using System.Linq.Expressions;
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Metadata;
namespace Project.Domain.Context
{
 public class EntityBuilder<T>(DbContext context, string alias)
 where T : class
 {
 private readonly string _tableName = context.Set<T>().EntityType.GetTableName() ?? context.Set<T>().EntityType.GetViewName() ?? string.Empty;
 private readonly IEntityType _entityType = context.Set<T>().EntityType;
 public string Table()
 {
 return _tableName + " as " + alias;
 }
 
 public string? Column<TProperty>(Expression<Func<T, TProperty>> property)
 {
 var name = property.Body.ToString().Split(".")[1];
 if (string.IsNullOrEmpty(_tableName) || string.IsNullOrEmpty(name))
 {
 return null;
 }
 return alias + "." + _entityType.FindProperty(name)?.GetColumnName();
 }
 public string? ColumnRaw<TProperty>(Expression<Func<T, TProperty>> property)
 {
 var name = property.Body.ToString().Split(".")[1];
 if (string.IsNullOrEmpty(_tableName) || string.IsNullOrEmpty(name))
 {
 return null;
 }
 return $"[{alias}].[{_entityType.FindProperty(name)?.GetColumnName()}]";
 }
 }
}

var webUserTable = new EntityBuilder<WebUser>(DbContext, "user");
var contactTable = new EntityBuilder<Contact>(DbContext, "contact");
var companyTable = new EntityBuilder<Rasclient>(DbContext, "company");
var users = queryFactory.Query(webUserTable.Table());
users = users.Join(contactTable.Table(), c => c
 .WhereRaw("Convert(varchar, " + contactTable.ColumnRaw(x => x.Id) + ") = " + webUserTable.ColumnRaw(x => x.ContactId))
 .OrOn(contactTable.Column(x => x.Username), webUserTable.Column(x => x.ContactId)));
users = users.LeftJoin(companyTable.Table(), c => c
 .On(companyTable.Column(x => x.Clientid), contactTable.Column(x => x.CompanyId)));
users = ApplyFilter(users, filter, webUserTable, contactTable, companyTable);