// -*- c++ -*-

#ifndef MAP_REGISTRY_H

#define MAP_REGISTRY_H

#include <vector>

using namespace std;

namespace hugo {

/** 

 * Registry class to register edge or node maps into the graph. The

 * registry helps you to implement an observer pattern. If you add

 * or erase an edge or node you must notify all the maps about the

 * event.

*/

  template <typename G, typename K, typename KIt>

  class MapRegistry {

  public:

    typedef G Graph;

    typedef K Key;

    typedef KIt KeyIt;

    /**

     * MapBase is the base class of the registered maps.

     * It defines the core modification operations on the maps and

     * implements some helper functions. 

     */

    class MapBase {

    public:

      typedef G Graph;

      typedef K Key;

      typedef KIt KeyIt;

      typedef MapRegistry<G, K, KIt> Registry;

      friend class MapRegistry<G, K, KIt>;

      /**

       * Default constructor for MapBase.

       */

      MapBase() : graph(0), registry(0) {}

      /** 

       * Simple constructor to register into a graph registry.

      */

      MapBase(const Graph& g, Registry& r) : graph(&g), registry(0) {

	r.attach(*this);

      }

      /** 

       * Copy constructor to register into the registry.

      */	

      MapBase(const MapBase& copy) : registry(0), graph(copy.graph) {

	if (copy.registry) {

	  copy.registry->attach(*this);

	}

      } 

      /** 

       * Assign operator.

      */	

      const MapBase& operator=(const MapBase& copy) {

	if (registry) {

	  registry->detach(*this);

	}

	graph = copy.graph;

	if (copy.registry) {

	  copy.registry->attach(*this);

	}

      }

      /** 

       * Destructor. 

      */		

      virtual ~MapBase() {

	if (registry) {

	  registry->detach(*this);

	}

      }

      /*

       * Returns the graph that the map belongs to.

      */

      const Graph* getGraph() const { return graph; }

    protected:

      const Graph* graph;     

      Registry* registry;

      int registry_index;

    protected:

      /**

	 Helper function to implement constructors in the subclasses.

      */

      virtual void init() {

	for (KeyIt it(*graph); it != INVALID; ++it) {

	  add(it);

	}

      }

      /**

	 Helper function to implement the destructor in the subclasses.

      */

      virtual void destroy() {

	for (KeyIt it(*getGraph()); it != INVALID; ++it) {

	  erase(it);

	}

      }

      /** 

	  The add member function should be overloaded in the subclasses.

	  \e Add extends the map with the new node.

      */

      virtual void add(const Key&) = 0;	

      /** 

	  The erase member function should be overloaded in the subclasses.

	  \e Erase removes the node from the map.

      */

      virtual void erase(const Key&) = 0;

      /**

       *  The clear member function should be overloaded in the subclasses.

       *  \e Clear makes empty the data structure.

       */

      virtual void clear() = 0;

      /**

	 Exception class to throw at unsupported operation.

      */

      class NotSupportedOperationException {};

    };

  protected:

    /** 

     * The container type of the maps.

     */

    typedef std::vector<MapBase*> Container; 

    /**

     * The container of the registered maps.

     */

    Container container;

  public:

    /**

     * Default Constructor of the MapRegistry. It creates an empty registry.

     */

    MapRegistry() {}

    /**

     * Copy Constructor of the MapRegistry. The new registry does not steal

     * the maps from the right value. The new registry will be an empty.

     */

    MapRegistry(const MapRegistry&) {}

    /**

     * Assign operator. The left value does not steal the maps 

     * from the right value. The left value will be an empty registry.

     */

    MapRegistry& operator=(const MapRegistry&) {

      typename Container::iterator it;

      for (it = container.begin(); it != container.end(); ++it) {

	(*it)->destroy();

	(*it)->graph = 0;

	(*it)->registry = 0;

      }

    }

    /**

     * Destructor of the MapRegistry.

     */

    ~MapRegistry() {

      typename Container::iterator it;

      for (it = container.begin(); it != container.end(); ++it) {

	(*it)->destroy();

	(*it)->registry = 0;

	(*it)->graph = 0;

      }

    }

    public:

    /**

     * Attach a map into thr registry. If the map has been attached

     * into an other registry it is detached from that automaticly.

     */

    void attach(MapBase& map) {

      if (map.registry) {

	map.registry->detach(map);

      }

      container.push_back(&map);

      map.registry = this;

      map.registry_index = container.size()-1;

    } 

    /**

     * Detach the map from the registry.

     */

    void detach(MapBase& map) {

      container.back()->registry_index = map.registry_index; 

      container[map.registry_index] = container.back();

      container.pop_back();

      map.registry = 0;

      map.graph = 0;

    }

    /**

     * Notify all the registered maps about a Key added.

     */

    virtual void add(Key& key) {

      typename Container::iterator it;

      for (it = container.begin(); it != container.end(); ++it) {

	(*it)->add(key);

      }

    }	

    /**

     * Notify all the registered maps about a Key erased.

     */ 

    virtual void erase(Key& key) {

      typename Container::iterator it;

      for (it = container.begin(); it != container.end(); ++it) {

	(*it)->erase(key);

      }

    }

    /**

     * Notify all the registered maps about the map should be cleared.

     */ 

    virtual void clear() {

      typename Container::iterator it;

      for (it = container.begin(); it != container.end(); ++it) {

	(*it)->clear();

      }

    }

  };

}

#endif