/* -*- Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil; -*- */

/*

 * Copyright (c) 2009 University of Washington

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation;

 *

 * This program 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 General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 */

#include <map>

#include "object.h"

#include "log.h"

#include "assert.h"

#include "abort.h"

#include "names.h"

#include "ns3/simulator.h"

namespace ns3 {

NS_LOG_COMPONENT_DEFINE ("Names");

class NameNode

{

public:

  NameNode ();

  NameNode (const NameNode &nameNode);

  NameNode (NameNode *parent, std::string name, Ptr<Object> object);

  NameNode &operator = (const NameNode &rhs);

 ~NameNode ();

  NameNode *m_parent;

  std::string m_name;

  Ptr<Object> m_object;

  std::map<std::string, NameNode *> m_nameMap;

};

NameNode::NameNode ()

  : m_parent (0), m_name (""), m_object (0)

{

}

NameNode::NameNode (const NameNode &nameNode)

{

  m_parent = nameNode.m_parent;

  m_name = nameNode.m_name;

  m_object = nameNode.m_object;

  m_nameMap = nameNode.m_nameMap;

}

NameNode &

NameNode::operator = (const NameNode &rhs)

{

  m_parent = rhs.m_parent;

  m_name = rhs.m_name;

  m_object = rhs.m_object;

  m_nameMap = rhs.m_nameMap;

  return *this;

}

NameNode::NameNode (NameNode *parent, std::string name, Ptr<Object> object)

  : m_parent (parent), m_name (name), m_object (object)

{

}

NameNode::~NameNode ()

{

}

class NamesPriv 

{

public:

  NamesPriv ();

  ~NamesPriv ();

  bool Add (std::string name, Ptr<Object> obj);

  bool Add (std::string context, std::string name, Ptr<Object> object);

  bool Add (Ptr<Object> context, std::string name, Ptr<Object> object);

  std::string FindShortName (Ptr<Object> object);

  std::string FindFullName (Ptr<Object> object);

  Ptr<Object> FindObjectFromFullName (std::string name);

  Ptr<Object> FindObjectFromShortName (Ptr<Object> context, std::string name);

  static NamesPriv *Get (void);

  static void Delete (void);

private:

  static NamesPriv **DoGet (void);

  NameNode *IsNamed (Ptr<Object>);

  bool IsDuplicateName (NameNode *node, std::string name);

  NameNode m_root;

  std::map<Ptr<Object>, NameNode *> m_objectMap;

};

NamesPriv *

NamesPriv::Get (void)

{

  return *(DoGet ());

}

NamesPriv **

NamesPriv::DoGet (void)

{

  static NamesPriv *ptr = 0;

  if (ptr == 0)

    {

      ptr = new NamesPriv;

      Simulator::ScheduleDestroy (&NamesPriv::Delete);

    }

  return &ptr;

}

void 

NamesPriv::Delete (void)

{

  NS_LOG_FUNCTION_NOARGS ();

  NamesPriv **ptr = DoGet ();

  delete *ptr;

  *ptr = 0;

}

NamesPriv::NamesPriv ()

{

  NS_LOG_FUNCTION_NOARGS ();

  m_root.m_parent = 0;

  m_root.m_name = "Names";

  m_root.m_object = 0;

}

NamesPriv::~NamesPriv ()

{

  NS_LOG_FUNCTION_NOARGS ();

  //

  // Every name is associated with an object in the object map, so freeing the

  // NameNodes in this map will free all of the memory allocated for the NameNodes

  //

  for (std::map<Ptr<Object>, NameNode *>::iterator i = m_objectMap.begin (); i != m_objectMap.end (); ++i)

    {

      delete i->second;

      i->second = 0;

    }

  m_root.m_parent = 0;

  m_root.m_name = "";

  m_root.m_object = 0;

}

bool

NamesPriv::Add (std::string name, Ptr<Object> object)

{

  NS_LOG_FUNCTION (name << object);

  //

  // This is the simple, easy to use version of Add, so we want it to be flexible.

  // We don't want to force a user to always type the fully qualified namespace 

  // name, so we allow the namespace name to be omitted.  For example, calling

  // Add ("Client/ath0", obj) should result in exactly the same behavior as

  // Add ("/Names/Client/ath0", obj).  Calling Add ("Client", obj) should have

  // the same effect as Add ("Names/Client", obj)

  //

  // The first thing to do, then, is to "canonicalize" the input string to always

  // be a fully qualified name.

  //

  // If we are given a name that begins with "/Names/" we assume that this is a

  // fullname to the object we want to create.  We split the fullname into a 

  // context string and and a final segment and then call the "Real" Add.

  //

  std::string namespaceName = "/Names";

  std::string::size_type offset = name.find (namespaceName);

  if (offset != 0)

    {

      //

      // This must be a name that has the "/Names" namespace prefix omitted.  

      // Do some reasonableness checking on the rest of the name.

      //

      offset = name.find ("/");

      if (offset == 0)

        {

          NS_ASSERT_MSG (false, "NamesPriv::Add(): Name begins with '/' but not \"/Names\"");

          return false;

        }

      name = "/Names/" + name;

    }

  //

  // There must now be a fully qualified longname in the string.  All fully 

  // qualified names begin with "/Names".  We have to split off the final 

  // segment which will become the shortname of the object.  A '/' that

  // separates the context from the final segment had better be there since

  // we just made sure that at least the namespace name was there.

  //

  std::string::size_type i = name.rfind ("/");

  NS_ASSERT_MSG (i != std::string::npos, "NamesPriv::Add(): Internal error.  Can't find '/' in name");

  //

  // The slash we found cannot be the slash at the start of the namespaceName.

  // This would indicate there is no shortname in the path at all.  It can be

  // any other index.

  //

  NS_ASSERT_MSG (i != 0, "NamesPriv::Add(): Can't find a shortname in the name string");

  //

  // We now know where the context string starts and ends, and where the

  // shortname starts and ends.  All we have to do is to call our available

  // function for creating addubg a shortname under a context string.

  //

  return Add (name.substr (0, i), name.substr (i + 1), object);

}

bool

NamesPriv::Add (std::string context, std::string name, Ptr<Object> object)

{

  if (context == "/Names")

    {

      return Add (Ptr<Object> (0, false), name, object);

    }

  return Add (FindObjectFromFullName (context), name, object);

}

bool

NamesPriv::Add (Ptr<Object> context, std::string name, Ptr<Object> object)

{

  NS_LOG_FUNCTION (context << name << object);

  if (IsNamed (object))

    {

      NS_LOG_LOGIC ("Object is already named");

      return false;

    }

  NameNode *node = 0;

  if (context)

    {

      node = IsNamed (context);

      NS_ASSERT_MSG (node, "NamesPriv::Name(): context must point to a previously named node");

    }

  else

    {

      node = &m_root;

    }

  if (IsDuplicateName (node, name))

    {

      NS_LOG_LOGIC ("Name is already taken");

      return false;

    }

  NameNode *newNode = new NameNode(node, name, object);

  node->m_nameMap[name] = newNode;

  m_objectMap[object] = newNode;

  return true;

}

std::string

NamesPriv::FindShortName (Ptr<Object> object)

{

  NS_LOG_FUNCTION (object);

  std::map<Ptr<Object>, NameNode *>::iterator i = m_objectMap.find (object);

  if (i == m_objectMap.end ())

    {

      NS_LOG_LOGIC ("Object does not exist in object map");

      return "";

    }

  else

    {

      NS_LOG_LOGIC ("Object exists in object map");

      return i->second->m_name;

    }

}

std::string

NamesPriv::FindFullName (Ptr<Object> object)

{

  NS_LOG_FUNCTION (object);

  std::map<Ptr<Object>, NameNode *>::iterator i = m_objectMap.find (object);

  if (i == m_objectMap.end ())

    {

      NS_LOG_LOGIC ("Object does not exist in object map");

      return "";

    }

  NameNode *p = i->second;

  NS_ASSERT_MSG (p, "NamesPriv::FindFullName(): Internal error: Invalid NameNode pointer from map");

  std::string fullname;

  do

    {

      fullname = "/" + p->m_name + fullname;

      NS_LOG_LOGIC ("fullname is " << fullname);

    }

  while ((p = p->m_parent) != 0);

  return fullname;

}

Ptr<Object>

NamesPriv::FindObjectFromFullName (std::string name)

{

  //

  // This is hooked in from simple, easy to use version of Find, so we want it

  // to be flexible.

  //

  // If we are provided a name that doesn't begin with "/Names", we assume 

  // that the caller has simply given us a path starting with a shortname that

  // is in the root namespace.  This allows peole to omit the "/Names" prefix.

  // and simply do a Find ("Client/eth0") instead of having to always do a

  // Find ("/Names/Client/eth0");

  //

  // So, if we are given a name that begins with "/Names/" the upshot is that we

  // just remove that prefix and treat the rest of the string as starting with a 

  // shortname in the root namespace.

  //

  std::string namespaceName = "/Names/";

  std::string remaining;

  std::string::size_type offset = name.find (namespaceName);

  if (offset == 0)

    {

      NS_LOG_LOGIC (name << " is a fully qualified name");

      remaining = name.substr (namespaceName.size ());

    }

  else

    {

      NS_LOG_LOGIC (name << " begins with a relative shortname");

      remaining = name;

    }

  NameNode *node = &m_root;

  //

  // The string <remaining> is now composed entirely of path segments in the

  // /Names name space and we have eaten the leading slash. e.g., 

  // remaining = "ClientNode/eth0"

  //

  // The start of the search is always at the root of the name space.

  //

  for (;;)

    {

      NS_LOG_LOGIC ("Looking for the object of name " << remaining);

      offset = remaining.find ("/");

      if (offset == std::string::npos)

        {

          //

          // There are no remaining slashes so this is the last segment of the 

          // specified name.  We're done when we find it

          //

          std::map<std::string, NameNode *>::iterator i = node->m_nameMap.find (remaining);

          if (i == node->m_nameMap.end ())

            {

              NS_LOG_LOGIC ("Name does not exist in name map");

              return 0;

            }

          else

            {

              NS_LOG_LOGIC ("Name parsed, found object");

              return i->second->m_object;

            }

        }

      else

        {

          //

          // There are more slashes so this is an intermediate segment of the 

          // specified name.  We need to "recurse" when we find this segment.

          //

          offset = remaining.find ("/");

          std::string segment = remaining.substr(0, offset);