#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2016 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
 *
 * This file is part of HeuristicLab.
 *
 * HeuristicLab is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * HeuristicLab is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
 */
#endregion

using System;
using System.Collections.Generic;
using System.Data.Linq;
using System.Linq;

namespace HeuristicLab.Services.Hive.DataAccess.Daos {
  public class ResourcePermissionDao : GenericDao<Guid, ResourcePermission> {

    public ResourcePermissionDao(DataContext dataContext) : base(dataContext) { }

    public override ResourcePermission GetById(Guid id) {
      throw new NotImplementedException();
    }

    public IEnumerable<Guid> GetByUserAndGroupIds(IEnumerable<Guid> userAndGroupIds) {
      string paramIds = string.Join(",", userAndGroupIds.Select(x => string.Format("'{0}'", x)));
      if (!string.IsNullOrWhiteSpace(paramIds)) {
        string query = string.Format(GetGrantedResourcesQuery, paramIds);
        return DataContext.ExecuteQuery<Guid>(query);
      }
      return Enumerable.Empty<Guid>();
    }

    #region Compiled queries
    private static readonly Func<DataContext, Guid, IEnumerable<ResourcePermission>> GetByResourceIdQuery =
      CompiledQuery.Compile((DataContext db, Guid resourceId) =>
      from resourcePermission in db.GetTable<ResourcePermission>()
      where resourcePermission.ResourceId == resourceId
      select resourcePermission);
    #endregion

    #region String queries
    private const string GetGrantedResourcesQuery = @"
      WITH rtree AS
      (
	      SELECT ResourceId, ParentResourceId
	      FROM [Resource]
	      UNION ALL
	      SELECT rt.ResourceId, r.ParentResourceId
	      FROM [Resource] r
	      JOIN rtree rt ON rt.ParentResourceId = r.ResourceId AND r.ParentResourceId <> r.ResourceId AND rt.ParentResourceId <> rt.ResourceId
      )
      SELECT DISTINCT rtree.ResourceId
      FROM rtree, [ResourcePermission] rp
      WHERE rtree.ParentResourceId = rp.ResourceId AND rp.GrantedUserId IN ({0})
      UNION ALL
      SELECT rp.ResourceId
      FROM [ResourcePermission] rp
      WHERE rp.GrantedUserId IN ({0})
      ;";

    #endregion
  }
}