Imports System.Net
Imports System.Net.Mail
Imports System.Drawing
Imports System.Configuration
Imports System.Data.SqlClient
Imports System.Data

Partial Class login_ForgotPW
    Inherits System.Web.UI.Page
    Protected Sub Page_Load(sender As Object, e As EventArgs)
        If txt_Username.Text = "" Then
            Try
                txt_Username.Text = Request.QueryString.Item("Par1")
            Catch ex As Exception
                MsgBox(ex.Message)
            End Try
        End If
    End Sub
    Protected Sub btn_Back_Click(sender As Object, e As EventArgs)
        Response.Redirect("login/login_FLEX.aspx")
    End Sub

    Protected Sub SendEmail(sender As Object, e As EventArgs)
        Dim username As String = txt_Username.Text
        Dim password As String = String.Empty
        Dim email As String = txtEmail.Text
        Dim tokenname As String = ""
        ' cDBFunctions.GetNewOpenConnection()
        Dim ConnectionString = ""
        If HttpContext.Current.Request.ServerVariables("SERVER_NAME") = "localhost" Then
            'ConnectionString = "Server=DEVELOPER\DEVSQL;Database=VERAG_HOMEPAGE;Uid=sa;Pwd=BmWr501956"
            ConnectionString = "Server=DEVELOPER\DEVSQL;Database=VERAG_HOMEPAGE;Uid=AppUser;Pwd=yp/THDd?xM+pZ$;"
        Else
            ConnectionString = "Server=DEVELOPER.verag.ost.dmn\DEVSQL;Database=VERAG_HOMEPAGE;Uid=AppUser;Pwd=yp/THDd?xM+pZ$;"
            'ConnectionString = "Server=db593295684.db.1and1.com;Database=db593295684;Uid=dbo593295684;Pwd=atilla#2;"
        End If

        ' Dim constr As String = ConfigurationManager.ConnectionStrings("constr").ConnectionString
        Using con As New SqlConnection(ConnectionString)
            ' Using cmd As New SqlCommand("Validate_User")
            Using cmd As New SqlCommand("SELECT Username,Password FROM [VERAG_HOMEPAGE].[dbo].[Users] WHERE Username=@Username")
                ' cmd.CommandType = CommandType.StoredProcedure
                cmd.Parameters.AddWithValue("@Username", username)
                cmd.Connection = con
                con.Open()
                'userId = Convert.ToInt32(cmd.ExecuteScalar())
                Dim dr As SqlDataReader = cmd.ExecuteReader()
                If dr.Read() Then
                    username = dr("Username").ToString()
                    password = dr("Password").ToString()
                    Try

                        email = txtEmail.Text

                    Catch ex As Exception
                        Dim Msg, Style, Title As String
                        Msg = "E-mail Prüfung fehlgeschlagen!" & vbCrLf + "Bitte erneut versuchen!"
                        Style = vbRetry + vbExclamation + vbDefaultButton1
                        Title = "Fehler bei E-mail Authentifizierung!"
                        MsgBox(Msg, Style, Title)

                        If MsgBox(Msg, Style, Title).Yes Then
                            txtEmail.Text = ""
                            txtEmail.Focus()
                        ElseIf MsgBox(Msg, Style, Title).No Then

                        End If
                    End Try

                End If
            End Using
            con.Close()
        End Using
        tokenname = genToken(username, password, email)
        If SendEmail(username, password, email) = True Then
            'password = RandomString(New Random, 10)

            If (getDateoftoken(tokenname) = True) Then
                Dim msgboxstyle = vbDefaultButton1 + vbOK

                MsgBox(tokenname, msgboxstyle)
            Else
                MsgBox("token nicht mehr Gültig! Neuer wird generiert!")
                tokenname = genToken(username, password, email)
            End If
            'SendEmail(username, password, email)
            MsgBox("Mail would be sent successfully!")
            lblMessage.ForeColor = Color.Green
            lblMessage.Text = "Passwort wurde erfolgreich an die angegebene E-Mail Adresse gesendet."
        ElseIf SendEmail(username, password, email) = False Then
            MsgBox("Mail would not be sent successfully!")
            lblMessage.ForeColor = Color.Red
            lblMessage.Text = "Diese E-Mail ist nicht in unserer Datenbank vorhanden."
        End If
    End Sub

    Function RandomString(r As Random, max As Integer) As String
        Dim s As String = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789!§$%&/?="
        Dim sb As New StringBuilder
        Dim cnt As Integer = r.Next(4, max)
        For i As Integer = 1 To cnt
            Dim idx As Integer = r.Next(0, s.Length)
            sb.Append(s.Substring(idx, 1))
        Next
        Return sb.ToString()
    End Function

    Function SendEmail(username As String, password As String, email As String) As Boolean
        Dim lkb As LinkButton = New LinkButton()
        lkb.PostBackUrl = "ChangePW.aspx"
        Try
            Dim tokennametemp = genToken(username, password, email)
            If getDateoftoken(tokennametemp) = True Then
                Dim mailto As String = email
                Dim Betreff As String = "Passwort reset"
                Dim htmlbody = String.Format("Sehr geehrte/r {0},<br /><br /> Der Link zum Zurücksetzen des Passwortes lautet:<br /><br /><br />.<br />" + Environment.NewLine + lkb.PostBackUrl + Environment.NewLine + "<br />Mit freundlichen Grüßen,", username, password)
                '     Dim attachment As Attachment = New Attachment(File.OpenRead(excel), "Kundenliste.xlsx")
                '     Msg.Attachments.Add(attachment)
                VERAG_PROG_ALLGEMEIN.cProgramFunctions.sendMail(mailto, Betreff, htmlbody)
                MsgBox("SENT")
                Return True
            Else
                Return False
            End If
        Catch ex As Exception
            MsgBox(Err.Number & ex.Message & ex.StackTrace.ToString) 'Falls ein Fehler auftritt wird eine MsgBox angezeigt
        End Try
        Return False
    End Function

    Function genToken(username As String, password As String, email As String) As String
        Dim time() As Byte = BitConverter.GetBytes(DateTime.UtcNow.ToBinary())
        Dim Key() As Byte = Guid.NewGuid().ToByteArray()
        Try
            Dim token As String
            token = Convert.ToBase64String(time.Concat(Key).ToArray())
            Return token
        Catch Ex As Exception
            Dim Msg, Style, Title As String
            Msg = "Tokengenerierung fehlgeschlagen!" & vbCrLf & "Eine E-Mail wurde erneut an " + email + " zugesedet."
            Style = vbRetry + vbExclamation + vbDefaultButton1
            Title = "Fehler bei Token-Generierung"
            MsgBox(Msg, Style, Title)

            If MsgBox(Msg, Style, Title).Retry Then
                If SendEmail(username, password, email) = True Then
                    MsgBox("SENT")
                Else
                    MsgBox("Error02: Mail not delivered!")
                End If
            End If
        End Try
    End Function

    Function getDateoftoken(tokenname As String) As Boolean
        Dim data() As Byte = Convert.FromBase64String(tokenname)
        Dim wenn As DateTime = DateTime.FromBinary(BitConverter.ToInt64(data, 0))
        If wenn < DateTime.UtcNow.AddHours(-24) Then
            Return False
            MsgBox("Token nicht gefunden oder zu alt!" + Environment.NewLine + "Bitte erneut Mail senden!")
        Else
            Return True
        End If
    End Function

    Protected Sub txtEmail_TextChanged(sender As Object, e As EventArgs)
        regexval_txt_Email.Validate()
    End Sub
End Class