Creating a new document from a already existing document inside of sharepoint

sample.cs

public static string SaveDocument(string docName, Guid libraryID, string templatePath)
        {
            string newDocPath = string.Empty;
            byte[] template = null;
            string fileExtension = string.Empty;
            string fileName = string.Empty;
            string templateName = string.Empty;
            string recordsSiteUrl = ConfigurationHelper.GetInstance().ConfigItems[GlobalConstants.SITE_RECORDS_URL];
            string templateFileExtension = templatePath.Substring(templatePath.LastIndexOf('.') + 1);
            string libraryName = SPContext.Current.Web.CurrentUser.LoginName;

            libraryName = libraryName.Substring(libraryName.LastIndexOf('\\') + 1);
            fileExtension = GetFileExtension(templatePath);
            fileName = string.Format("{0}.{1}", docName.TrimStart(), fileExtension);

            using (SPSite recordsSite = new SPSite(recordsSiteUrl))
            {
                using (SPWeb recordsSiteWeb = recordsSite.OpenWeb())
                {
                    SPFile file = recordsSiteWeb.GetFile(templatePath);
                    template = file.OpenBinary();
                    templateName = file.Name;
                }
            }

            byte[] documentData = default(byte[]);
            using (MemoryStream stream = new MemoryStream(template))
            {

                using (var document = WordprocessingDocument.Open(stream, true))
                {
                    // delete from custom properties first
                    if (document.CustomFilePropertiesPart != null && document.CustomFilePropertiesPart.Properties != null)
                    {
                        document.CustomFilePropertiesPart.Properties.RemoveAllChildren();
                        document.CustomFilePropertiesPart.Properties.Save();
                    }

                    // then from custom xml part "properties"
                    if (document.MainDocumentPart != null &&  document.MainDocumentPart.CustomXmlParts != null)
                    {
                        Func<CustomXmlPart, bool> predicate =
                            p =>
                            {
                                using (var reader = new StreamReader(p.GetStream()))
                                {
                                    var root = XElement.Load(reader);
                                    return (root.Name.LocalName == "properties");
                                }
                            };

                        var propertiesPart = document.MainDocumentPart.CustomXmlParts.FirstOrDefault(p => predicate(p));
                        if (propertiesPart != null)
                        {
                            document.MainDocumentPart.DeletePart(propertiesPart);
                        }
                    }
                }
                documentData = new byte[stream.Length];
                stream.Position = 0;
                stream.Read(documentData, 0, Convert.ToInt32(stream.Length));
            }

            SPContext.Current.Web.AllowUnsafeUpdates = true;
            TermSessionHelper _termSessionHelper = new TermSessionHelper(new TaxonomySession(SPContext.Current.Site));
            TaxonomyFieldValue kind = _termSessionHelper.GetTaxonomyFieldByTerm(GlobalConstants.METADATA_GROUP_NAME, GlobalConstants.METADATA_TERM_TIPOS, GlobalConstants.METADATA_TERM_TIPO_EN_ELABORACION);
            TaxonomyFieldValue status = _termSessionHelper.GetTaxonomyFieldByTerm(GlobalConstants.METADATA_GROUP_NAME, GlobalConstants.METADATA_TERM_STATUS, GlobalConstants.METADATA_TERM_STATUS_EN_ELABORACION);
            Hashtable properties = new Hashtable();
            properties.Add(CustomSiteColumns.FIELD_DOCSET_ID_RADICADO, fileName);
            properties.Add("ContentType", GlobalConstants.CTTN_ARCHIVE_POXTA);
            SPList targetList = SPContext.Current.Web.Lists[libraryID];
            SPFileCollection listFileCollection = targetList.RootFolder.Files;
            SPFile newFile = listFileCollection.Add(fileName, documentData, properties, false);
            SPListItem fileItem = newFile.Item;
            //newFile.Item[SPBuiltInFieldId.ContentType] = GlobalConstants.CTTN_ARCHIVE_POXTA;
            TaxonomyField kindField = fileItem.Fields.GetFieldByInternalName(CustomSiteColumns.FIELD_DOCSET_KIND) as TaxonomyField;
            TaxonomyField statusField = fileItem.Fields.GetFieldByInternalName(CustomSiteColumns.FIELD_DOCUMENT_STATUS) as TaxonomyField;

            kindField.SetFieldValue(fileItem, kind);
            statusField.SetFieldValue(fileItem, status);
            //fileItem[CustomSiteColumns.FIELD_DOCSET_ID_RADICADO] = fileName;
            fileItem.Log(string.Empty, DateTime.Now, Support.Enums.TraceableOperation.Creación, SPContext.Current.Web.CurrentUser.LoginName, string.Format("Documento creado a partir de la plantilla {0}", templateName));
            //newFile.ReleaseLock(newFile.LockId);
            fileItem.Update();

            SPListItem item = SPContext.Current.Web.GetListItem(SPContext.Current.Web.Url + "/" + newFile.Url);
            item[SPBuiltInFieldId.ContentTypeId] = targetList.ContentTypes[GlobalConstants.CTTN_ARCHIVE_POXTA].Id;
            item.Update();

            SPContext.Current.Web.AllowUnsafeUpdates = false;
            newDocPath = string.Format("{0}/{1}", SPContext.Current.Web.Url, newFile.Url);

            return newDocPath;
        }