Imports System.ComponentModel
Imports DigitalData.Modules.Logging
Imports DigitalData.Modules.Database
Imports DigitalData.Modules.Messaging
Imports DigitalData.Modules.Filesystem
Imports DigitalData.Modules.Language
Imports System.Timers
Imports System.IO
Imports DigitalData.Modules.Encryption

Public Class EmailService
    Private _Logger As Logger
    Private _LogConfig As LogConfig
    Private _Firebird As Firebird
    Private _MSSQL As MSSQLServer
    Private _MSSQL_Test As MSSQLServer
    Private _Encryption As EncryptionLegacy
    Private _EmailQueue As BackgroundWorker
    Private _QueueTimer As Timer
    Private _AnyDatabaseInitialized As Boolean = False
    Private _limilab As DigitalData.Modules.Messaging.Limilab
    Private _messageSend As Boolean = False

    Private Enum DatabaseType
        Firebird
        MSSQL
    End Enum

    Protected Overrides Sub OnStart(ByVal args() As String)
        Try
            ' === Initialize Logger ===
            _LogConfig = New LogConfig(LogConfig.PathType.CustomPath, Path.Combine(My.Application.Info.DirectoryPath, "Log"), Nothing, "Digital Data", "EmailService")
            _LogConfig.Debug = My.Settings.DEBUG

            _Logger = _LogConfig.GetLogger()
            Try
                Dim directory As New IO.DirectoryInfo(_LogConfig.LogDirectory)

                For Each file As IO.FileInfo In directory.GetFiles
                    If (Now - file.CreationTime).Days > 29 Then
                        file.Delete()
                    Else
                        Exit For
                    End If


                Next
            Catch ex As Exception

            End Try
            _Logger.Info("Starting {0}", ServiceName)

            ' === Inititalize Encryption ===

            _Logger.NewBlock("Inititalize Encryption")

            _Encryption = New EncryptionLegacy()

            _Logger.EndBlock()

            ' === Initialize Databases ===

            _Logger.NewBlock("Inititalize Databases")

            If My.Settings.FB_ConnString <> String.Empty Then
                _Firebird = New Firebird(_LogConfig, My.Settings.FB_ConnString, My.Settings.FB_DATABASE, My.Settings.FB_USER, My.Settings.FB_PW)

                If _Firebird._DBInitialized = False Then
                    _Logger.Warn("Firebird Connection could not be established. Check the Error Log")
                End If
            End If

            If My.Settings.SQLSERVER_CS <> String.Empty Then
                _MSSQL = New MSSQLServer(_LogConfig, My.Settings.SQLSERVER_CS)

                If _MSSQL.DBInitialized = False Then
                    _Logger.Warn("MSSQL Connection could not be established. Check the Error Log")
                End If
            End If

            If My.Settings.SQLSERVER_CS_TEST <> String.Empty Then

                _MSSQL_Test = New MSSQLServer(_LogConfig, My.Settings.SQLSERVER_CS_TEST)

                If _MSSQL_Test.DBInitialized = False Then
                    _Logger.Warn("MSSQL Test Connection could not be established. Check the Error Log")
                End If
            End If

            _AnyDatabaseInitialized = _Firebird?._DBInitialized Or _MSSQL?.DBInitialized Or _MSSQL_Test?.DBInitialized

            _Logger.EndBlock()

            ' === Initialize Email ===

            _Logger.NewBlock("Inititalize Email")

            _limilab = New Limilab(_LogConfig)

            _Logger.EndBlock()

            ' === Initialize Queue ===

            _Logger.NewBlock("Inititalize Queue")

            If _AnyDatabaseInitialized Then
                _EmailQueue = New BackgroundWorker() With {
                    .WorkerReportsProgress = True,
                    .WorkerSupportsCancellation = True
                }

                AddHandler _EmailQueue.DoWork, AddressOf EmailQueue_DoWork
                AddHandler _EmailQueue.RunWorkerCompleted, AddressOf EmailQueue_Completed
            End If

            _Logger.EndBlock()

            ' === Initialize & Start Timer ===

            _Logger.NewBlock("Initialize & Start Timer")

            If _AnyDatabaseInitialized Then
                _QueueTimer = New Timer With {
                   .Interval = 60000,
                   .Enabled = True
                }

                AddHandler _QueueTimer.Elapsed, AddressOf QueueTimer_Elapsed
            End If

            _Logger.EndBlock()

            ' === Initial Run ===

            If _AnyDatabaseInitialized Then
                _Logger.Info("Starting Initial Run...")
                _EmailQueue.RunWorkerAsync()
            End If
        Catch ex As Exception
            _Logger.Error(ex)
        End Try
    End Sub

    Private Sub QueueTimer_Elapsed(sender As Object, e As ElapsedEventArgs)
        If Not _EmailQueue.IsBusy Then
            _EmailQueue.RunWorkerAsync()
            _Logger.Debug("Worker is ready, executing.")
        Else
            _Logger.Info("Worker is busy, skipping execution.")
        End If
    End Sub

    Private Sub EmailQueue_DoWork(sender As Object, e As DoWorkEventArgs)
        Try
            If _Firebird?._DBInitialized Then
                _Logger.Debug("Starting Firebird Sending")
                SendEmailFrom(DatabaseType.Firebird, Nothing)
            End If

            If _MSSQL?.DBInitialized Then
                _Logger.Debug("Starting MSSQL Sending")
                SendEmailFrom(DatabaseType.MSSQL, _MSSQL)
            End If

            If _MSSQL_Test?.DBInitialized Then
                _Logger.Debug("Starting MSSQL Test Sending")
                SendEmailFrom(DatabaseType.MSSQL, _MSSQL_Test)
            End If
        Catch ex As Exception
            _Logger.Error(ex)
        End Try
    End Sub

    Private Function SendEmailFrom(Database As DatabaseType, MSSQLInstance As MSSQLServer)
        Try
            Dim oSQL As String = String.Empty
            Dim oEmailAccounts As DataTable
            Dim oEmailQueue As DataTable

            Select Case Database
                Case DatabaseType.Firebird
                    oSQL = "SELECT * FROM TBEDM_EMAIL_ACCOUNT WHERE ACTIVE = True"
                    oEmailAccounts = _Firebird.GetDatatable(oSQL)
                Case DatabaseType.MSSQL
                    oSQL = "SELECT * FROM TBDD_EMAIL_ACCOUNT WHERE ACTIVE = 1"
                    oEmailAccounts = MSSQLInstance.GetDatatable(oSQL)
            End Select

            If IsNothing(oEmailAccounts) Then
                _Logger.Warn("Error in TBEDM_EMAIL_ACCOUNT Query. Exiting.")
                _Logger.Warn("Query: {0}", oSQL)
                Return False
            End If

            If oEmailAccounts.Rows.Count = 0 Then
                _Logger.Warn("No Active Email Accounts Configured! Exiting.")
                Return False
            End If

            Select Case Database
                Case DatabaseType.Firebird
                    oSQL = "SELECT * FROM TBEDM_EMAIL_QUEUE WHERE EMAIL_SENT IS NULL and EMAIL_TO <> ''"
                    oEmailQueue = _Firebird.GetDatatable(oSQL)
                Case DatabaseType.MSSQL
                    oSQL = "SELECT * FROM TBEMLP_EMAIL_OUT WHERE EMAIL_SENT IS NULL and EMAIL_ADRESS <> ''"
                    oEmailQueue = MSSQLInstance.GetDatatable(oSQL)
            End Select

            If IsNothing(oEmailQueue) Then
                _Logger.Warn("Error in EmailQueue Query. Exiting.")
                _Logger.Warn("Query: {0}", oSQL)
                Return False
            End If

            If oEmailQueue.Rows.Count = 0 Then
                _Logger.Debug("Email Queue is empty. Exiting.")
                Return False
            End If

            Dim oEmailTo, oSubject, oBody As String
            Dim oMailFrom, oMailSMTP, oMailport, oMailUser, oMailPW, oAuthType, oAttachment, ofromName, oErrorMsg, oMailADDED
            Dim oAccountId, oGuid, oJobId As Integer

            For Each oEmailToRow As DataRow In oEmailQueue.Rows
                Dim oAccountMatch As Boolean = False
                Dim oComment As String = String.Empty

                Select Case Database
                    Case DatabaseType.Firebird
                        oAccountId = oEmailToRow.Item("EMAIL_ACCOUNT_ID")
                    Case DatabaseType.MSSQL
                        oAccountId = oEmailToRow.Item("SENDING_PROFILE")
                End Select
                oErrorMsg = ""
                For Each oAccountRow As DataRow In oEmailAccounts.Rows
                    If oAccountRow.Item("GUID") = oAccountId Then
                        oAccountMatch = True

                        Select Case Database
                            Case DatabaseType.Firebird
                                oMailFrom = oAccountRow.Item("EMAIL_FROM")
                                ofromName = oMailFrom
                                oMailSMTP = oAccountRow.Item("SERVER_OUT")
                                oMailport = oAccountRow.Item("PORT_OUT")
                                oMailUser = oAccountRow.Item("EMAIL_USER")
                                oAuthType = oAccountRow.Item("AUTH_TYPE")
                                oMailPW = oAccountRow.Item("EMAIL_PW")
                                oMailADDED = ""

                            Case DatabaseType.MSSQL
                                oMailFrom = oAccountRow.Item("EMAIL_FROM")
                                ofromName = oAccountRow.Item("EMAIL_FROM_NAME")
                                oMailSMTP = oAccountRow.Item("EMAIL_SMTP")
                                oMailport = oAccountRow.Item("PORT")
                                oMailUser = oAccountRow.Item("EMAIL_USER")
                                oAuthType = oAccountRow.Item("AUTH_TYPE")
                                oMailPW = oAccountRow.Item("EMAIL_PW")
                                oMailADDED = oAccountRow.Item("ADDED_WHEN").ToString
                                Try
                                    oErrorMsg = IIf(IsDBNull(oAccountRow.Item("ERROR_MSG")), "", oAccountRow.Item("ERROR_MSG"))
                                Catch ex As Exception
                                    oErrorMsg = ""
                                End Try

                        End Select

                        Dim oPasswordPlain = _Encryption.DecryptData(oMailPW)
                        If Not IsNothing(oPasswordPlain) Then
                            oMailPW = oPasswordPlain
                        Else
                            _Logger.Warn("Could not decrypt email password. Exiting.")
                            Return False
                        End If
                    End If
                Next

                If IsNothing(oMailFrom) Or IsNothing(oMailPW) Then
                    If oAccountMatch Then
                        _Logger.Warn("Account credentials are empty. Exiting.")
                    Else
                        _Logger.Warn("Account credentials are empty and account with Id {0} does not match the configuration. Exiting.", oAccountId)
                    End If

                    Return False
                End If
                If oErrorMsg <> String.Empty Then

                End If

                Select Case Database
                    Case DatabaseType.Firebird
                        oGuid = oEmailToRow.Item("GUID")
                        oEmailTo = oEmailToRow.Item("EMAIL_TO")
                        _Logger.Debug("oEmailTo: {0}", oEmailTo)
                        oSubject = oEmailToRow.Item("EMAIL_SUBJ")
                        _Logger.Debug("oSubject: {0}", oSubject)
                        oBody = oEmailToRow.Item("EMAIL_BODY")
                        _Logger.Debug("oBody: {0}", oBody)
                        oJobId = oEmailToRow.Item("JOB_ID")
                        _Logger.Debug("oJOB_ID: {0}", oJobId)
                        oAttachment = Utils.NotNull(oEmailToRow.Item("EMAIL_ATTMT1"), String.Empty)

                    Case DatabaseType.MSSQL
                        oGuid = oEmailToRow.Item("GUID")
                        oEmailTo = oEmailToRow.Item("EMAIL_ADRESS")
                        _Logger.Debug($"oEmailTo: {oEmailTo}")
                        oSubject = oEmailToRow.Item("EMAIL_SUBJ")
                        _Logger.Debug($"oSubject: {oSubject}")
                        oBody = oEmailToRow.Item("EMAIL_BODY")
                        _Logger.Debug($"oBody: {oBody}")
                        oJobId = oEmailToRow.Item("REFERENCE_ID")
                        _Logger.Debug($"oJOB_ID: {oJobId}")
                        oAttachment = Utils.NotNull(oEmailToRow.Item("EMAIL_ATTMT1"), String.Empty)
                End Select

                If oAttachment <> String.Empty Then
                    If oAttachment.ToString.Contains("\") Then
                        If IO.File.Exists(oAttachment) = False Then
                            _Logger.Warn($"Email Attachment [{oAttachment}] not existing!")
                            oComment = $"Email Attachment [{oAttachment}] not existing!"
                            oAttachment = String.Empty
                        Else
                            _Logger.Debug("Email Attachment is: {0}", oAttachment)
                        End If
                    End If

                End If

                _messageSend = _limilab.NewSMTPEmail(oEmailTo, oSubject, oBody, oMailFrom, oMailSMTP, oMailport, oMailUser, oMailPW, oAuthType, "DDEmailService", oMailADDED, oAttachment)

                If _messageSend Then

                    Select Case Database
                        Case DatabaseType.Firebird
                            oSQL = $"UPDATE TBEDM_EMAIL_QUEUE SET EMAIL_SENT = CURRENT_TIMESTAMP,COMMENT = '{oComment}' WHERE GUID = {oGuid}"
                            If oSQL.Contains(",COMMENT = ''") Then
                                oSQL.Replace(",COMMENT = ''", "")
                            End If
                            _Firebird.ExecuteNonQuery(oSQL)
                        Case DatabaseType.MSSQL
                            oSQL = $"UPDATE TBEMLP_EMAIL_OUT SET EMAIL_SENT = GETDATE(),COMMENT = '{oComment}' WHERE GUID = {oGuid} "
                            If oSQL.Contains(",COMMENT = ''") Then
                                oSQL.Replace(",COMMENT = ''", "")
                            End If
                            MSSQLInstance.ExecuteNonQuery(oSQL)
                    End Select
                    _Logger.Info($"EmailID [{oGuid.ToString}] has been send to: {oEmailTo}")
                    Threading.Thread.Sleep(500)
                Else
                    Select Case Database
                        'Case DatabaseType.Firebird
                        '    oSQL = $"UPDATE TBEDM_EMAIL_QUEUE SET EMAIL_SENT = CURRENT_TIMESTAMP,COMMENT = '{oComment}' WHERE GUID = {oGuid}"
                        '    If oSQL.Contains(",COMMENT = ''") Then
                        '        oSQL.Replace(",COMMENT = ''", "")
                        '    End If
                        '    _Firebird.ExecuteNonQuery(oSQL)
                        Case DatabaseType.MSSQL
                            oSQL = $"UPDATE TBEMLP_EMAIL_OUT SET ERROR_TIMESTAMP = GETDATE(),ERROR_MSG = '{_limilab.ErrorMessage}' WHERE GUID = {oGuid} "
                            MSSQLInstance.ExecuteNonQuery(oSQL)
                            If _messageSend = True Then
                                Select Case Database
                                    Case DatabaseType.Firebird
                                        oSQL = $"UPDATE TBEDM_EMAIL_QUEUE SET EMAIL_SENT = CURRENT_TIMESTAMP,COMMENT = '{oComment}' WHERE GUID = {oGuid}"
                                        If oSQL.Contains(",COMMENT = ''") Then
                                            oSQL.Replace(",COMMENT = ''", "")
                                        End If
                                        _Firebird.ExecuteNonQuery(oSQL)
                                    Case DatabaseType.MSSQL
                                        oSQL = $"UPDATE TBEMLP_EMAIL_OUT SET EMAIL_SENT = GETDATE(),COMMENT = '{oComment}' WHERE GUID = {oGuid} "
                                        If oSQL.Contains(",COMMENT = ''") Then
                                            oSQL.Replace(",COMMENT = ''", "")
                                        End If
                                        MSSQLInstance.ExecuteNonQuery(oSQL)
                                End Select
                                _Logger.Info($"EmailID [{oGuid.ToString}] has been send to: {oEmailTo} - althogh there was an error in connection close!")

                            End If

                    End Select
                End If
            Next

            Return True
        Catch ex As Exception
            _Logger.Warn("Error in SendEmailFrom. Email was not sent.")
            _Logger.Error(ex)
            Return False
        End Try
    End Function

    Private Sub EmailQueue_Completed(sender As Object, e As RunWorkerCompletedEventArgs)
        Try
            If e.Cancelled Then
                _Logger.Warn("EmailQueue has been cancelled manually!")
            ElseIf e.Error IsNot Nothing Then
                _Logger.Warn("Unexpected Error in EmailQueue: {0}", e.Error.Message)
                _Logger.Error(e.Error)
            End If
        Catch ex As Exception
            _Logger.Error(e.Error)
        End Try
    End Sub

    Protected Overrides Sub OnStop()
        Try
            _Logger.Warn("Service {0} was stopped.", ServiceName)
        Catch ex As Exception
            _Logger.Error(ex)
        End Try
    End Sub
End Class