Disco.Services.JobExtensions.UpdateSubTypes C# (CSharp) Method

        public static void UpdateSubTypes(this Job j, DiscoDataContext Database, List<JobSubType> SubTypes, bool AddComponents, User TechUser)
        {
            if (SubTypes == null || SubTypes.Count == 0)
                throw new ArgumentException("The Job must contain at least one Sub Type");

            List<JobSubType> addedSubTypes = new List<JobSubType>();
            List<JobSubType> removedSubTypes = new List<JobSubType>();

            // Removed Sub Types
            foreach (var t in j.JobSubTypes.ToArray())
                if (!SubTypes.Contains(t))
                {
                    removedSubTypes.Add(t);
                    j.JobSubTypes.Remove(t);
                }
            // Added Sub Types
            foreach (var t in SubTypes)
                if (!j.JobSubTypes.Contains(t))
                {
                    addedSubTypes.Add(t);
                    j.JobSubTypes.Add(t);
                }

            // Write Log
            if (addedSubTypes.Count > 0 || removedSubTypes.Count > 0)
            {
                StringBuilder logBuilder = new StringBuilder();
                logBuilder.AppendLine("# Updated Job Sub Types");
                if (removedSubTypes.Count > 0)
                {
                    logBuilder.AppendLine().AppendLine("Removed:");
                    foreach (var t in removedSubTypes)
                        logBuilder.Append("- **").Append(t.ToString()).AppendLine("**");
                }
                if (addedSubTypes.Count > 0)
                {
                    logBuilder.AppendLine().AppendLine("Added:");
                    foreach (var t in addedSubTypes)
                        logBuilder.Append("- **").Append(t.ToString()).AppendLine("**");
                }
                Database.JobLogs.Add(new JobLog()
                {
                    JobId = j.Id,
                    TechUserId = TechUser.UserId,
                    Timestamp = DateTime.Now,
                    Comments = logBuilder.ToString()
                });
            }

            // Add Components
            if (AddComponents && addedSubTypes.Count > 0 && j.DeviceSerialNumber != null)
            {
                var components = Database.DeviceComponents.Include("JobSubTypes").Where(c => !c.DeviceModelId.HasValue || c.DeviceModelId == j.Device.DeviceModelId);
                var addedComponents = new List<DeviceComponent>();
                foreach (var c in components)
                {
                    foreach (var st in c.JobSubTypes)
                    {
                        foreach (var jst in addedSubTypes)
                        {
                            if (st.JobTypeId == jst.JobTypeId && st.Id == jst.Id)
                            {
                                addedComponents.Add(c);
                                break;
                            }
                        }
                        if (addedComponents.Contains(c))
                            break;
                    }
                }
                foreach (var c in addedComponents)
                {
                    if (!j.JobComponents.Any(jc => jc.Description.Equals(c.Description, StringComparison.OrdinalIgnoreCase)))
                    { // Job Component with matching Description doesn't exist.
                        Database.JobComponents.Add(new JobComponent()
                        {
                            Job = j,
                            TechUserId = TechUser.UserId,
                            Cost = c.Cost,
                            Description = c.Description
                        });
                    }
                }
            }
        }