using PdfSharp;
using PdfSharp.Drawing;
using System;
using System.Collections.Generic;
using System.IO;
using System.IO.Packaging;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.Windows.Threading;
using System.Windows.Xps;
using System.Windows.Xps.Packaging;

namespace Tango.PDF
{
    public class PdfWpfWriter
    {
        private List<FrameworkElement> _elements;

        public PdfWpfWriter()
        {
            _elements = new List<FrameworkElement>();
        }

        public void AddElement(FrameworkElement element)
        {
            _elements.Add(element);
        }

        public void RemoveElement(FrameworkElement element)
        {
            _elements.Remove(element);
        }

        public Size GetA4Size()
        {
            XSize a4Size = PageSizeConverter.ToSize(PageSize.A4);
            return new Size(a4Size.Width, a4Size.Height);
        }

        public void Save(String filePath)
        {
            using (MemoryStream lMemoryStream = new MemoryStream())
            {
                Package package = Package.Open(lMemoryStream, FileMode.Create);
                XpsDocument doc = new XpsDocument(package);
                XpsDocumentWriter writer = XpsDocument.CreateXpsDocumentWriter(doc);

                List<StackPanel> stacks = new List<StackPanel>();

                StackPanel currentStack = new StackPanel();
                stacks.Add(currentStack);

                XSize a4Size = PageSizeConverter.ToSize(PageSize.A4);

                foreach (var element in _elements.ToList())
                {
                    //element.Width = a4Size.Width * 0.80;
                    currentStack.Children.Add(element);

                    currentStack.Measure(new Size(Double.MaxValue, Double.MaxValue));
                    Size visualSize = currentStack.DesiredSize;
                    currentStack.Arrange(new Rect(new Point(0, 0), visualSize));
                    currentStack.UpdateLayout();

                    if (visualSize.Height > a4Size.Height)
                    {
                        currentStack.Children.Remove(element);
                        currentStack.UpdateLayout();
                        currentStack.InvalidateVisual();

                        currentStack = new StackPanel();
                        currentStack.Children.Add(element);
                        stacks.Add(currentStack);
                    }
                }

                Application.Current.Dispatcher.BeginInvoke(DispatcherPriority.ApplicationIdle, new Action(() => { })).Wait();
                Application.Current.Dispatcher.BeginInvoke(DispatcherPriority.Render, new Action(() => { })).Wait();

                FixedDocument fixedDoc = new FixedDocument();

                foreach (var stack in stacks)
                {
                    PageContent pageContent = new PageContent();
                    FixedPage fixedPage = new FixedPage();
                    fixedPage.Height = a4Size.Height;
                    fixedPage.Width = a4Size.Width;

                    fixedPage.Children.Add(stack);
                    ((System.Windows.Markup.IAddChild)pageContent).AddChild(fixedPage);
                    fixedDoc.Pages.Add(pageContent);
                }

                writer.Write(fixedDoc);
                doc.Close();
                package.Close();

                MemoryStream outStream = new MemoryStream();
                PdfSharp.Xps.XpsConverter.Convert(lMemoryStream, outStream, true);

                File.WriteAllBytes(filePath, outStream.ToArray());

                lMemoryStream.Dispose();
                outStream.Dispose();
            }
        }
    }
}