//
// Copyright (c) 2001-2012 by PDFTron Systems Inc. All Rights Reserved.
//

using System;
using System.IO;
using System.Collections;
using W = System.Web.UI;

using pdftron;
using pdftron.Common;
using pdftron.Filters;
using pdftron.SDF;
using pdftron.PDF;

namespace pdftron
{
	/// <summary>
	/// PdfToHtml implements a PDF to HTML converter using PDFNet.
	/// </summary>
	class PdfToHtml
	{
		public void Convert(TextWriter wri, PDFDoc doc)
		{
			Convert(wri, doc, -1, 1, "");
		}

		public void Convert(TextWriter wri, PDFDoc doc, int page_number, double zoom, string outpath)
		{
			_doc = doc;
			_zoom = zoom;
			_out_path = outpath;

			using (W.HtmlTextWriter html = new W.HtmlTextWriter(wri))
			{
				html.RenderBeginTag(W.HtmlTextWriterTag.Html);
				html.RenderBeginTag(W.HtmlTextWriterTag.Head);
				html.AddAttribute("http-equiv", "Content-Type");
				html.AddAttribute("content", "text/html");
				html.AddAttribute("charset", html.Encoding.WebName);
				html.RenderBeginTag(W.HtmlTextWriterTag.Meta);
				html.RenderEndTag(); // </meta>

				html.RenderBeginTag(W.HtmlTextWriterTag.Title);
				html.Write("PDFTron PdfToHtml Sample");
				html.RenderEndTag(); // </title>
				html.RenderEndTag(); // </head>

				html.RenderBeginTag(W.HtmlTextWriterTag.Body);

				ArrayList html_page_list = new ArrayList();
				_page_offset = 0;
				if (page_number == -1)
				{
					for (PageIterator itr = doc.GetPageIterator(); itr.HasNext(); itr.Next())
					{
						_page_height = (int)(itr.Current().GetPageHeight() * _zoom);
						html_page_list.Add(RenderHTMLBody(itr.Current()));
						_page_offset += _page_height;
					}
				}
				else
				{
					Page page = doc.GetPage(page_number);
					_page_height = (int)(page.GetPageHeight() * _zoom);
					html_page_list.Add(RenderHTMLBody(page));
				}

				// Write global CSS style section.
				html.RenderBeginTag(W.HtmlTextWriterTag.Style);
				html.AddAttribute("type", "text/css");
				foreach (DictionaryEntry style in _style_map)
					html.Write(".f" + style.Value +  "{" + style.Key + "}\n");
				html.RenderEndTag(); // </Style>
                
				foreach (Object page in html_page_list)
					html.Write(page);
                                
				html.RenderEndTag(); // </body>
				html.RenderEndTag(); // </html>

				wri.Close();
			}
		}

		private string RenderHTMLBody(Page page)
		{
			StringWriter strw = new StringWriter();
			using (W.HtmlTextWriter html = new W.HtmlTextWriter(strw, "	"))
			{
				using (TextExtractor txt = new TextExtractor())
				{
					// write page size info
					html.AddAttribute("id", page.GetIndex().ToString());
					html.AddStyleAttribute("position", "absolute");
					html.AddStyleAttribute("white-space", "nowrap");
					html.AddStyleAttribute("color", "#000000");
					html.AddStyleAttribute("top", _page_offset + "px");
					html.AddStyleAttribute("left", "0px");
					html.AddStyleAttribute("width", ((int)(page.GetPageWidth()* _zoom)).ToString() + "px");
					html.AddStyleAttribute("height", _page_height.ToString() + "px");
					html.RenderBeginTag("div");

					txt.Begin(page, null, TextExtractor.ProcessingFlags.e_none); // txt.Begin(page, null, TextExtractor.ProcessingFlags.e_remove_hidden_text);

					TextExtractor.Style s, line_style;

					// For each line on the page...
					for (TextExtractor.Line line = txt.GetFirstLine(); line.IsValid(); line = line.GetNextLine())
					{
						if (line.GetNumWords() == 0)
						{
							continue;
						}

						// For now, skip rotated lines
						if (!line.IsSimpleLine()) {
							continue;
						}

						line_style = line.GetStyle();
						Rect line_bbox = line.GetBBox();
						// AddStyle(html, line_style, line_bbox, page, false);
						// html.RenderBeginTag("span");

						// For each word in the line...
						bool first_word = true;
						for (TextExtractor.Word word = line.GetFirstWord(); word.IsValid(); word = word.GetNextWord())
						{
							int sz = word.GetStringLen();
							if (sz == 0) continue;

							s = word.GetStyle();
							Font f = new Font(s.GetFont());
							if (f.GetName().IndexOf("ZapfDingbats") >= 0)
								// f.IsSymbolic())
								// don't output the word if it is using ZapfDingbats?
								continue;

							if (true) // s != line_style) // If the word style is different from the parent style, output the a child span with a different style.
							{
								//html.RenderEndTag(); // </span - for line>

								Rect word_bbox = word.GetBBox(); 
								// Make the word box relative to the line.
								//word_bbox.x1 -= line_bbox.x1; word_bbox.y1 -= line_bbox.y1;
								//word_bbox.x2 -= line_bbox.x1; word_bbox.y2 -= line_bbox.y1;
								AddStyle(html, s, word_bbox, page, false);                                
								html.RenderBeginTag("span"); // Use each word as a span
								html.WriteEncodedText(word.GetString());
								html.RenderEndTag(); // </span - for word>

								//AddStyle(html, line_style, line_bbox, page, false);
								//html.RenderBeginTag("span");
							}
							else
							{
								if (first_word) first_word = false;
								else html.Write(" ");
								html.WriteEncodedText(word.GetString());
							}
						}

						// html.RenderEndTag(); // </span - for line>
					}
				}

				if (_draw_back_image)
				{
					string img = RenderHTMLBackgroundImage(page);
					if (img != "")
					{
						html.AddAttribute("src", img);
						html.AddAttribute("alt", "background image");

						html.RenderBeginTag("img");
						html.RenderEndTag(); // </img>
					}
				}

				html.RenderEndTag(); // </div>

				return strw.ToString();
			}
		}

		private string RenderHTMLBackgroundImage(Page page)
		{
			_reader = new ElementReader();
			_writer = new ElementWriter();
			_builder = new ElementBuilder();

			Page new_page = _doc.PageCreate();
			_writer.Begin(new_page);
			_reader.Begin(page);
			ProcessElements();
			_writer.End();
			_reader.End();

			_writer.Dispose();
			_reader.Dispose();
			_builder.Dispose();

			new_page.SetMediaBox(page.GetCropBox());
			new_page.SetRotation(page.GetRotation());

			string filename = "";
			using (PDFDraw draw = new PDFDraw())
			{
				draw.SetDPI(_zoom * 72);
				filename = String.Format("page{0}.png", page.GetIndex());
				draw.Export(new_page, _out_path+filename, "png");
			}

			return filename;
		}

		private void AddStyle(W.HtmlTextWriter html, TextExtractor.Style s, Rect bbox, Page page, bool relative)
		{
			double xpos = _zoom * bbox.x1, ypos;
			if (relative)
			{
				ypos = _zoom * bbox.y1;
			}
			else
			{
				ypos = _zoom * (page.GetPageHeight() - bbox.y1 - bbox.Height());
			}

			html.AddStyleAttribute("top", ((int)ypos).ToString() + "px");
			html.AddStyleAttribute("left", ((int)xpos).ToString() + "px");
			html.AddStyleAttribute("width", ((int)(_zoom * bbox.Width())).ToString() + "px");

			string font_class = "position:" + (relative ? "relative" : "absolute");
			font_class += ";font-size:" + (_zoom * s.GetFontSize()).ToString("G4");

			if (s.GetColor().ToArgb() != System.Drawing.Color.Black.ToArgb())
				font_class += ";color:" + System.Drawing.ColorTranslator.ToHtml(s.GetColor());

			// Trim away some characters from the font name that are not liked by CSS.
			string fnt = s.GetFontName();
			int idx = fnt.IndexOf('-');
			if (idx >= 0) fnt = fnt.Substring(0, idx);

			fnt += ",ArialUnicode,Arial,Helvetica";
			if (s.IsSerif()) fnt += ",sans-serif";
			font_class += ";font-family:" + fnt;

			if (s.IsItalic()) font_class += ";font-style:" + "italic";
			font_class += ";font-weight" + s.GetWeight().ToString();

			int class_id = 0;
			if (!_style_map.ContainsKey(font_class))
			{
				class_id = _style_map.Count;
				_style_map.Add(font_class, class_id);
			}
			else 
			{
				class_id = (int) _style_map[font_class];
			}

			html.AddAttribute("class", "f"+class_id.ToString());                        
		}

		Hashtable _style_map = new Hashtable();
        
		private void ProcessElements()
		{
			Element element;
			while ((element = _reader.Next()) != null)
			{
				switch (element.GetType())
				{
                    case Element.Type.e_text:
					{
						bool output_as_bitmap = false;

						Matrix2D mtx = element.GetCTM() * element.GetTextMatrix();
						if (mtx.m_b != 0)  // rotated or vertically skewed text -> output as text.
							output_as_bitmap = true;

						Font f = element.GetGState().GetFont();
						if (f.GetName().IndexOf("ZapfDingbats") >= 0) 
							// f.IsSymbolic())
							output_as_bitmap = true;

						if (output_as_bitmap) _writer.WriteElement(element);
						else continue;
					}
					break;
					case Element.Type.e_form:
						// Save GState ...
						Element e = _builder.CreateGroupBegin();
						Matrix2D form_mtx = element.GetGState().GetTransform();
						Obj m = element.GetXObject().FindObj("Matrix");
						if (m != null) form_mtx.Concat(m.GetAt(0).GetNumber(), m.GetAt(1).GetNumber(), m.GetAt(2).GetNumber(), m.GetAt(3).GetNumber(), m.GetAt(4).GetNumber(), m.GetAt(5).GetNumber());
						e.GetGState().SetTransform(form_mtx);
						_writer.WriteElement(e);

						_reader.FormBegin();

						// Output the clipping path for the Form XObject
						Obj box_obj = element.GetXObject().FindObj("BBox");
						if (box_obj != null)
						{
							Rect bbox = new Rect(box_obj);
							Element clip = _builder.CreateRect(bbox.x1, bbox.y1, bbox.Width(), bbox.Height());
							clip.SetPathClip(true); 
							clip.SetPathFill(false); 
							clip.SetPathStroke(false);
							_writer.WriteElement(clip);
						}
						ProcessElements();

						// Restore the graphics state
						_writer.WriteElement(_builder.CreateGroupEnd());
						_reader.End();
						break;
					default:
						_writer.WriteElement(element);
						break;
				}
			}
		}

		private string _out_path;
		private double _zoom = 1.0;

		private ElementWriter _writer = null;
		private ElementReader _reader = null;
		private ElementBuilder _builder = null;
		private PDFDoc _doc = null;
		private int _page_offset, _page_height;
		bool _draw_back_image = true;

		static void Main(string[] args)
		{
			PDFNet.Initialize();

			try	
			{
				using (PDFDoc doc = new PDFDoc("../../../../TestFiles/newsletter.pdf"))
				{
					doc.InitSecurityHandler();

					string output_path = "";
					using (TextWriter wri = File.CreateText(output_path + "out.html"))
					{
						PdfToHtml pdf2html = new PdfToHtml();
						pdf2html.Convert(wri, doc, -1, 96.0 / 72.0, output_path);
					}
				}
			}
			catch (PDFNetException e)
			{
				Console.WriteLine(e.Message);
			}

			Console.WriteLine("Done.");
		}
	}	
}