Imports System.Xml
Imports System.Xml.Serialization
Imports System.Xml.XPath
Imports System.Xml.Xsl
Imports DigitalData.Modules.Interfaces.Exceptions
Imports DigitalData.Modules.Logging

Public Class ZUGFeRDInterface
    Private _logConfig As LogConfig
    Private _logger As Logger

    Private Const ZUGFERD_CONVERTER_EXE = ".\pdf_zugferd_test.exe"
    Private Const ZUGFERD_CONVERTER_SUCCESS_MESSAGE = "Document contains ZUGFeRD data."

    Public Enum ErrorType
        NoValidFile
        ExtractionFailed
    End Enum

    Public Sub New(LogConfig As LogConfig)
        _logConfig = LogConfig
        _logger = _logConfig.GetLogger()
    End Sub

    ''' <summary>
    ''' Validates a ZUGFeRD File and extracts the XML Document from it
    ''' </summary>
    ''' <param name="Path"></param>
    ''' <exception cref="ZUGFeRDExecption"></exception>
    ''' <returns></returns>
    Public Function ExtractXMLFile(Path As String) As XPathDocument
        Dim oException As New Exception
        Dim oXmlDocument = ExtractZugferd(Path)

        If IsNothing(oXmlDocument) Then
            Throw New ZUGFeRDExecption(ErrorType.ExtractionFailed, "Datei ist kein gültiges ZUGFeRD Format.")
        End If

        Return oXmlDocument
    End Function

    Public Function ExtractZugferd(Path As String) As XPathDocument
        Dim oProcessOutput, oProcessError, oFileContent As String
        Dim oXmlDocument As XPathDocument
        Dim oTempFile = System.IO.Path.GetTempFileName()

        Dim oProcessStartInfo As New ProcessStartInfo() With {
            .FileName = ZUGFERD_CONVERTER_EXE,
            .RedirectStandardError = True,
            .RedirectStandardOutput = True,
            .UseShellExecute = False,
            .Arguments = $"-i ""{Path}"" -o ""{oTempFile}"""
        }
        Dim oProcess As New Process() With {
            .StartInfo = oProcessStartInfo
        }

        Try
            oProcess.Start()
            oProcessOutput = oProcess.StandardOutput.ReadToEnd()
            oProcessError = oProcess.StandardError.ReadToEnd()
            oProcess.WaitForExit()
        Catch ex As Exception
            _logger.Error(ex)
            Return Nothing
        End Try

        If Not oProcessOutput.Contains(ZUGFERD_CONVERTER_SUCCESS_MESSAGE) Then
            _logger.Warn("File {0} is not a valid ZUGFeRD File!", Path)
            Return Nothing
        End If

        Try
            oXmlDocument = New XPath.XPathDocument(oTempFile)

        Catch ex As Exception
            _logger.Error(ex)
            Return Nothing
        End Try

        Return oXmlDocument
    End Function

    Public Function ParseXMLDocument(doc As XPathDocument)
        Dim nav As XPathNavigator = doc.CreateNavigator()
        Dim reader = nav.ReadSubtree()

        Dim serializer As New XmlSerializer(GetType(CrossIndustryDocumentType))
        Dim cross As CrossIndustryDocumentType = serializer.Deserialize(reader)
    End Function
End Class