package org.simantics.export.core.pdf;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import com.lowagie.text.pdf.PRStream;
import com.lowagie.text.pdf.PdfArray;
import com.lowagie.text.pdf.PdfDictionary;
import com.lowagie.text.pdf.PdfName;
import com.lowagie.text.pdf.PdfReader;
import com.lowagie.text.pdf.PdfString;

public class ImportPdfReader {

	/** File if opened from file */
	public File file;
	
	/** iText pdf reader */
	public PdfReader reader;
	
	List<Attachment> attachments;
	
	public ImportPdfReader() {		
	}
	
	public ImportPdfReader(File file) throws IOException {
		this.file = file;
		reader = new PdfReader(file.getAbsolutePath());
	}

	public List<Attachment> getAttachments() {
		if ( attachments != null ) return attachments;		
		attachments = new ArrayList<Attachment>();
		PdfDictionary root = reader.getCatalog();
		PdfDictionary names = (PdfDictionary)PdfReader.getPdfObject(root.get(PdfName.NAMES));
		if (names == null)
			return attachments;
		PdfDictionary embeddedfiles = names.getAsDict(PdfName.EMBEDDEDFILES);
		if (embeddedfiles == null)
			return attachments;
		PdfArray filespecs = embeddedfiles.getAsArray(PdfName.NAMES);
		if (filespecs == null)
			return attachments;
		for (int i = 0; i < filespecs.size();) {
			Attachment a = new Attachment();
			filespecs.getAsString(i++);
			a.filespec = filespecs.getAsDict(i++);
			a.refs = a.filespec.getAsDict(PdfName.EF);
			for (Object _key : a.refs.getKeys()) {
				a.key = (PdfName) _key;
				a.filename = a.filespec.getAsString(a.key);
				attachments.add( a );
			}
		}		
		return attachments;
	}
	
	public List<Attachment> getAttachments(String extension) {
		ArrayList<Attachment> result = new ArrayList<Attachment>();
		for ( Attachment a : getAttachments() ) {
			if ( a.getFilename().endsWith(extension) ) {
				result.add( a );
			}
		}
		return result;
	}
	
	public void close() {
		if ( reader!=null ) {
			reader.close();
			reader = null;
		}
	}

	public static class Attachment {
		PdfDictionary filespec;
		PdfDictionary refs;
		PdfName key;
		PdfString filename;
		
		public String getFilename() {
			return filename.toUnicodeString();
		}
		
		public void saveTo(File file) throws IOException {
			FileOutputStream fos;
			PRStream stream;
			if ( !file.exists() ) file.createNewFile();
			fos = new FileOutputStream(file); 
			try {
				stream = (PRStream) PdfReader.getPdfObject(refs.getAsIndirectObject(key));
				fos.write(PdfReader.getStreamBytes(stream));
				fos.flush();
			} finally {
				fos.close();
			}
		}
		
	}
	
}