/**
 * ===========================================
 * LibLayout : a free Java layouting library
 * ===========================================
 *
 * Project Info:  http://reporting.pentaho.org/liblayout/
 *
 * (C) Copyright 2006-2007, by Pentaho Corporation and Contributors.
 *
 * This library is free software; you can redistribute it and/or modify it under the terms
 * of the GNU Lesser General Public License as published by the Free Software Foundation;
 * either version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License along with this
 * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
 * Boston, MA 02111-1307, USA.
 *
 * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
 * in the United States and other countries.]
 *
 * ------------
 * $Id: StyleKeyRegistry.java 6653 2008-12-02 14:53:40Z tmorgner $
 * ------------
 * (C) Copyright 2006-2007, by Pentaho Corporation.
 */
package org.jfree.layouting.input.style;

import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.util.HashMap;
import java.util.Iterator;

import org.jfree.layouting.LibLayoutBoot;
import org.pentaho.reporting.libraries.base.config.Configuration;
import org.pentaho.reporting.libraries.base.util.ObjectUtilities;
import org.pentaho.reporting.libraries.base.util.DebugLog;

/**
 * This class should not be static, or we might create a memory leak.
 *
 * @author Thomas Morgner
 */
public class StyleKeyRegistry
{
  private static StyleKeyRegistry registry;

  public static synchronized StyleKeyRegistry getRegistry()
  {
    if (registry == null)
    {
      registry = new StyleKeyRegistry();
      registry.registerDefaults();
    }
    return registry;
  }

  private HashMap knownStyleKeys;

  private StyleKeyRegistry()
  {
    knownStyleKeys = new HashMap();
  }

  public StyleKey findKeyByName(final String name)
  {
    return (StyleKey) knownStyleKeys.get(name);
  }

  public int getIndexForKey(final StyleKey key)
  {
    final Integer index = (Integer) knownStyleKeys.get(key.getName());
    if (index != null)
    {
      return index.intValue();
    }

    throw new IllegalStateException("This key is not registered. How could that be?");
  }

  public int getKeyCount()
  {
    return knownStyleKeys.size();
  }

  public synchronized void registerDefaults()
  {
    final Configuration config = LibLayoutBoot.getInstance().getGlobalConfig();
    final Iterator it = config.findPropertyKeys("org.jfree.layouting.stylekeys.");
    final ClassLoader classLoader =
            ObjectUtilities.getClassLoader(StyleKeyRegistry.class);

    while (it.hasNext())
    {
      final String key = (String) it.next();
      try
      {
        final Class c = classLoader.loadClass(config.getConfigProperty(key));
        registerClass(c);
      }
      catch (ClassNotFoundException e)
      {
        // ignore that class
      }
      catch (NullPointerException e)
      {
        // ignore invalid values as well.
      }
    }

  }

  public synchronized void registerClass(final Class c)
  {
    // Log.debug ("Registering stylekeys from " + c);
    try
    {
      final Field[] fields = c.getFields();
      for (int i = 0; i < fields.length; i++)
      {
        final Field field = fields[i];
        final int modifiers = field.getModifiers();
        if (Modifier.isPublic(modifiers) &&
            Modifier.isStatic(modifiers))
        {
          if (Modifier.isFinal(modifiers) == false)
          {
            DebugLog.log("Invalid implementation: StyleKeys should be 'public static final': " + c);
          }
          if (field.getType().isAssignableFrom(StyleKey.class))
          {
            final StyleKey value = (StyleKey) field.get(null);
            // ignore the returned value, all we want is to trigger the key
            // creation
            // Log.debug ("Loaded key " + value);
          }
        }
      }
    }
    catch (IllegalAccessException e)
    {
      // wont happen, we've checked it..
    }
  }

  public synchronized StyleKey createKey(final String name,
                                         final boolean trans,
                                         final boolean inherited,
                                         final int validity)
  {
    final StyleKey existingKey = findKeyByName(name);
    if (existingKey != null)
    {
      return existingKey;
    }
    final StyleKey createdKey = new StyleKey
            (name, trans, inherited, knownStyleKeys.size(), validity);
    knownStyleKeys.put(name, createdKey);
    return createdKey;
  }

  public synchronized StyleKey[] getKeys()
  {
    return getKeys(new StyleKey[knownStyleKeys.size()]);
  }

  public synchronized StyleKey[] getKeys(final StyleKey[] input)
  {
    return (StyleKey[]) knownStyleKeys.values().toArray(input);
  }


}
