/*
  Copyright (C) 2006-2008 Helge Hess

  This file is part of JOPE.

  JOPE 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, or (at your option) any
  later version.

  JOPE 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 JOPE; see the file COPYING.  If not, write to the
  Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA
  02111-1307, USA.
*/
package org.opengroupware.jope.appserver.publisher;

import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.opengroupware.jope.appserver.core.WOApplication;
import org.opengroupware.jope.foundation.NSKeyValueCoding;
import org.opengroupware.jope.foundation.NSObject;
import org.opengroupware.jope.foundation.UString;

/**
 * JoClassRegistry
 * <p>
 * Caches JoClasses.
 * <p> 
 * THREAD: the whole JoClass system is currently NOT threadsafe.
 */
// TODO: document more
public class JoClassRegistry extends NSObject {
  protected static final Log log = LogFactory.getLog("JoClassRegistry");
  
  protected WOApplication        application;
  protected Map<String, JoClass> nameToClass;
  
  public JoClassRegistry(WOApplication _app) {
    this.application = _app;
    this.nameToClass = new ConcurrentHashMap<String, JoClass>(128);
  }
  
  /* accessors */
  
  public WOApplication application() {
    return this.application;
  }
  
  /* exposing Java classes as So classes */
  
  /**
   * First attempts to retrieve the JoClass by evaluating the 'joClass'
   * KVC key. If that doesn't return anything, we call joClassForJavaClass()
   * with the objects class.
   * 
   * @param _object - Object to get the JoClass for
   * @param _ctx    - context in which the object is active
   * @return the JoClass, or null if none could be found
   */
  public JoClass joClassForJavaObject(Object _object, IJoContext _ctx) {
    if (_object == null)
      return null;
    
    if (_object instanceof NSKeyValueCoding) {
      /* we assume that all relevant classes inherit from NSObject */
      Object oc = ((NSKeyValueCoding)_object).valueForKey("joClass");
      if (oc != null) {
        if (oc instanceof JoClass)
          return (JoClass)oc;
        
        log.error("joClass property of object did not return a joClass: " + oc);
      }
    }
    
    return this.joClassForJavaClass(_object.getClass(), _ctx);
  }

  public JoClass joClassForJavaClass(Class _cls, IJoContext _ctx) {
    if (_cls == null)
      return null;
    
    /* check cache */
    // TODO: need to consider threading?! (multireader?) Possibly we want to
    //       load or create classes as runtime and not just in bootstrapping
    
    JoClass joClass = this.nameToClass.get(_cls.getName());
    if (joClass != null)
      return joClass;
    
    /* process superclass */
    
    Class   superClass   = _cls.getSuperclass();
    JoClass joSuperClass = this.joClassForJavaClass(superClass, _ctx);
    
    /* process class */
    
    joClass = this.generateJoClassFromJavaClass(_cls, joSuperClass, _ctx);
    if (joClass == null) {
      log.error("could not create JoClass from Java class: " + _cls);
      return null;
    }
    
    /* cache result */
    // THREAD
    
    this.nameToClass.put(_cls.getName(), joClass);
    return joClass;
  }
  
  public JoJavaClass generateJoClassFromJavaClass
    (Class _cls, JoClass _superClass, IJoContext _ctx)
  {
    if (_cls == null)
      return null;
    
    /* collect mapped methods */
    
    Map<String, Object> nameToMethod = new HashMap<String, Object>(32);
    for (Method method: _cls.getDeclaredMethods()) {
      JoJavaMethod joMethod = this.generateJoMethodFromJavaMethod(method, _ctx);
      if (joMethod == null)
        continue; /* not moved */
      
      nameToMethod.put(joMethod.name(), joMethod);
    }
    
    /* construct class */
    
    return new JoJavaClass(_cls.getSimpleName(), _superClass, nameToMethod);
  }
  
  public JoJavaMethod generateJoMethodFromJavaMethod
    (Method _method, IJoContext _ctx)
  {
    // TODO: implement me
    // TODO: check for xyzAction methods and auto-expose them
    // TODO: check annotations
    
    // _method.isAnnotationPresent(CLASS);
    // _method.getAnnotation(annotationClass);
    
    return null;
  }
  
  /* description */
  
  public void appendAttributesToDescription(StringBuilder _d) {
    super.appendAttributesToDescription(_d);
    
    if (this.nameToClass != null) {
      _d.append(" classes=" +
          UString.componentsJoinedByString
          (this.nameToClass.keySet().toArray(), ","));
    }
    
    if (this.application != null)
      _d.append(" app=" + this.application);
  }
}