Imports DigitalData.Modules.Logging
Imports DigitalData.Modules.ZooFlow.Base
Imports DigitalData.Modules.Language.DateTimeEx
Imports System.IO
Imports System.Text
Imports System.Timers

Namespace DocumentResultList
    Public Class Opener
        Inherits BaseClass

        Private WithEvents FileOpenTimer As New Timer

        ' TODO: Hashes for checking if the opened file was modified externally
        Private HashOriginalFile As String = Nothing
        Private HashOpenedFile As String = Nothing

        Private OpenFiles As New Dictionary(Of Integer, Document)

        Public Event ProcessEnded As EventHandler(Of Document)

        Public Sub New(pLogConfig As LogConfig)
            MyBase.New(pLogConfig)
        End Sub

        Public Function OpenDocument(pDocument As Document) As Boolean
            Dim oProcessId As Integer = Nothing

            If pDocument.FullPath Is Nothing OrElse pDocument.FullPath.Trim = String.Empty Then
                oProcessId = OpenFileFromPath(pDocument)

            ElseIf pDocument.Extension IsNot Nothing AndAlso pDocument.Contents IsNot Nothing Then
                oProcessId = OpenFileFromByteArry(pDocument)

            End If

            If IsNothing(oProcessId) Then
                Logger.Warn("Process Id was empty. Returning false.")
                Return False
            End If

            OpenFiles.Add(oProcessId, pDocument)

            Return True
        End Function

        Private Function OpenFileFromByteArry(pDocument As Document) As Integer
            Try
                ' TODO: Open file from temp folder
                Dim oTempPath = Path.Combine(Path.GetTempPath(), Constants.TEMP_PATH_SUBFOLDER)
                Dim oDirectory = Directory.CreateDirectory(oTempPath)
                Dim oFileName = $"{pDocument.Id}-{Now.UnixTimestamp}.{pDocument.Extension}"
                Dim oFilePath = Path.Combine(oTempPath, oFileName)

                Using oMemoryStream As New MemoryStream(pDocument.Contents)
                    Using oStreamWriter As New StreamWriter(oFilePath, append:=False, Encoding.UTF8)
                        oMemoryStream.CopyTo(oMemoryStream)
                    End Using
                End Using

                Dim oProcess = OpenFile(oFilePath)
                Return oProcess.Id

            Catch ex As Exception
                Logger.Error(ex)
                Return Nothing

            End Try
        End Function

        Private Function OpenFileFromPath(pDocument As Document) As Integer
            Try
                Dim oProcess = OpenFile(pDocument.FullPath)
                Return oProcess.Id

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

        Private Function OpenFile(pFilePath As String) As Process
            Dim oProcess = Process.Start(New ProcessStartInfo With {
                .FileName = pFilePath
            })

            Return oProcess
        End Function

        Private Sub FileOpenTimer_Elapsed() Handles FileOpenTimer.Elapsed
            Try
                Dim oIds = Process.GetProcesses().
                    Select(Function(process) process.Id).
                    ToList()

                Dim oNewFileOpenList As New Dictionary(Of Integer, Document)
                For Each oOpenFile In OpenFiles
                    If oIds.Contains(oOpenFile.Key) Then
                        oNewFileOpenList.Add(oOpenFile.Key, oOpenFile.Value)
                    End If
                Next

                If oNewFileOpenList.Count < OpenFiles.Count Then
                    Dim oClosedFiles = OpenFiles.
                        Except(oNewFileOpenList).
                        ToList()

                    If oClosedFiles.Count = 1 Then
                        Dim oOpenFile = oClosedFiles.First()
                        RaiseEvent ProcessEnded(Me, oOpenFile.Value)
                    End If

                    OpenFiles = oNewFileOpenList
                End If
            Catch ex As Exception
                Logger.Error(ex)
            End Try
        End Sub
    End Class

End Namespace