Imports System.Data.SqlClient

Public Class SQLServer
    Private Shared Logger As NLog.Logger = NLog.LogManager.GetCurrentClassLogger
    Public DBInitialized As Boolean = False
    Public CurrentSQLConnectionString As String = ""
    Public Sub New(CONSTRING As String)
        Init(CONSTRING)
    End Sub
    Public Function Init(CONSTRING As String)
        Try
            Dim oSQLconnect As New SqlClient.SqlConnection
            oSQLconnect.ConnectionString = CONSTRING
            oSQLconnect.Open()
            oSQLconnect.Close()
            CurrentSQLConnectionString = CONSTRING
            DBInitialized = True
            Return True
        Catch ex As Exception
            Logger.Error(ex)
            'clsLogger.Add("Error in DatabaseInit: " & ex.Message, True)
            Return False
        End Try
    End Function
    ''' <summary>
    ''' Returns a datatable for a sql-statement 
    ''' </summary>
    ''' <param name="sqlcommand">sqlcommand for datatable (select XYZ from TableORView)</param>
    ''' <param name="commandtimeout">Optional Timeout</param>
    ''' <returns>Returns a datatable</returns>
    ''' <remarks></remarks>
    Public Function GetDatatable(sqlcommand As String, Optional commandtimeout As Integer = 120) As DataTable
        Try
            Dim oSQLconnect As New SqlClient.SqlConnection
            Dim oSQLCOmmand As SqlClient.SqlCommand
            oSQLconnect.ConnectionString = CurrentSQLConnectionString
            oSQLconnect.Open()
            oSQLCOmmand = oSQLconnect.CreateCommand()
            oSQLCOmmand.CommandText = sqlcommand
            oSQLCOmmand.CommandTimeout = commandtimeout
            Dim adapter1 As SqlClient.SqlDataAdapter = New SqlClient.SqlDataAdapter(oSQLCOmmand)
            Dim dt As DataTable = New DataTable()
            adapter1.Fill(dt)
            oSQLconnect.Close()
            Return dt
        Catch ex As Exception
            Logger.Error(ex)
            Logger.Debug("sqlcommand: " & sqlcommand)
            Return Nothing
        End Try
    End Function
    ''' <summary>
    ''' Executes the passed sql-statement 
    ''' </summary>
    ''' <param name="executeStatement">the sql statement</param>
    ''' <param name="commandtimeout">Optional Timeout</param>
    ''' <returns>Returns true if properly executed, else false</returns>
    ''' <remarks></remarks>
    Public Function NewExecutenonQuery(executeStatement As String, Optional commandtimeout As Integer = 120) As Boolean
        Try
            Dim oSQLconnect As New SqlClient.SqlConnection
            Dim oSQLCOmmand As SqlClient.SqlCommand
            oSQLconnect.ConnectionString = CurrentSQLConnectionString
            oSQLconnect.Open()
            oSQLCOmmand = oSQLconnect.CreateCommand()
            oSQLCOmmand.CommandText = executeStatement
            oSQLCOmmand.CommandTimeout = commandtimeout
            oSQLCOmmand.ExecuteNonQuery()
            oSQLCOmmand.Dispose()
            oSQLconnect.Close()
            Return True
        Catch ex As Exception
            Logger.Error(ex)
            Logger.Debug("executeStatement: " & executeStatement)
            Return False
        End Try
    End Function
    ''' <summary>
    ''' Executes the passed sql-statement in asyncmode
    ''' </summary>
    ''' <param name="executeStatement">the sql statement</param>
    ''' <param name="commandtimeout">Optional Timeout</param>
    ''' <remarks></remarks>
    Public Sub NewExecuteNonQueryAsync(executeStatement As String, Optional commandtimeout As Integer = 120)
        Dim oSQLconnect As New SqlClient.SqlConnection
        Dim oSQLCOmmand As SqlClient.SqlCommand
        Dim callback As New AsyncCallback(AddressOf Execute_non_Query_Async_Callback)
        Try
            oSQLconnect.ConnectionString = CurrentSQLConnectionString
            oSQLconnect.Open()
            oSQLCOmmand = oSQLconnect.CreateCommand()
            oSQLCOmmand.CommandText = executeStatement
            oSQLCOmmand.CommandTimeout = commandtimeout
            oSQLCOmmand.BeginExecuteNonQuery(callback, oSQLCOmmand)
        Catch ex As Exception
            Logger.Error(ex)
            Logger.Debug("executeStatement: " & executeStatement)
        Finally
            oSQLCOmmand.Dispose()
            oSQLconnect.Close()
        End Try
    End Sub

    Private Sub Execute_non_Query_Async_Callback(ByVal result As IAsyncResult)
        Dim command As SqlClient.SqlCommand = CType(result.AsyncState, SqlClient.SqlCommand)
        Dim res = command.EndExecuteNonQuery(result)
        Logger.Info(String.Format("Finished executing Async database operation: {0}", command.CommandText))
    End Sub
    ''' <summary>
    ''' Executes the passed sql-statement as Scalar
    ''' </summary>
    ''' <param name="executeStatement">the sql statement</param>
    ''' <param name="commandtimeout">Optional Timeout</param>
    ''' <returns>Returns true if properly executed, else false</returns>
    ''' <remarks></remarks>
    Public Function NewExecuteScalar(executeStatement As String, Optional commandtimeout As Integer = 120)
        Dim result
        Try
            Dim oSQLconnect As New SqlClient.SqlConnection
            Dim oSQLCOmmand As SqlClient.SqlCommand
            oSQLconnect.ConnectionString = CurrentSQLConnectionString
            oSQLconnect.Open()
            oSQLCOmmand = oSQLconnect.CreateCommand()

            oSQLCOmmand.CommandText = executeStatement
            oSQLCOmmand.CommandTimeout = commandtimeout
            result = oSQLCOmmand.ExecuteScalar()
            oSQLCOmmand.Dispose()
            oSQLconnect.Close()

            Return result
        Catch ex As Exception
            Logger.Error(ex)
            Logger.Debug("executeStatement: " & executeStatement)
            Return Nothing
        End Try
    End Function
End Class