/*

   Licensed to the Apache Software Foundation (ASF) under one or more
   contributor license agreements.  See the NOTICE file distributed with
   this work for additional information regarding copyright ownership.
   The ASF licenses this file to You under the Apache License, Version 2.0
   (the "License"); you may not use this file except in compliance with
   the License.  You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.

 */
package org.apache.batik.bridge;

import java.awt.Cursor;
import java.awt.Dimension;
import java.awt.Point;
import java.awt.geom.AffineTransform;
import java.awt.geom.Dimension2D;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;

import org.apache.batik.gvt.event.EventDispatcher;
import org.apache.batik.gvt.font.DefaultFontFamilyResolver;
import org.apache.batik.gvt.font.FontFamilyResolver;
import org.apache.batik.gvt.text.Mark;
import org.apache.batik.util.ParsedURL;
import org.apache.batik.util.SVGFeatureStrings;
import org.apache.batik.util.XMLResourceDescriptor;

import org.w3c.dom.Element;
import org.w3c.dom.svg.SVGAElement;
import org.w3c.dom.svg.SVGDocument;

/**
 * An abstract user agent adaptor implementation.  It exists to simply
 * the creation of UserAgent instances.
 *
 * @author <a href="mailto:thomas.deweese@kodak.com">Thomas DeWeese</a>
 * @version $Id$
 */
public class UserAgentAdapter implements UserAgent {
    protected Set FEATURES   = new HashSet();
    protected Set extensions = new HashSet();

    /**
     * The BridgeContext to use for error information.
     */
    protected BridgeContext ctx;

    /**
     * Sets the BridgeContext to be used for error information.
     */
    public void setBridgeContext(BridgeContext ctx) {
        this.ctx = ctx;
    }

    /**
     * Adds the standard SVG feature strings to the set of features supported
     * by this user agent.
     */
    public void addStdFeatures() {
        SVGFeatureStrings.addSupportedFeatureStrings(FEATURES);
    }

    /**
     * Returns the default size of this user agent (400x400).
     */
    public Dimension2D getViewportSize() {
        return new Dimension(1, 1);
    }

    /**
     * Display the specified message.
     */
    public void displayMessage(String message) {
    }

    /**
     * Display the specified error message (forwards call to displayMessage).
     */
    public void displayError(String message) {
        displayMessage(message);
    }

    /**
     * Display the specified error (forwards call to displayError(String))
     */
    public void displayError(Exception e) {
        displayError(e.getMessage());
    }

    /**
     * Shows an alert dialog box.
     */
    public void showAlert(String message) {
    }

    /**
     * Shows a prompt dialog box.
     */
    public String showPrompt(String message) {
        return null;
    }

    /**
     * Shows a prompt dialog box.
     */
    public String showPrompt(String message, String defaultValue) {
        return null;
    }

    /**
     * Shows a confirm dialog box.
     */
    public boolean showConfirm(String message) {
        return false;
    }

    /**
     * Returns the size of a px CSS unit in millimeters.
     */
    public float getPixelUnitToMillimeter() {
        return 0.26458333333333333333333333333333f; // 96dpi
    }

    /**
     * Returns the size of a px CSS unit in millimeters.
     * This will be removed after next release.
     * @see #getPixelUnitToMillimeter()
     */
    public float getPixelToMM() {
        return getPixelUnitToMillimeter();
            
    }

    /**
     * Returns the default font family.
     */
    public String getDefaultFontFamily() {
        return "Arial, Helvetica, sans-serif";
    }

    /** 
     * Returns the  medium font size. 
     */
    public float getMediumFontSize() {
        // 9pt (72pt = 1in)
        return 9f * 25.4f / (72f * getPixelUnitToMillimeter());
    }

    /**
     * Returns a lighter font-weight.
     */
    public float getLighterFontWeight(float f) { 
        return getStandardLighterFontWeight(f);
    }

    /**
     * Returns a bolder font-weight.
     */
    public float getBolderFontWeight(float f) {
        return getStandardBolderFontWeight(f);
    }


    /**
     * Returns the user language "en" (english).
     */
    public String getLanguages() {
        return "en";
    }

    /**
     * Returns this user agent's CSS media.
     */
    public String getMedia() {
        return "all";
    }

    /**
     * Returns this user agent's alternate style-sheet title.
     */
    public String getAlternateStyleSheet() {
        return null;
    }

    /**
     * Returns the user stylesheet 
     */
    public String getUserStyleSheetURI() {
        return null;
    }

    /**
     * Returns the XML parser to use
     */
    public String getXMLParserClassName() {
        return XMLResourceDescriptor.getXMLParserClassName();
    }

    /**
     * Returns <code>false</code>. The XML parser is not in validation mode.
     */
    public boolean isXMLParserValidating() {
        return false;
    }

    /**
     * Unsupported operation.
     */
    public EventDispatcher getEventDispatcher() {
        return null;
    }

    /**
     * Unsupported operation.
     */
    public void openLink(SVGAElement elt) { }

    /**
     * Unsupported operation.
     */
    public void setSVGCursor(Cursor cursor) { }

    /**
     * This user agent doesn't display text selections.
     */
    public void setTextSelection(Mark start, Mark end) { }

    /**
     * This user agent doesn't display text selections so nothing to clear.
     */
    public void deselectAll() { }

    /**
     * Unsupported operation.
     */
    public void runThread(Thread t) { }

    /**
     * Unsupported operation.
     */
    public AffineTransform getTransform() {
        return null;
    }

    /**
     * Unsupported operation.
     */
    public void setTransform(AffineTransform at) {
        // Do nothing.
    }

    /**
     * Unsupported operation.
     */
    public Point getClientAreaLocationOnScreen() {
        return new Point();
    }

    /**
     * Tells whether the given feature is supported by this
     * user agent.
     */
    public boolean hasFeature(String s) {
        return FEATURES.contains(s);
    }

    /**
     * Tells whether the given extension is supported by this
     * user agent.
     */
    public boolean supportExtension(String s) {
        return extensions.contains(s);
    }

    /**
     * Lets the bridge tell the user agent that the following
     * ex   tension is supported by the bridge.  
     */
    public void registerExtension(BridgeExtension ext) {
        Iterator i = ext.getImplementedExtensions();
        while (i.hasNext())
            extensions.add(i.next());
    }


    /**
     * Notifies the UserAgent that the input element 
     * has been found in the document. This is sometimes
     * called, for example, to handle &lt;a&gt; or
     * &lt;title&gt; elements in a UserAgent-dependant
     * way.
     */
    public void handleElement(Element elt, Object data){
    }

    /**
     * Returns the security settings for the given script
     * type, script url and document url
     * 
     * @param scriptType type of script, as found in the 
     *        type attribute of the &lt;script&gt; element.
     * @param scriptURL url for the script, as defined in
     *        the script's xlink:href attribute. If that
     *        attribute was empty, then this parameter should
     *        be null
     * @param docURL url for the document into which the 
     *        script was found.
     */
    public ScriptSecurity getScriptSecurity(String    scriptType,
                                            ParsedURL scriptURL,
                                            ParsedURL docURL){
        return new DefaultScriptSecurity(scriptType, scriptURL, docURL);
    }
    
    /**
     * This method throws a SecurityException if the script
     * of given type, found at url and referenced from docURL
     * should not be loaded.
     * 
     * This is a convenience method to call checkLoadScript
     * on the ScriptSecurity strategy returned by 
     * getScriptSecurity.
     *
     * @param scriptType type of script, as found in the 
     *        type attribute of the &lt;script&gt; element.
     * @param scriptURL url for the script, as defined in
     *        the script's xlink:href attribute. If that
     *        attribute was empty, then this parameter should
     *        be null
     * @param docURL url for the document into which the 
     *        script was found.
     */
    public void checkLoadScript(String scriptType,
                                ParsedURL scriptURL,
                                ParsedURL docURL) throws SecurityException {
        ScriptSecurity s = getScriptSecurity(scriptType,
                                             scriptURL,
                                             docURL);
        if (s != null) {
            s.checkLoadScript();
        }
    }

    /**
     * Returns the security settings for the given resource
     * url and document url
     * 
     * @param resourceURL url for the resource, as defined in
     *        the resource's xlink:href attribute. If that
     *        attribute was empty, then this parameter should
     *        be null
     * @param docURL url for the document into which the 
     *        resource was found.
     */
    public ExternalResourceSecurity 
        getExternalResourceSecurity(ParsedURL resourceURL,
                                    ParsedURL docURL) {
        return new RelaxedExternalResourceSecurity(resourceURL, docURL);
    }
    
    /**
     * This method throws a SecurityException if the resource
     * found at url and referenced from docURL
     * should not be loaded.
     * 
     * This is a convenience method to call checkLoadExternalResource
     * on the ExternalResourceSecurity strategy returned by 
     * getExternalResourceSecurity.
     *
     * @param resourceURL url for the resource, as defined in
     *        the resource's xlink:href attribute. If that
     *        attribute was empty, then this parameter should
     *        be null
     * @param docURL url for the document into which the 
     *        resource was found.
     */
    public void 
        checkLoadExternalResource(ParsedURL resourceURL,
                                  ParsedURL docURL) throws SecurityException {
        ExternalResourceSecurity s 
            =  getExternalResourceSecurity(resourceURL, docURL);

        if (s != null) {
            s.checkLoadExternalResource();
        }
    }

    /**
     * Returns a lighter font-weight.
     */
    public static float getStandardLighterFontWeight(float f) {
        // Round f to nearest 100...
        int weight = ((int)((f+50)/100))*100;
        switch (weight) {
        case 100: return 100;
        case 200: return 100;
        case 300: return 200;
        case 400: return 300;
        case 500: return 400;
        case 600: return 400;
        case 700: return 400;
        case 800: return 400;
        case 900: return 400;
        default:
            throw new IllegalArgumentException("Bad Font Weight: " + f);
        }
    }

    /**
     * Returns a bolder font-weight.
     */
    public static float getStandardBolderFontWeight(float f) {
        // Round f to nearest 100...
        int weight = ((int)((f+50)/100))*100;
        switch (weight) {
        case 100: return 600;
        case 200: return 600;
        case 300: return 600;
        case 400: return 600;
        case 500: return 600;
        case 600: return 700;
        case 700: return 800;
        case 800: return 900;
        case 900: return 900;
        default:
            throw new IllegalArgumentException("Bad Font Weight: " + f);
        }
    }

    /**
     * This Implementation simply throws a BridgeException.
     *
     * @param e   The &lt;image> element that can't be loaded.
     * @param url The resolved url that can't be loaded.
     * @param message As best as can be determined the reason it can't be
     *                loaded (not available, corrupt, unknown format,...).
     */
    public SVGDocument getBrokenLinkDocument(Element e, 
                                             String url, 
                                             String message) {
        throw new BridgeException(ctx, e, ErrorConstants.ERR_URI_IMAGE_BROKEN,
                                  new Object[] {url, message });
    }

    /**
     * This method should load a new document described by the supplied URL.
     *
     * @param url The url to be loaded as a string.
     */
    public void loadDocument(String url) {
        // Do nothing.
    }

    /**
     * Returns the Font Family Resolver
     */
    public FontFamilyResolver getFontFamilyResolver() {
        return DefaultFontFamilyResolver.SINGLETON;
    }
}