#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2013 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.Common;
using System.Globalization;
using HeuristicLab.DataImporter.DbExplorer.Interfaces;

namespace HeuristicLab.DataImporter.DbExplorer.MsSqlServer {
  public class SqlServerExplorer : DbExplorerBase {

    protected override string EscapeSqlString(string s) {
      return "[" + s + "]";
    }

    private enum NumericDataType { Numeric, Decimal, Tinyint, Smallint, Int, bigint, Float, Real }
    public override bool IsNumericDataType(string type) {
      try {
        Enum.Parse(typeof(NumericDataType), type, true);
        return true;
      }
      catch (ArgumentException) { }
      return false;
    }

    private enum DateDataType { DateTime, SmallDateTime }
    public override bool IsDateDataType(string type) {
      try {
        Enum.Parse(typeof(DateDataType), type, true);
        return true;
      }
      catch (ArgumentException) { }
      return false;
    }

    private enum StringDataType { Char, NChar, Varchar, NVarchar }
    public override bool IsStringDataType(string type) {
      try {
        Enum.Parse(typeof(StringDataType), type, true);
        return true;
      }
      catch (ArgumentException) { }
      return false;
    }

    public override bool IsFilterableDataType(string type) {
      return IsNumericDataType(type) || IsDateDataType(type) || IsStringDataType(type);
    }

    protected override string ConvertDate(DateTime date) {
      string ret = "'" + date.ToString(CultureInfo.InvariantCulture) + "'";
      return ret;
    }

    protected override string ConvertDouble(double value) {
      return value.ToString(CultureInfo.InvariantCulture);
    }

    public override string MenuItemDescription {
      get { return "Connect to Microsoft SqlServer"; }
    }

    private SqlServerConnectionWizard wizard;
    protected override IDbConnectionWizard DbConnectionWizard {
      get {
        if (wizard == null)
          wizard = new SqlServerConnectionWizard();
        return wizard;
      }
    }

    public override IEnumerable<DbTable> AllTables {
      get {
        if (Connection == null)
          throw new InvalidOperationException("Connection to database not correctly set!");
        List<DbTable> allTables = new List<DbTable>();
        using (DbConnection conn = Connection.CreateConnection()) {
          conn.Open();
          using (DbCommand cmd = conn.CreateCommand()) {
            cmd.CommandText = @"select table_schema,table_name from INFORMATION_SCHEMA.tables";
            using (DbDataReader reader = cmd.ExecuteReader()) {
              while (reader.Read()) {
                allTables.Add(new DbTable(reader.GetString(0), reader.GetString(1)));
              }
              reader.Close();
            }//end using reader
            cmd.Dispose();
          }//end using command

          //fill columns for table
          foreach (DbTable table in allTables) {
            using (DbCommand cmd = conn.CreateCommand()) {
              cmd.CommandText = @"select column_name,data_type from INFORMATION_SCHEMA.columns where table_name = '" + table.TableName + "'";
              using (DbDataReader reader = cmd.ExecuteReader()) {
                while (reader.Read()) {
                  table.AddColumn(new DbColumn(reader.GetString(0), reader.GetString(1)));
                }
                reader.Close();
              }//end using reader
            }//end using command

          }//end foreach table
          conn.Close();
        }//end using connection
        allTables.Sort(new DbTableComparator());
        return allTables;
      }
    }
  }
}