props/Props/Models/User/SearchOutline.cs

using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Linq;
using Props.Shop.Framework;

namespace Props.Models
{
    public class SearchOutline
    {
        public int Id { get; set; }
        [Required]
        public string ApplicationUserId { get; set; }

        public Filters Filters { get; set; }
        public int MaxResults { get; set; } = 100;

        [Required]
        public ShopToggler ShopStates { get; set; } = new ShopToggler();

        public sealed class ShopToggler : HashSet<string>
        {
            public int TotalShops { get; set; }
            public bool this[string name]
            {
                get
                {
                    return !this.Contains(name);
                }
                set
                {
                    if (value == false && TotalShops - Count <= 1) return;
                    if (value)
                    {
                        this.Remove(name);
                    }
                    else
                    {
                        this.Add(name);
                    }
                }
            }

            public ShopToggler Copy()
            {
                ShopToggler copy = new ShopToggler();
                copy.Union(this);
                return copy;
            }

            public bool IsShopToggleable(string shop)
            {
                return (!Contains(shop) && TotalShops - Count > 1) || Contains(shop);
            }
        }

        public override bool Equals(object obj)
        {
            if (obj == null || GetType() != obj.GetType())
            {
                return false;
            }
            SearchOutline other = (SearchOutline)obj;
            return
                Id == other.Id &&
                MaxResults == other.MaxResults &&
                Filters.Equals(other.Filters) &&
                ShopStates.Equals(other.ShopStates);
        }

        public override int GetHashCode()
        {
            return Id;
        }
    }
}