ZugferdInfo.cs
//
// This code is part of GrapeCity Documents for PDF samples.
// Copyright (c) GrapeCity, Inc. All rights reserved.
//
using System;
using System.IO;
using System.Drawing;
using System.Linq;
using System.Reflection;
using System.Collections.Generic;
using System.Globalization;
using GrapeCity.Documents.Pdf;
using GrapeCity.Documents.Text;
using s2industries.ZUGFeRD;

namespace GcPdfWeb.Samples
{
    // This sample demonstrates how to retrieve invoice data from a ZUGFeRD compliant XML attachment.
    // Selected portions of the fetched invoice data are printed to the PDF generated by this sample.
    // See ZugferdInfoExt for a similar sample that prints out all ZUGFeRD data.

    // The sample PDF invoice containing ZUGFeRD data which this sample uses as input
    // was generated by ZugferdInvoice.
    //
    // ZUGFeRD is a German e-invoicing standard based around PDF and XML file formats.
    // Its poised to change the way invoices are handled and can be used by any sort of business.
    // It will make invoice processing more efficient for senders and customers.
    // For details please see What is ZUGFeRD?.
    //
    // This sample uses the ZUGFeRD-csharp package
    // to parse the ZUGFeRD-compatible XML that is attached to the invoice.
    public class ZugferdInfo
    {
        public int CreatePDF(Stream stream)
        {
            // The sample invoice with ZUGFeRD data:
            var invoicePdf = Path.Combine("Resources", "PDFs", "zugferd-invoice.pdf");

            // Text formats for output:
            var tfData = new TextFormat() {
                Font = Font.FromFile(Path.Combine("Resources", "Fonts", "segoeui.ttf")), 
                FontSize = 12
            };
            var tfStrong = new TextFormat(tfData) {
                Font = Font.FromFile(Path.Combine("Resources", "Fonts", "segoeuib.ttf"))
            };
            var tfLabels = new TextFormat(tfData) {
                Font = Font.FromFile(Path.Combine("Resources", "Fonts", "segoeuii.ttf")),
                FontSize = 11
            };
            float margin = 36;

            // Output document:
            var doc = new GcPdfDocument();
            using (FileStream fs = File.OpenRead(invoicePdf))
            {
                // Load the ZUGFeRD compliant invoice PDF:
                var invoice = new GcPdfDocument();
                invoice.Load(fs);

                // Get the ZUGFeRD attachment from the invoice by the ZUGFeRD 1.x standard file name:
                var attachment = invoice.EmbeddedFiles.Values.FirstOrDefault(it => it.File.FileName == "ZUGFeRD-invoice.xml");
                if (attachment != null)
                {
                    using (var xmlstream = attachment.GetStream())
                    {
                        // Load the invoice descriptor:
                        var descriptor = InvoiceDescriptor.Load(xmlstream);
                        var culture = CultureInfo.CreateSpecificCulture("en-US");

                        // Print out the invoice data:
                        var page = doc.NewPage();
                        var g = page.Graphics;
                        var tl = g.CreateTextLayout();

                        tl.MaxWidth = page.Size.Width;
                        tl.MaxHeight = page.Size.Height;
                        tl.MarginAll = margin;

                        // The invoice header:
                        tl.Append($"Invoice Number: ", tfLabels);
                        tl.AppendLine($"{descriptor.InvoiceNo}", tfData);
                        tl.Append($"Invoice Date: ", tfLabels);
                        tl.AppendLine($"{descriptor.InvoiceDate.Value:yyyy-MM-dd}", tfData);
                        tl.Append($"Seller Name: ", tfLabels);
                        tl.AppendLine($"{descriptor.Seller.Name}", tfData);
                        tl.Append($"Seller Address: ", tfLabels);
                        tl.AppendLine($"{descriptor.Seller.Street}, {descriptor.Seller.City}, {descriptor.Seller.Postcode}, {descriptor.Seller.Country}", tfData);
                        tl.Append($"Buyer Name: ", tfLabels);
                        tl.AppendLine($"{descriptor.BuyerContact.Name} {descriptor.Buyer.Name}", tfData);
                        tl.Append($"Buyer Address: ", tfLabels);
                        tl.AppendLine($"{descriptor.Buyer.Street}, {descriptor.Buyer.City}, {descriptor.Buyer.Postcode}, {descriptor.Buyer.Country}", tfData);
                        tl.AppendLine();

                        // The invoice positions:
                        tl.TabStops = new List<TabStop>()
                        {
                            new TabStop(margin, TabStopAlignment.Leading),
                            new TabStop(page.Size.Width - margin * 2 - 144, TabStopAlignment.Trailing),
                            new TabStop(page.Size.Width - margin * 2, TabStopAlignment.Trailing),
                        };
                        decimal totals = 0;
                        var index = 1;
                        tl.AppendLine("#\tName\tQuantity\tAmount", tfLabels);
                        descriptor.TradeLineItems.ForEach(it =>
                        {
                            tl.AppendLine($"{index++}\t{it.Name}\t{Convert.ToInt32(it.BilledQuantity)}\t{it.LineTotalAmount.Value.ToString("C", culture)}", tfData);
                            totals += it.LineTotalAmount.Value;
                        });
                        // The invoice total:
                        tl.AppendLine($"\tTOTAL:\t\t{totals.ToString("C", culture)}", tfStrong);

                        g.DrawTextLayout(tl, PointF.Empty);

                        // Done:
                        doc.Save(stream);
                        return doc.Pages.Count;
                    }
                }
                else
                    return 0;
            }
        }
    }
}