/************************************************************************
 *
 *  ImageLoader.java
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License version 2.1, as published by the Free Software Foundation.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 *  MA  02111-1307  USA
 *
 *  Copyright: 2002-2012 by Henrik Just
 *
 *  All Rights Reserved.
 * 
 *  Version 1.4 (2012-04-03)
 *
 */

package writer2latex.office;

import java.text.DecimalFormat;
import java.text.NumberFormat;
import java.util.HashSet;

import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

import writer2latex.api.GraphicConverter;
import writer2latex.util.Base64;
import writer2latex.util.Misc;
import writer2latex.xmerge.BinaryGraphicsDocument;

/**
 *  <p>This class extracts images from an OOo file.
 *  The images are returned as BinaryGraphicsDocument.</p>
 */
public final class ImageLoader {
    // The Office document to load images from
    private OfficeDocument oooDoc;
	
    // Data for file name generation
    private String sBaseFileName = "";
    private String sSubDirName = "";
    private int nImageCount = 0;
    private NumberFormat formatter;
	
    // should EPS be extracted from SVM?
    private boolean bExtractEPS;
	
    // Data for image conversion
    private GraphicConverter gcv = null;
    private boolean bAcceptOtherFormats = true;
    private String sDefaultFormat = null;
    private String sDefaultVectorFormat = null;
    private HashSet<String> acceptedFormats = new HashSet<String>();

    public ImageLoader(OfficeDocument oooDoc, boolean bExtractEPS) {
        this.oooDoc = oooDoc;
        this.bExtractEPS = bExtractEPS;
        this.formatter = new DecimalFormat("000");
    }
	
    public void setBaseFileName(String sBaseFileName) { this.sBaseFileName = sBaseFileName; }
    
    public void setUseSubdir(String sSubDirName) { this.sSubDirName = sSubDirName+"/"; }
    
    public void setAcceptOtherFormats(boolean b) { bAcceptOtherFormats = b; }
	
    public void setDefaultFormat(String sMime) {
        addAcceptedFormat(sMime);
        sDefaultFormat = sMime;
    }
	
    public void setDefaultVectorFormat(String sMime) {
        addAcceptedFormat(sMime);
        sDefaultVectorFormat = sMime;
    }
	
    public void addAcceptedFormat(String sMime) { acceptedFormats.add(sMime); }
	
    private boolean isAcceptedFormat(String sMime) { return acceptedFormats.contains(sMime); }
	
    public void setGraphicConverter(GraphicConverter gcv) { this.gcv = gcv; }
    
    public BinaryGraphicsDocument getImage(Node node) {
        // node must be a draw:image element.
        // variables to hold data about the image:
        String sMIME = null;
        String sExt = null;
        byte[] blob = null;

        String sHref = Misc.getAttribute(node,XMLString.XLINK_HREF);
        if (sHref==null || sHref.length()==0) {
            // Image must be contained in an office:binary-element as base64:
            Node obd = Misc.getChildByTagName(node,XMLString.OFFICE_BINARY_DATA);
            if (obd!=null) {
                StringBuffer buf = new StringBuffer();
                NodeList nl = obd.getChildNodes();
                int nLen = nl.getLength();
                for (int i=0; i<nLen; i++) {
                    if (nl.item(i).getNodeType()==Node.TEXT_NODE) {
                        buf.append(nl.item(i).getNodeValue());
                    }
                }
                blob = Base64.decode(buf.toString());
                sMIME = MIMETypes.getMagicMIMEType(blob);
                sExt = MIMETypes.getFileExtension(sMIME);
            }
        }
        else {
            // Image may be embedded in package:
            if (sHref.startsWith("#")) { sHref = sHref.substring(1); }
            if (sHref.startsWith("./")) { sHref = sHref.substring(2); }
            EmbeddedObject obj = oooDoc.getEmbeddedObject(sHref);
            if (obj!=null && obj instanceof EmbeddedBinaryObject) {
                EmbeddedBinaryObject object = (EmbeddedBinaryObject) obj;
                blob = object.getBinaryData();
                sMIME = object.getType();
                if (sMIME.length()>0) {
                    // If the manifest provides a media type, trust that
                	sExt = MIMETypes.getFileExtension(sMIME);
                }
                else {
                    // Otherwise determine it by byte inspection
                	sMIME = MIMETypes.getMagicMIMEType(blob);
                	sExt = MIMETypes.getFileExtension(sMIME);
                }
            }
            else {
                // This is a linked image
                // TODO: Perhaps we should download the image from the url in sHref?
                // Alternatively BinaryGraphicsDocument should be extended to
                // handle external graphics.
            }
        }

        if (blob==null) { return null; }

        // Assign a name (without extension) 
        String sName = sSubDirName+sBaseFileName+formatter.format(++nImageCount);
     
        BinaryGraphicsDocument bgd = null;

        if (bExtractEPS && MIMETypes.SVM.equals(MIMETypes.getMagicMIMEType(blob))) {
            // Look for postscript:
            int[] offlen = new int[2];
            if (SVMReader.readSVM(blob,offlen)) {
                bgd = new BinaryGraphicsDocument(sName,
                             MIMETypes.EPS_EXT,MIMETypes.EPS);
                bgd.read(blob,offlen[0],offlen[1]);
             }
        }

        if (bgd==null) {
            // If we have a converter AND a default format AND this image
            // is not in an accepted format AND the converter knows how to
            // convert it - try to convert...
            if (gcv!=null && !isAcceptedFormat(sMIME) && sDefaultFormat!=null) {
            	byte[] newBlob = null;
                String sTargetMIME = null;

                if (MIMETypes.isVectorFormat(sMIME) && sDefaultVectorFormat!=null &&
                    gcv.supportsConversion(sMIME,sDefaultVectorFormat,false,false)) {
                	// Try vector format first
                    newBlob = gcv.convert(blob, sMIME, sTargetMIME=sDefaultVectorFormat);
                }
                if (newBlob==null && gcv.supportsConversion(sMIME,sDefaultFormat,false,false)) {
                	// Then try bitmap format
                    newBlob = gcv.convert(blob,sMIME,sTargetMIME=sDefaultFormat);
                }

                if (newBlob!=null) {
                	// Conversion successful - create new data
                	blob = newBlob;
                	sMIME = sTargetMIME;
                	sExt = MIMETypes.getFileExtension(sMIME);
                }
            }

            if (isAcceptedFormat(sMIME) || bAcceptOtherFormats) {
                bgd = new BinaryGraphicsDocument(sName,sExt,sMIME);
                bgd.read(blob);
            }
        }
		
        return bgd;
    }
}