Pilz/Pilz.Cryptography/UniquieID.cs

using Newtonsoft.Json;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Management;
using System.Security.Cryptography;
using System.Text;
using System.Threading.Tasks;

namespace Pilz.Cryptography
{
    public class UniquieID<TargetType> : IUniquieID
    {
        private static int currentSimpleID = 0;

        [JsonProperty(nameof(ID))]
        private string _iD;

        [JsonIgnore]
        public string ID
        {
            get
            {
                if (GenerateOnGet)
                    GenerateIfNull();
                return _iD;
            }
            internal set
                => _iD = value;
        }

        [JsonIgnore]
        public bool HasID { get => !string.IsNullOrEmpty(_iD); }
        [JsonIgnore]
        public bool SimpleMode { get; set; } = false;
        [JsonIgnore]
        public bool GenerateOnGet { get; set; } = false;

        public UniquieID() : this(false)
        {
        }

        public UniquieID(bool autoGenerate)
        {
            if (autoGenerate)
                GenerateIfNull();
        }

        public void Generate()
        {
            if (SimpleMode)
                ID = typeof(TargetType).ToString() + currentSimpleID++.ToString();
            else
                ID = GenerateUniquieID<TargetType>(string.Empty);
        }
        public void GenerateIfNull()
        {
            if (!HasID) Generate();
        }

        private static string GenerateUniquieID<T>(string var)
        {
            var sn = TryGetSerialNumberOfFirstHardDrive();
            var dateTime = DateTime.UtcNow.ToString("yyyyMMddHHmmssfffffff");
            var type = typeof(T).ToString();
            var together = sn + dateTime + type + var;

            var md5 = MD5.Create();
            var hash = BitConverter.ToString(md5.ComputeHash(Encoding.Default.GetBytes(together))).Replace("-", string.Empty);
            md5.Dispose();

            return hash;
        }

        private static string TryGetSerialNumberOfFirstHardDrive()
        {
            var searcher = new ManagementObjectSearcher("SELECT * FROM Win32_PhysicalMedia");
            var sn = string.Empty;

            foreach (ManagementObject wmi_HD in searcher.Get())
            {
                if (string.IsNullOrEmpty(sn) && wmi_HD["SerialNumber"] != null)
                    sn = wmi_HD["SerialNumber"].ToString().Trim();
            }

            return sn;
        }

        public override string ToString() => ID;

        public override bool Equals(object obj)
        {
            var res = false;
            var iD = obj as UniquieID<TargetType>;

            if (iD is object)
            {
                if (ReferenceEquals(res, iD))
                    res = true;
                else
                {
                    var leftHasID = iD.HasID;
                    var rightHasID = HasID;

                    if (!leftHasID && iD.GenerateOnGet)
                    {
                        iD.Generate();
                        leftHasID = iD.HasID;
                    }

                    if (!rightHasID && GenerateOnGet)
                    {
                        Generate();
                        rightHasID = HasID;
                    }

                    if (leftHasID && rightHasID)
                        res = _iD.Equals(iD._iD);
                }
            }

            return res;
        }

        public override int GetHashCode()
        {
            return -1430039477 + EqualityComparer<string>.Default.GetHashCode(_iD);
        }

        public static implicit operator string(UniquieID<TargetType> id)    => id.ID;
        public static implicit operator UniquieID<TargetType>(string id)    => new UniquieID<TargetType>() { ID = id };
        public static implicit operator UniquieID<TargetType>(int id)       => new UniquieID<TargetType>() { ID = Convert.ToString(id) };

        public static bool operator ==(UniquieID<TargetType> left, UniquieID<TargetType> right) => left.ID.Equals(right.ID);
        public static bool operator !=(UniquieID<TargetType> left, UniquieID<TargetType> right) => !left.ID.Equals(right.ID);
    }
}