#include "system-path.h"

#include "fatal-error.h"

#include "assert.h"

#include "ns3/core-config.h"

#include <stdlib.h>

#include <errno.h>

#include <string.h>

#if defined (HAVE_DIRENT_H) and defined (HAVE_SYS_TYPES_H)

#define HAVE_OPENDIR

#include <sys/types.h>

#include <dirent.h>

#endif

#if defined (HAVE_SYS_STAT_H) and defined (HAVE_SYS_TYPES_H)

#define HAVE_MKDIR_H

#include <sys/types.h>

#include <sys/stat.h>

#endif

#include <sstream>

#ifdef __APPLE__

#include <mach-o/dyld.h>

#endif /* __APPLE__ */

#ifdef __FreeBSD__

#include <sys/types.h>

#include <sys/sysctl.h>

#endif

#if defined (__win32__)

#define SYSTEM_PATH_SEP "\\"

#else

#define SYSTEM_PATH_SEP "/"

#endif

namespace ns3 {

namespace SystemPath {

std::string Dirname (std::string path)

{

  std::list<std::string> elements = Split (path);

  std::list<std::string>::const_iterator last = elements.end();

  last--;

  return Join (elements.begin (), last);

}

std::string FindSelfDirectory (void)

{

  /** 

   * This function returns the path to the running $PREFIX.

   * Mac OS X: _NSGetExecutablePath() (man 3 dyld)

   * Linux: readlink /proc/self/exe

   * Solaris: getexecname()

   * FreeBSD: sysctl CTL_KERN KERN_PROC KERN_PROC_PATHNAME -1

   * BSD with procfs: readlink /proc/curproc/file

   * Windows: GetModuleFileName() with hModule = NULL

   */

  std::string filename;

#if defined(__linux__)

  {

    ssize_t size = 1024;

    char *buffer = (char*)malloc (size);

    memset (buffer, 0, size);

    int status;

    while (true)

      {

        status = readlink("/proc/self/exe", buffer, size);

        if (status != 1 || (status == -1 && errno != ENAMETOOLONG))

          {

            break;

          }

        size *= 2;

        free (buffer);

        buffer = (char*)malloc (size);

	memset (buffer, 0, size);

      }

    if (status == -1)

      {

        NS_FATAL_ERROR ("Oops, could not find self directory.");

      }

    filename = buffer;

    free (buffer);

  }

#elif defined (__win32__)

  {

    // XXX: untested. it should work if code is compiled with

    // LPTSTR = char *

    DWORD size = 1024;

    LPTSTR lpFilename = (LPTSTR) malloc (sizeof(TCHAR) * size);

    DWORD status = GetModuleFilename (0, lpFilename, size);

    while (status == size)

      {

	size = size * 2;

	free (lpFilename);

	lpFilename = (LPTSTR) malloc (sizeof(TCHAR) * size);

	status = GetModuleFilename (0, lpFilename, size);

      }

    NS_ASSERT (status != 0);

    filename = lpFilename;

    free (lpFilename);

  }

#elif defined (__APPLE__)

  {

    uint32_t bufsize = 1024;

    char *buffer = (char *) malloc (bufsize);

    NS_ASSERT (buffer != 0);

    int status = _NSGetExecutablePath (buffer, &bufsize);

    if (status == -1)

      {

	free (buffer);

	buffer = (char *) malloc (bufsize);

	status = _NSGetExecutablePath (buffer, &bufsize);

      }

    NS_ASSERT (status == 0);

    filename = buffer;

    free (buffer);

  } 

#elif defined (__FreeBSD__)

  {

    int     mib[4];

    size_t  bufSize = 1024;

    char   *buf = (char *) malloc(bufSize);

    mib[0] = CTL_KERN;

    mib[1] = KERN_PROC;

    mib[2] = KERN_PROC_PATHNAME;

    mib[3] = -1;

    sysctl(mib, 4, buf, &bufSize, NULL, 0);

    filename = buf;

  }

#endif

    return Dirname (filename);

}

std::string Append (std::string left, std::string right)

{

  // removing trailing separators from 'left'

  while (true)

    {

      std::string::size_type lastSep = left.rfind (SYSTEM_PATH_SEP);

      if (lastSep != left.size () - 1)

	{

	  break;

	}

      left = left.substr (0, left.size () - 1);

    } 

  std::string retval = left + SYSTEM_PATH_SEP + right;

  return retval;

}

std::list<std::string> Split (std::string path)

{

  std::list<std::string> retval;

  std::string::size_type current = 0, next = 0;

  next = path.find (SYSTEM_PATH_SEP, current);

  while (next != std::string::npos)

    {

      std::string item = path.substr (current, next - current);

      retval.push_back (item);

      current = next + 1;

      next = path.find (SYSTEM_PATH_SEP, current);

    }

  std::string item = path.substr (current, next - current);

  retval.push_back (item);

  return retval;

}

std::string Join (std::list<std::string>::const_iterator begin,

		  std::list<std::string>::const_iterator end)

{

  std::string retval = "";

  for (std::list<std::string>::const_iterator i = begin; i != end; i++)

    {

      if (i == begin)

	{

	  retval = *i;

	}

      else

	{

	  retval = retval + SYSTEM_PATH_SEP + *i;

	}

    }

  return retval;

}

std::list<std::string> ReadFiles (std::string path)

{

  std::list<std::string> files;

#if defined HAVE_OPENDIR

  DIR *dp = opendir (path.c_str ());

  if (dp == NULL)

    {

      NS_FATAL_ERROR ("Could not open directory=" << path);

    }

  struct dirent *de = readdir (dp);

  while (de != 0)

    {

      files.push_back (de->d_name);

      de = readdir (dp);

    }

  closedir (dp);

#elif defined (HAVE_FIND_FIRST_FILE)

  // XXX: untested

  HANDLE hFind;

  WIN32_FIND_DATA fileData;

  hFind = FindFirstFile (path.c_str (), &FindFileData);

  if (hFind == INVALID_HANDLE_VALUE)

    {

      NS_FATAL_ERROR ("Could not open directory=" << path);

    }

  do

    {

      files.push_back (fileData.cFileName);

    } while (FindNextFile (hFind, &fileData));

  FindClose(hFind);

#else

#error "No support for reading a directory on this platform"

#endif

  return files;

}

std::string 

MakeTemporaryDirectoryName (void)

{

  char *path = NULL;

  path = getenv ("TMP");

  if (path == NULL)

    {

      path = getenv ("TEMP");

      if (path == NULL)

	{

	  path = const_cast<char *> ("/tmp");

	}

    }

  //

  // Just in case the user wants to go back and find the output, we give

  // a hint as to which dir we created by including a time hint.

  //

  time_t now = time (NULL);

  struct tm *tm_now = localtime (&now);

  //

  // But we also randomize the name in case there are multiple users doing

  // this at the same time

  //

  srand (time (0));

  long int n = rand ();

  //

  // The final path to the directory is going to look something like

  // 

  //   /tmp/ns3-14.30.29.32767

  //

  // The first segment comes from one of the temporary directory env 

  // variables or /tmp if not found.  The directory name starts with an

  // identifier telling folks who is making all of the temp directories

  // and then the local time (in this case 14.30.29 -- which is 2:30 and

  // 29 seconds PM).

  //

  std::ostringstream oss;

  oss << path << SYSTEM_PATH_SEP << "ns-3." << tm_now->tm_hour << "."

      << tm_now->tm_min << "." << tm_now->tm_sec << "." << n;

  return oss.str ();

}

void 

MakeDirectories (std::string path)

{

  std::list<std::string> elements = Split (path);

  for (std::list<std::string>::const_iterator i = elements.begin (); i != elements.end (); ++i)

    {

      std::string tmp = Join (elements.begin (), i);

#if defined(HAVE_MKDIR_H)

      mkdir (tmp.c_str (), S_IRWXU);

#endif

    }

#if defined(HAVE_MKDIR_H)

  mkdir (path.c_str (), S_IRWXU);

#endif

}

} // namespace SystemPath

} // namespace ns3