//default package

import java.io.FileInputStream;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Calendar;

import org.pdfbox.pdfparser.PDFParser;
import org.pdfbox.pdmodel.PDDocument;
import org.pdfbox.pdmodel.PDDocumentInformation;

import com.hp.hpl.jena.rdf.model.Model;
import com.hp.hpl.jena.rdf.model.ModelFactory;
import com.hp.hpl.jena.rdf.model.Resource;
import com.hp.hpl.jena.util.URIref;
import com.hp.hpl.jena.vocabulary.DC;
import com.hp.hpl.jena.vocabulary.DCTerms;
import com.hp.hpl.jena.vocabulary.DCTypes;
import com.hp.hpl.jena.vocabulary.RDF;

/**
 * quick'n'dirty PDF to RDF converter
 * 
 * @author mimas@mimas.ceti.pl
 * @version 1.0
 * 
 * @see <a href="http://www.pdfbox.org/">PDFBox - Java PDF Library</a>
 * @see <a href="http://jena.sourceforge.net/">Jena - Semantic Web Framework</a>
 */
public class PDF2RDF {

	public static void main(String[] args) throws Exception {
		if (args.length < 1) {
			System.out.println( "Usage: java PDF2RDF <pdf-file-name>" );
			System.exit(1);
		}

		Model model = ModelFactory.createDefaultModel();
		new PDF2RDF().addPDFResource(model, args[0]);
		
		// w ramach testu wyświetlam RDF odczytany z PDF
		// w zoptymalizowanej notacji RDF/XML
		System.out.println("*** RDF/XML:\n");
		model.write(System.out, "RDF/XML-ABBREV");
		// i w notacji N3
		System.out.println("\n*** N3:\n");
		model.write(System.out, "N3");
	}

	/**
	 * @param model Model RDF, do którego dodajemy zasób PDF 
	 * @param filename Nazwa pliku PDF-a
	 */
	public Resource addPDFResource(Model model, String filename) throws IOException {
		Resource pdf = null;
		PDDocument document = null;
		FileInputStream file = null;
		try {
			file = new FileInputStream(filename);
			PDFParser parser = new PDFParser(file);
			parser.parse();
			document = parser.getPDDocument();

			String nsPdf = "http://ns.adobe.com/pdf/1.3/";

			model.setNsPrefix("rdf", RDF.getURI());
			model.setNsPrefix("dc", DC.NS);
			model.setNsPrefix("dct", DCTerms.NS);
			model.setNsPrefix("pdf", nsPdf);

			pdf = model.createResource(URIref.encode("file://" + filename));
			pdf.addProperty(DC.type, DCTypes.Text);
			pdf.addProperty(DC.format, "application/pdf" );
			
			if (document.isEncrypted()) {
				try {
					document.decrypt("");
				} catch (Exception e) {
					System.err.println("Error: Failed to decrypt document.");
					return pdf;
				}
			}

			PDDocumentInformation info = document.getDocumentInformation();
			addProperty(model, pdf, nsPdf+"Title", info.getTitle());
			addProperty(model, pdf, nsPdf+"Subject", info.getSubject());
			addProperty(model, pdf, nsPdf+"Author", info.getAuthor());
			addProperty(model, pdf, nsPdf+"CreationDate", formatDate(info.getCreationDate()));
			addProperty(model, pdf, nsPdf+"ModDate", formatDate(info.getModificationDate()));
			addProperty(model, pdf, nsPdf+"Creator", info.getCreator());
			addProperty(model, pdf, nsPdf+"Producer", info.getProducer());
			addProperty(model, pdf, nsPdf+"Keywords", info.getKeywords());
			if ( info.getKeywords() != null )
			{
				String[] k = info.getKeywords().split(" ");
				for (int i = 0; i < k.length; i++) {
					pdf.addProperty(DC.subject, k[i]);
				}
			}

		} finally {
			if (file != null) {
				file.close();
			}
			if (document != null) {
				document.close();
			}
		}
		return pdf;
	}
	
	private void addProperty(Model m, Resource r, String p, String s) {
		if ( s != null )
			r.addProperty(m.createProperty(p), s);		
	}

	private String formatDate(Calendar date) {
		String retval = null;
		if (date != null) {
			SimpleDateFormat formatter = new SimpleDateFormat("yyyy.MM.dd HH:mm:ss");
			retval = formatter.format(date.getTime());
		}
		return retval;
	}

}