Imports System.Data.SqlClient
Imports DigitalData.Modules.Logging

Public Class MSSQLServer
    Public DBInitialized As Boolean = False
    Public CurrentSQLConnectionString As String = ""
    Private _Logger As Logger

    Public Sub New(LogConfig As LogConfig, ConnectionString As String)
        _Logger = LogConfig.GetLogger()

        CurrentSQLConnectionString = ConnectionString

        Try
            DBInitialized = TestCanConnect()
        Catch ex As Exception
            DBInitialized = False
            _Logger.Error(ex)
        End Try
    End Sub

    Private Function TestCanConnect() As Boolean
        Try
            Dim oConnection As New SqlConnection(CurrentSQLConnectionString)
            oConnection.Open()
            oConnection.Close()
            Return True
        Catch ex As Exception
            _Logger.Error(ex)
            Return False
        End Try
    End Function

    Private Function GetSQLConnection() As SqlConnection
        Try
            Dim oConnection As New SqlConnection(CurrentSQLConnectionString)
            oConnection.Open()
            Return oConnection
        Catch ex As Exception
            _Logger.Error(ex)
            Return Nothing
        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="Timeout">Optional Timeout</param>
    ''' <returns>Returns a datatable</returns>
    ''' <remarks></remarks>
    Public Function GetDatatable(sqlcommand As String, Optional Timeout As Integer = 120) As DataTable
        Try
            If TestCanConnect() = False Then
                Return Nothing
            End If

            Using oConnection = GetSQLConnection()
                Using oSQLCOmmand = oConnection.CreateCommand()
                    oSQLCOmmand.CommandText = sqlcommand
                    oSQLCOmmand.CommandTimeout = Timeout

                    Dim dt As DataTable = New DataTable()
                    Dim oAdapter As SqlDataAdapter = New SqlDataAdapter(oSQLCOmmand)
                    oAdapter.Fill(dt)
                    Return dt
                End Using
            End Using
        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="Timeout">Optional Timeout</param>
    ''' <returns>Returns true if properly executed, else false</returns>
    ''' <remarks></remarks>
    Public Function NewExecutenonQuery(executeStatement As String, Optional Timeout As Integer = 120) As Boolean
        Try
            If TestCanConnect() = False Then
                Return Nothing
            End If

            Using oConnection = GetSQLConnection()
                Using oSQLCOmmand = oConnection.CreateCommand()
                    oSQLCOmmand.CommandText = executeStatement
                    oSQLCOmmand.CommandTimeout = Timeout
                    oSQLCOmmand.ExecuteNonQuery()
                    Return True
                End Using
            End Using
        Catch ex As Exception
            _Logger.Error(ex)
            _Logger.Debug("executeStatement: " & executeStatement)
            Return False
        End Try
    End Function

    ''' <summary>
    ''' Executes the passed sql-statement as Scalar
    ''' </summary>
    ''' <param name="ScalarSQL">the sql statement</param>
    ''' <param name="Timeout">Optional Timeout</param>
    ''' <returns>Returns true if properly executed, else false</returns>
    ''' <remarks></remarks>
    Public Function NewExecuteScalar(ScalarSQL As String, Optional Timeout As Integer = 120) As Object
        Try
            If TestCanConnect() = False Then
                Return Nothing
            End If

            Using oConnection As SqlConnection = GetSQLConnection()
                Using oSQLCOmmand = oConnection.CreateCommand()
                    oSQLCOmmand.CommandText = ScalarSQL
                    oSQLCOmmand.CommandTimeout = Timeout
                    Dim oResult As Object = oSQLCOmmand.ExecuteScalar()
                    Return oResult
                End Using
            End Using
        Catch ex As Exception
            _Logger.Error(ex)
            _Logger.Debug("executeStatement: " & ScalarSQL)
            Return Nothing
        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)
        If TestCanConnect() = False Then
            Exit Sub
        End If

        Try
            Dim oCallback As New AsyncCallback(AddressOf NewExecuteNonQueryAsync_Callback)

            Using oConnection As SqlConnection = GetSQLConnection()
                Using oSQLCOmmand = oConnection.CreateCommand()
                    oSQLCOmmand.CommandText = executeStatement
                    oSQLCOmmand.CommandTimeout = commandtimeout
                    oSQLCOmmand.BeginExecuteNonQuery(oCallback, oSQLCOmmand)
                End Using
            End Using
        Catch ex As Exception
            _Logger.Error(ex)
            _Logger.Debug("executeStatement: " & executeStatement)
        End Try
    End Sub

    Private Sub NewExecuteNonQueryAsync_Callback(ByVal result As IAsyncResult)
        Dim command As SqlCommand = CType(result.AsyncState, SqlCommand)
        Dim res = command.EndExecuteNonQuery(result)
        _Logger.Info("Finished executing Async database operation: {0}", command.CommandText)
    End Sub
End Class