PhoneToolMX/PhoneToolMX.Models/ViewModels/PhoneVM.cs

using PhoneToolMX.Data;
using System.ComponentModel.DataAnnotations;
using System.Net.NetworkInformation;

namespace PhoneToolMX.Models.ViewModels
{
    [CheckExtensions]
    public class PhoneVM : IViewModel
    {
        public int? Id { get; set; }
        
        [Header("MAC Address")]
        [Required]
        [RegularExpression("(?:[0-9a-fA-F]{2}[-:]?){6}", ErrorMessage = "Must be of the form XX:XX:XX:XX:XX:XX, XX-XX-XX-XX-XX-XX, or XXXXXXXXXXXX")]
        public string MacAddress { get; set; }
        
        [Header("Name", Primary = true)]
        [Required]
        public string FriendlyName { get; set; }
        
        [Required]
        public int? Model { get; set; }
        
        public ICollection<int?> Extensions { get; set; }
        
        [AllowNull]
        public int? PrimaryExtension { get; set; }
        
        public int MaxExtensions { get; set; }
        
        public IOwnedModel ToEntity(PTMXContext ctx)
        {
            var exts = Extensions?.Select(x => ctx.Extensions.FirstOrDefault(e => e.Id == x)).ToList();
            return new Phone
            {
                Id = Id,
                MacAddress = PhysicalAddress.Parse(MacAddress),
                FriendlyName = FriendlyName,
                Model = ctx.PhoneModels.FirstOrDefault(p => p.Id == Model)!,
                Extensions = exts,
                Owners = new List<User>(),
                PrimaryExtension = PrimaryExtension != null
                    ? exts?.FirstOrDefault(x => x.Id == PrimaryExtension)
                    : null,
            };
        }
        
        public IOwnedModel ToEntity(PTMXContext ctx, IOwnedModel current)
        {
            var ent = ToEntity(ctx);
            ent.Owners = current.Owners;
            return ent;
        }
        
        public IViewModel FromEntity(IOwnedModel entity)
        {
            if (entity is not Phone phoneEnt) throw new ArgumentException("entity must be of type Phone");
            return new PhoneVM
            {
                Id = entity.Id,
                MacAddress = phoneEnt.MacAddress.ToString(),
                FriendlyName = phoneEnt.FriendlyName,
                Model = phoneEnt.Model!.Id,
                Extensions = phoneEnt.Extensions?.Select(x => x.Id).ToList(),
                MaxExtensions = (int)phoneEnt.Model!.MaxExtensions,
                PrimaryExtension = phoneEnt.PrimaryExtension?.Id,
            };
        }

        // a bit of a hack, but we can just choose any extension that belongs to this phone
        public string NotifyOnChange() => Extensions.Count > 0
            ? (Extensions.First() + 1000).ToString()
            : null;
    }
}