RFID tag handed to the party at check-in, picked from the club's managed
        /// tag inventory (RfidTag) -- never free-typed. Released back to "Available" by the
        /// Complete action or the no-show/completion sweep, whichever runs first (both use the
        /// same idempotent guarded update, so a race between them is a harmless no-op).</summary>
        public Guid? FKRfidTagId { get; set; }
        [ForeignKey(nameof(FKRfidTagId))]
        public RfidTag? RfidTag { get; set; }
        public DateTime? RfidAssignedAt { get; set; }
        public DateTime? RfidReturnedAt { get; set; }

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

        public bool IsGuest { get; set; } = false;

        // Member path. Tenant-bucket entity: holds a TenantCustomerLinkId, not the central
        // Customer.CusId directly -- see Models/TenantCustomerLink.cs.
        public Guid? FKCustomerId { get; set; }
        [ForeignKey(nameof(FKCustomerId))]
        public TenantCustomerLink? TenantCustomerLink { get; set; }

        // A member's booking draws down this specific subscription's per-cycle session
        // allowance; null for guest bookings (they have no subscription at all).
        public Guid? FKCustomerSubscriptionId { get; set; }
        [ForeignKey(nameof(FKCustomerSubscriptionId))]
        public CustomerSubscription? CustomerSubscription { get; set; }

        // Guest path -- no member record exists at all, so identity is captured inline.
        [MaxLength(200)]
        public string? GuestName { get; set; }
        [MaxLength(32)]
        public string? GuestPhone { get; set; }

        /// <summary>Issued when the booking is created; the guest presents this at the door
        /// instead of a fingerprint/face profile. Members don't need one -- their existing
        /// access credential covers check-in.</summary>
        [MaxLength(10)]
        public string? OtpCode { get; set; }
        public DateTime? OtpVerifiedAt { get; set; }

        /// <summary>"Paid" | "Unpaid" | "NotRequired" (member using a plan's included session).</summary>
        public string PaymentStatus { get; set; } = "NotRequired";
        public decimal AmountCharged { get; set; } = 0m;

        // Set only once payment is confirmed for a pay-per-session guest booking, or
        // immediately for a member session (no payment gate) -- see PaymentStatus.
        public Guid? FKPaymentTransactionId { get; set; }
        [ForeignKey(nameof(FKPaymentTransactionId))]
        public PaymentTransaction? PaymentTransaction { get; set; }

        /// <summary>"Confirmed" | "CheckedIn" | "Cancelled" | "NoShow" | "Completed". NoShow and
        /// Completed are reached either by explicit staff action (MarkNoShow/Complete) or lazily,
        /// swept by BookingService.SweepOverdueBookingsAsync at the top of every check-in call
        /// (not a background job -- overdue bookings are reconciled the next time any check-in
        /// happens for this client, across every facility).</summary>
        public string Status { get; set; } = "Confirmed";

        public DateTime BookedAt { get; set; } = DateTime.UtcNow;
        public DateTime? CheckedInAt { get; set; }
        /// <summary>Set when the booking reaches Completed, whether via the manual Complete
        /// action or the lazy overdue-sweep -- the actual moment it was reconciled, not
        /// necessarily EndTime.</summary>
        public DateTime? CheckedOutAt { get; set; }
        public DateTime CreatedAt { get; set; } = DateTime.UtcNow;
    }
}