Public Class Helpers

    ''' <summary>
    ''' Encodes the EnvelopeUUID and the ReceiverSignature into an EnvelopeKey
    ''' </summary>
    ''' <param name="pEnvelopeUuid"></param>
    ''' <param name="pReceiverSignature"></param>
    ''' <returns>The EnvelopeKey</returns>
    Public Shared Function EncodeEnvelopeReceiverId(pEnvelopeUuid As String, pReceiverSignature As String) As String
        Dim oString = $"{pEnvelopeUuid}::{pReceiverSignature}"
        Dim oBytes = Text.Encoding.UTF8.GetBytes(oString)
        Dim oBase64String = Convert.ToBase64String(oBytes)

        Return oBase64String
    End Function

    ''' <summary>
    ''' Decodes the EnvelopeKey and returns the EnvelopeUUID and the ReceiverSignature
    ''' </summary>
    ''' <param name="pEnvelopeReceiverId">The EnvelopeKey</param>
    ''' <returns>A tuple containing EnvelopeUUID and Receiver Signature</returns>
    Public Shared Function DecodeEnvelopeReceiverId(pEnvelopeReceiverId As String) As Tuple(Of String, String)
        Dim oBytes = Convert.FromBase64String(pEnvelopeReceiverId)
        Dim oString = Text.Encoding.UTF8.GetString(oBytes)
        Dim oSplit = oString.Split(New String() {"::"}, StringSplitOptions.None)

        Return New Tuple(Of String, String)(oSplit(0), oSplit(1))
    End Function

    Public Shared Function GetEnvelopeURL(pHost As String, pEnvelopeUuid As String, pReceiverSignature As String) As String
        Dim oEnvelopeUserReference As String = EncodeEnvelopeReceiverId(pEnvelopeUuid, pReceiverSignature)
        Dim oURL As String = String.Format("{0}/EnvelopeKey/{1}", pHost.Trim(), oEnvelopeUserReference)
        Return oURL

    End Function
End Class