Imports System.IO
Imports DigitalData.Modules.Database
Imports DigitalData.Modules.Logging
Imports DigitalData.Modules.Patterns
Imports DigitalData.Modules.ZooFlow.State
Imports DigitalData.Services.EDMIService.GlobalState

Namespace Methods.GlobalIndexer.ImportFile.Steps
    Public Class AutomaticIndexing
        Inherits BaseClass

        Private ReadOnly GlobalState As GlobalState
        Private ReadOnly AutomaticIndexes As List(Of AutomaticIndex)
        Private ReadOnly Patterns As Patterns2
        Private ReadOnly Database As MSSQLServer

        Public Sub New(pLogConfig As LogConfig, pDatabase As MSSQLServer, pAutomaticIndexes As List(Of AutomaticIndex), pGlobalState As GlobalState)
            MyBase.New(pLogConfig)
            Database = pDatabase
            GlobalState = pGlobalState
            AutomaticIndexes = pAutomaticIndexes
            Patterns = New Patterns2(pLogConfig)

            Logger.Info("Starting Automatic Indexing")
        End Sub

        Public Function ApplyAutomaticeAttributes(pUserAttributes As List(Of UserAttributeValue), pFileInfo As FileInfo, pUserState As UserState) As List(Of UserAttributeValue)
            Logger.Debug("Start of Method [ApplyAutomaticAttributes]")

            If AutomaticIndexes Is Nothing OrElse AutomaticIndexes.Count = 0 Then
                Logger.Warn("No Automatix Indexes supplied. Exiting.")
                Return pUserAttributes
            End If

            Logger.Info("Processing [{0}] automatic indexes", AutomaticIndexes.Count)
            Dim oAttributes As List(Of UserAttributeValue) = pUserAttributes

            For Each oAutomaticIndex In AutomaticIndexes
                ' We add oAttributes from the previous run into the current run so it is in theory possible to reference
                ' automatic attributes which have been set just before.
                Dim oAttribute = ApplyAutomaticIndex(oAutomaticIndex, pFileInfo, pUserState, oAttributes)

                If oAttribute IsNot Nothing Then
                    Logger.Info("Adding Attribute [{0}]", oAttribute)
                    oAttributes.Add(oAttribute)
                End If
            Next

            Return oAttributes
        End Function


        Private Function ApplyAutomaticIndex(pAutomaticIndex As AutomaticIndex, pFileInfo As FileInfo, pUserState As UserState, pAttributes As List(Of UserAttributeValue)) As UserAttributeValue
            Try
                Dim oAttributeDict = pAttributes.ToDictionary(
               Function(attr) attr.AttributeName,
               Function(attr) attr.AttributeValues)

                Logger.Info("Applying Automatic Index [{0}]", pAutomaticIndex.Name)

                Dim oHasSqlCommand As Boolean = pAutomaticIndex.HasSqlCommand

                Logger.Debug("Index has SQLCommand: [{0}]", oHasSqlCommand)

                ' If there is no SQL command, we use the Value property and replace all placeholders in it.
                If oHasSqlCommand = False Then
                    Dim oResult As String = GetPlaceholderValue(pAutomaticIndex.Value, pFileInfo, pUserState, oAttributeDict)

                    Return New UserAttributeValue With {
                        .AttributeValues = New List(Of String) From {oResult},
                        .AttributeName = pAutomaticIndex.Name,
                        .AttributeId = pAutomaticIndex.Id
                    }
                End If

                ' Otherwise we will replace placeholders in the SQL command and then execute it
                Dim oConnectionString As String = GlobalState.GetConnectionString(pAutomaticIndex.SQLConnectionId)
                Dim oFinalSQLCommand = pAutomaticIndex.SQLCommand

                Logger.Debug("SQL Command is: [{0}]", oFinalSQLCommand)

                oFinalSQLCommand = GetPlaceholderValue(oFinalSQLCommand, pFileInfo, pUserState, oAttributeDict)

                ' Now we have a SQL command which only contains vector placeholders
                ' Next, we execute the command to get our result
                Dim oValue = Database.GetScalarValueWithConnection(oFinalSQLCommand, oConnectionString)

                If oValue Is Nothing Then
                    Logger.Warn("SQL for Automatic Index [{0}] returned an error. Exiting.")
                    Return Nothing
                End If

                Logger.Info("Value for Automatic Index [{0}] is [{1}]", pAutomaticIndex.Name, oValue.ToString)

                ' TODO: Return multiple values
                Return New UserAttributeValue With {
                    .AttributeValues = New List(Of String) From {oValue},
                    .AttributeName = pAutomaticIndex.Name,
                    .AttributeId = pAutomaticIndex.Id
                }
            Catch ex As Exception
                Logger.Warn("Automatic Indexing for index failed.")
                Logger.Error(ex)

                Return Nothing
            End Try
        End Function

        Private Function GetPlaceholderValue(pValue As String, pFileInfo As FileInfo, pUserState As UserState, pAttributes As Dictionary(Of String, List(Of String))) As String
            Dim oResult As String = pValue


            oResult = Patterns.ReplaceInternalValues(oResult)
            oResult = Patterns.ReplaceFileValues(oResult, pFileInfo)
            oResult = Patterns.ReplaceUserValues(oResult, pUserState)
            oResult = Patterns.ReplaceGlobixValues(oResult, pAttributes)

            Return oResult
        End Function
    End Class

End Namespace