Verifactu Visual Basic: Complying with Verifactu regulations

Imports System.Net.Http
Imports System.Net.Http.Headers
Imports System.Text
Imports System.Threading.Tasks

Module Module1
    Sub Main()
        ' Call the asynchronous method and wait for completion
        CreateInvoiceAsync().Wait()
    End Sub

    Private Async Function CreateInvoiceAsync() As Task
        Dim apiKey As String = "<API_KEY>"
        Dim url As String = "https://api.verifacti.com/verifactu/create"

        ' Build the JSON payload as a string
        Dim jsonPayload As String = "{" & _
            """serie"": ""A""," & _
            """numero"": ""234634""," & _
            """fecha_expedicion"": ""02-12-2024""," & _
            """tipo_factura"": ""F1""," & _
            """descripcion"": ""Descripcion de la operacion""," & _
            """nif"": ""A15022510""," & _
            """nombre"": ""Nombre cliente""," & _
            """lineas"": [{" & _
                """base_imponible"": ""200""," & _
                """tipo_impositivo"": ""21""," & _
                """cuota_repercutida"": ""42""" & _
            "}]," & _
            """importe_total"": ""242""" & _
            "}"

        Using client As New HttpClient()
            ' Set the authorization header
            client.DefaultRequestHeaders.Authorization = New AuthenticationHeaderValue("Bearer", apiKey)
            ' Set the Content-Type header
            client.DefaultRequestHeaders.Accept.Add(New MediaTypeWithQualityHeaderValue("application/json"))

            ' Create the StringContent with the JSON payload
            Dim content As New StringContent(jsonPayload, Encoding.UTF8, "application/json")

            ' Send the POST request asynchronously
            Dim response As HttpResponseMessage = Await client.PostAsync(url, content)

            If response.IsSuccessStatusCode Then
                Dim result As String = Await response.Content.ReadAsStringAsync()
                Console.WriteLine("Success: " & result)
            Else
                Console.WriteLine("Error: " & response.StatusCode.ToString())
            End If
        End Using
    End Function
End Module

Imports System.IO
Imports iTextSharp.text
Imports iTextSharp.text.pdf
  
Sub InsertarQR(ByVal pdfPath As String, ByVal qrBase64 As String)
    Dim pdfReader As New PdfReader(pdfPath)
    Dim pdfStamper As New PdfStamper(pdfReader, New FileStream("FacturaConQR.pdf", FileMode.Create))
    Dim content As PdfContentByte = pdfStamper.GetOverContent(1)

    Dim qrBytes As Byte() = Convert.FromBase64String(qrBase64)
    Dim qrImage As Image = Image.GetInstance(qrBytes)
    qrImage.SetAbsolutePosition(50, 50)
    content.AddImage(qrImage)

    pdfStamper.Close()
    pdfReader.Close()
End Sub

Imports ZXing
Imports System.Drawing

Sub GenerarQR(ByVal texto As String)
    Dim qrWriter As New BarcodeWriter()
    qrWriter.Format = BarcodeFormat.QR_CODE

    Dim bitmap As Bitmap = qrWriter.Write(texto)
    bitmap.Save("QR.png", Imaging.ImageFormat.Png)
End Sub