/*
 * AuthBackendFile.cpp
 *
 * Copyright (C) 2009 Matthias Schiffer <matthias@gamezock.de>
 *
 * This program is free software: you can redistribute it and/or modify it
 * under the terms of the GNU Lesser 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License along
 * with this program. If not, see <http://www.gnu.org/licenses/>.
 */

#include "AuthProviderFile.h"

#include <Core/ConfigEntry.h>
#include <Common/Hash.h>

#include <cstdio>
#include <fstream>

#include <boost/regex.hpp>
#include <boost/thread/locks.hpp>

namespace Mad {
namespace Modules {
namespace AuthProviderFile {

void AuthProviderFile::readFile(const std::string &name) {
  std::ifstream stream(name.c_str());
  if(!stream.good()) {
    application->logf(Core::Logger::LOG_WARNING, "AuthProviderFile: Can't read file '%s'.", name.c_str());
    return;
  }

  while(stream.good() && !stream.eof()) {
    std::string line;
    std::getline(stream, line);

    if(line.empty())
      continue;

    static const boost::regex regex("([^:]+):(.+)", boost::regex_constants::perl);
    boost::smatch match;

    if(!boost::regex_match(line, match, regex)) {
      application->logf(Core::Logger::LOG_WARNING, "AuthProviderFile: Malformed line in file '%s'.", name.c_str());
      continue;
    }

    Core::String password = match[2].str().c_str();

    if(filehash.isEmpty()) {
      std::string utf8pass = password.extractUTF8();

      boost::lock_guard<boost::mutex> lock(mutex);
      userMap.insert(std::make_pair(match[1].str().c_str(), std::vector<boost::uint8_t>(utf8pass.begin(), utf8pass.end())));
    }
    else {
      std::vector<boost::uint8_t> data;
      data.reserve(password.length()/2);

      for(boost::int32_t c = 0; c < password.length()-1; c += 2) {
        char buffer[3] = {password[c], password[c+1], 0};
        unsigned char byte;

        if(std::sscanf(buffer, "%hhx", &byte) != 1) {
          application->logf(Core::Logger::LOG_WARNING, "AuthProviderFile: Malformed hash in file '%s'.", name.c_str());
          data.clear();
          break;
        }

        data.push_back(byte);
      }

      if(!data.empty()) {
        boost::lock_guard<boost::mutex> lock(mutex);
        userMap.insert(std::make_pair(match[1].str().c_str(), data));
      }
    }
  }
}

bool AuthProviderFile::handleConfigEntry(const Core::ConfigEntry &entry, bool /*handled*/) {
  if(!entry[0].getKey().matches("AuthProviderFile"))
    return false;

  if(entry[1].isEmpty())
    return true;

  if(entry[1].getKey().matches("Hash")) {
    if(entry[2].isEmpty()) {
      filehash = entry[1][0];

      if(!Common::Hash::isHashSupported(filehash))
        application->logf(Core::Logger::LOG_WARNING, "AuthProviderFile: Unsupported hash '%s'", filehash.extract().c_str());
    }
  }
  else if(entry[1].getKey().matches("File")) {
    if(entry[2].isEmpty()) {
      files.push_back(entry[1][0]);
    }
  }
  else if(!entry[2].isEmpty())
    return false;

  return true;
}

void AuthProviderFile::configFinished() {
  if(filehash.isEmpty() || filehash.matches("clear")) {
    hashes = Common::Hash::getHashList();
    filehash.remove();
  }
  else {
    hashes.clear();
    hashes.push_back(filehash);
  }

  hashes.push_back("Clear");

  for(std::vector<Core::String>::iterator file = files.begin(); file != files.end(); ++file)
    readFile(file->extract());
}

bool AuthProviderFile::checkPassword(const Core::String &user, const std::vector<boost::uint8_t> &data, const Core::String &hash) throw(Core::Exception) {
  if((hash.isEmpty() || hash.matches("clear")) && !filehash.isEmpty()) {
    std::vector<boost::uint8_t> password = getPassword(user, filehash);
    std::vector<boost::uint8_t> hashdata = Common::Hash::hash(data, filehash);

    return (!password.empty() && hashdata.size() == password.size() && std::equal(hashdata.begin(), hashdata.end(), password.begin()));
  }
  else {
    std::vector<boost::uint8_t> password = getPassword(user, hash);
    return (!password.empty() && data.size() == password.size() && std::equal(data.begin(), data.end(), password.begin()));
  }
}

std::vector<boost::uint8_t> AuthProviderFile::getPassword(const Core::String &user, const Core::String &hash) throw(Core::Exception) {
  boost::lock_guard<boost::mutex> lock(mutex);

  std::map<Core::String, std::vector<boost::uint8_t> >::iterator userIt = userMap.find(user);
  if(userIt == userMap.end())
    return std::vector<boost::uint8_t>();

  if(filehash.isEmpty()) {
    if(hash.matches("clear"))
      return userIt->second;
    else
      return Common::Hash::hash(userIt->second, hash);
  }
  else if(filehash.matches(hash)) {
    return userIt->second;
  }
  else
    throw Core::Exception(Core::Exception::NOT_AVAILABLE);
}

}
}
}