Option Strict Off
Imports System
Imports Microsoft.VisualBasic
Imports System.Windows.Forms
Imports System.Collections
Imports System.Threading
Imports System.Net
Imports System.Web.HttpUtility
Imports System.Text
Imports System.ComponentModel

Public Enum WebProcessStatus
    Idle = 0
    ReadingData = 1
    DataReady = 2
    PostingData = 3
    DataPosted = 4
    ReadingResult = 5
    ResultReady = 6
    Canceled = 7
    ErrorReading = 8
End Enum

Public Class WebProcess
    Public Status As WebProcessStatus
    Public ActionName As String
    Public URL As String
    Public lastError As String = ""
    Public sReadedHTML As String
    Public Event BeginReading()
    Public Event DataReaded(ByVal sender As Object)
    Public Event ErrorReading()
    Public Event ProgressChanged(ByVal sender As Object)
    Public progressStatus As Integer = 0
    Public WithEvents bgWork As New BackgroundWorker
    Public isCanceled As Boolean = False

    Public Sub New()
        bgWork.WorkerSupportsCancellation = True
    End Sub

    Public Sub StopProcess()
        isCanceled = True
        bgWork.CancelAsync()
    End Sub

    Public Function IsReady() As Boolean
        Select Case Status
            Case WebProcessStatus.Idle, WebProcessStatus.DataReady, WebProcessStatus.ResultReady
                Return True
            Case Else
                Return False
        End Select
    End Function

    Public Sub BeginRead()
        If Not bgWork.IsBusy Then
            progressStatus = 0
            bgWork.RunWorkerAsync()
        End If
    End Sub

    Private Sub bgWork_DoWork(ByVal sender As Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles bgWork.DoWork
        If bgWork.CancellationPending Then
            e.Cancel = True
        End If
        RaiseEvent BeginReading()
        Try
            Dim wRemote As System.Net.WebRequest
            Dim bBuffer(999) As Byte
            Dim iBytesRead As Integer
            wRemote = System.Net.WebRequest.Create(URL)
            Dim myWebResponse As System.Net.WebResponse = wRemote.GetResponse()
            Dim scaricati As Integer
            Dim dimensione As Integer
            lastError = myWebResponse.ContentLength.ToString
            If myWebResponse.ContentLength > -1 Then
                dimensione = Convert.ToInt32(myWebResponse.ContentLength)
            Else
                dimensione = 200000
            End If
            Dim bReadedHTML(dimensione) As Byte
            Dim sw As System.IO.MemoryStream = New System.IO.MemoryStream(bReadedHTML)
            Dim sChunks As System.IO.Stream = myWebResponse.GetResponseStream
            Do
                iBytesRead = sChunks.Read(bBuffer, 0, 256)
                lastError = "1"
                scaricati += iBytesRead
                lastError = "2"
                If scaricati > dimensione Then
                    dimensione += 9062
                    ReDim bReadedHTML(dimensione)
                End If
                progressStatus = Convert.ToInt32((scaricati * 100) / dimensione)
                If iBytesRead > 0 Then
                    sw.Write(bBuffer, 0, iBytesRead)
                End If
                RaiseEvent ProgressChanged(Me)
                Application.DoEvents()
            Loop While Not (iBytesRead = 0)
            progressStatus = 100
            RaiseEvent ProgressChanged(Me)
            sChunks.Close()
            sw.Close()
            Dim objUTF8 As New UTF8Encoding()
            sReadedHTML = objUTF8.GetString(bReadedHTML)
        Catch
            sReadedHTML = ""
            progressStatus = 100
            Status = WebProcessStatus.ErrorReading
            RaiseEvent ErrorReading()
        End Try
    End Sub

    Private Sub bgWork_RunWorkerCompleted(ByVal sender As Object, ByVal e As System.ComponentModel.RunWorkerCompletedEventArgs) Handles bgWork.RunWorkerCompleted
        '  If e.Error.Message <> "" Then
        'RaiseEvent ErrorReading()
        'End If
        If Not isCanceled Then
            Status = WebProcessStatus.DataReady
        Else
            Status = WebProcessStatus.Canceled
        End If
        RaiseEvent DataReaded(Me)
    End Sub

End Class