// Copyright (c) 2005,2006,2007,2008,2009,2010,2011 Tel-Aviv University (Israel).
// All rights reserved.
//
// This file is part of CGAL (www.cgal.org).
// 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 3 of the License, or (at your option) any later version.
//
// Licensees holding a valid commercial license may use this file in
// accordance with the commercial license agreement provided with the software.
//
// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
//
// $URL$
// $Id$
// 
//
// Author(s)     : Iddo Hanniel <hanniel@math.tau.ac.il>
//                 Oren Nechushtan <theoren@math.tau.ac.il>

/* Directed acyclic binary graph template class */

#ifndef CGAL_TD_DAG_H
#define CGAL_TD_DAG_H

#include <CGAL/basic.h>
#include <CGAL/number_utils.h>
#include <CGAL/kernel_assertions.h>
#include <CGAL/Handle.h>

#include <cstdlib>
#include <iostream>
#include <list>
#include <functional>

namespace CGAL {

template<class T>
class Td_dag_base : public Handle
{
public: //iddo (for CC-7.2) maybe protected?
  typedef T * pointer;
  typedef T & reference;
  typedef const T & const_reference;

protected:
  void init() { PTR = 0; }

public:
  Td_dag_base() {init();}
  Td_dag_base(const Td_dag_base<T> & x) : Handle(x) {}
  Td_dag_base & operator=(const Td_dag_base<T> & x) 
  {Handle::operator=(x); return *this; }
  bool operator!() const { return PTR == 0; }
};

template<class T>
class Td_dag : public Td_dag_base<T>
{
public:
  typedef T* pointer;
  typedef T& reference;
  typedef const T& const_reference;
  typedef Td_dag_base<T> Td_dag_handle;
  typedef Td_dag<T> Self;
  typedef std::list<pointer> list_pointer;

#ifndef CGAL_CFG_USING_BASE_MEMBER_BUG_2
public:
  using Td_dag_handle::PTR;
  using Td_dag_handle::operator!;
#endif

protected:	
  class node : public Rep
  {
    friend class Td_dag<T>;
  public:
    node(const T& e,unsigned long _depth=0) : 
      data(e),leftPtr(),rightPtr(),depth_(_depth){}
    node(const T& e, const Td_dag_handle& left, 
         const Td_dag_handle& right,unsigned long _depth=0) : 
      data(e),leftPtr(left),rightPtr(right),depth_(_depth){}
    //		node(const T& e) : data(e),leftPtr(),rightPtr(){}
    //		node(const T& e, const Td_dag_handle& left, 
    // const Td_dag_handle& right) : data(e),leftPtr(left),rightPtr(right) {}
    ~node(){}
    bool is_inner_node() const {return !!leftPtr && !!rightPtr;}
    bool visited() const {return visited_;}
  protected:
    T data;			// information stored in node
    Td_dag_handle leftPtr,rightPtr;
    mutable unsigned long depth_;
    mutable bool visited_;
  };
  
public:
  /* -------constructors destructors -----*/
  Td_dag(){}
  Td_dag(const Td_dag_handle& dag):Td_dag_handle(dag){}
  Td_dag(const Self& dag):Td_dag_handle(dag){}
  Td_dag(const T& rootValue){PTR = new node(rootValue);}
  Td_dag(const T& rootValue, const Self& left, const Self& right)
  {PTR = new node(rootValue, left, right); rebalance_depth();}
  ~Td_dag(){}

  /* --------information retrieval -------*/
  const Self& left() const
  {
    CGAL_precondition(!operator!());
    return *(const Self*)&ptr()->leftPtr;
    
  }
  const Self& right() const
  {
    CGAL_precondition(!operator!());
    return *(const Self*)&ptr()->rightPtr;
  }
  reference get_data() const
  {
    CGAL_precondition(!operator!());
    return ptr()->data;
  }
  reference operator*() const
  {
    return get_data();
  }
  pointer data_ptr() const
  {
    CGAL_precondition(!operator!());
    return &operator*();
  }
  pointer operator->() const
  {
    return data_ptr();
  }
  bool is_inner_node() const 
  {return !operator!() && ptr()->is_inner_node();}
  unsigned long size() const
  {
    visit_none();
    return recursive_size();
  }
  unsigned long depth() const
  {
    visit_none();
    return recursive_depth();
  }
  bool operator==(const Self& b) const
  {
    return PTR==b.PTR;
  }
  bool operator!=(const Self& b) const
  {
    return !operator==(b);
  }
  /* dynamic management ---------*/
  
  /* description:
     Shallow copy	*/
  Self& operator=(const Self& b)
  {
    Handle::operator=(b);
    return *this;
  }
  /*
  Self& deep_copy(const Self& b)
  {
    if (this != &b)
      {
        clear();
        operator=(b);
      }
    return *this;
  }
  void clear()
  {
    if (!operator!())
      {
        left().clear();
        right().clear();
        operator=(Self());
      }
  }
  void detach_left()
  {
    if (!operator!())
      {
        // create dummy Td_dag
        T tmp;
        Self dummy(tmp);
        // detach left son,redirect to dummy
        set_left(dummy);
        // set left son pointer to 0
        ptr()->leftPtr.PTR=0;
        // delete dummy Td_dag
        delete dummy.ptr();
      }
  }
  void detach_right()
  {
    if (!operator!())
      {
				// create dummy Td_dag
        T tmp;
        Self dummy(tmp);
				// detach right son,redirect to dummy
        set_right(dummy);
				// set right son pointer to 0
        ptr()->rightPtr.PTR=0;
				// delete dummy Td_dag
        delete dummy.ptr();
      }
  }
  void detach()
  {
    detach_left();
    detach_right();
  }
  */
  void set_data(const T& data)
  {
    if (!operator!()) ptr()->data=data;
    else operator=(Self(data));
  }
  void set_depth(unsigned long _depth) const
  {
    ptr()->depth_=_depth;
  }
  void set_left(const Self& left)
  {
    CGAL_precondition(!operator!());
    ptr()->leftPtr=left;
    if (left.depth()<depth()+1) left.ptr()->depth_=depth()+1;
    left.rebalance_depth(); 
    // does nothing if right is a leaf
  }
  void set_right(const Self& right)
  {
    CGAL_precondition(!operator!());
    ptr()->rightPtr=right;
    if (right.depth()<depth()+1) right.ptr()->depth_=depth()+1;
    right.rebalance_depth(); 
    // does nothing if right is a leaf
  }
  void replace(const T& data,const Self& left,const Self& right)
  {
    set_data(data);
    set_left(left);
    set_right(right);
  }

  // Td_dag implementation not thread safe!
  void visit_none() const
  {
    if (!operator!())
      {
        ptr()->visited_=false;
        left().visit_none();
        right().visit_none();
      }
  }
  void visit_one() const
  {
    if (!operator!())
      ptr()->visited_=true;
  }
  /* -----output ---------------*/
#ifdef CGAL_PRE_IN_POST_ORDER
  void preorder() const
  {
    if (!operator!())
      {
        std::cout << operator*() << '\t';
        left().preorder();
        right().preorder();
      }
  }
  void inorder() const
  {
    if (!operator!())
      {
        left().inorder();
        std::cout << operator*() << '\t';
        right().inorder();
      }
  }
  void postorder() const
  {
    if (!operator!())
      {
        left().postorder();
        right().postorder();
        std::cout << operator*() << '\t';
      }
  }
#endif
  
  template <class Container,class Predicate>
  Container& filter(Container& c,const Predicate& pr) const
  {
    visit_none();
    return recursive_filter(c,pr);
  }
#if 0
  template <class Container,class Predicate>
  Container& hash_filter(Container& c,const Predicate& pr) const
  {
    visit_none();
    return recursive_hash_filter(c,pr);
  }
#endif
protected:
  void rebalance_depth() const
  {
    if (is_inner_node()) 
    {  
      unsigned long depth_=depth();
      if (left().depth()<depth_+1)
      {
        left().set_depth(depth_+1);
        left().rebalance_depth();
      }
      if (right().depth()<depth_+1)
      {
        right().set_depth(depth_+1);
        right().rebalance_depth();
      }
    }
  }
  
  unsigned long recursive_size() const
  {
    if (!operator!() && !ptr()->visited())
      return 1+left().recursive_size()+right().recursive_size();
    else
      return 0;
  }
  unsigned long recursive_depth() const
  {
    if (!operator!() && !ptr()->visited())
      return 1+ (std::max)(left().recursive_depth(),right().recursive_depth());
    else
      return 0;
  }
  template <class Container,class Predicate>
  Container& recursive_filter(Container& c,const Predicate& pr) const
  {
    if (!operator!() && !ptr()->visited())
    {
      if (pr(operator*())) 
        c.insert(c.end(),operator*());
      visit_one();
      left().recursive_filter(c,pr);
      right().recursive_filter(c,pr);
    }
    return c;
  }
#if 0
  template <class Container, class Predicate> 
  Container& recursive_hash_filter(Container& c, const Predicate& ptr) const 
    /* Generate a copy of the Dag filtered according to the predicate */
  {
    if (!operator!() && !ptr()->visited())
    {
      if (pr(operator*())) 
        c.insert(pair<&operator*(), new X_trapezoid(operator*()));
      // The hash links between the old trapezoid to the new one.
      visit_one();
      left().recursive_hash_filter(c,pr);
      right().recursive_hash_filter(c,pr);
    }
    return c;
  }
#endif
 private:
  node* ptr() const {return (node*)PTR;}
};

template<class T,class Traits> 
std::ostream& write(std::ostream&  out, 
                    const Td_dag<T>& t,
                    const Traits& traits)
{
  static int depth;
  int i;
  if (!!t) {
    out << "\n";
    for(i=0;i<depth;i++)out << ">";
    out << "Data=";
    write(out,*t,traits);
    {
      depth++;
      out << "\n";
      for(i=0;i<depth;i++)out << ">";
      out << "left=";
      write(out,t.left(),traits);
      out << "\n";
      for(i=0;i<depth;i++)out << ">";
      out << "right=";
      write(out,t.right(),traits);
      depth--;
    }
  }
  else
  {
    out << "Empty";
  }
  return out ;
}

template<class T> std::ostream& operator<<(std::ostream&  out, 
                                           const Td_dag<T>& t)
{
  static int depth;
  int i;
  if (!!t) {
    out << "\n";
    for(i=0;i<depth;i++)out << ">";
    out << "Data=" << *t;
    {
      depth++;
      out << "\n";
      for(i=0;i<depth;i++)out << ">";
      out << "left=" << t.left();
      out << "\n";
      for(i=0;i<depth;i++)out << ">";
      out << "right=" <<t.right();
      depth--;
    }
  }
  else
  {
    out << "Empty";
  }
  return out ;
}

} //namespace CGAL

#endif

/* 
   tech notes:
   The code is Handle designed.
   left(),right() are designed to cope with Handle(Handle& x) 
     precondition x.PTR!=0
   operator=() performs shallow copy
   operator*() returns data type
   output is done as a binary tree.
*/