/* -*- C++ -*-
 * src/lemon/concept/graph_component.h - Part of LEMON, a generic C++ optimization library
 *
 * Copyright (C) 2004 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
 * (Egervary Combinatorial Optimization Research Group, 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.
 *
 */

///\ingroup concept
///\file
///\brief The graph components.


#ifndef LEMON_CONCEPT_GRAPH_COMPONENT_H
#define LEMON_CONCEPT_GRAPH_COMPONENT_H

#include <lemon/invalid.h>
#include <lemon/concept/maps.h>

namespace lemon {
  namespace concept {


    /****************   Graph iterator concepts   ****************/

    /// Skeleton class for graph Node and Edge

    /// \note Because Node and Edge are forbidden to inherit from the same
    /// base class, this is a template. For Node you shoul instantiate it
    /// with character 'n' and for Edge with 'e'.

    template<char Ch>
    class GraphItem {
    public:
      GraphItem() {}
      GraphItem(Invalid) {}

      // We explicitely list these:
      GraphItem(GraphItem const&) {}
      GraphItem& operator=(GraphItem const&) { return *this; }

      bool operator==(GraphItem) const { return false; }
      bool operator!=(GraphItem) const { return false; }

      // Technical requirement. Do we really need this?
      bool operator<(GraphItem) const { return false; }
    };


    template<typename GI>
    struct GraphItemConcept {
      void constraints() {
	GI i1;
	GI i2 = i1;
	GI i3 = INVALID;
	
	i1 = i2 = i3;

	bool b;
	b = (ia == ib) && (ia != ib) && (ia < ib);
	b = (ia == INVALID) && (ib != INVALID);
      }

      const GI &ia;
      const GI &ib;
    };


    template<typename Iter, typename Graph, typename BaseItem>
    struct GraphIteratorConcept {
      void constraints() {
	function_requires< GraphItemConcept<Iter> >();
	Iter it1(g);

	/// \todo Do we need NodeIt(Node) kind of constructor?
	//	Iter it2(bj);
	Iter it2;

	it2 = ++it1;
	++it2 = it1;
	++(++it1);
	/// \bug This should be: is_base_and_derived<BaseItem, Iter>
	BaseItem bi = it1;
	bi = it2;
      }

      BaseItem bj;
      Graph g;
    };

    template<typename Iter, typename Graph>
    struct GraphIncIteratorConcept {
      typedef typename Graph::Node Node;
      typedef typename Graph::Edge Edge;
      void constraints() {
	function_requires< GraphItemConcept<Iter> >();
	Iter it1(graph, node);
	/// \todo Do we need OutEdgeIt(Edge) kind of constructor?
	//	Iter it2(edge);
	Iter it2;

	it2 = ++it1;
	++it2 = it1;
	++(++it1);
	Edge e = it1;
	e = it2;
      }

      Edge edge;
      Node node;
      Graph graph;
    };



    /// An empty base graph class.
  
    /// This class provides the minimal set of features needed for a graph
    /// structure. All graph concepts have to be conform to this base
    /// graph.
    ///
    /// \bug This is not true. The minimal graph concept is the
    /// BaseIterableGraphComponent.

    class BaseGraphComponent {
    public:

      typedef BaseGraphComponent Graph;
      
      /// Node class of the graph.

      /// This class represents the Nodes of the graph. 
      ///
      class Node {
      public:

	/// Default constructor.

	/// @warning The default constructor sets the iterator
	/// to an undefined value.

	Node() {}
	/// Copy constructor.

	/// Copy constructor.
	///
	Node(const Node&) {}

	/// Invalid constructor \& conversion.

	/// This constructor initializes the iterator to be invalid.
	/// \sa Invalid for more details.
	Node(Invalid) {}


	Node& operator=(const Node&) { return *this;}

	/// Equality operator.

	/// Two iterators are equal if and only if they represents the
	/// same node in the graph or both are invalid.
	bool operator==(const Node&) const { return true;}


	/// Inequality operator.
	
	/// \sa operator==(const Node& n)
	///
	bool operator!=(const Node&) const { return true;}

 	/// Comparison operator.

	/// This is a strict ordering between the nodes.
	///
	/// This ordering can be different from the iterating order of nodes.
	/// \todo Possibly we don't need it.
	bool operator<(const Node&) const { return true;}
      };

      /// Edge class of the graph.

      /// This class represents the Edges of the graph. 
      ///
      class Edge {
      public:

	/// Default constructor.

	/// @warning The default constructor sets the iterator
	/// to an undefined value.

	Edge() {}
	/// Copy constructor.

	/// Copy constructor.
	///
	Edge(const Edge&) {}

	/// Invalid constructor \& conversion.

	/// This constructor initializes the iterator to be invalid.
	/// \sa Invalid for more details.
	Edge(Invalid) {}


	Edge& operator=(const Edge&) { return *this;}

	/// Equality operator.

	/// Two iterators are equal if and only if they represents the
	/// same edge in the graph or both are invalid.
	bool operator==(const Edge&) const { return true;}


	/// Inequality operator.
	
	/// \sa operator==(const Edge& n)
	///
	bool operator!=(const Edge&) const { return true;}

 	/// Comparison operator.

	/// This is a strict ordering between the edges.
	///
	/// This ordering can be different from the iterating order of edges.
	/// \todo Possibly we don't need it.
	bool operator<(const Edge&) const { return true;}
      };

      ///Gives back the head node of an edge.

      ///Gives back the head node of an edge.
      ///
      Node head(const Edge&) const { return INVALID;}

      ///Gives back the tail node of an edge.

      ///Gives back the tail node of an edge.
      ///
      Node tail(const Edge&) const { return INVALID;}
    };


    /// Concept check structure for BaseGraph.

    /// Concept check structure for BaseGraph.
    ///

    template <typename Graph>
    struct BaseGraphComponentConcept {
      typedef typename Graph::Node Node;
      typedef typename Graph::Edge Edge;
      
      void constraints() {
	function_requires< GraphItemConcept<Node> >();
	function_requires< GraphItemConcept<Edge> >();
	{
	  Node n;
	  Edge e;
	  n = graph.tail(e);
	  n = graph.head(e);
	}      
      }
      
      const Graph& graph;
    };

    /// An empty iterable base graph class.
  
    /// This class provides beside the core graph features
    /// core iterable interface for the graph structure.
    /// Most of the base graphs should be conform to this concept.

    class BaseIterableGraphComponent : virtual public BaseGraphComponent {
    public:

      typedef BaseGraphComponent::Node Node;
      typedef BaseGraphComponent::Edge Edge;

      /// Gives back the first Node in the iterating order.
      
      /// Gives back the first Node in the iterating order.
      ///     
      void first(Node&) const {}

      /// Gives back the next Node in the iterating order.
      
      /// Gives back the next Node in the iterating order.
      ///     
      void next(Node&) const {}

      /// Gives back the first Edge in the iterating order.
      
      /// Gives back the first Edge in the iterating order.
      ///     
      void first(Edge&) const {}
      /// Gives back the next Edge in the iterating order.
      
      /// Gives back the next Edge in the iterating order.
      ///     
      void next(Edge&) const {}


      /// Gives back the first of the Edges point to the given Node.
      
      /// Gives back the first of the Edges point to the given Node.
      ///     
      void firstIn(Edge&, const Node&) const {}

      /// Gives back the next of the Edges points to the given Node.


      /// Gives back the next of the Edges points to the given Node.
      ///
      void nextIn(Edge&) const {}

      /// Gives back the first of the Edges start from the given Node.
      
      /// Gives back the first of the Edges start from the given Node.
      ///     
      void firstOut(Edge&, const Node&) const {}

      /// Gives back the next of the Edges start from the given Node.
      
      /// Gives back the next of the Edges start from the given Node.
      ///     
      void nextOut(Edge&) const {}
    };


    /// Concept check structure for IterableBaseGraph.

    /// Concept check structure for IterableBaseGraph.
    ///
    template <typename Graph>
    struct BaseIterableGraphComponentConcept {
      
      void constraints() {
	function_requires< BaseGraphComponentConcept<Graph> >();
	typename Graph::Node node;      
	typename Graph::Edge edge;
	{
	  graph.first(node);
	  graph.next(node);
	}
	{
	  graph.first(edge);
	  graph.next(edge);
	}
	{
	  graph.firstIn(edge, node);
	  graph.nextIn(edge);
	}
	{
	  graph.firstOut(edge, node);
	  graph.nextOut(edge);
	}
      }

      const Graph& graph;
    };

    /// An empty idable base graph class.
  
    /// This class provides beside the core graph features
    /// core id functions for the graph structure.
    /// The most of the base graphs should be conform to this concept.
    /// The id's are unique and immutable.

    class IDableGraphComponent : virtual public BaseGraphComponent {
    public:

      typedef BaseGraphComponent::Node Node;
      typedef BaseGraphComponent::Edge Edge;

      /// Gives back an unique integer id for the Node. 

      /// Gives back an unique integer id for the Node. 
      ///
      int id(const Node&) const { return -1;}

      /// Gives back an unique integer id for the Edge. 

      /// Gives back an unique integer id for the Edge. 
      ///
      int id(const Edge&) const { return -1;}
    };


    /// Concept check structure for IdableBaseGraph.

    /// Concept check structure for IdableBaseGraph.
    ///
    template <typename Graph>
    struct IDableGraphComponentConcept {

      void constraints() {
	function_requires< BaseGraphComponentConcept<Graph> >();
	typename Graph::Node node;
	int nid = graph.id(node);
	nid = graph.id(node);
	typename Graph::Edge edge;
	int eid = graph.id(edge);
	eid = graph.id(edge);
      }

      const Graph& graph;
    };


    /// An empty max-idable base graph class.
  
    /// This class provides beside the core graph features
    /// core max id functions for the graph structure.
    /// The most of the base graphs should be conform to this concept.
    /// The id's are unique and immutable.
    class MaxIDableGraphComponent : virtual public BaseGraphComponent {
    public:

      /// Gives back an integer greater or equal to the maximum Node id. 

      /// Gives back an integer greater or equal to the maximum Node id. 
      ///
      int maxEdgeId() const { return -1;}

      /// Gives back an integer greater or equal to the maximum Edge id. 

      /// Gives back an integer greater or equal to the maximum Edge id. 
      ///
      int maxNodeId() const { return -1;}
    };

    /// Concept check structure for MaxIdableBaseGraph.

    /// Concept check structure for MaxIdableBaseGraph.
    ///
    template <typename Graph>
    struct MaxIDableGraphComponentConcept {

      void constraints() {
	function_requires< BaseGraphComponentConcept<Graph> >();
	int nid = graph.maxEdgeId();
	ignore_unused_variable_warning(nid);
	int eid = graph.maxNodeId();
	ignore_unused_variable_warning(eid);
      }

      const Graph& graph;
    };

    /// An empty extendable base graph class.
  
    /// This class provides beside the core graph features
    /// core graph extend interface for the graph structure.
    /// The most of the base graphs should be conform to this concept.
    class BaseExtendableGraphComponent : virtual public BaseGraphComponent {
    public:

      typedef BaseGraphComponent::Node Node;
      typedef BaseGraphComponent::Edge Edge;

      /// Adds a new Node to the graph.

      /// Adds a new Node to the graph.
      ///
      Node addNode() {
	return INVALID;
      }
    
      /// Adds a new Edge connects the two Nodes to the graph.

      /// Adds a new Edge connects the two Nodes to the graph.
      ///
      Edge addEdge(const Node& from, const Node& to) {
	return INVALID;
      }

    };

    /// Concept check structure for ExtendableBaseGraph.

    /// Concept check structure for ExtendableBaseGraph.
    ///
    template <typename Graph>
    struct BaseExtendableGraphComponentConcept {
      void constraints() {
	function_requires< BaseGraphComponentConcept<Graph> >();
	typename Graph::Node node_a, node_b;
	node_a = graph.addNode();
	typename Graph::Edge edge;
	edge = graph.addEdge(node_a, node_b);
      }

      Graph& graph;
    };

    /// An empty erasable base graph class.
  
    /// This class provides beside the core graph features
    /// core erase functions for the graph structure.
    /// The most of the base graphs should be conform to this concept.
    class BaseErasableGraphComponent : virtual public BaseGraphComponent {
    public:

      typedef BaseGraphComponent::Node Node;
      typedef BaseGraphComponent::Edge Edge;

      /// Erase a Node from the graph.
      
      /// Erase a Node from the graph. This function should not
      /// erase edges connecting to the Node.
      void erase(const Node&) {}    

      /// Erase an Edge from the graph.

      /// Erase an Edge from the graph.
      ///
      void erase(const Edge&) {}

    };

    /// Concept check structure for ErasableBaseGraph.

    /// Concept check structure for ErasableBaseGraph.
    ///
    template <typename Graph>
    struct BaseErasableGraphComponentConcept {
      void constraints() {
	function_requires< BaseGraphComponentConcept<Graph> >();
	typename Graph::Node node;
	graph.erase(node);
	typename Graph::Edge edge;
	graph.erase(edge);
      }

      Graph& graph;
    };

    /// An empty clearable base graph class.
  
    /// This class provides beside the core graph features
    /// core clear functions for the graph structure.
    /// The most of the base graphs should be conform to this concept.
    class BaseClearableGraphComponent : virtual public BaseGraphComponent {
    public:

      /// Erase all the Nodes and Edges from the graph.

      /// Erase all the Nodes and Edges from the graph.
      ///
      void clear() {}    
    };

    /// Concept check function for ErasableBaseGraph.

    /// Concept check function for ErasableBaseGraph.
    ///
    template <typename Graph>
    struct BaseClearableGraphComponentConcept {
      void constraints() {
	function_requires< BaseGraphComponentConcept<Graph> >();
	graph.clear();
      }

      Graph& graph;
    };


    class IterableGraphComponent :
      virtual public BaseIterableGraphComponent {

    public:
    
      typedef IterableGraphComponent Graph;

      typedef BaseGraphComponent::Node Node;
      typedef BaseGraphComponent::Edge Edge;

      class NodeIt : public Node {
      public:
	NodeIt() {}
	NodeIt(Invalid) {}
	// explicit NodeIt(Node) {}
	explicit NodeIt(const Graph&) {}

	NodeIt& operator++() { return *this; }
	//	Node operator*() const { return INVALID; }

	bool operator==(const NodeIt&) const { return true;}
	bool operator!=(const NodeIt&) const { return true;}
      };

      class EdgeIt : public Edge {
      public:
	EdgeIt() {}
	EdgeIt(Invalid) {}
	// explicit EdgeIt(Edge) {}
	explicit EdgeIt(const Graph&) {}

	EdgeIt& operator++() { return *this; }
	//	Edge operator*() const { return INVALID; }

	bool operator==(const EdgeIt&) const { return true;}
	bool operator!=(const EdgeIt&) const { return true;}
      };

      class InEdgeIt : public Edge {
      public:
	InEdgeIt() {}
	InEdgeIt(Invalid) {}
	// explicit InEdgeIt(Edge) {}
	explicit InEdgeIt(const Graph&, const Node&) {}

	InEdgeIt& operator++() { return *this; }
	//	Edge operator*() const { return INVALID; }

	bool operator==(const InEdgeIt&) const { return true;}
	bool operator!=(const InEdgeIt&) const { return true;}
      };

      class OutEdgeIt : public Edge {
      public:
	OutEdgeIt() {}
	OutEdgeIt(Invalid) {}
	// explicit OutEdgeIt(Edge) {}
	explicit OutEdgeIt(const Graph&, const Node&) {}

	OutEdgeIt& operator++() { return *this; }
	//	Edge operator*() const { return INVALID; }

	bool operator==(const OutEdgeIt&) const { return true;}
	bool operator!=(const OutEdgeIt&) const { return true;}
      };

    };
    
    template <typename Graph> 
    struct IterableGraphComponentConcept {
      void constraints() {
  	function_requires< BaseIterableGraphComponentConcept<Graph> >();

	typedef typename Graph::Node Node;
	typedef typename Graph::NodeIt NodeIt;
	typedef typename Graph::Edge Edge;
	typedef typename Graph::EdgeIt EdgeIt;
	typedef typename Graph::InEdgeIt InEdgeIt;
	typedef typename Graph::OutEdgeIt OutEdgeIt;
  
	function_requires< GraphIteratorConcept<NodeIt, Graph, Node> >();
	function_requires< GraphIteratorConcept<EdgeIt, Graph, Edge> >();
	function_requires< GraphIncIteratorConcept<OutEdgeIt, Graph> >();
	function_requires< GraphIncIteratorConcept<InEdgeIt, Graph> >();
      }
    };


    class IdMappableGraphComponent : virtual public BaseGraphComponent {

      typedef IdMappableGraphComponent Graph;

    public:

      typedef BaseGraphComponent::Node Node;
      typedef BaseGraphComponent::Edge Edge;

      class NodeIdMap : public ReadMap<Node, int> {
      public:
	NodeIdMap(const Graph&) {}
	int maxId() const { return -1;}
      };

      class EdgeIdMap : public ReadMap<Edge, int> {
      public:
	EdgeIdMap(const Graph&) {}
	int maxId() const { return -1;}
      };

    };
    
    template <typename Graph>
    struct IdMappableGraphComponentConcept {
      void constraints() {	
	function_requires< BaseGraphComponentConcept<Graph> >();
	{
	  typedef typename Graph::EdgeIdMap EdgeIdMap;
	  function_requires<ReadMapConcept<EdgeIdMap> >();
	  EdgeIdMap edge_map(graph);
	  int n = edge_map.maxId();
	  ignore_unused_variable_warning(n);
	}
	{
	  typedef typename Graph::NodeIdMap NodeIdMap;
	  function_requires<ReadMapConcept<NodeIdMap> >();
	  NodeIdMap node_map(graph);
	  int n = node_map.maxId();
	  ignore_unused_variable_warning(n);
	}
      }
      Graph& graph;
    };


    class MappableGraphComponent : virtual public BaseGraphComponent {
    public:

      typedef MappableGraphComponent Graph;

      typedef BaseGraphComponent::Node Node;
      typedef BaseGraphComponent::Edge Edge;

      template <typename Value>
      class NodeMap : public ReferenceMap<Node, Value> {
      public:
	NodeMap(const Graph&) {}
	NodeMap(const Graph&, const Value&) {}
	NodeMap(const NodeMap&) {}

	NodeMap& operator=(const NodeMap&) { return *this;}
	
      };

      template <typename Value>
      class EdgeMap : public ReferenceMap<Edge, Value> {
      public:
	EdgeMap(const Graph&) {}
	EdgeMap(const Graph&, const Value&) {}
	EdgeMap(const EdgeMap&) {}

	EdgeMap& operator=(const EdgeMap&) { return *this;}
	
      };

    };

    template <typename Graph>
    struct MappableGraphComponentConcept {

      struct Type {
	int value;
	Type() : value(0) {}
	Type(int _v) : value(_v) {}
      };

      void constraints() {
	function_requires< BaseGraphComponentConcept<Graph> >();
	{ // int map test
	  typedef typename Graph::template NodeMap<int> IntNodeMap;
	  function_requires<GraphMapConcept<IntNodeMap,Graph> >();
	} { // bool map test
	  typedef typename Graph::template NodeMap<bool> BoolNodeMap;
	  function_requires<GraphMapConcept<BoolNodeMap,Graph> >();
	} { // Type map test
	  typedef typename Graph::template NodeMap<Type> TypeNodeMap;
	  function_requires<GraphMapConcept<TypeNodeMap,Graph> >();
	} 

	{ // int map test
	  typedef typename Graph::template EdgeMap<int> IntEdgeMap;
	  function_requires<GraphMapConcept<IntEdgeMap,Graph> >();
	} { // bool map test
	  typedef typename Graph::template EdgeMap<bool> BoolEdgeMap;
	  function_requires<GraphMapConcept<BoolEdgeMap,Graph> >();
	} { // Type map test
	  typedef typename Graph::template EdgeMap<Type> TypeEdgeMap;
	  function_requires<GraphMapConcept<TypeEdgeMap,Graph> >();
	} 
      }

      Graph& graph;
    };


    class ExtendableGraphComponent : virtual public BaseGraphComponent {
    public:

      typedef ExtendableGraphComponent Graph;

      typedef BaseGraphComponent::Node Node;
      typedef BaseGraphComponent::Edge Edge;

      Node addNode() {
	return INVALID;
      }
    
      Edge addEdge(const Node& from, const Node& to) {
	return INVALID;
      }

    };

    template <typename Graph>
    struct ExtendableGraphComponentConcept {
      void constraints() {
	function_requires< BaseGraphComponentConcept<Graph> >();
	typename Graph::Node node_a, node_b;
	node_a = graph.addNode();
	typename Graph::Edge edge;
	edge = graph.addEdge(node_a, node_b);      
      }
      Graph& graph;
    };

    class ErasableGraphComponent : virtual public BaseGraphComponent {
    public:

      typedef ErasableGraphComponent Graph;

      typedef BaseGraphComponent::Node Node;
      typedef BaseGraphComponent::Edge Edge;

      void erase(const Node&) {}    
      void erase(const Edge&) {}

    };

    template <typename Graph>
    struct ErasableGraphComponentConcept {
      void constraints() {
	function_requires< BaseGraphComponentConcept<Graph> >();
	typename Graph::Node node;
	graph.erase(node);
	typename Graph::Edge edge;
	graph.erase(edge);      
      }

      Graph& graph;
    };

    class ClearableGraphComponent : virtual public BaseGraphComponent {
    public:

      typedef ClearableGraphComponent Graph;

      typedef BaseGraphComponent::Node Node;
      typedef BaseGraphComponent::Edge Edge;

      void clear() {}    

    };

    template <typename Graph>
    struct ClearableGraphComponentConcept {
      void constraints() {
	function_requires< BaseGraphComponentConcept<Graph> >();
	graph.clear();
      }
      Graph& graph;
    };

  }

}

#endif