/*
   orxonox - the future of 3D-vertical-scrollers

   Copyright (C) 2004 orx

   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; either version 2, or (at your option)
   any later version.

   ### File Specific:
   main-programmer: Christian Meyer
   co-programmer: Benjamin Grauer
*/

/*!
 * @file factory.h
 * @brief A loadable object handler
*/


#ifndef _FACTORY_H
#define _FACTORY_H

class BaseObject;

#include "tinyxml.h"
#include "base_object.h"
#include "debug.h"

/**
 * Creates a factory to a Loadable Class.
 * this should be used at the beginning of all the Classes that should be loadable (in the cc-file)
*/
#define CREATE_FACTORY(CLASS_NAME, CLASS_ID) \
    tFactory<CLASS_NAME>* global_##CLASS_NAME##_Factory = new tFactory<CLASS_NAME>(#CLASS_NAME, CLASS_ID)

//! The Factory is a loadable object handler
class Factory : public BaseObject {

 public:
  Factory (const char* factoryName = NULL, ClassID classID = CL_NULL);
  virtual ~Factory ();

  void fabricate(const char* className, const char* entityName);
  virtual BaseObject* fabricate(ClassID classID) = NULL;
  virtual BaseObject* fabricate(const TiXmlElement* root) = NULL;
  virtual BaseObject* fabricateDirect() = NULL;

  static void registerFactory( Factory* factory);
  /** @returns the first factory */
  static Factory* getFirst() { return Factory::first; };

  protected:
    /** sets the Next factory in the list @param nextFactory the next factory */
    inline void setNext( Factory* nextFactory) { this->next = nextFactory; };
    /** @returns the next factory */
    Factory* getNext() const { return this->next; };


  protected:
    ClassID           classID;              //!< The CLass-Identifyer of the Factory.

  private:
    Factory*          next;                 //!< pointer to the next factory.
    static Factory*   first;                //!< A pointer to the first factory.
};

/**
 *  a factory that is able to load any kind of Object
 * (this is a Functor)
 */
template<class T> class tFactory : public Factory
{
  public:
    tFactory(const char* factoryName, ClassID classID);
    virtual ~tFactory();

  private:
    virtual BaseObject* fabricate(ClassID classID);
    virtual BaseObject* fabricate(const TiXmlElement* root);
    virtual BaseObject* fabricateDirect();
};

/**
 *  construnts a factory with
 * @param factoryName the name of the factory
*/
template<class T>
    tFactory<T>::tFactory(const char* factoryName, ClassID classID) : Factory(factoryName, classID)
{
  PRINTF(4)("Class: %s loadable\n", this->getName());
}

/**
 * destructs the type-Factory
 */
template<class T>
    tFactory<T>::~tFactory()
{}

/**
 * fabricates an Object of type T, with the constructor T::T(const TiXmlElemnt*)
 * @param root the TiXmlElement T should load parameters from.
 * @return the newly fabricated T, NULL otherwise.
 */
template<class T>
    BaseObject* tFactory<T>::fabricate(const TiXmlElement* root)
{
  if (root == NULL)
    return NULL;

  if(!strcmp(root->Value(), this->getName()))
    return new T ( root);
  else if( getNext() != NULL)
    return getNext()->fabricate( root);
  else
    return NULL;
}


/**
 * fabricates an Object of type T, with the constructor T::T(const TiXmlElemnt*)
 * @param classID the ClassID of T that should be created.
 * @return the newly fabricated T if fabricated NULL otherwise.
 */
template<class T>
    BaseObject* tFactory<T>::fabricate(ClassID classID)
{
  if(classID == this->classID)
    return this->fabricateDirect();
  else if( getNext() != NULL)
    return getNext()->fabricate( classID);
  else
    return NULL;
}

/**
 * directly fabricate an Entity of this factory.
 */
template<class T>
    BaseObject* tFactory<T>::fabricateDirect()
{
  return new T((const TiXmlElement*)NULL);
}

#endif /* _FACTORY_H */