Core_Be/Models/GoodsReceivedNote.cs

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

namespace Fitness_core_BE.Models
{
    /// <summary>Stock coming in, optionally from a Supplier -- some GRNs don't have one (e.g.
    /// self-produced stock, or the supplier just isn't on file). Creating one increments each
    /// line's Product.QuantityOnHand and overwrites Product.CostPrice with that line's UnitCost
    /// (a simple latest-cost approach, not a weighted average).</summary>
    public class GoodsReceivedNote
    {
        [Key]
        public Guid GrnId { get; set; }

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

        public Guid? FKSupplierId { get; set; }
        [ForeignKey(nameof(FKSupplierId))]
        public Supplier? Supplier { get; set; }

        [MaxLength(32)]
        public string GrnNumber { get; set; } = string.Empty;

        public DateTime ReceivedAt { get; set; } = DateTime.UtcNow;

        [MaxLength(300)]
        public string? Notes { get; set; }

        public decimal TotalAmount { get; set; } = 0m;

        public DateTime CreatedAt { get; set; } = DateTime.UtcNow;

        public virtual ICollection<GoodsReceivedNoteItem> Items { get; set; } = new List<GoodsReceivedNoteItem>();
    }

    public class GoodsReceivedNoteItem
    {
        [Key]
        public Guid GrnItemId { get; set; }

        public Guid FKGrnId { get; set; }
        [ForeignKey(nameof(FKGrnId))]
        public GoodsReceivedNote? Grn { get; set; }

        public Guid FKProductId { get; set; }
        [ForeignKey(nameof(FKProductId))]
        public Product? Product { get; set; }

        public decimal Quantity { get; set; }
        public decimal UnitCost { get; set; }
        public decimal LineTotal { get; set; }
    }
}