/**

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.

 *

 * Copyright 1997-2010 Oracle and/or its affiliates. All rights reserved.

 *

 * Oracle and Java are registered trademarks of Oracle and/or its affiliates.

 * Other names may be trademarks of their respective owners.

 *

 * The contents of this file are subject to the terms of either the GNU

 * General Public License Version 2 only ("GPL") or the Common

 * Development and Distribution License("CDDL") (collectively, the

 * "License"). You may not use this file except in compliance with the

 * License. You can obtain a copy of the License at

 * http://www.netbeans.org/cddl-gplv2.html

 * or nbbuild/licenses/CDDL-GPL-2-CP. See the License for the

 * specific language governing permissions and limitations under the

 * License.  When distributing the software, include this License Header

 * Notice in each file and include the License file at

 * nbbuild/licenses/CDDL-GPL-2-CP.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the GPL Version 2 section of the License file that

 * accompanied this code. If applicable, add the following below the

 * License Header, with the fields enclosed by brackets [] replaced by

 * your own identifying information:

 * "Portions Copyrighted [year] [name of copyright owner]"

 *

 * Contributor(s):

 *

 * The Original Software is NetBeans. The Initial Developer of the Original

 * Software is Oracle. Portions Copyright 2013-2013 Oracle. All Rights Reserved.

 *

 * If you wish your version of this file to be governed by only the CDDL

 * or only the GPL Version 2, indicate your decision by adding

 * "[Contributor] elects to include this software in this distribution

 * under the [CDDL or GPL Version 2] license." If you do not indicate a

 * single choice of license, a recipient has the option to distribute

 * your version of this file under either the CDDL, the GPL Version 2 or

 * to extend the choice of license to its licensees as provided above.

 * However, if you add GPL Version 2 code and therefore, elected the GPL

 * Version 2 license, then the option applies only if the new code is

 * made subject to such option by the copyright holder.

 */

package net.java.html.boot;

import java.io.File;

import java.io.IOException;

import java.lang.reflect.Method;

import java.net.MalformedURLException;

import java.net.URL;

import java.util.Arrays;

import java.util.Collection;

import java.util.Enumeration;

import java.util.ServiceLoader;

import java.util.logging.Level;

import java.util.logging.Logger;

import net.java.html.js.JavaScriptBody;

import org.netbeans.html.boot.impl.FnUtils;

import org.apidesign.html.boot.spi.Fn;

import org.netbeans.html.boot.impl.FindResources;

import org.netbeans.html.boot.impl.FnContext;

/** Use this builder to launch your Java/HTML based application. Typical

 * usage in a main method of your application looks like this: 

 * <pre>

 * 

 * <b>public static void</b> <em>main</em>(String... args) {

 *     BrowserBuilder.{@link #newBrowser}.

 *          {@link #loadClass(java.lang.Class) loadClass(YourMain.class)}.

 *          {@link #loadPage(java.lang.String) loadPage("index.html")}.

 *          {@link #invoke(java.lang.String, java.lang.String[]) invoke("initialized", args)}.

 *          {@link #showAndWait()};

 *     System.exit(0);

 * }

 * </pre>

 * The above will load <code>YourMain</code> class via

 * a special classloader, it will locate an <code>index.html</code> (relative

 * to <code>YourMain</code> class) and show it in a browser window. When the

 * initialization is over, a <b>public static</b> method <em>initialized</em>

 * in <code>YourMain</code> will be called with provided string parameters.

 * <p>

 * This module provides only API for building browsers. To use it properly one

 * also needs an implementation on the classpath of one's application. For example

 * use: <pre>

 * <dependency>

 *   <groupId>org.netbeans.html</groupId>

 *   <artifactId>net.java.html.boot.fx</artifactId>

 *   <scope>runtime</scope>

 * </dependency>

 * </pre>

 *

 * @author Jaroslav Tulach <jtulach@netbeans.org>

 */

public final class BrowserBuilder {

    private static final Logger LOG = Logger.getLogger(BrowserBuilder.class.getName());

    private String resource;

    private Class<?> clazz;

    private Class[] browserClass;

    private Runnable onLoad;

    private String methodName;

    private String[] methodArgs;

    private final Object[] context;

    private BrowserBuilder(Object[] context) {

        this.context = context;

    }

    /** Entry method to obtain a new browser builder. Follow by calling 

     * its instance methods like {@link #loadClass(java.lang.Class)} and

     * {@link #loadPage(java.lang.String)}.

     * 

     * @param context any instances that should be available to the builder -

     *   implemenation dependant

     * @return new browser builder

     */

    public static BrowserBuilder newBrowser(Object... context) {

        return new BrowserBuilder(context);

    }

    /** The class to load when the browser is initialized. This class

     * is loaded by a special classloader (that supports {@link JavaScriptBody}

     * and co.). 

     * 

     * @param mainClass the class to load and resolve when the browser is ready

     * @return this builder

     */

    public BrowserBuilder loadClass(Class<?> mainClass) {

        this.clazz = mainClass;

        return this;

    }

    /** Page to load into the browser. If the <code>page</code> represents

     * a {@link URL} known to the Java system, the URL is passed to the browser. 

     * If system property <code>browser.rootdir</code> is specified, then a

     * file <code>page</code> relative to this directory is used as the URL.

     * If no such file exists, the system seeks for the 

     * resource via {@link Class#getResource(java.lang.String)}

     * method (relative to the {@link #loadClass(java.lang.Class) specified class}). 

     * If such resource is not found, a file relative to the location JAR

     * that contains the {@link #loadClass(java.lang.Class) main class} is 

     * searched for.

     * 

     * @param page the location (relative, absolute, or URL) of a page to load

     * @return this browser

     */

    public BrowserBuilder loadPage(String page) {

        this.resource = page;

        return this;

    }

    /** Specifies callback method to notify the application that the browser is ready.

     * There should be a <b>public static</b> method in the class specified

     * by {@link #loadClass(java.lang.Class)} which takes an array of {@link String}

     * argument. The method is called on the browser dispatch thread one

     * the browser finishes loading of the {@link #loadPage(java.lang.String) HTML page}.

     * 

     * @param methodName name of a method to seek for

     * @param args parameters to pass to the method

     * @return this builder

     */

    public BrowserBuilder invoke(String methodName, String... args) {

        this.methodName = methodName;

        this.methodArgs = args;

        return this;

    }

    /** Shows the browser, loads specified page in and executes the 

     * {@link #invoke(java.lang.String, java.lang.String[]) initialization method}.

     * The method returns when the browser is closed.

     * 

     * @throws NullPointerException if some of essential parameters (like {@link #loadPage(java.lang.String) page} or

     *    {@link #loadClass(java.lang.Class) class} have not been specified

     */

    public void showAndWait() {

        if (resource == null) {

            throw new NullPointerException("Need to specify resource via loadPage method");

        }

        URL url = null;

        MalformedURLException mal = null;

        try {

            String baseURL = System.getProperty("browser.rootdir");

            if (baseURL != null) {

                url = new File(baseURL, resource).toURI().toURL();

            } else {

                url = new URL(resource);

            }

        } catch (MalformedURLException ex) {

            mal = ex;

        }

        if (url == null) {

            url = clazz.getResource(resource);

        }

        if (url == null) {

            URL jar = clazz.getProtectionDomain().getCodeSource().getLocation();

            try {

                url = new URL(jar, resource);

            } catch (MalformedURLException ex) {

                ex.initCause(mal);

                mal = ex;

            }

        }

        if (url == null) {

            IllegalStateException ise = new IllegalStateException("Can't find resouce: " + resource + " relative to " + clazz);

            if (mal != null) {

                ise.initCause(mal);

            }

            throw ise;

        }

        Fn.Presenter dfnr = null;

        for (Object o : context) {

            if (o instanceof Fn.Presenter) {

                dfnr = (Fn.Presenter)o;

                break;

            }

        }

        if (dfnr == null) for (Fn.Presenter o : ServiceLoader.load(Fn.Presenter.class)) {

            dfnr = o;

            break;

        }

        if (dfnr == null) {

            throw new IllegalStateException("Can't find any Fn.Presenter");

        }

        final ClassLoader loader;

        if (FnUtils.isJavaScriptCapable(clazz.getClassLoader())) {

            loader = clazz.getClassLoader();

        } else {

            FImpl impl = new FImpl(clazz.getClassLoader());

            loader = FnUtils.newLoader(impl, dfnr, clazz.getClassLoader().getParent());

        }

        final Fn.Presenter currentP = dfnr;

        class OnPageLoad implements Runnable {

            @Override

            public void run() {

                try {

                    Thread.currentThread().setContextClassLoader(loader);

                    Class<?> newClazz = Class.forName(clazz.getName(), true, loader);

                    if (browserClass != null) {

                        browserClass[0] = newClazz;

                    }

                    if (onLoad != null) {

                        onLoad.run();

                    }

                    INIT: if (methodName != null) {

                        Throwable firstError = null;

                        if (methodArgs.length == 0) {

                            try {

                                Method m = newClazz.getMethod(methodName);

                                FnContext.currentPresenter(currentP);

                                m.invoke(null);

                                break INIT;

                            } catch (Throwable ex) {

                                firstError = ex;

                            } finally {

                                FnContext.currentPresenter(null);

                            }

                        }

                        try {

                            Method m = newClazz.getMethod(methodName, String[].class);

                            FnContext.currentPresenter(currentP);

                            m.invoke(m, (Object) methodArgs);

                        } catch (Throwable ex) {

                            if (firstError != null) {

                                LOG.log(Level.SEVERE, "Can't call " + methodName, firstError);

                            }

                            LOG.log(Level.SEVERE, "Can't call " + methodName + " with args " + Arrays.toString(methodArgs), ex);

                        } finally {

                            FnContext.currentPresenter(null);

                        }

                    }

                } catch (ClassNotFoundException ex) {

                    LOG.log(Level.SEVERE, "Can't load " + clazz.getName(), ex);

                }

            }

        }

        dfnr.displayPage(url, new OnPageLoad());

        return;

    }

    private static final class FImpl implements FindResources {

        final ClassLoader l;

        public FImpl(ClassLoader l) {

            this.l = l;

        }

        @Override

        public void findResources(String path, Collection<? super URL> results, boolean oneIsEnough) {

            if (oneIsEnough) {

                URL u = l.getResource(path);

                if (u != null) {

                    results.add(u);

                }

            } else {

                try {

                    Enumeration<URL> en = l.getResources(path);

                    while (en.hasMoreElements()) {

                        results.add(en.nextElement());

                    }

                } catch (IOException ex) {

                    // no results

                }

            }

        }

    }

}