/*
 * Copyright (c) 2011, 2015, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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 General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package javafx.css.converter;

import javafx.application.Application;
import javafx.css.ParsedValue;
import javafx.css.StyleConverter;
import javafx.scene.text.Font;
import sun.util.logging.PlatformLogger;

import java.net.MalformedURLException;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
import java.security.AccessController;
import java.security.CodeSource;
import java.security.PrivilegedActionException;
import java.security.PrivilegedExceptionAction;
import java.security.ProtectionDomain;

/**
 * Convert url("<path>") a URL string resolved relative to the location of the stylesheet.
 *
 * @since 9
 */
public final class URLConverter extends StyleConverter<ParsedValue[], String> {

    // lazy, thread-safe instatiation
    private static class Holder {
        static final URLConverter INSTANCE = new URLConverter();
        static final SequenceConverter SEQUENCE_INSTANCE = new SequenceConverter();
    }

    public static StyleConverter<ParsedValue[], String> getInstance() {
        return Holder.INSTANCE;
    }

    private URLConverter() {
        super();
    }

    @Override
    public String convert(ParsedValue<ParsedValue[], String> value, Font font) {

        String url = null;

        ParsedValue[] values = value.getValue();

        String resource = values.length > 0 ? StringConverter.getInstance().convert(values[0], font) : null;

        if (resource != null && resource.trim().isEmpty() == false) {

            if (resource.startsWith("url(")) {
                resource = com.sun.javafx.util.Utils.stripQuotes(resource.substring(4, resource.length() - 1));
            } else {
                resource = com.sun.javafx.util.Utils.stripQuotes(resource);
            }

            String stylesheetURL = values.length > 1 && values[1] != null ? (String)values[1].getValue() : null;
            URL resolvedURL = resolve(stylesheetURL, resource);

            if (resolvedURL != null) url = resolvedURL.toExternalForm();
        }

        return url;
    }

    // package for testing
    URL resolve(String stylesheetUrl, String resource) {


        final String resourcePath = (resource != null) ? resource.trim() : null;
        if (resourcePath == null || resourcePath.isEmpty()) return null;

        try {

            // Note: the same code (pretty much) also appears in StyleManager

            // if stylesheetUri is null, then we're dealing with an in-line style.
            // If there is no scheme part, then the url is interpreted as being relative to the application's class-loader.
            URI resourceUri = new URI(resourcePath);

            if (resourceUri.isAbsolute()) {
                return resourceUri.toURL();
            }

            URL rtJarUrl = resolveRuntimeImport(resourceUri);
            if (rtJarUrl != null) {
                return rtJarUrl;
            }

            final String path = resourceUri.getPath();
            if (path.startsWith("/")) {
                final ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader();
                return contextClassLoader.getResource(path.substring(1));
            }

            final String stylesheetPath = (stylesheetUrl != null) ?  stylesheetUrl.trim() : null;

            if (stylesheetPath != null && stylesheetPath.isEmpty() == false) {

                URI stylesheetUri = new URI(stylesheetPath);

                if (stylesheetUri.isOpaque() == false) {

                    URI resolved = stylesheetUri.resolve(resourceUri);
                    return resolved.toURL();

                } else {

                    // stylesheet URI is something like jar:file:
                    URL url = stylesheetUri.toURL();
                    return new URL(url, resourceUri.getPath());
                }
            }


            // URL doesn't have scheme or stylesheetUrl is null
            final ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader();
            return contextClassLoader.getResource(path);


        } catch (final MalformedURLException|URISyntaxException e) {
            PlatformLogger cssLogger = com.sun.javafx.util.Logging.getCSSLogger();
            if (cssLogger.isLoggable(PlatformLogger.Level.WARNING)) {
                cssLogger.warning(e.getLocalizedMessage());
            }

            return null;
        }

    }


    //
    // Resolve a path from an @import that implies jfxrt.jar,
    // e.g., @import "com/sun/javafx/scene/control/skin/modena/modena.css".
    //
    // See also StyleSheet#loadStylesheet(String)
    //
    private URL resolveRuntimeImport(final URI resourceUri) {


        final String path = resourceUri.getPath();
        final String resourcePath = path.startsWith("/") ? path.substring(1) : path;

        if ((resourcePath.startsWith("com/sun/javafx/scene/control/skin/modena/") ||
             resourcePath.startsWith("com/sun/javafx/scene/control/skin/caspian/")) &&
            (resourcePath.endsWith(".css") || resourcePath.endsWith(".bss"))) {

            final SecurityManager sm = System.getSecurityManager();
            if (sm == null) {
                // If the SecurityManager is not null, then just look up the resource on the class-path.
                // If there is a SecurityManager, the URLClassPath getResource call will return null,
                // so fall through and create a URL from the code-source URI
                final ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader();
                final URL resolved = contextClassLoader.getResource(resourcePath);
                return resolved;
            }

            // check whether the path is file from our runtime jar
            try {
                final URL rtJarURL = AccessController.doPrivileged((PrivilegedExceptionAction<URL>) () -> {
                    // getProtectionDomain either throws a SecurityException or returns a non-null value
                    final ProtectionDomain protectionDomain = Application.class.getProtectionDomain();
                    // If we're running with a SecurityManager, then the ProtectionDomain will have a CodeSource
                    final CodeSource codeSource = protectionDomain.getCodeSource();
                    // The CodeSource location will be our runtime jar
                    return codeSource.getLocation();
                });

                final URI rtJarURI = rtJarURL.toURI();

                String scheme = rtJarURI.getScheme();
                String rtJarPath = rtJarURI.getPath();

                //
                // Just because we're running with a SecurityManager doesn't mean the jfxrt jar path is
                // a jar: URL. But the code in StyleManager wants it to be. So if we have
                // file:/blah/rt/lib/ext/jfxrt.jar make it jar:file:/blah/rt/lib/ext/jfxrt.jar!/
                //
                // If the path doesn't end with .jar, then we are just dealing with a normal file: path
                //
                if ("file".equals(scheme) && rtJarPath.endsWith(".jar")) {
                    if ("file".equals(scheme)) {
                        scheme = "jar:file";
                        rtJarPath = rtJarPath.concat("!/");
                    }
                }
                rtJarPath = rtJarPath.concat(resourcePath);

                final String rtJarUserInfo = rtJarURI.getUserInfo();
                final String rtJarHost = rtJarURI.getHost();
                final int rtJarPort = rtJarURI.getPort();

                //
                // Put together a new URI from the pieces of rtJarURI. We cannot use resolve here since
                // the scheme and path may have been munged.
                //
                URI resolved = new URI(scheme, rtJarUserInfo, rtJarHost, rtJarPort, rtJarPath, null, null);
                return resolved.toURL();

            } catch (URISyntaxException | MalformedURLException | PrivilegedActionException ignored) {
                // Allow this method to return null so the caller will try to further resolve the path.
                // If nothing else, an error message will result when the converted URL is consumed.
            }
        }
        return null;
    }

    @Override
    public String toString() {
        return "URLType";
    }

    public static final class SequenceConverter extends StyleConverter<ParsedValue<ParsedValue[], String>[], String[]> {

        public static SequenceConverter getInstance() {
            return Holder.SEQUENCE_INSTANCE;
        }

        private SequenceConverter() {
            super();
        }

        @Override
        public String[] convert(ParsedValue<ParsedValue<ParsedValue[], String>[], String[]> value, Font font) {
            ParsedValue<ParsedValue[], String>[] layers = value.getValue();
            String[] urls = new String[layers.length];
            for (int layer = 0; layer < layers.length; layer++) {
                urls[layer] = URLConverter.getInstance().convert(layers[layer], font);
            }
            return urls;
        }

        @Override
        public String toString() {
            return "URLSeqType";
        }
    }

}