Imports DigitalData.Modules.Logging
Imports DigitalData.Modules.Filesystem
Imports Limilabs.Mail
Imports Limilabs.Client.IMAP
Imports Limilabs.Mail.MIME
Imports System.IO
Imports Limilabs.Mail.MSG

Public Class Email2
    Private ReadOnly Logger As Logger
    Private ReadOnly LogConfig As LogConfig
    Private ReadOnly FileEx As Filesystem.File
    Private ReadOnly MailBuilder As New MailBuilder()

    Public Sub New(pLogConfig As LogConfig)
        LogConfig = pLogConfig
        Logger = pLogConfig.GetLogger()
        FileEx = New Filesystem.File(pLogConfig)
    End Sub

    Public Enum EmailSecurity
        SSLTLS
        STARTTLS
    End Enum

    Private Function Get_PortForSecurityOption(pSecurity As EmailSecurity) As Integer
        If pSecurity = EmailSecurity.STARTTLS Then
            Return 143
        Else ' EmailSecurity.SSL
            Return 993
        End If
    End Function

    Private Function New_Connection(pIMAP As Imap, pServer As String, pUsername As String, pPassword As String, pPort As Integer, pSecurity As EmailSecurity) As Boolean
        Try
            Logger.Debug("Connecting to IMAP server [{0}]", pServer)

            Dim oPort As Integer = pPort
            If oPort = 0 Then
                oPort = Get_PortForSecurityOption(pSecurity)
            End If
            Logger.Debug("Using Port [{0}] for connection", oPort)

            If pSecurity = EmailSecurity.STARTTLS Then
                Logger.Debug("Using STARTTLS as Security Option")
                pIMAP.Connect(pServer, oPort)
                pIMAP.StartTLS()
            Else
                Logger.Debug("Using SSL/TLS as Security Option")
                pIMAP.ConnectSSL(pServer, oPort)
            End If
            Logger.Debug("Connection to IMAP Server [{0}] established!", pServer)

            Logger.Debug("Logging in with user [{0}]", pUsername)
            pIMAP.UseBestLogin(pUsername, pPassword)

            Return True

        Catch ex As Exception
            Logger.Warn("Could not connect to server [{0}] with user [{1}]", pServer, pUsername)
            Logger.Error(ex)
            Return False

        End Try
    End Function

    Public Function Test_Login(pServer As String, pUsername As String, pPassword As String, pSecurity As EmailSecurity, Optional pFolder As String = "Inbox", Optional pPort As Integer = 0) As Boolean
        Logger.Debug("Testing Login to Server [{0}:{1}] with user [{2}]", pServer, pPort, pUsername)

        Try
            Using oClient As New Imap()
                If New_Connection(oClient, pServer, pUsername, pPassword, pPort, pSecurity) Then
                    Logger.Debug("Fetching Inbox")
                    Dim oStatus As FolderStatus = oClient.SelectInbox()

                    Logger.Debug("Test finished!")
                    oClient.Close()

                End If

            End Using

            Return True
        Catch ex As Exception
            Logger.Warn("Login failed for server [{0}:{1}] with user [{2}]!", pServer, pPort, pUsername)
            Logger.Error(ex)

            Return False
        End Try
    End Function

    Public Function Get_Messages(pServer As String, pUsername As String, pPassword As String, pSecurity As EmailSecurity, Optional pFolder As String = "Inbox", Optional pPort As Integer = 0) As List(Of IMail)
        Logger.Debug("Fetching Messages from Server [{0}:{1}] with user [{2}]", pServer, pPort, pUsername)

        Dim oMails As New List(Of IMail)

        Try
            Using oClient As New Imap()
                If New_Connection(oClient, pServer, pUsername, pPassword, pPort, pSecurity) Then
                    Logger.Debug("Fetching Folder [{0}]", pFolder)
                    Dim oStatus As FolderStatus = oClient.Select(pFolder)

                    Logger.Debug("Fetching Unseen UUIDs")
                    Dim oUUIDs As List(Of Long) = oClient.Search(Flag.Unseen)
                    Dim oMailBuilder As New MailBuilder()

                    Logger.Debug("Fetching Unseen Mails")
                    For Each oUUID As Long In oUUIDs
                        Dim oEmlFile As Byte() = oClient.GetMessageByUID(oUUID)
                        Dim oEmail As IMail = oMailBuilder.CreateFromEml(oEmlFile)
                        oMails.Add(oEmail)

                    Next

                    Logger.Debug("Emails fetched!")
                    oClient.Close()

                End If

            End Using

            Return oMails

        Catch ex As Exception
            Logger.Warn("Login failed for server [{0}:{1}] with user [{2}]!", pServer, pPort, pUsername)
            Logger.Error(ex)
            Return New List(Of IMail)

        End Try
    End Function

    Public Function Get_Message(pServer As String, pUsername As String, pPassword As String, pSecurity As EmailSecurity, pMessageId As String, Optional pFolder As String = "Inbox", Optional pPort As Integer = 0) As IMail
        Logger.Debug("Fetching Message [{0}] from Server [{1}:{2}] with user [{3}]", pMessageId, pServer, pPort, pUsername)

        Dim oMail As IMail = Nothing

        Try
            Using oClient As New Imap()
                If New_Connection(oClient, pServer, pUsername, pPassword, pPort, pSecurity) Then
                    Logger.Debug("Fetching Folder [{0}]", pFolder)
                    Dim oStatus As FolderStatus = oClient.Select(pFolder)

                    Logger.Debug("Fetching UUIDs")
                    Dim oUUIDs As List(Of Long) = oClient.Search(Flag.All)
                    Logger.Debug("Fetching Mails")
                    Dim oInfos As List(Of MessageInfo) = oClient.GetMessageInfoByUID(oUUIDs)

                    Dim oMailInfo = oInfos.Where(Function(i) i.Envelope.MessageID = pMessageId).FirstOrDefault()

                    If oMailInfo IsNot Nothing Then
                        Dim oMailData As Byte() = oClient.GetMessageByUID(oMailInfo.UID)
                        oMail = MailBuilder.CreateFromEml(oMailData)
                    End If

                    Logger.Debug("Emails fetched!")
                    oClient.Close()

                End If

            End Using

            Return oMail

        Catch ex As Exception
            Logger.Warn("Login failed for server [{0}:{1}] with user [{2}]!", pServer, pPort, pUsername)
            Logger.Error(ex)

            Return Nothing

        End Try
    End Function

    Public Function Remove_AttachmentsFromEmail(pFileName As String, Optional pSuffix As String = "") As String
        Try
            Dim oTempFileName As String = Path.Combine(Path.GetTempPath(), AddFilenameSuffix(pFileName, pSuffix))
            Dim oMail = MailBuilder.CreateFromEmlFile(pFileName)

            oMail.RemoveAttachments()
            oMail.Save(oTempFileName)

            Return oTempFileName
        Catch ex As Exception
            Logger.Error(ex)

            Return Nothing
        End Try
    End Function

    Public Function Save_AttachmentsToDisk(pFileName As String) As List(Of String)
        Try
            Dim oAttachmentPaths As New List(Of String)
            Dim oMail = MailBuilder.CreateFromEmlFile(pFileName)
            Dim oTempPath As String = IO.Path.GetTempPath()

            If oMail.Attachments.Count = 0 Then
                Return New List(Of String)
            End If

            For Each oAttachment As MimeData In oMail.Attachments
                Dim oPath As String = IO.Path.Combine(oTempPath, oAttachment.SafeFileName)
                Dim oVersionedPath As String = FileEx.GetVersionedFilename(oPath)

                oAttachment.Save(oVersionedPath)
                oAttachmentPaths.Add(oVersionedPath)
            Next

            Return oAttachmentPaths
        Catch ex As Exception
            Logger.Error(ex)

            Return New List(Of String)
        End Try
    End Function

    Public Function ConvertMsgToEml(pEmailFileName As String) As String
        Dim oInfo As New FileInfo(pEmailFileName)

        If oInfo.Extension.ToUpper = ".EML" Then
            Return pEmailFileName

        ElseIf oInfo.Extension.ToUpper = ".MSG" Then
            Return DoConvertMsgToEmlFile(pEmailFileName)

        Else
            Return Nothing

        End If
    End Function

    Private Function DoConvertMsgToEmlFile(pMsgFile As String) As String
        Try
            Dim oFileNameWithoutExtension = Path.GetFileNameWithoutExtension(pMsgFile)
            Dim oEmlPath As String = $"{oFileNameWithoutExtension}.eml"

            Using oConverter As New MsgConverter(pMsgFile)
                Dim oEmail As IMail = oConverter.CreateMessage()
                Dim oData As Byte() = oEmail.Render()

                oEmail.Save(oEmlPath)
            End Using

            Return oEmlPath

        Catch ex As Exception
            Return Nothing

        End Try
    End Function

    Private Function GetTempFileNameWithExtension(pExtension As String) As String
        Dim oTempFileName As String = IO.Path.GetTempFileName()
        Dim oInfo As New IO.FileInfo(oTempFileName)
        Dim oExtension As String = IIf(pExtension.StartsWith("."), pExtension, $".{pExtension}")
        Dim oNewFileName = IO.Path.Combine(oInfo.DirectoryName, oInfo.Name.Replace(oInfo.Extension, oExtension))

        Return oNewFileName
    End Function

    Private Function AddFilenameSuffix(pFilename As String, pSuffix As String)
        Dim oFileInfo As New FileInfo(pFilename)
        Dim oExtension As String = oFileInfo.Extension
        Dim oFileNameWithoutExtension = Path.GetFileNameWithoutExtension(pFilename)

        Return $"{oFileNameWithoutExtension}{pSuffix}{oExtension}"
    End Function
End Class