/**
 * Orthanc - A Lightweight, RESTful DICOM Store
 * Copyright (C) 2012-2016 Sebastien Jodogne, Medical Physics
 * Department, University Hospital of Liege, Belgium
 * Copyright (C) 2017-2018 Osimis S.A., Belgium
 *
 * 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.
 *
 * In addition, as a special exception, the copyright holders of this
 * program give permission to link the code of its release with the
 * OpenSSL project's "OpenSSL" library (or with modified versions of it
 * that use the same license as the "OpenSSL" library), and distribute
 * the linked executables. You must obey the GNU General Public License
 * in all respects for all of the code used other than "OpenSSL". If you
 * modify file(s) with this exception, you may extend this exception to
 * your version of the file(s), but you are not obligated to do so. If
 * you do not wish to do so, delete this exception statement from your
 * version. If you delete this exception statement from all source files
 * in the program, then also delete it here.
 * 
 * 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 "PrecompiledHeadersServer.h"
#include "OrthancConfiguration.h"

#include "../Core/HttpServer/MongooseServer.h"
#include "../Core/Logging.h"
#include "../Core/OrthancException.h"
#include "../Core/SystemToolbox.h"
#include "../Core/Toolbox.h"

namespace Orthanc
{
  static void AddFileToConfiguration(Json::Value& target,
                                     const boost::filesystem::path& path)
  {
    std::map<std::string, std::string> env;
    SystemToolbox::GetEnvironmentVariables(env);
    
    LOG(WARNING) << "Reading the configuration from: " << path;

    Json::Value config;

    {
      std::string content;
      SystemToolbox::ReadFile(content, path.string());

      content = Toolbox::SubstituteVariables(content, env);

      Json::Value tmp;
      Json::Reader reader;
      if (!reader.parse(content, tmp) ||
          tmp.type() != Json::objectValue)
      {
        LOG(ERROR) << "The configuration file does not follow the JSON syntax: " << path;
        throw OrthancException(ErrorCode_BadJson);
      }

      Toolbox::CopyJsonWithoutComments(config, tmp);
    }

    if (target.size() == 0)
    {
      target = config;
    }
    else
    {
      // Merge the newly-added file with the previous content of "target"
      Json::Value::Members members = config.getMemberNames();
      for (Json::Value::ArrayIndex i = 0; i < members.size(); i++)
      {
        if (target.isMember(members[i]))
        {
          LOG(ERROR) << "The configuration section \"" << members[i] << "\" is defined in 2 different configuration files";
          throw OrthancException(ErrorCode_BadFileFormat);          
        }
        else
        {
          target[members[i]] = config[members[i]];
        }
      }
    }
  }

    
  static void ScanFolderForConfiguration(Json::Value& target,
                                         const char* folder)
  {
    using namespace boost::filesystem;

    LOG(WARNING) << "Scanning folder \"" << folder << "\" for configuration files";

    directory_iterator end_it; // default construction yields past-the-end
    for (directory_iterator it(folder);
         it != end_it;
         ++it)
    {
      if (!is_directory(it->status()))
      {
        std::string extension = boost::filesystem::extension(it->path());
        Toolbox::ToLowerCase(extension);

        if (extension == ".json")
        {
          AddFileToConfiguration(target, it->path().string());
        }
      }
    }
  }

    
  static void ReadConfiguration(Json::Value& target,
                                const char* configurationFile)
  {
    target = Json::objectValue;

    if (configurationFile)
    {
      if (!boost::filesystem::exists(configurationFile))
      {
        LOG(ERROR) << "Inexistent path to configuration: " << configurationFile;
        throw OrthancException(ErrorCode_InexistentFile);
      }
      
      if (boost::filesystem::is_directory(configurationFile))
      {
        ScanFolderForConfiguration(target, configurationFile);
      }
      else
      {
        AddFileToConfiguration(target, configurationFile);
      }
    }
    else
    {
#if ORTHANC_STANDALONE == 1
      // No default path for the standalone configuration
      LOG(WARNING) << "Using the default Orthanc configuration";
      return;

#else
      // In a non-standalone build, we use the
      // "Resources/Configuration.json" from the Orthanc source code

      boost::filesystem::path p = ORTHANC_PATH;
      p /= "Resources";
      p /= "Configuration.json";

      AddFileToConfiguration(target, p);
#endif
    }
  }

    
  void OrthancConfiguration::ValidateConfiguration() const
  {
    std::set<std::string> ids;

    GetListOfOrthancPeers(ids);
    for (std::set<std::string>::const_iterator it = ids.begin(); it != ids.end(); ++it)
    {
      WebServiceParameters peer;
      GetOrthancPeer(peer, *it);
      peer.CheckClientCertificate();
    }

    GetListOfDicomModalities(ids);
    for (std::set<std::string>::const_iterator it = ids.begin(); it != ids.end(); ++it)
    {
      RemoteModalityParameters modality;
      GetDicomModalityUsingSymbolicName(modality, *it);
    }
  }


  OrthancConfiguration& OrthancConfiguration::GetInstance()
  {
    static OrthancConfiguration configuration;
    return configuration;
  }


  std::string OrthancConfiguration::GetStringParameter(const std::string& parameter,
                                                       const std::string& defaultValue) const
  {
    if (json_.isMember(parameter))
    {
      if (json_[parameter].type() != Json::stringValue)
      {
        LOG(ERROR) << "The configuration option \"" << parameter << "\" must be a string";
        throw OrthancException(ErrorCode_BadParameterType);
      }
      else
      {
        return json_[parameter].asString();
      }
    }
    else
    {
      return defaultValue;
    }
  }

    
  int OrthancConfiguration::GetIntegerParameter(const std::string& parameter,
                                                int defaultValue) const
  {
    if (json_.isMember(parameter))
    {
      if (json_[parameter].type() != Json::intValue)
      {
        LOG(ERROR) << "The configuration option \"" << parameter << "\" must be an integer";
        throw OrthancException(ErrorCode_BadParameterType);
      }
      else
      {
        return json_[parameter].asInt();
      }
    }
    else
    {
      return defaultValue;
    }
  }

    
  unsigned int OrthancConfiguration::GetUnsignedIntegerParameter(
    const std::string& parameter,
    unsigned int defaultValue) const
  {
    int v = GetIntegerParameter(parameter, defaultValue);

    if (v < 0)
    {
      LOG(ERROR) << "The configuration option \"" << parameter << "\" must be a positive integer";
      throw OrthancException(ErrorCode_ParameterOutOfRange);
    }
    else
    {
      return static_cast<unsigned int>(v);
    }
  }


  bool OrthancConfiguration::GetBooleanParameter(const std::string& parameter,
                                                 bool defaultValue) const
  {
    if (json_.isMember(parameter))
    {
      if (json_[parameter].type() != Json::booleanValue)
      {
        LOG(ERROR) << "The configuration option \"" << parameter
                   << "\" must be a Boolean (true or false)";
        throw OrthancException(ErrorCode_BadParameterType);
      }
      else
      {
        return json_[parameter].asBool();
      }
    }
    else
    {
      return defaultValue;
    }
  }


  void OrthancConfiguration::Read(const char* configurationFile)
  {
    // Read the content of the configuration
    configurationFileArg_ = configurationFile;
    ReadConfiguration(json_, configurationFile);

    // Adapt the paths to the configurations
    defaultDirectory_ = boost::filesystem::current_path();
    configurationAbsolutePath_ = "";

    if (configurationFile)
    {
      if (boost::filesystem::is_directory(configurationFile))
      {
        defaultDirectory_ = boost::filesystem::path(configurationFile);
        configurationAbsolutePath_ = boost::filesystem::absolute(configurationFile).parent_path().string();
      }
      else
      {
        defaultDirectory_ = boost::filesystem::path(configurationFile).parent_path();
        configurationAbsolutePath_ = boost::filesystem::absolute(configurationFile).string();
      }
    }
    else
    {
#if ORTHANC_STANDALONE != 1
      // In a non-standalone build, we use the
      // "Resources/Configuration.json" from the Orthanc source code

      boost::filesystem::path p = ORTHANC_PATH;
      p /= "Resources";
      p /= "Configuration.json";
      configurationAbsolutePath_ = boost::filesystem::absolute(p).string();
#endif
    }

    ValidateConfiguration();
  }


  void OrthancConfiguration::GetDicomModalityUsingSymbolicName(
    RemoteModalityParameters& modality,
    const std::string& name) const
  {
    if (!json_.isMember("DicomModalities"))
    {
      LOG(ERROR) << "No modality with symbolic name: " << name;
      throw OrthancException(ErrorCode_InexistentItem);
    }

    const Json::Value& modalities = json_["DicomModalities"];
    if (modalities.type() != Json::objectValue ||
        !modalities.isMember(name))
    {
      LOG(ERROR) << "No modality with symbolic name: " << name;
      throw OrthancException(ErrorCode_InexistentItem);
    }

    try
    {
      modality.Unserialize(modalities[name]);
    }
    catch (OrthancException&)
    {
      LOG(ERROR) << "Syntax error in the definition of DICOM modality \"" << name 
                 << "\". Please check your configuration file.";
      throw;
    }
  }


  bool OrthancConfiguration::GetOrthancPeer(WebServiceParameters& peer,
                                            const std::string& name) const
  {
    if (!json_.isMember("OrthancPeers"))
    {
      return false;
    }

    try
    {
      const Json::Value& modalities = json_["OrthancPeers"];
      if (modalities.type() != Json::objectValue ||
          !modalities.isMember(name))
      {
        return false;
      }
      else
      {
        peer.Unserialize(modalities[name]);
        return true;
      }
    }
    catch (OrthancException&)
    {
      LOG(ERROR) << "Syntax error in the definition of peer \"" << name 
                 << "\". Please check your configuration file.";
      throw;
    }
  }


  bool OrthancConfiguration::ReadKeys(std::set<std::string>& target,
                                      const char* parameter,
                                      bool onlyAlphanumeric) const
  {
    target.clear();
  
    if (!json_.isMember(parameter))
    {
      return true;
    }

    const Json::Value& modalities = json_[parameter];
    if (modalities.type() != Json::objectValue)
    {
      LOG(ERROR) << "Bad format of the \"DicomModalities\" configuration section";
      throw OrthancException(ErrorCode_BadFileFormat);
    }

    Json::Value::Members members = modalities.getMemberNames();
    for (size_t i = 0; i < members.size(); i++)
    {
      if (onlyAlphanumeric)
      {
        for (size_t j = 0; j < members[i].size(); j++)
        {
          if (!isalnum(members[i][j]) && members[i][j] != '-')
          {
            return false;
          }
        }
      }

      target.insert(members[i]);
    }

    return true;
  }


  void OrthancConfiguration::GetListOfDicomModalities(std::set<std::string>& target) const
  {
    target.clear();
      
    if (!ReadKeys(target, "DicomModalities", true))
    {
      LOG(ERROR) << "Only alphanumeric and dash characters are allowed in the names of the modalities";
      throw OrthancException(ErrorCode_BadFileFormat);
    }
  }


  void OrthancConfiguration::GetListOfOrthancPeers(std::set<std::string>& target) const
  {
    target.clear();

    if (!ReadKeys(target, "OrthancPeers", true))
    {
      LOG(ERROR) << "Only alphanumeric and dash characters are allowed in the names of Orthanc peers";
      throw OrthancException(ErrorCode_BadFileFormat);
    }
  }


  void OrthancConfiguration::SetupRegisteredUsers(MongooseServer& httpServer) const
  {
    httpServer.ClearUsers();

    if (!json_.isMember("RegisteredUsers"))
    {
      return;
    }

    const Json::Value& users = json_["RegisteredUsers"];
    if (users.type() != Json::objectValue)
    {
      LOG(ERROR) << "Badly formatted list of users";
      throw OrthancException(ErrorCode_BadFileFormat);
    }

    Json::Value::Members usernames = users.getMemberNames();
    for (size_t i = 0; i < usernames.size(); i++)
    {
      const std::string& username = usernames[i];
      std::string password = users[username].asString();
      httpServer.RegisterUser(username.c_str(), password.c_str());
    }
  }
    

  std::string OrthancConfiguration::InterpretStringParameterAsPath(
    const std::string& parameter) const
  {
    return SystemToolbox::InterpretRelativePath(defaultDirectory_.string(), parameter);
  }

    
  void OrthancConfiguration::GetGlobalListOfStringsParameter(
    std::list<std::string>& target,
    const std::string& key) const
  {
    target.clear();
  
    if (!json_.isMember(key))
    {
      return;
    }

    const Json::Value& lst = json_[key];

    if (lst.type() != Json::arrayValue)
    {
      LOG(ERROR) << "Badly formatted list of strings";
      throw OrthancException(ErrorCode_BadFileFormat);
    }

    for (Json::Value::ArrayIndex i = 0; i < lst.size(); i++)
    {
      target.push_back(lst[i].asString());
    }    
  }

    
  bool OrthancConfiguration::IsSameAETitle(const std::string& aet1,
                                           const std::string& aet2) const
  {
    if (GetBooleanParameter("StrictAetComparison", false))
    {
      // Case-sensitive matching
      return aet1 == aet2;
    }
    else
    {
      // Case-insensitive matching (default)
      std::string tmp1, tmp2;
      Toolbox::ToLowerCase(tmp1, aet1);
      Toolbox::ToLowerCase(tmp2, aet2);
      return tmp1 == tmp2;
    }
  }


  bool OrthancConfiguration::LookupDicomModalityUsingAETitle(
    RemoteModalityParameters& modality,
    const std::string& aet) const
  {
    std::set<std::string> modalities;
    GetListOfDicomModalities(modalities);

    for (std::set<std::string>::const_iterator 
           it = modalities.begin(); it != modalities.end(); ++it)
    {
      try
      {
        GetDicomModalityUsingSymbolicName(modality, *it);

        if (IsSameAETitle(aet, modality.GetApplicationEntityTitle()))
        {
          return true;
        }
      }
      catch (OrthancException&)
      {
      }
    }

    return false;
  }


  bool OrthancConfiguration::IsKnownAETitle(const std::string& aet,
                                            const std::string& ip) const
  {
    RemoteModalityParameters modality;
    
    if (!LookupDicomModalityUsingAETitle(modality, aet))
    {
      LOG(WARNING) << "Modality \"" << aet
                   << "\" is not listed in the \"DicomModalities\" configuration option";
      return false;
    }
    else if (!GetBooleanParameter("DicomCheckModalityHost", false) ||
             ip == modality.GetHost())
    {
      return true;
    }
    else
    {
      LOG(WARNING) << "Forbidding access from AET \"" << aet
                   << "\" given its hostname (" << ip << ") does not match "
                   << "the \"DicomModalities\" configuration option ("
                   << modality.GetHost() << " was expected)";
      return false;
    }
  }


  RemoteModalityParameters OrthancConfiguration::GetModalityUsingSymbolicName(
    const std::string& name) const
  {
    RemoteModalityParameters modality;
    GetDicomModalityUsingSymbolicName(modality, name);

    return modality;
  }

    
  RemoteModalityParameters OrthancConfiguration::GetModalityUsingAet(
    const std::string& aet) const
  {
    RemoteModalityParameters modality;
      
    if (LookupDicomModalityUsingAETitle(modality, aet))
    {
      return modality;
    }
    else
    {
      LOG(ERROR) << "Unknown modality for AET: " << aet;
      throw OrthancException(ErrorCode_InexistentItem);
    }
  }

    
  void OrthancConfiguration::UpdateModality(const std::string& symbolicName,
                                            const RemoteModalityParameters& modality)
  {
    if (!json_.isMember("DicomModalities"))
    {
      json_["DicomModalities"] = Json::objectValue;
    }

    Json::Value& modalities = json_["DicomModalities"];
    if (modalities.type() != Json::objectValue)
    {
      LOG(ERROR) << "Bad file format for modality: " << symbolicName;
      throw OrthancException(ErrorCode_BadFileFormat);
    }

    modalities.removeMember(symbolicName);

    Json::Value v;
    modality.Serialize(v, true /* force advanced format */);
    modalities[symbolicName] = v;
  }


  void OrthancConfiguration::RemoveModality(const std::string& symbolicName)
  {
    if (!json_.isMember("DicomModalities"))
    {
      LOG(ERROR) << "No modality with symbolic name: " << symbolicName;
      throw OrthancException(ErrorCode_BadFileFormat);
    }

    Json::Value& modalities = json_["DicomModalities"];
    if (modalities.type() != Json::objectValue)
    {
      LOG(ERROR) << "Bad file format for the \"DicomModalities\" configuration section";
      throw OrthancException(ErrorCode_BadFileFormat);
    }

    modalities.removeMember(symbolicName.c_str());
  }

    
  void OrthancConfiguration::UpdatePeer(const std::string& symbolicName,
                                        const WebServiceParameters& peer)
  {
    peer.CheckClientCertificate();

    if (!json_.isMember("OrthancPeers"))
    {
      LOG(ERROR) << "No peer with symbolic name: " << symbolicName;
      json_["OrthancPeers"] = Json::objectValue;
    }

    Json::Value& peers = json_["OrthancPeers"];
    if (peers.type() != Json::objectValue)
    {
      LOG(ERROR) << "Bad file format for the \"OrthancPeers\" configuration section";
      throw OrthancException(ErrorCode_BadFileFormat);
    }

    peers.removeMember(symbolicName);

    Json::Value v;
    peer.Serialize(v, 
                   false /* use simple format if possible */, 
                   true  /* include passwords */);
    peers[symbolicName] = v;
  }


  void OrthancConfiguration::RemovePeer(const std::string& symbolicName)
  {
    if (!json_.isMember("OrthancPeers"))
    {
      LOG(ERROR) << "No peer with symbolic name: " << symbolicName;
      throw OrthancException(ErrorCode_BadFileFormat);
    }

    Json::Value& peers = json_["OrthancPeers"];
    if (peers.type() != Json::objectValue)
    {
      LOG(ERROR) << "Bad file format for the \"OrthancPeers\" configuration section";
      throw OrthancException(ErrorCode_BadFileFormat);
    }

    peers.removeMember(symbolicName.c_str());
  }


  void OrthancConfiguration::Format(std::string& result) const
  {
    Json::StyledWriter w;
    result = w.write(json_);
  }


  void OrthancConfiguration::SetDefaultEncoding(Encoding encoding)
  {
    SetDefaultDicomEncoding(encoding);

    // Propagate the encoding to the configuration file that is
    // stored in memory
    json_["DefaultEncoding"] = EnumerationToString(encoding);
  }


  bool OrthancConfiguration::HasConfigurationChanged() const
  {
    Json::Value current;
    ReadConfiguration(current, configurationFileArg_);

    Json::FastWriter writer;
    std::string a = writer.write(json_);
    std::string b = writer.write(current);

    return a != b;
  }
}