/*
 * 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 org.apache.myfaces.extensions.scripting.loaders.java;

import org.apache.myfaces.extensions.scripting.api.ClassScanListener;
import org.apache.myfaces.extensions.scripting.api.ClassScanner;
import org.apache.myfaces.extensions.scripting.api.ScriptingConst;
import org.apache.myfaces.extensions.scripting.api.ScriptingWeaver;
import org.apache.myfaces.extensions.scripting.core.dependencyScan.StandardDependencyScanner;
import org.apache.myfaces.extensions.scripting.core.dependencyScan.api.DependencyScanner;
import org.apache.myfaces.extensions.scripting.core.dependencyScan.filter.WhitelistFilter;
import org.apache.myfaces.extensions.scripting.core.dependencyScan.registry.DependencyRegistryImpl;
import org.apache.myfaces.extensions.scripting.core.dependencyScan.registry.ExternalFilterDependencyRegistry;
import org.apache.myfaces.extensions.scripting.core.util.WeavingContext;
import org.apache.myfaces.extensions.scripting.monitor.ClassResource;
import org.apache.myfaces.extensions.scripting.monitor.RefreshAttribute;

import java.security.AccessController;
import java.security.PrivilegedActionException;
import java.security.PrivilegedExceptionAction;
import java.util.*;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 * @author Werner Punz (latest modification by $Author$)
 * @version $Revision$ $Date$
 *          <p/>
 *          A  dependency scanner which utilizes the scan infrastructure
 *          from the core
 */
public class JavaDependencyScanner implements ClassScanner {

    List<String> _scanPaths = new LinkedList<String>();

    DependencyScanner _depencyScanner = new StandardDependencyScanner();

    ScriptingWeaver _weaver;
    Logger _log = Logger.getLogger(JavaDependencyScanner.class.getName());

    public JavaDependencyScanner(ScriptingWeaver weaver) {
        this._weaver = weaver;

    }

    public synchronized void scanPaths() {
        //only one dependency check per refresh makes sense in our case
        if (WeavingContext.getRefreshContext().isDependencyScanned(getEngineType())) {
            return;
        } else {
            WeavingContext.getRefreshContext().setDependencyScanned(getEngineType(), true);
        }

        if (_log.isLoggable(Level.INFO)) {
            _log.info("[EXT-SCRITPING] starting class dependency scan");
        }
        long start = System.currentTimeMillis();
        final Set<String> possibleDynamicClasses = new HashSet<String>(_weaver.loadPossibleDynamicClasses());

        final ClassLoader loader = getClassLoader();
        for (String dynamicClass : possibleDynamicClasses) {
            runScan(possibleDynamicClasses, loader, dynamicClass);
        }

        long end = System.currentTimeMillis();
        if (_log.isLoggable(Level.FINE)) {
            _log.log(Level.FINE, "[EXT-SCRITPING] class dependency scan finished, duration: {0} ms", Long.toString(end - start));
        }

    }

    protected int getEngineType() {
        return ScriptingConst.ENGINE_TYPE_JSF_JAVA;
    }

    private void runScan(final Set<String> possibleDynamicClasses, final ClassLoader loader, String dynamicClass) {

        ExternalFilterDependencyRegistry scanRegistry = (ExternalFilterDependencyRegistry) WeavingContext.getRefreshContext().getDependencyRegistry(getEngineType());
        if (scanRegistry == null) {
            scanRegistry = new DependencyRegistryImpl(getEngineType(), WeavingContext.getFileChangedDaemon().getDependencyMap());
            WeavingContext.getRefreshContext().setDependencyRegistry(getEngineType(), scanRegistry);
        } else {
            scanRegistry.clearFilters();
        }

        //We have to dynamically readjust the filters
        scanRegistry.addFilter(new WhitelistFilter(possibleDynamicClasses));

        _depencyScanner.fetchDependencies(loader, getEngineType(), dynamicClass, WeavingContext.getRefreshContext().getDependencyRegistry());
    }

    protected ClassLoader getClassLoader() {
        try {
            return AccessController.doPrivileged(new PrivilegedExceptionAction<ScannerClassloader>() {
                public ScannerClassloader run() {
                    return new ScannerClassloader(Thread.currentThread().getContextClassLoader(), getEngineType(), ".java", WeavingContext.getConfiguration().getCompileTarget());
                }
            });
        } catch (PrivilegedActionException e) {
            _log.log(Level.SEVERE,"", e);
        }
        return null;
    }

    public void clearListeners() {
    }

    public void addListener(ClassScanListener listener) {

    }

    public void addScanPath(String scanPath) {
        _scanPaths.add(scanPath);
    }

    public synchronized void scanClass(Class clazz) {
        //not needed anymore since we only rely on full scans and full recompile now
    }

    public void scanAndMarkChange() {

        final Set<String> possibleDynamicClasses = new HashSet<String>(_weaver.loadPossibleDynamicClasses());
        Map<Integer, Boolean> recompileMap = WeavingContext.getRefreshContext().getDaemon().getSystemRecompileMap();
        Map<String, ClassResource> classMap = WeavingContext.getRefreshContext().getDaemon().getClassMap();
        Boolean alreadyTainted = recompileMap.get(getEngineType());
        if (alreadyTainted != null && alreadyTainted) {
            return;
        }

        for (String clazz : possibleDynamicClasses) {
            if (!classMap.containsKey(clazz)) {
                recompileMap.put(getEngineType(), Boolean.TRUE);
            }
        }
    }

}