/**

  * HTML via Java(tm) Language Bindings

  * Copyright (C) 2013 Jaroslav Tulach <jaroslav.tulach@apidesign.org>

  *

  * This program is free software: you can redistribute it and/or modify

  * it under the terms of the GNU General Public License as published by

  * the Free Software Foundation, version 2 of the License.

  *

  * This program 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 for more details. apidesign.org

  * designates this particular file as subject to the

  * "Classpath" exception as provided by apidesign.org

  * in the License file that accompanied this code.

  *

  * You should have received a copy of the GNU General Public License

  * along with this program. Look for COPYING file in the top folder.

  * If not, see http://wiki.apidesign.org/wiki/GPLwithClassPathException

  */

 package org.apidesign.html.boot.impl;

 import java.io.InputStream;

 import java.io.InputStreamReader;

 import java.io.Reader;

 import java.net.URL;

 import java.util.ArrayList;

 import java.util.Collections;

 import java.util.Enumeration;

 import java.util.List;

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

 /**

  *

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

  */

 public final class FnUtils {

     private static final ThreadLocal<Fn.Presenter> CURRENT = new ThreadLocal<Fn.Presenter>();

     private FnUtils() {

     }

     public static Fn define(Class<?> caller, String code, String... names) {

         return currentPresenter().defineFn(code, names);

     }

     public static boolean isJavaScriptCapable(ClassLoader l) {

         return l instanceof JsClassLoader;

     }

     public static boolean isValid(Fn fn) {

         return fn != null && fn.isValid();

     }

     public static ClassLoader newLoader(final FindResources f, final Fn.Presenter d, ClassLoader parent) {

         return new JsClassLoader(parent) {

             @Override

             protected URL findResource(String name) {

                 List<URL> l = res(name, true);

                 return l.isEmpty() ? null : l.get(0);

             }

             @Override

             protected Enumeration<URL> findResources(String name) {

                 return Collections.enumeration(res(name, false));

             }

             private List<URL> res(String name, boolean oneIsEnough) {

                 List<URL> l = new ArrayList<URL>();

                 f.findResources(name, l, oneIsEnough);

                 return l;

             }

             @Override

             protected Fn defineFn(String code, String... names) {

                 return d.defineFn(code, names);

             }

             @Override

             protected void loadScript(Reader code) throws Exception {

                 d.loadScript(code);

             }

         };

     }

     static String callback(final String body) {

         return new JsCallback() {

             @Override

             protected CharSequence callMethod(

                 String ident, String fqn, String method, String params

             ) {

                 StringBuilder sb = new StringBuilder();

                 sb.append("vm.").append(mangle(fqn, method, params));

                 sb.append("(");

                 if (ident != null) {

                     sb.append(ident);

                 }

                 return sb;

             }

         }.parse(body);

     }

     static void loadScript(JsClassLoader jcl, String resource) {

         final InputStream script = jcl.getResourceAsStream(resource);

         if (script == null) {

             throw new NullPointerException("Can't find " + resource);

         }

         try {

             Reader isr = null;

             try {

                 isr = new InputStreamReader(script, "UTF-8");

                 jcl.loadScript(isr);

             } finally {

                 if (isr != null) {

                     isr.close();

                 }

             }

         } catch (Exception ex) {

             throw new IllegalStateException("Can't execute " + resource, ex);

         } 

     }

     public static Fn.Presenter currentPresenter() {

         Fn.Presenter p = CURRENT.get();

         if (p == null) {

             throw new IllegalStateException("No current WebView context around!");

         }

         return p;

     }

     public static Fn.Presenter currentPresenter(Fn.Presenter p) {

         Fn.Presenter prev = CURRENT.get();

         CURRENT.set(p);

         return prev;

     }

 }