/**

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

 *

 * Copyright 2013-2014 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 2013-2014 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.io.InputStream;

import java.lang.reflect.Method;

import java.net.HttpURLConnection;

import java.net.JarURLConnection;

import java.net.MalformedURLException;

import java.net.URL;

import java.net.URLConnection;

import java.security.ProtectionDomain;

import java.util.Arrays;

import java.util.Collection;

import java.util.Enumeration;

import java.util.Locale;

import java.util.ServiceLoader;

import java.util.concurrent.Executor;

import java.util.logging.Level;

import java.util.logging.Logger;

import net.java.html.BrwsrCtx;

import net.java.html.js.JavaScriptBody;

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

import org.netbeans.html.boot.spi.Fn.Presenter;

import org.netbeans.html.context.spi.Contexts;

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

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

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

/** 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 newBrowser()}.

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

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

 *          {@link #locale(java.util.Locale) locale}({@link Locale#getDefault()}).

 *          {@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

 */

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 ClassLoader loader;

    private Locale locale;

    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 -

     *   implementation 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;

    }

    /** Allows one to specify a runnable that should be invoked when a load

     * of a page is finished. This method may be used in addition or instead

     * of {@link #loadClass(java.lang.Class)} and 

     * {@link #invoke(java.lang.String, java.lang.String...)} methods.

     * 

     * @param r the code to run when the page is loaded

     * @return this builder

     * @since 0.8.1

     */

    public BrowserBuilder loadFinished(Runnable r) {

        this.onLoad = r;

        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.

     * <p>

     * The search honors provided {@link #locale}, if specified.

     * E.g. it will prefer <code>index_cs.html</code> over <code>index.html</code>

     * if the locale is set to <code>cs_CZ</code>.

     * 

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

     * @return this builder

     */

    public BrowserBuilder loadPage(String page) {

        this.resource = page;

        return this;

    }

    /** Locale to use when searching for an initial {@link #loadPage(java.lang.String) page to load}.

     * Localization is best done by providing different versions of the 

     * initial page with appropriate suffixes (like <code>index_cs.html</code>).

     * Then one can call this method with value of {@link Locale#getDefault()}

     * to instruct the builder to use the user's current locale.

     * 

     * @param locale the locale to use or <code>null</code> if no suffix search should be performed

     * @return this builder

     * @since 1.0

     */

    public BrowserBuilder locale(Locale locale) {

        this.locale = locale;

        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;

    }

    /** Loader to use when searching for classes to initialize. 

     * If specified, this loader is going to be used to load {@link Presenter}

     * and {@link Contexts#fillInByProviders(java.lang.Class, org.netbeans.html.context.spi.Contexts.Builder) fill} {@link BrwsrCtx} in.

     * Specifying special classloader may be useful in modular systems, 

     * like OSGi, where one needs to load classes from many otherwise independent

     * modules.

     * 

     * @param l the loader to use (or <code>null</code>)

     * @return this builder

     * @since 0.9

     */

    public BrowserBuilder classloader(ClassLoader l) {

        this.loader = l;

        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");

        }

        final Class<?> myCls;

        if (clazz != null) {

            myCls = clazz;

        } else if (onLoad != null) {

            myCls = onLoad.getClass();

        } else {

            throw new NullPointerException("loadClass, neither loadFinished was called!");

        }

        IOException mal[] = { null };

        URL url = findLocalizedResourceURL(resource, locale, mal, myCls);

        Fn.Presenter dfnr = null;

        for (Object o : context) {

            if (o instanceof Fn.Presenter) {

                dfnr = (Fn.Presenter)o;

                break;

            }

        }

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

            dfnr = 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 activeLoader;

        if (loader != null) {

            if (!FnContext.isJavaScriptCapable(loader)) {

                throw new IllegalStateException("Loader cannot resolve @JavaScriptBody: " + loader);

            }

            activeLoader = loader;

        } else if (FnContext.isJavaScriptCapable(myCls.getClassLoader())) {

            activeLoader = myCls.getClassLoader();

        } else {

            if (!FnContext.isAsmPresent()) {

                throw new IllegalStateException("Cannot find asm-5.0.jar classes!");

            }

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

            activeLoader = FnUtils.newLoader(impl, dfnr, myCls.getClassLoader().getParent());

        }

        final Fn.Presenter dP = dfnr;

        class OnPageLoad implements Runnable {

            @Override

            public void run() {

                try {

                    final Fn.Presenter aP = Fn.activePresenter();

                    final Fn.Presenter currentP = aP != null ? aP : dP;

                    Thread.currentThread().setContextClassLoader(activeLoader);

                    final Class<?> newClazz = Class.forName(myCls.getName(), true, activeLoader);

                    if (browserClass != null) {

                        browserClass[0] = newClazz;

                    }

                    Contexts.Builder cb = Contexts.newBuilder();

                    if (!Contexts.fillInByProviders(newClazz, cb)) {

                        LOG.log(Level.WARNING, "Using empty technology for {0}", newClazz);

                    }

                    if (currentP instanceof Executor) {

                        cb.register(Executor.class, (Executor)currentP, 1000);

                    }

                    cb.register(Fn.Presenter.class, currentP, 1000);

                    BrwsrCtx c = cb.build();

                    class CallInitMethod implements Runnable {

                        @Override

                        public void run() {

                            Throwable firstError = null;

                            if (onLoad != null) {

                                try {

                                    FnContext.currentPresenter(currentP);

                                    onLoad.run();

                                } catch (Throwable ex) {

                                    firstError = ex;

                                } finally {

                                    FnContext.currentPresenter(null);

                                }

                            }

                            INIT: if (methodName != null) {

                                if (methodArgs.length == 0) {

                                    try {

                                        Method m = newClazz.getMethod(methodName);

                                        FnContext.currentPresenter(currentP);

                                        m.invoke(null);

                                        firstError = 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);

                                    firstError = null;

                                } catch (Throwable ex) {

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

                                } finally {

                                    FnContext.currentPresenter(null);

                                }

                            }

                            if (firstError != null) {

                                LOG.log(Level.SEVERE, "Can't initialize the view", firstError);

                            }

                        }

                    }

                    c.execute(new CallInitMethod());

                } catch (ClassNotFoundException ex) {

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

                }

            }

        }

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

    }

    private static URL findResourceURL(String resource, String suffix, IOException[] mal, Class<?> relativeTo) {

        if (suffix != null) {

            int lastDot = resource.lastIndexOf('.');

            if (lastDot != -1) {

                resource = resource.substring(0, lastDot) + suffix + resource.substring(lastDot);

            } else {

                resource = resource + suffix;

            }

        }

        URL url = null;

        try {

            String baseURL = System.getProperty("browser.rootdir"); // NOI18N

            if (baseURL != null) {

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

                if (isReal(u)) {

                    url = u;

                }

            } 

            {

                URL u = new URL(resource);

                if (suffix == null || isReal(u)) {

                    url = u;

                }

                return url;

            }

        } catch (MalformedURLException ex) {

            mal[0] = ex;

        }

        if (url == null) {

            url = relativeTo.getResource(resource);

        }

        if (url == null) {

            final ProtectionDomain pd = relativeTo.getProtectionDomain();

            if (pd != null && pd.getCodeSource() != null) {

                URL jar = pd.getCodeSource().getLocation();

                try {

                    URL u = new URL(jar, resource);

                    if (isReal(u)) {

                        url = u;

                    }

                } catch (MalformedURLException ex) {

                    ex.initCause(mal[0]);

                    mal[0] = ex;

                }

            }

        }

        if (url == null) {

            URL res = BrowserBuilder.class.getResource("html4j.txt");

            LOG.log(Level.FINE, "Found html4j {0}", res);

            if (res != null) {

                try {

                    URLConnection c = res.openConnection();

                    LOG.log(Level.FINE, "testing : {0}", c);

                    if (c instanceof JarURLConnection) {

                        JarURLConnection jc = (JarURLConnection) c;

                        URL base = jc.getJarFileURL();

                        for (int i = 0; i < 50; i++) {

                            URL u = new URL(base, resource);

                            if (isReal(u)) {

                                url = u;

                                break;

                            }

                            base = new URL(base, "..");

                        }

                    }

                } catch (IOException ex) {

                    mal[0] = ex;

                }

            }

        }

        return url;

    }

    static URL findLocalizedResourceURL(String resource, Locale l, IOException[] mal, Class<?> relativeTo) {

        URL url = null;

        if (l != null) {

            url = findResourceURL(resource, "_" + l.getLanguage() + "_" + l.getCountry(), mal, relativeTo);

            if (url != null) {

                return url;

            }

            url = findResourceURL(resource, "_" + l.getLanguage(), mal, relativeTo);

        }

        if (url != null) {

            return url;

        }

        return findResourceURL(resource, null, mal, relativeTo);

    }

    private static boolean isReal(URL u) {

        try {

            URLConnection conn = u.openConnection();

            if (conn instanceof HttpURLConnection) {

                HttpURLConnection hc = (HttpURLConnection) conn;

                hc.setReadTimeout(5000);

                if (hc.getResponseCode() >= 300) {

                    throw new IOException("Wrong code: " + hc.getResponseCode());

                }

            }

            InputStream is = conn.getInputStream();

            is.close();

            LOG.log(Level.FINE, "found real url: {0}", u);

            return true;

        } catch (IOException ignore) {

            LOG.log(Level.FINE, "Cannot open " + u, ignore);

            return false;

        }

    }

    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

                }

            }

        }

    }

}