/*

 * lftp - file transfer program

 *

 * Copyright (c) 1996-2013 by Alexander V. Lukyanov (lav@yars.free.net)

 *

 * This program is free software; 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.

 *

 * 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, see <http://www.gnu.org/licenses/>.

 */

#include <config.h>

#include <sys/types.h>

#include <sys/stat.h>

#include <fcntl.h>

#include <unistd.h>

#include <stddef.h>

#include "trio.h"

#include "History.h"

#include "url.h"

#include "misc.h"

#define super KeyValueDB

History::History()

{

   full=0;

   stamp=0;

   fd=-1;

   modified=false;

   const char *home=get_lftp_data_dir();

   if(home)

      file.vset(home,"/cwd_history",NULL);

}

History::~History()

{

   Close();

   if(full)

      delete full;

}

const char *History::extract_url(const char *res)

{

   const char *url=strchr(res,':');

   if(url)

      url++;

   else

      url=res;

   if(url::is_url(url))

      return url;

   return url::decode(url);

}

time_t History::extract_stamp(const char *res)

{

   return atol(res);

}

const char *History::Lookup(const FileAccess *s)

{

   const char *url=s->GetConnectURL(s->NO_PATH|s->NO_PASSWORD);

   if(!url)

      return 0;

   const char *res=super::Lookup(url);

   if(res)

      return extract_url(res);

   Refresh();

   Close();

   if(!full)

      return 0;

   res=full->Lookup(url);

   if(res)

      return extract_url(res);

   return 0;

}

void History::Refresh()

{

   if(!file)

      return;

   struct stat st;

   if((fd==-1 ? stat(file,&st) : fstat(fd,&st)) == -1)

      return;

   if(st.st_mtime==stamp)

      return;

   Load();

}

void History::Load()

{

   if(full)

      full->Empty();

   if(!file)

      return;

   if(fd==-1)

   {

      fd=open(file,O_RDONLY);

      if(fd==-1)

	 return;

      fcntl(fd,F_SETFD,FD_CLOEXEC);

      if(Lock(fd,F_RDLCK)==-1)

	 fprintf(stderr,"%s: lock for reading failed, trying to read anyway\n",file.get());

   }

   if(!full)

      full=new KeyValueDB;

   struct stat st;

   fstat(fd,&st);

   stamp=st.st_mtime;

   lseek(fd,0,SEEK_SET);

   full->Read(dup(fd));	// Read	closes fd

}

void History::Close()

{

   if(fd!=-1)

   {

      close(fd);

      fd=-1;

   }

}

void History::Set(const FileAccess *s,const FileAccess::Path &cwd)

{

   if(cwd.path==0 || !strcmp(cwd.path,"~") || s->GetHostName()==0)

      return;

   xstring res;

   res.setf("%lu:",(unsigned long)time(0));

   if(!cwd.url)

   {

      res.append_url_encoded(cwd,URL_PATH_UNSAFE);

      if(!cwd.is_file && url::dir_needs_trailing_slash(s->GetProto()) && res.last_char()!='/')

	 res.append('/');

   }

   else

      res.append(cwd.url);

   super::Add(s->GetConnectURL(s->NO_PATH|s->NO_PASSWORD),res);

   modified=true;

}

void History::Save()

{

   Close();

   if(!file)

      return;

   if(!modified)

      return;

   fd=open(file,O_RDWR|O_CREAT,0600);

   if(fd==-1)

      return;

   fcntl(fd,F_SETFD,FD_CLOEXEC);

   if(Lock(fd,F_WRLCK)==-1)

   {

      fprintf(stderr,"%s: lock for writing failed\n",file.get());

      Close();

      return;

   }

   Refresh();

   // merge

   int count=0;

   for(Pair *p=chain; p; p=p->next)

   {

      time_t new_stamp=extract_stamp(p->value);

      time_t old_stamp=0;

      const char *old_value=full->Lookup(p->key);

      if(old_value)

	 old_stamp=extract_stamp(old_value);

      if(old_stamp

      {

	 full->Add(p->key,p->value);

      	 count++;

      }

   }

   if(count==0)

   {

      Close();

      return;

   }

   lseek(fd,0,SEEK_SET);

#ifdef HAVE_FTRUNCATE

   if(ftruncate(fd,0)==-1) // note the following statement

#endif

   close(open(file,O_WRONLY|O_TRUNC));

   full->Write(fd);

   fd=-1;   // Write closes file

}