/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package rewrite.org.apache.myfaces.extensions.scripting.core.api;

import rewrite.org.apache.myfaces.extensions.scripting.core.common.util.ClassUtils;
import rewrite.org.apache.myfaces.extensions.scripting.core.common.util.ReflectUtil;
import rewrite.org.apache.myfaces.extensions.scripting.core.engine.FactoryEngines;
import rewrite.org.apache.myfaces.extensions.scripting.core.engine.api.ClassScanner;
import rewrite.org.apache.myfaces.extensions.scripting.core.engine.api.ScriptingEngine;
import rewrite.org.apache.myfaces.extensions.scripting.core.loader.ThrowAwayClassloader;
import rewrite.org.apache.myfaces.extensions.scripting.core.monitor.ClassResource;
import rewrite.org.apache.myfaces.extensions.scripting.core.monitor.WatchedResource;
import rewrite.org.apache.myfaces.extensions.scripting.core.reloading.GlobalReloadingStrategy;
import rewrite.org.apache.myfaces.extensions.scripting.core.reloading.MethodLevelReloadingHandler;
import rewrite.org.apache.myfaces.extensions.scripting.jsf.adapters.ImplementationSPI;

import java.io.IOException;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Proxy;
import java.util.Collection;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.logging.Logger;

/**
 * @author Werner Punz (latest modification by $Author$)
 * @version $Revision$ $Date$
 *          <p/>
 *          Central weaving context
 */

public class WeavingContext
{
    /**
     * lock var which can be used for recompilation
     */
    public AtomicBoolean recompileLock = new AtomicBoolean(false);
    protected Configuration configuration = new Configuration();

    //ClassDependencies _dependencyMap = new ClassDependencies();

    ImplementationSPI _implementation = null;
    GlobalReloadingStrategy _reloadingStrategy = new GlobalReloadingStrategy();
    ClassScanner _annotationScanner = null;
    Logger log = Logger.getLogger(this.getClass().getName());
    boolean _scriptingEnabled = true;

    /*holder for various operations within our lifecycle*/
    ConcurrentHashMap<String, Long> lifecycleRegistry = new ConcurrentHashMap<String, Long>();

    public void initEngines() throws IOException
    {
        FactoryEngines.getInstance().init();
        initScanner();
    }

    public void initScanner()
    {
        try
        {
            Class scanner = ClassUtils.getContextClassLoader().loadClass("rewrite.org.apache.myfaces.extensions.scripting.jsf.annotation.GenericAnnotationScanner");
            this._annotationScanner = (ClassScanner) ReflectUtil.instantiate(scanner);

        }
        catch (ClassNotFoundException e)
        {
            //we do nothing here
            //generic annotation scanner can be missing in jsf 1.2 environments
            //_logger.log(Level.FINER, "", e);
        }
    }

    public Collection<ScriptingEngine> getEngines()
    {
        return FactoryEngines.getInstance().getEngines();
    }

    public ScriptingEngine getEngine(int engineType)
    {
        return FactoryEngines.getInstance().getEngine(engineType);
    }

    /**
     * returns the mitable watche resource maps for the various engines
     *
     * @return
     */
    public Map<Integer, Map<String, ClassResource>> getWatchedResources()
    {
        Map<Integer, Map<String, ClassResource>> ret = new HashMap<Integer, Map<String, ClassResource>>();
        for (ScriptingEngine engine : getEngines())
        {
            ret.put(engine.getEngineType(), engine.getWatchedResources());
        }
        return ret;
    }

    public Map<String, ClassResource> getAllWatchedResources()
    {
        Map<String, ClassResource> ret = new HashMap<String, ClassResource>();
        for (ScriptingEngine engine : getEngines())
        {
            Map<String, ClassResource> watchedResourceMap = engine.getWatchedResources();
            for (Map.Entry<String, ClassResource> entry : watchedResourceMap.entrySet())
            {
                ret.put(entry.getKey(), entry.getValue());
            }
        }
        return ret;
    }

    public ClassResource getWatchedResource(String key)
    {
        for (ScriptingEngine engine : getEngines())
        {
            if (!engine.getWatchedResources().containsKey(key)) continue;
            return engine.getWatchedResources().get(key);
        }
        return null;
    }

    public boolean isTainted(String key)
    {
        ClassResource res = getWatchedResource(key);
        if (res == null) return false;
        return res.isTainted();
    }

    public Set<String> loadPossibleDynamicClasses()
    {
        return getAllWatchedResources().keySet();
    }

    public Configuration getConfiguration()
    {
        return configuration;
    }

    public void setConfiguration(Configuration configuration)
    {
        this.configuration = configuration;
    }

    public boolean needsRecompile()
    {
        for (ScriptingEngine engine : getEngines())
        {
            //log.info("[EXT-SCRIPTING] scanning " + engine.getEngineType() + " files");
            if (engine.needsRecompile()) return true;
            //log.info("[EXT-SCRIPTING] scanning " + engine.getEngineType() + " files done");
        }
        return false;
    }

    public void initialFullScan()
    {
        for (ScriptingEngine engine : getEngines())
        {
            engine.scanForAddedDeleted();
        }
        //the scanner scans only the tainted classes
        //hence this should work whatever happens

    }

    public void annotationScan()
    {
        if (_annotationScanner != null)
            _annotationScanner.scanPaths();
    }

    public boolean compile()
    {
        boolean compile = false;
        for (ScriptingEngine engine : getEngines())
        {
            if (!engine.needsRecompile()) continue;
            compile = true;
            log.info("[EXT-SCRIPTING] compiling " + engine.getEngineTypeAsStr() + " files");
            engine.compile();
            log.info("[EXT-SCRIPTING] compiling " + engine.getEngineTypeAsStr() + " files done");
        }
        return compile;
    }

    public void scanDependencies()
    {
        for (ScriptingEngine engine : getEngines())
        {
            if (engine.isTainted())
            {
                log.info("[EXT-SCRIPTING] scanning " + engine.getEngineTypeAsStr() + " dependencies");
                engine.scanDependencies();
                log.info("[EXT-SCRIPTING] scanning " + engine.getEngineTypeAsStr() + " dependencies end");
            }
        }
    }

    public void markTaintedDependends()
    {
        for (ScriptingEngine engine : getEngines())
        {
            engine.markTaintedDependencies();
        }
    }

    public WatchedResource getResource(String className)
    {
        WatchedResource ret = null;
        for (ScriptingEngine engine : getEngines())
        {
            ret = engine.getWatchedResources().get(className);
            if (ret != null) return ret;
        }
        return ret;
    }

    public boolean isDynamic(Class clazz)
    {
        return clazz.getClassLoader() instanceof ThrowAwayClassloader;
    }

    /**
     * we create a proxy to an existing object
     * which does reloading of the internal class
     * on method level
     * <p/>
     * this works only on classes which implement contractual interfaces
     * it cannot work on things like the navigation handler
     * which rely on base classes
     *
     * @param o            the source object to be proxied
     * @param theInterface the proxying interface
     * @param artifactType the artifact type to be reloaded
     * @return a proxied reloading object of type theInterface
     */
    public Object createMethodReloadingProxyFromObject(Object o, Class theInterface, int artifactType)
    {
        //if (!isScriptingEnabled()) {
        //    return o;
        //}
        return Proxy.newProxyInstance(o.getClass().getClassLoader(),
                new Class[]{theInterface},
                new MethodLevelReloadingHandler(o, artifactType));
    }

    /**
     * reload the class dynamically
     */
    public Class reload(Class clazz)
    {
        if (!isDynamic(clazz)) return clazz;
        ClassResource resource = (ClassResource) getResource(clazz.getName());
        if (resource == null) return clazz;
        if (resource.isTainted() || resource.getAClass() == null)
        {
            clazz = _implementation.forName(clazz.getName());
            //TODO not needed anymore, done by the forName now
            resource.setAClass(clazz);
        }
        return clazz;
    }

    public Object reload(Object instance, int strategyType)
    {
        return _reloadingStrategy.reload(instance, strategyType);
    }

    /**
     * we create a proxy to an existing object
     * which does reloading of the internal class
     * on newInstance level
     *
     * @param o            the original object
     * @param theInterface the proxy interface
     * @param artifactType the artifact type to be handled
     * @return the proxy of the object if scripting is enabled, the original one otherwise
     */
    @SuppressWarnings("unused")
    public static Object createConstructorReloadingProxyFromObject(Object o, Class theInterface, int artifactType)
    {
        //if (!isScriptingEnabled()) {
        //    return o;
        //}
        return Proxy.newProxyInstance(o.getClass().getClassLoader(),
                new Class[]{theInterface},
                new MethodLevelReloadingHandler(o, artifactType));
    }

    /**
     * un-mapping of a proxied object
     *
     * @param o the proxied object
     * @return the un-proxied object
     */
    public static Object getDelegateFromProxy(Object o)
    {
        if (o == null)
        {
            return null;
        }
        if (o instanceof Decorated)
            return ((Decorated) o).getDelegate();

        if (!Proxy.isProxyClass(o.getClass())) return o;
        InvocationHandler handler = Proxy.getInvocationHandler(o);
        if (handler instanceof Decorated)
        {
            return ((Decorated) handler).getDelegate();
        }
        return o;
    }

    public void addDependency(int engineType, String fromClass, String toClass)
    {
        //TODO implement this tomorrow
    }

    //----------------------------------------------------------------------
    //lifecycle related tasks
    public boolean isPostInit()
    {
        return (lifecycleRegistry.get("LIFECYCLE_POST_INIT") != null);
    }

    public void markPostInit()
    {
        lifecycleRegistry.put("LIFECYCLE_POST_INIT", System.currentTimeMillis());
    }

    public void markLastTaint()
    {
        lifecycleRegistry.put("LIFECYCLE_LAST_TAINTED", System.currentTimeMillis());
    }

    public long getLastTaint()
    {
        Long lastTainted = lifecycleRegistry.get("LIFECYCLE_LAST_TAINTED");
        lastTainted = (lastTainted != null) ? lastTainted : -1L;
        return lastTainted;
    }

    public void markLastAnnotationScan()
    {
        lifecycleRegistry.put("LIFECYCLE_LAST_ANN_SCAN", System.currentTimeMillis());
    }

    public long getLastAnnotationScan()
    {
        Long lastTainted = lifecycleRegistry.get("LIFECYCLE_LAST_ANN_SCAN");
        lastTainted = (lastTainted != null) ? lastTainted : -1L;
        return lastTainted;
    }

    //----------------------------------------------------------------------
    /*public ClassDependencies getDependencyMap()
    {
        return _dependencyMap;
    }

    public void setDependencyMap(ClassDependencies dependencyMap)
    {
        _dependencyMap = dependencyMap;
    } */

    protected static WeavingContext _instance = new WeavingContext();

    public static WeavingContext getInstance()
    {
        return _instance;
    }

    public ImplementationSPI getImplementation()
    {
        return _implementation;
    }

    public void setImplementation(ImplementationSPI implementation)
    {
        _implementation = implementation;
    }

    public boolean isScriptingEnabled()
    {
        return _scriptingEnabled;
    }

    public void setScriptingEnabled(boolean scriptingEnabled)
    {
        _scriptingEnabled = scriptingEnabled;
    }

}