/*
 * Copyright (C) 1998, 2000-2007, 2010, 2011, 2012, 2013 SINTEF ICT,
 * Applied Mathematics, Norway.
 * Copyright (C) 2013 CERN
 * @author Maciej Suminski <maciej.suminski@cern.ch>
 *
 * Contact information: E-mail: tor.dokken@sintef.no                      
 * SINTEF ICT, Department of Applied Mathematics,                         
 * P.O. Box 124 Blindern,                                                 
 * 0314 Oslo, Norway.                                                     
 *
 * This file is part of TTL.
 *
 * TTL is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version. 
 *
 * TTL 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public
 * License along with TTL. If not, see
 * <http://www.gnu.org/licenses/>.
 *
 * In accordance with Section 7(b) of the GNU Affero General Public
 * License, a covered work must retain the producer line in every data
 * file that is created or manipulated using TTL.
 *
 * Other Usage
 * You can be released from the requirements of the license by purchasing
 * a commercial license. Buying such a license is mandatory as soon as you
 * develop commercial activities involving the TTL library without
 * disclosing the source code of your own applications.
 *
 * This file may be used in accordance with the terms contained in a
 * written agreement between you and SINTEF ICT. 
 */

#ifndef _HE_TRIANG_H_
#define _HE_TRIANG_H_


#define TTL_USE_NODE_ID   // Each node gets it's own unique id
#define TTL_USE_NODE_FLAG // Each node gets a flag (can be set to true or false)


#include <list>
#include <vector>
#include <iostream>
#include <fstream>
#include <ttl/ttl_util.h>
#include <boost/shared_ptr.hpp>

namespace ttl {
  class TriangulationHelper;
};

//--------------------------------------------------------------------------------------------------
// The half-edge data structure
//--------------------------------------------------------------------------------------------------

namespace hed {
  // Helper typedefs
  class Node;
  class Edge;
  typedef boost::shared_ptr<Node> NodePtr;
  typedef boost::shared_ptr<Edge> EdgePtr;
  typedef std::vector<NodePtr> NodesContainer;

  //------------------------------------------------------------------------------------------------
  // Node class for data structures
  //------------------------------------------------------------------------------------------------

  /** \class Node
   *   \brief \b Node class for data structures (Inherits from HandleId)
   *
   *   \note
   *   - To enable node IDs, TTL_USE_NODE_ID must be defined.
   *   - To enable node flags, TTL_USE_NODE_FLAG must be defined.
   *   - TTL_USE_NODE_ID and TTL_USE_NODE_FLAG should only be enabled if this functionality is
   *     required by the application, because they increase the memory usage for each Node object.
   */

  class Node {

protected:
#ifdef TTL_USE_NODE_FLAG
    /// TTL_USE_NODE_FLAG must be defined
    bool flag_;
#endif

#ifdef TTL_USE_NODE_ID
    /// TTL_USE_NODE_ID must be defined
    static int id_count;

    /// A unique id for each node (TTL_USE_NODE_ID must be defined)
    int id_;
#endif

    int x_, y_;

    unsigned int refCount_;

public:
    /// Constructor
    Node( int x = 0, int y = 0 ) :
#ifdef TTL_USE_NODE_FLAG
    flag_( false ),
#endif
#ifdef TTL_USE_NODE_ID
    id_( id_count++ ),
#endif
    x_( x ), y_( y ), refCount_( 0 ) {}

    /// Destructor
    ~Node() {}

    /// Returns the x-coordinate
    int GetX() const { return x_; }

    /// Returns the y-coordinate
    int GetY() const { return y_; }

#ifdef TTL_USE_NODE_ID
    /// Returns the id (TTL_USE_NODE_ID must be defined)
    int Id() const { return id_; }
#endif

#ifdef TTL_USE_NODE_FLAG
    /// Sets the flag (TTL_USE_NODE_FLAG must be defined)
    void SetFlag(bool aFlag) { flag_ = aFlag; }

    /// Returns the flag (TTL_USE_NODE_FLAG must be defined)
    const bool& GetFlag() const { return flag_; }
#endif

    void IncRefCount() { refCount_++; }
    void DecRefCount() { refCount_--; }
    unsigned int GetRefCount() const { return refCount_; }
  }; // End of class Node

  
  //------------------------------------------------------------------------------------------------
  // Edge class in the half-edge data structure
  //------------------------------------------------------------------------------------------------

  /** \class Edge
  *   \brief \b %Edge class in the in the half-edge data structure.
  */

  class Edge {
  public:
    /// Constructor
    Edge() : weight_(0)
        { flags_.isLeadingEdge_ = false; flags_.isConstrained_ = false; }

    /// Destructor
    virtual ~Edge() {}

    /// Sets the source node
    void setSourceNode(const NodePtr& node) { sourceNode_ = node; }

    /// Sets the next edge in face
    void setNextEdgeInFace(const EdgePtr& edge) { nextEdgeInFace_ = edge; }

    /// Sets the twin edge
    void setTwinEdge(const EdgePtr& edge) { twinEdge_ = edge; }

    /// Sets the edge as a leading edge
    void setAsLeadingEdge(bool val=true) { flags_.isLeadingEdge_ = val; }

    /// Checks if an edge is a leading edge
    bool isLeadingEdge() const { return flags_.isLeadingEdge_; }

    /// Sets the edge as a constrained edge
    void setConstrained(bool val=true) { flags_.isConstrained_ = val;
      if (twinEdge_) twinEdge_->flags_.isConstrained_ = val; }

    /// Checks if an edge is constrained
    bool isConstrained() const { return flags_.isConstrained_; }

    /// Returns the twin edge
    const EdgePtr& getTwinEdge() const { return twinEdge_; };

    /// Returns the next edge in face
    const EdgePtr& getNextEdgeInFace() const { return nextEdgeInFace_; }

    /// Retuns the source node
    virtual const NodePtr& getSourceNode() const { return sourceNode_; }

    /// Returns the target node
    virtual const NodePtr& getTargetNode() const { return getNextEdgeInFace()->getSourceNode(); }

    void setWeight( unsigned int weight ) { weight_ = weight; }

    unsigned int getWeight() const { return weight_; }

  protected:
    NodePtr sourceNode_;
    EdgePtr twinEdge_;
    EdgePtr nextEdgeInFace_;
    unsigned int weight_;

    struct {
      bool isLeadingEdge_;
      bool isConstrained_;
    } flags_;
  }; // End of class Edge


  /** \class EdgeMST
  *   \brief \b %Specialization of Edge class to be used for Minimum Spanning Tree algorithm.
  */
  class EdgeMST : public Edge
  {
  private:
    NodePtr target_;

  public:
    EdgeMST( const NodePtr& source, const NodePtr& target, unsigned int weight = 0 ) :
        target_(target)
        { sourceNode_ = source; weight_ = weight; }

    ~EdgeMST() {};

    /// @copydoc Edge::setSourceNode()
    const NodePtr& getTargetNode() const { return target_; }
  };


  //------------------------------------------------------------------------------------------------
  class Dart; // Forward declaration (class in this namespace)

  //------------------------------------------------------------------------------------------------
  // Triangulation class in the half-edge data structure
  //------------------------------------------------------------------------------------------------

  /** \class Triangulation
  *   \brief \b %Triangulation class for the half-edge data structure with adaption to TTL.
  */

  class Triangulation {

  protected:
    std::list<EdgePtr> leadingEdges_; // one half-edge for each arc

    ttl::TriangulationHelper* helper;

    void addLeadingEdge(EdgePtr& edge) {
        edge->setAsLeadingEdge();
        leadingEdges_.push_front( edge );
    }

    bool removeLeadingEdgeFromList(EdgePtr& leadingEdge);

    void cleanAll();
    
    /** Swaps the edge associated with \e dart in the actual data structure.
    *
    *   <center>
    *   \image html swapEdge.gif
    *   </center>
    *
    *   \param dart
    *   Some of the functions require a dart as output.
    *   If this is required by the actual function, the dart should be delivered
    *   back in a position as seen if it was glued to the edge when swapping (rotating)
    *   the edge CCW; see the figure.
    *
    *   \note
    *   - If the edge is \e constrained, or if it should not be swapped for
    *     some other reason, this function need not do the actual swap of the edge.
    *   - Some functions in TTL require that \c swapEdge is implemented such that
    *     darts outside the quadrilateral are not affected by the swap.
    */
    void swapEdge(Dart& dart);

    /** Splits the triangle associated with \e dart in the actual data structure into
    *   three new triangles joining at \e point.
    *
    *   <center>
    *   \image html splitTriangle.gif
    *   </center>
    *
    *   \param dart
    *   Output: A CCW dart incident with the new node; see the figure.
    */
    void splitTriangle(Dart& dart, NodePtr point);

    /** The reverse operation of TTLtraits::splitTriangle.
    *   This function is only required for functions that involve
    *   removal of interior nodes; see for example TrinagulationHelper::removeInteriorNode.
    *
    *   <center>
    *   \image html reverse_splitTriangle.gif
    *   </center>
    */
    void reverse_splitTriangle(Dart& dart);

    /** Removes a triangle with an edge at the boundary of the triangulation
    *   in the actual data structure
    */
    void removeBoundaryTriangle(Dart& d);

  public:
    /// Default constructor
    Triangulation();
    
    /// Copy constructor
    Triangulation(const Triangulation& tr);

    /// Destructor
    ~Triangulation();
    
    /// Creates a Delaunay triangulation from a set of points
    void createDelaunay(NodesContainer::iterator first,
                        NodesContainer::iterator last);

    /// Creates an initial Delaunay triangulation from two enclosing triangles
    //  When using rectangular boundary - loop through all points and expand.
    //  (Called from createDelaunay(...) when starting)
    EdgePtr initTwoEnclosingTriangles(NodesContainer::iterator first,
                                      NodesContainer::iterator last);


    // These two functions are required by TTL for Delaunay triangulation
    
    /// Swaps the edge associated with diagonal
    void swapEdge(EdgePtr& diagonal);

    /// Splits the triangle associated with edge into three new triangles joining at point 
    EdgePtr splitTriangle(EdgePtr& edge, NodePtr& point);


    // Functions required by TTL for removing nodes in a Delaunay triangulation
    
    /// Removes the boundary triangle associated with edge
    void removeTriangle(EdgePtr& edge); // boundary triangle required

    /// The reverse operation of removeTriangle
    void reverse_splitTriangle(EdgePtr& edge);

    /// Creates an arbitrary CCW dart
    Dart createDart();

    /// Returns a list of "triangles" (one leading half-edge for each triangle)
    const std::list<EdgePtr>& getLeadingEdges() const { return leadingEdges_; }

    /// Returns the number of triangles
      int noTriangles() const { return (int)leadingEdges_.size(); }
    
    /// Returns a list of half-edges (one half-edge for each arc)
    std::list<EdgePtr>* getEdges(bool skip_boundary_edges = false) const;

#ifdef TTL_USE_NODE_FLAG
    /// Sets flag in all the nodes  
    void flagNodes(bool flag) const;

    /// Returns a list of nodes. This function requires TTL_USE_NODE_FLAG to be defined. \see Node.
    std::list<NodePtr>* getNodes() const;
#endif

    /// Swaps edges until the triangulation is Delaunay (constrained edges are not swapped)
    void optimizeDelaunay();

    /// Checks if the triangulation is Delaunay
    bool checkDelaunay() const;    

    /// Returns an arbitrary interior node (as the source node of the returned edge)
    EdgePtr getInteriorNode() const;

    EdgePtr getBoundaryEdgeInTriangle(const EdgePtr& e) const;

    /// Returns an arbitrary boundary edge
    EdgePtr getBoundaryEdge() const;

    /// Print edges for plotting with, e.g., gnuplot
    void printEdges(std::ofstream& os) const;

    friend class ttl::TriangulationHelper;

  }; // End of class Triangulation


}; // End of hed namespace

#endif
