/**

 * 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 static final ThreadLocal<List<Runnable>> LATER = new ThreadLocal<List<Runnable>>();

    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) {

        if (p == null) {

            List<Runnable> list = LATER.get();

            LATER.set(null);

            if (list != null) for (Runnable runnable : list) {

                try {

                    runnable.run();

                } catch (Throwable t) {

                    t.printStackTrace();

                }

            }

        }

        Fn.Presenter prev = CURRENT.get();

        CURRENT.set(p);

        return prev;

    }

    public static void runLater(Runnable r) {

        currentPresenter();

        List<Runnable> list = LATER.get();

        if (list == null) {

            list = new ArrayList<Runnable>();

            LATER.set(list);

        }

        list.add(r);

    }

}