/*
 * $Id$
 * Copyright (C) 2001 The Apache Software Foundation. All rights reserved.
 * For details on use and redistribution please refer to the
 * LICENSE file included with these sources.
 */

package org.apache.fop.image.analyser;

// Java
import java.io.BufferedInputStream;
import java.io.IOException;

import org.w3c.dom.svg.SVGDocument;
import org.w3c.dom.svg.SVGSVGElement;

// FOP
import org.apache.fop.image.SVGImage;

import org.xml.sax.InputSource;
import org.xml.sax.XMLReader;

import org.apache.batik.dom.svg.SAXSVGDocumentFactory;

import org.apache.batik.dom.svg.*;
import org.w3c.dom.*;
import org.w3c.dom.svg.*;
import org.w3c.dom.svg.SVGLength;
import org.apache.batik.bridge.*;
import org.apache.batik.swing.svg.*;
import org.apache.batik.swing.gvt.*;
import org.apache.batik.gvt.*;
import org.apache.batik.gvt.renderer.*;
import org.apache.batik.gvt.filter.*;
import org.apache.batik.gvt.event.*;

import org.w3c.dom.DOMImplementation;
import org.apache.batik.dom.svg.SVGDOMImplementation;

import java.io.File;
import java.net.URL;
import java.util.List;
import java.util.ArrayList;
import java.awt.geom.AffineTransform;
import java.awt.Point;
import java.awt.geom.Dimension2D;
import java.awt.Dimension;

import org.apache.fop.fo.FOUserAgent;
import org.apache.fop.svg.SVGUserAgent;

/**
 * ImageReader object for SVG document image type.
 */
public class SVGReader extends AbstractImageReader {
    public static final String SVG_MIME_TYPE = "image/svg+xml";
    FOUserAgent userAgent;
    SVGDocument doc;

    public boolean verifySignature(String uri, BufferedInputStream fis,
                                   FOUserAgent ua) throws IOException {
        this.imageStream = fis;
        userAgent = ua;
        return loadImage(uri);
    }

    public String getMimeType() {
        return SVG_MIME_TYPE;
    }

    public SVGDocument getDocument() {
        return doc;
    }

    /**
     * This means the external svg document will be loaded twice.
     * Possibly need a slightly different design for the image stuff.
     */
    protected boolean loadImage(String uri) {
        // parse document and get the size attributes of the svg element
        try {
            int length = imageStream.available();
            imageStream.mark(length);
            SAXSVGDocumentFactory factory =
              new SAXSVGDocumentFactory(SVGImage.getParserName());
            doc = factory.createDocument(uri, imageStream);

            Element e = ((SVGDocument) doc).getRootElement();
            String s;
            SVGUserAgent userAg = new SVGUserAgent(new AffineTransform());
            userAg.setLogger(userAgent.getLogger());
            BridgeContext ctx = new BridgeContext(userAg);
            UnitProcessor.Context uctx =
              UnitProcessor.createContext(ctx, e);

            // 'width' attribute - default is 100%
            s = e.getAttributeNS(null, SVGOMDocument.SVG_WIDTH_ATTRIBUTE);
            if (s.length() == 0) {
                s = SVGOMDocument.SVG_SVG_WIDTH_DEFAULT_VALUE;
            }
            width = (int) UnitProcessor.svgHorizontalLengthToUserSpace (
                      s, SVGOMDocument.SVG_WIDTH_ATTRIBUTE, uctx);

            // 'height' attribute - default is 100%
            s = e.getAttributeNS(null, SVGOMDocument.SVG_HEIGHT_ATTRIBUTE);
            if (s.length() == 0) {
                s = SVGOMDocument.SVG_SVG_HEIGHT_DEFAULT_VALUE;
            }
            height = (int) UnitProcessor.svgVerticalLengthToUserSpace (
                       s, SVGOMDocument.SVG_HEIGHT_ATTRIBUTE, uctx);

            return true;
        } catch (NoClassDefFoundError ncdfe) {
            //userAgent.getLogger().error("Batik not in class path", ncdfe);
            return false;
        }
        catch (Exception e) {
            //userAgent.getLogger().error("Could not load external SVG: " +
            //                       e.getMessage(), e);
            // assuming any exception means this document is not svg
            // or could not be loaded for some reason
            try {
                imageStream.reset();
            } catch (IOException ioe) { }

            return false;
        }
    }

}