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

namespace Fitness_core_BE.Models
{
    /// <summary>One scheduled, bookable occurrence of a Facility (e.g. "Pool, Tue 6-7pm").
    /// Capacity is enforced by counting non-cancelled Bookings against this row, not by a
    /// denormalized counter, to avoid drift between the two.</summary>
    public class FacilitySession
    {
        [Key]
        public Guid FacilitySessionId { get; set; }

        public Guid FKFacilityId { get; set; }
        [ForeignKey(nameof(FKFacilityId))]
        public Facility Facility { get; set; }

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

        public DateTime StartTime { get; set; }
        public DateTime EndTime { get; set; }

        /// <summary>Overrides Facility.DefaultCapacity when set; null = use the facility default.
        /// Ignored when IsUnlimitedCapacity is true.</summary>
        public int? Capacity { get; set; }

        /// <summary>Copied from FacilityClass.IsUnlimitedCapacity at generation time (or set
        /// directly for a manually-created session) -- see that flag's doc comment for why this
        /// isn't just a Capacity sentinel value.</summary>
        public bool IsUnlimitedCapacity { get; set; } = false;

        public bool IsCancelled { get; set; } = false;
        public DateTime CreatedAt { get; set; } = DateTime.UtcNow;

        /// <summary>Null for a manually-created session (the pre-Classes path, unaffected).
        /// Set for a class occurrence -- which FacilityClass generated or explicitly added it.</summary>
        public Guid? FKFacilityClassId { get; set; }
        [ForeignKey(nameof(FKFacilityClassId))]
        public FacilityClass? FacilityClass { get; set; }

        /// <summary>Set together by FacilityService's "mark not held" cascade (which replaces
        /// the old bare-IsCancelled CancelFacilitySession) -- null means this occurrence is
        /// either still scheduled or was never a class occurrence at all.</summary>
        public string? NotHeldReason { get; set; }
        public DateTime? NotHeldAt { get; set; }

        public virtual ICollection<Booking> Bookings { get; set; }
    }
}