Imports DigitalData.Modules.Base
Imports DigitalData.Modules.Logging

Public Class Dispatcher
    Public ReadOnly Property Connections As New List(Of DispatcherConnection)

    Public ReadOnly Logger As Logger
    Public ReadOnly LogConfig As LogConfig

    Public Sub New(pLogConfig As LogConfig, pConnections As List(Of DispatcherConnection))
        LogConfig = pLogConfig
        Logger = pLogConfig.GetLogger()
        Connections = pConnections
    End Sub

    Public Function GetDatatable(pSQLCommand As String, pConnectionId As Integer) As DataTable
        Dim oAdapter As IDatabase = GetAdapterClass(pConnectionId)
        Return oAdapter.GetDatatable(pSQLCommand)
    End Function

    Public Function ExectueNonQuery(pSQLCommand As String, pConnectionId As Integer) As Boolean
        Dim oAdapter As IDatabase = GetAdapterClass(pConnectionId)
        Return oAdapter.ExecuteNonQuery(pSQLCommand)
    End Function

    Public Function GetScalarValue(pSQLCommand As String, pConnectionId As Integer) As Object
        Dim oAdapter As IDatabase = GetAdapterClass(pConnectionId)
        Return oAdapter.GetScalarValue(pSQLCommand)
    End Function

    Private Function GetConnection(pConnectionId As Integer) As DispatcherConnection
        Dim oConnection As DispatcherConnection = Connections.
            Where(Function(conn) conn.Id = pConnectionId).
            FirstOrDefault()

        If oConnection IsNot Nothing Then
            Logger.Debug("Resolved ConnectionId [{0}] into Connection [{1}]", pConnectionId, oConnection.Name)
        End If

        Return oConnection
    End Function

    Private Function GetAdapterClass(pConnectionId As Integer) As IDatabase
        Dim oConnection = GetConnection(pConnectionId)
        Dim oArgs As New List(Of Object) From {LogConfig, oConnection.ConnectionString, Constants.DEFAULT_TIMEOUT}
        Logger.Debug("Creating database adapter object for type [{0}]", ConnectionType.MSSQL)

        ' TODO: Cache Database instances to avoid constructing them for every call

        Select Case oConnection.ConnectionType
            Case ConnectionType.MSSQL
                Return New MSSQLServer(LogConfig, oConnection.ConnectionString, Constants.DEFAULT_TIMEOUT)

            Case ConnectionType.Oracle
                Return New Oracle(LogConfig, oConnection.ConnectionString, Constants.DEFAULT_TIMEOUT)

            Case ConnectionType.Firebird
                Dim oBuilder As New FirebirdSql.Data.FirebirdClient.FbConnectionStringBuilder(oConnection.ConnectionString)
                Return New Firebird(LogConfig, oBuilder.DataSource, oBuilder.Database, oBuilder.UserID, oBuilder.Password)

            Case ConnectionType.ODBC
                'Dim oBuilder As New Data.Odbc.OdbcConnectionStringBuilder(pConnection.ConnectionString)
                'Return New ODBC(LogConfig)
                Return Nothing

            Case Else
                Return Nothing
        End Select
    End Function

    Public Enum ConnectionType
        MSSQL
        Oracle
        ODBC
        Firebird
    End Enum

    Public Class DispatcherOptions
        Public Property QueryTimeout As Integer = Constants.DEFAULT_TIMEOUT
    End Class

    Public Class DispatcherConnection
        Public Property Id As Integer
        Public Property Name As String
        Public Property ConnectionString As String
        Public Property ConnectionType As ConnectionType
    End Class
End Class