/*
 * s3fs - FUSE-based file system backed by Amazon S3
 *
 * Copyright(C) 2007 Randy Rizun <rrizun@gmail.com>
 *
 * 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 2
 * 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, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <curl/curl.h>
#include <sstream>
#include <fstream>
#include <string>
#include <map>
#include <list>
#include <vector>

#include "common.h"
#include "addhead.h"
#include "curl.h"
#include "s3fs.h"

using namespace std;

//-------------------------------------------------------------------
// Symbols
//-------------------------------------------------------------------
#define ADD_HEAD_REGEX              "reg:"

//-------------------------------------------------------------------
// Class AdditionalHeader
//-------------------------------------------------------------------
AdditionalHeader AdditionalHeader::singleton;

//-------------------------------------------------------------------
// Class AdditionalHeader method
//-------------------------------------------------------------------
AdditionalHeader::AdditionalHeader()
{
  if(this == AdditionalHeader::get()){
    is_enable = false;
  }else{
    abort();
  }
}

AdditionalHeader::~AdditionalHeader()
{
  if(this == AdditionalHeader::get()){
    Unload();
  }else{
    abort();
  }
}

bool AdditionalHeader::Load(const char* file)
{
  if(!file){
    S3FS_PRN_WARN("file is NULL.");
    return false;
  }
  Unload();

  ifstream AH(file);
  if(!AH.good()){
    S3FS_PRN_WARN("Could not open file(%s).", file);
    return false;
  }

  // read file
  string   line;
  ADDHEAD *paddhead;
  while(getline(AH, line)){
    if('#' == line[0]){
      continue;
    }
    if(line.empty()){
      continue;
    }
    // load a line
    istringstream ss(line);
    string        key;           // suffix(key)
    string        head;          // additional HTTP header
    string        value;         // header value
    if(0 == isblank(line[0])){
      ss >> key;
    }
    if(ss){
      ss >> head;
      if(ss && static_cast<size_t>(ss.tellg()) < line.size()){
        value = line.substr(static_cast<int>(ss.tellg()) + 1);
      }
    }

    // check it
    if(head.empty()){
      if(key.empty()){
        continue;
      }
      S3FS_PRN_ERR("file format error: %s key(suffix) is no HTTP header value.", key.c_str());
      Unload();
      return false;
    }

    paddhead = new ADDHEAD;
    if(0 == strncasecmp(key.c_str(), ADD_HEAD_REGEX, strlen(ADD_HEAD_REGEX))){
      // regex
      if(key.size() <= strlen(ADD_HEAD_REGEX)){
        S3FS_PRN_ERR("file format error: %s key(suffix) does not have key string.", key.c_str());
        delete paddhead;
        continue;
      }
      key = key.substr(strlen(ADD_HEAD_REGEX));

      // compile
      regex_t*  preg = new regex_t;
      int       result;
      if(0 != (result = regcomp(preg, key.c_str(), REG_EXTENDED | REG_NOSUB))){ // we do not need matching info
        char    errbuf[256];
        regerror(result, preg, errbuf, sizeof(errbuf));
        S3FS_PRN_ERR("failed to compile regex from %s key by %s.", key.c_str(), errbuf);
        delete preg;
        delete paddhead;
        continue;
      }

      // set
      paddhead->pregex     = preg;
      paddhead->basestring = key;
      paddhead->headkey    = head;
      paddhead->headvalue  = value;

    }else{
      // not regex, directly comparing
      paddhead->pregex     = NULL;
      paddhead->basestring = key;
      paddhead->headkey    = head;
      paddhead->headvalue  = value;
    }

    // add list
    addheadlist.push_back(paddhead);

    // set flag
    if(!is_enable){
      is_enable = true;
    }
  }
  return true;
}

void AdditionalHeader::Unload()
{
  is_enable = false;

  for(addheadlist_t::iterator iter = addheadlist.begin(); iter != addheadlist.end(); iter = addheadlist.erase(iter)){
    ADDHEAD *paddhead = *iter;
    if(paddhead){
      if(paddhead->pregex){
        regfree(paddhead->pregex);
        delete paddhead->pregex;
      }
      delete paddhead;
    }
  }
}

bool AdditionalHeader::AddHeader(headers_t& meta, const char* path) const
{
  if(!is_enable){
    return true;
  }
  if(!path){
    S3FS_PRN_WARN("path is NULL.");
    return false;
  }

  size_t pathlength = strlen(path);

  // loop
  //
  // [NOTE]
  // Because to allow duplicate key, and then scanning the entire table.
  //
  for(addheadlist_t::const_iterator iter = addheadlist.begin(); iter != addheadlist.end(); ++iter){
    const ADDHEAD *paddhead = *iter;
    if(!paddhead){
      continue;
    }

    if(paddhead->pregex){
      // regex
      regmatch_t match;         // not use
      if(0 == regexec(paddhead->pregex, path, 1, &match, 0)){
        // match -> adding header
        meta[paddhead->headkey] = paddhead->headvalue;
      }
    }else{
      // directly comparing
      if(paddhead->basestring.length() < pathlength){
        if(0 == paddhead->basestring.length() || 0 == strcmp(&path[pathlength - paddhead->basestring.length()], paddhead->basestring.c_str())){
          // match -> adding header
          meta[paddhead->headkey] = paddhead->headvalue;
        }
      }
    }
  }
  return true;
}

struct curl_slist* AdditionalHeader::AddHeader(struct curl_slist* list, const char* path) const
{
  headers_t meta;

  if(!AddHeader(meta, path)){
    return list;
  }
  for(headers_t::iterator iter = meta.begin(); iter != meta.end(); ++iter){
    // Adding header
    list = curl_slist_sort_insert(list, iter->first.c_str(), iter->second.c_str());
  }
  meta.clear();
  S3FS_MALLOCTRIM(0);
  return list;
}

bool AdditionalHeader::Dump() const
{
  if(!IS_S3FS_LOG_DBG()){
    return true;
  }

  ostringstream ssdbg;
  int           cnt = 1;

  ssdbg << "Additional Header list[" << addheadlist.size() << "] = {" << endl;

  for(addheadlist_t::const_iterator iter = addheadlist.begin(); iter != addheadlist.end(); ++iter, ++cnt){
    const ADDHEAD *paddhead = *iter;

    ssdbg << "    [" << cnt << "] = {" << endl;

    if(paddhead){
      if(paddhead->pregex){
        ssdbg << "        type\t\t--->\tregex" << endl;
      }else{
        ssdbg << "        type\t\t--->\tsuffix matching" << endl;
      }
      ssdbg << "        base string\t--->\t" << paddhead->basestring << endl;
      ssdbg << "        add header\t--->\t"  << paddhead->headkey << ": " << paddhead->headvalue << endl;
    }
    ssdbg << "    }" << endl;
  }


  ssdbg << "}" << endl;

  // print all
  S3FS_PRN_DBG("%s", ssdbg.str().c_str());

  return true;
}

/*
* Local variables:
* tab-width: 4
* c-basic-offset: 4
* End:
* vim600: noet sw=4 ts=4 fdm=marker
* vim<600: noet sw=4 ts=4
*/