/* -*- C++ -*-
 *
 * This file is a part of LEMON, a generic C++ optimization library
 *
 * Copyright (C) 2003-2008
 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
 * (Egervary Research Group on Combinatorial Optimization, EGRES).
 *
 * Permission to use, modify and distribute this software is granted
 * provided that this copyright notice appears in all copies. For
 * precise terms see the accompanying LICENSE file.
 *
 * This software is provided "AS IS" with no warranty of any kind,
 * express or implied, and with no claim as to its suitability for any
 * purpose.
 *
 */

#ifndef LEMON_CONCEPT_MAPS_H
#define LEMON_CONCEPT_MAPS_H

#include <lemon/bits/utility.h>
#include <lemon/concept_check.h>

///\ingroup concept
///\file
///\brief Map concepts checking classes for testing and documenting.

namespace lemon {

  namespace concepts {
  
    /// \addtogroup concept
    /// @{

    /// Readable map concept

    /// Readable map concept.
    ///
    template<typename K, typename T>
    class ReadMap
    {
    public:
      /// The key type of the map.
      typedef K Key;    
      /// The value type of the map. (The type of objects associated with the keys).
      typedef T Value;

      /// Returns the value associated with a key.

      /// \bug Value shouldn't need to be default constructible.
      ///
      Value operator[](const Key &) const {return Value();}

      template<typename _ReadMap>
      struct Constraints {

	void constraints() {
	  Value val = m[key];
	  val = m[key];
	  typename _ReadMap::Value own_val = m[own_key]; 
	  own_val = m[own_key]; 

	  ignore_unused_variable_warning(val);
	  ignore_unused_variable_warning(own_val);
	  ignore_unused_variable_warning(key);
	}
	Key& key;
	typename _ReadMap::Key& own_key;
	_ReadMap& m;
      };
      
    };


    /// Writable map concept
    
    /// Writable map concept.
    ///
    template<typename K, typename T>
    class WriteMap
    {
    public:
      /// The key type of the map.
      typedef K Key;    
      /// The value type of the map. (The type of objects associated with the keys).
      typedef T Value;

      /// Sets the value associated with a key.
      void set(const Key &,const Value &) {}

      ///Default constructor
      WriteMap() {}

      template <typename _WriteMap>
      struct Constraints {
	void constraints() {
	  // No constraints for constructor.
	  m.set(key, val);
	  m.set(own_key, own_val);
	  ignore_unused_variable_warning(key);
	  ignore_unused_variable_warning(val);
	  ignore_unused_variable_warning(own_key);
	  ignore_unused_variable_warning(own_val);
	}

	Value& val;
	typename _WriteMap::Value own_val;
	Key& key;
	typename _WriteMap::Key& own_key;
	_WriteMap& m;

      };
    };

    /// Read/Writable map concept
    
    /// Read/writable map concept.
    ///
    template<typename K, typename T>
    class ReadWriteMap : public ReadMap<K,T>,
			 public WriteMap<K,T>
    {
    public:
      /// The key type of the map.
      typedef K Key;    
      /// The value type of the map. (The type of objects associated with the keys).
      typedef T Value;

      /// Returns the value associated with a key.
      Value operator[](const Key &) const {return Value();}
      /// Sets the value associated with a key.
      void set(const Key & ,const Value &) {}

      template<typename _ReadWriteMap>
      struct Constraints {
	void constraints() {
	  checkConcept<ReadMap<K, T>, _ReadWriteMap >();
	  checkConcept<WriteMap<K, T>, _ReadWriteMap >();
	}
      };
    };
  
  
    /// Dereferable map concept
    
    /// Dereferable map concept.
    ///
    template<typename K, typename T, typename R, typename CR>
    class ReferenceMap : public ReadWriteMap<K,T>
    {
    public:
      /// Tag for reference maps.
      typedef True ReferenceMapTag;
      /// The key type of the map.
      typedef K Key;    
      /// The value type of the map. (The type of objects associated with the keys).
      typedef T Value;
      /// The reference type of the map.
      typedef R Reference;
      /// The const reference type of the map.
      typedef CR ConstReference;

    protected:
      Value tmp;
    public:

      ///Returns a reference to the value associated to a key.
      Reference operator[](const Key &) { return tmp; }
      ///Returns a const reference to the value associated to a key.
      ConstReference operator[](const Key &) const { return tmp; }
      /// Sets the value associated with a key.
      void set(const Key &k,const Value &t) { operator[](k)=t; }

      /// \todo Rethink this concept. 
      template<typename _ReferenceMap>
      struct ReferenceMapConcept {

	void constraints() {
	  checkConcept<ReadWriteMap, _ReferenceMap >();
	  m[key] = val;
	  val  = m[key];
	  m[key] = ref;
	  ref = m[key];
	  m[own_key] = own_val;
	  own_val  = m[own_key];
	  m[own_key] = own_ref;
	  own_ref = m[own_key];	  	  
	}

	typename _ReferenceMap::Key& own_key;
	typename _ReferenceMap::Value& own_val;
	typename _ReferenceMap::Reference& own_ref;
	Key& key;
	Value& val;
	Reference& ref;
	_ReferenceMap& m;
      };
    };

    // @}

  } //namespace concepts

} //namespace lemon

#endif // LEMON_CONCEPT_MAPS_H