/**
 * Stone of Orthanc
 * Copyright (C) 2012-2016 Sebastien Jodogne, Medical Physics
 * Department, University Hospital of Liege, Belgium
 * Copyright (C) 2017-2020 Osimis S.A., Belgium
 *
 * This program is free software: you can redistribute it and/or
 * modify it under the terms of the GNU Affero 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
 * Affero General Public License for more details.
 * 
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 **/


#include "GenericOracleRunner.h"

#if !defined(ORTHANC_ENABLE_DCMTK)
#  error The macro ORTHANC_ENABLE_DCMTK must be defined
#endif

#include "GetOrthancImageCommand.h"
#include "GetOrthancWebViewerJpegCommand.h"
#include "HttpCommand.h"
#include "OracleCommandExceptionMessage.h"
#include "OrthancRestApiCommand.h"
#include "ParseDicomFromFileCommand.h"
#include "ParseDicomFromWadoCommand.h"
#include "ReadFileCommand.h"

#if ORTHANC_ENABLE_DCMTK == 1
#  include "ParseDicomSuccessMessage.h"
#  include <dcmtk/dcmdata/dcdeftag.h>
#  include <dcmtk/dcmdata/dcfilefo.h>
static unsigned int BUCKET_DICOMDIR = 0;
static unsigned int BUCKET_SOP = 1;
#endif

#include <Compression/GzipCompressor.h>
#include <HttpClient.h>
#include <OrthancException.h>
#include <Toolbox.h>
#include <SystemToolbox.h>

#include <boost/filesystem.hpp>



namespace OrthancStone
{
  static void CopyHttpHeaders(Orthanc::HttpClient& client,
                              const Orthanc::HttpClient::HttpHeaders& headers)
  {
    for (Orthanc::HttpClient::HttpHeaders::const_iterator
           it = headers.begin(); it != headers.end(); it++ )
    {
      client.AddHeader(it->first, it->second);
    }
  }


  static void DecodeAnswer(std::string& answer,
                           const Orthanc::HttpClient::HttpHeaders& headers)
  {
    Orthanc::HttpCompression contentEncoding = Orthanc::HttpCompression_None;

    for (Orthanc::HttpClient::HttpHeaders::const_iterator it = headers.begin(); 
         it != headers.end(); ++it)
    {
      std::string s;
      Orthanc::Toolbox::ToLowerCase(s, it->first);

      if (s == "content-encoding")
      {
        if (it->second == "gzip")
        {
          contentEncoding = Orthanc::HttpCompression_Gzip;
        }
        else 
        {
          throw Orthanc::OrthancException(Orthanc::ErrorCode_NetworkProtocol,
                                          "Unsupported HTTP Content-Encoding: " + it->second);
        }

        break;
      }
    }

    if (contentEncoding == Orthanc::HttpCompression_Gzip)
    {
      std::string compressed;
      answer.swap(compressed);
          
      Orthanc::GzipCompressor compressor;
      compressor.Uncompress(answer, compressed.c_str(), compressed.size());

      LOG(INFO) << "Uncompressing gzip Encoding: from " << compressed.size()
                << " to " << answer.size() << " bytes";
    }
  }


  static void RunHttpCommand(std::string& answer,
                             Orthanc::HttpClient::HttpHeaders& answerHeaders,
                             const HttpCommand& command)
  {
    Orthanc::HttpClient client;
    client.SetUrl(command.GetUrl());
    client.SetMethod(command.GetMethod());
    client.SetTimeout(command.GetTimeout());

    CopyHttpHeaders(client, command.GetHttpHeaders());

    if (command.HasCredentials())
    {
      client.SetCredentials(command.GetUsername().c_str(), command.GetPassword().c_str());
    }

    if (command.GetMethod() == Orthanc::HttpMethod_Post ||
        command.GetMethod() == Orthanc::HttpMethod_Put)
    {
      client.SetBody(command.GetBody());
    }

    client.ApplyAndThrowException(answer, answerHeaders);
    DecodeAnswer(answer, answerHeaders);
  }


  static void RunInternal(boost::weak_ptr<IObserver> receiver,
                          IMessageEmitter& emitter,
                          const HttpCommand& command)
  {
    std::string answer;
    Orthanc::HttpClient::HttpHeaders answerHeaders;
    RunHttpCommand(answer, answerHeaders, command);
    
    HttpCommand::SuccessMessage message(command, answerHeaders, answer);
    emitter.EmitMessage(receiver, message);
  }

  
  static void RunOrthancRestApiCommand(std::string& answer,
                                       Orthanc::HttpClient::HttpHeaders& answerHeaders,
                                       const Orthanc::WebServiceParameters& orthanc,
                                       const OrthancRestApiCommand& command)
  {
    Orthanc::HttpClient client(orthanc, command.GetUri());
    client.SetRedirectionFollowed(false);
    client.SetMethod(command.GetMethod());
    client.SetTimeout(command.GetTimeout());

    CopyHttpHeaders(client, command.GetHttpHeaders());

    if (command.GetMethod() == Orthanc::HttpMethod_Post ||
        command.GetMethod() == Orthanc::HttpMethod_Put)
    {
      client.SetBody(command.GetBody());
    }

    client.ApplyAndThrowException(answer, answerHeaders);
    DecodeAnswer(answer, answerHeaders);
  }

  
  static void RunInternal(boost::weak_ptr<IObserver> receiver,
                          IMessageEmitter& emitter,
                          const Orthanc::WebServiceParameters& orthanc,
                          const OrthancRestApiCommand& command)
  {
    std::string answer;
    Orthanc::HttpClient::HttpHeaders answerHeaders;
    RunOrthancRestApiCommand(answer, answerHeaders, orthanc, command);

    OrthancRestApiCommand::SuccessMessage message(command, answerHeaders, answer);
    emitter.EmitMessage(receiver, message);
  }


  static void RunInternal(boost::weak_ptr<IObserver> receiver,
                          IMessageEmitter& emitter,
                          const Orthanc::WebServiceParameters& orthanc,
                          const GetOrthancImageCommand& command)
  {
    Orthanc::HttpClient client(orthanc, command.GetUri());
    client.SetRedirectionFollowed(false);
    client.SetTimeout(command.GetTimeout());

    CopyHttpHeaders(client, command.GetHttpHeaders());
    
    std::string answer;
    Orthanc::HttpClient::HttpHeaders answerHeaders;
    client.ApplyAndThrowException(answer, answerHeaders);

    DecodeAnswer(answer, answerHeaders);

    command.ProcessHttpAnswer(receiver, emitter, answer, answerHeaders);
  }


  static void RunInternal(boost::weak_ptr<IObserver> receiver,
                          IMessageEmitter& emitter,
                          const Orthanc::WebServiceParameters& orthanc,
                          const GetOrthancWebViewerJpegCommand& command)
  {
    Orthanc::HttpClient client(orthanc, command.GetUri());
    client.SetRedirectionFollowed(false);
    client.SetTimeout(command.GetTimeout());

    CopyHttpHeaders(client, command.GetHttpHeaders());

    std::string answer;
    Orthanc::HttpClient::HttpHeaders answerHeaders;
    client.ApplyAndThrowException(answer, answerHeaders);

    DecodeAnswer(answer, answerHeaders);

    command.ProcessHttpAnswer(receiver, emitter, answer);
  }


  static std::string GetPath(const std::string& root,
                             const std::string& file)
  {
    boost::filesystem::path a(root);
    boost::filesystem::path b(file);

    boost::filesystem::path c;
    if (b.is_absolute())
    {
      c = b;
    }
    else
    {
      c = a / b;
    }

    return c.string();
  }


  static void RunInternal(boost::weak_ptr<IObserver> receiver,
                          IMessageEmitter& emitter,
                          const std::string& root,
                          const ReadFileCommand& command)
  {
    std::string path = GetPath(root, command.GetPath());
    LOG(TRACE) << "Oracle reading file: " << path;

    std::string content;
    Orthanc::SystemToolbox::ReadFile(content, path, true /* log */);

    ReadFileCommand::SuccessMessage message(command, content);
    emitter.EmitMessage(receiver, message);
  }


#if ORTHANC_ENABLE_DCMTK == 1
  static Orthanc::ParsedDicomFile* ParseDicom(uint64_t& fileSize,  /* OUT */
                                              const std::string& path,
                                              bool isPixelData)
  {
    if (!Orthanc::SystemToolbox::IsRegularFile(path))
    {
      throw Orthanc::OrthancException(Orthanc::ErrorCode_InexistentFile);
    }
    
    LOG(TRACE) << "Parsing DICOM file, " << (isPixelData ? "with" : "without")
               << " pixel data: " << path;
    
    boost::posix_time::ptime start = boost::posix_time::microsec_clock::local_time();
    
    fileSize = Orthanc::SystemToolbox::GetFileSize(path);
    
    // Check for 32bit systems
    if (fileSize != static_cast<uint64_t>(static_cast<size_t>(fileSize)))
    {
      throw Orthanc::OrthancException(Orthanc::ErrorCode_NotEnoughMemory);
    }
    
    DcmFileFormat dicom;
    bool ok;
    
    if (isPixelData)
    {
      ok = dicom.loadFile(path.c_str()).good();
    }
    else
    {
#if DCMTK_VERSION_NUMBER >= 362
      /**
       * NB : We could stop at (0x3007, 0x0000) instead of
       * DCM_PixelData as the Stone framework does not use further
       * tags (cf. the Orthanc::DICOM_TAG_* constants), but we still
       * use "PixelData" as this does not change the runtime much, and
       * as it is more explicit.
       **/
      static const DcmTagKey STOP = DCM_PixelData;
      //static const DcmTagKey STOP(0x3007, 0x0000);

      ok = dicom.loadFileUntilTag(path.c_str(), EXS_Unknown, EGL_noChange,
                                  DCM_MaxReadLength, ERM_autoDetect, STOP).good();
#else
      // The primitive "loadFileUntilTag" was introduced in DCMTK 3.6.2
      ok = dicom.loadFile(path.c_str()).good();
#endif
    }

    if (ok)
    {
      std::unique_ptr<Orthanc::ParsedDicomFile> result(new Orthanc::ParsedDicomFile(dicom));

      boost::posix_time::ptime end = boost::posix_time::microsec_clock::local_time();
      LOG(TRACE) << path << ": parsed in " << (end-start).total_milliseconds() << " ms";

      return result.release();
    }
    else
    {
      throw Orthanc::OrthancException(Orthanc::ErrorCode_BadFileFormat,
                                      "Cannot parse file: " + path);
    }
  }

  
  static void RunInternal(boost::weak_ptr<IObserver> receiver,
                          IMessageEmitter& emitter,
                          boost::shared_ptr<ParsedDicomCache> cache,
                          const std::string& root,
                          const ParseDicomFromFileCommand& command)
  {
    const std::string path = GetPath(root, command.GetPath());

    if (cache)
    {
      ParsedDicomCache::Reader reader(*cache, BUCKET_DICOMDIR, path);
      if (reader.IsValid() &&
          (!command.IsPixelDataIncluded() ||
           reader.HasPixelData()))
      {
        // Reuse the DICOM file from the cache
        ParseDicomSuccessMessage message(command, command.GetSource(), reader.GetDicom(),
                                         reader.GetFileSize(), reader.HasPixelData());
        emitter.EmitMessage(receiver, message);
        return;
      }
    }

    uint64_t fileSize;
    std::unique_ptr<Orthanc::ParsedDicomFile> parsed(ParseDicom(fileSize, path, command.IsPixelDataIncluded()));

    if (fileSize != static_cast<size_t>(fileSize))
    {
      // Cannot load such a large file on 32-bit architecture
      throw Orthanc::OrthancException(Orthanc::ErrorCode_NotEnoughMemory);
    }
    
    {
      ParseDicomSuccessMessage message
        (command, command.GetSource(), *parsed,
         static_cast<size_t>(fileSize), command.IsPixelDataIncluded());
      emitter.EmitMessage(receiver, message);
    }

    if (cache)
    {
      // Store it into the cache for future use
      
      // Invalidate to overwrite DICOM instance that would already
      // be stored without pixel data
      cache->Invalidate(BUCKET_DICOMDIR, path);
      
      cache->Acquire(BUCKET_DICOMDIR, path, parsed.release(),
                     static_cast<size_t>(fileSize), command.IsPixelDataIncluded());
    }
  }

  
  static void RunInternal(boost::weak_ptr<IObserver> receiver,
                          IMessageEmitter& emitter,
                          boost::shared_ptr<ParsedDicomCache> cache,
                          const Orthanc::WebServiceParameters& orthanc,
                          const ParseDicomFromWadoCommand& command)
  {
    if (cache)
    {
      ParsedDicomCache::Reader reader(*cache, BUCKET_SOP, command.GetSopInstanceUid());
      if (reader.IsValid() &&
          reader.HasPixelData())
      {
        // Reuse the DICOM file from the cache
        ParseDicomSuccessMessage message(command, command.GetSource(), reader.GetDicom(),
                                         reader.GetFileSize(), reader.HasPixelData());
        emitter.EmitMessage(receiver, message);
        return;
      }
    }

    std::string answer;
    Orthanc::HttpClient::HttpHeaders answerHeaders;

    switch (command.GetRestCommand().GetType())
    {
      case IOracleCommand::Type_Http:
        RunHttpCommand(answer, answerHeaders, dynamic_cast<const HttpCommand&>(command.GetRestCommand()));
        break;
        
      case IOracleCommand::Type_OrthancRestApi:
        RunOrthancRestApiCommand(answer, answerHeaders, orthanc,
                                 dynamic_cast<const OrthancRestApiCommand&>(command.GetRestCommand()));
        break;

      default:
        throw Orthanc::OrthancException(Orthanc::ErrorCode_NotImplemented);
    }

    size_t fileSize;
    std::unique_ptr<Orthanc::ParsedDicomFile> parsed(ParseDicomSuccessMessage::ParseWadoAnswer(fileSize, answer, answerHeaders));

    {
      ParseDicomSuccessMessage message(command, command.GetSource(), *parsed, fileSize,
                                       true /* pixel data always is included in WADO-RS */);
      emitter.EmitMessage(receiver, message);
    }

    if (cache)
    {
      // Store it into the cache for future use
      cache->Acquire(BUCKET_SOP, command.GetSopInstanceUid(), parsed.release(), fileSize, true);
    }
  }
#endif


  void GenericOracleRunner::Run(boost::weak_ptr<IObserver> receiver,
                                IMessageEmitter& emitter,
                                const IOracleCommand& command)
  {
    Orthanc::ErrorCode error = Orthanc::ErrorCode_Success;
    
    try
    {
      switch (command.GetType())
      {
        case IOracleCommand::Type_Sleep:
          throw Orthanc::OrthancException(Orthanc::ErrorCode_BadParameterType,
                                          "Sleep command cannot be executed by the runner");

        case IOracleCommand::Type_Http:
          RunInternal(receiver, emitter, dynamic_cast<const HttpCommand&>(command));
          break;

        case IOracleCommand::Type_OrthancRestApi:
          RunInternal(receiver, emitter, orthanc_,
                      dynamic_cast<const OrthancRestApiCommand&>(command));
          break;

        case IOracleCommand::Type_GetOrthancImage:
          RunInternal(receiver, emitter, orthanc_,
                      dynamic_cast<const GetOrthancImageCommand&>(command));
          break;

        case IOracleCommand::Type_GetOrthancWebViewerJpeg:
          RunInternal(receiver, emitter, orthanc_,
                      dynamic_cast<const GetOrthancWebViewerJpegCommand&>(command));
          break;

        case IOracleCommand::Type_ReadFile:
          RunInternal(receiver, emitter, rootDirectory_,
                      dynamic_cast<const ReadFileCommand&>(command));
          break;

        case IOracleCommand::Type_ParseDicomFromFile:
        case IOracleCommand::Type_ParseDicomFromWado:
#if ORTHANC_ENABLE_DCMTK == 1
          switch (command.GetType())
          {
            case IOracleCommand::Type_ParseDicomFromFile:
              RunInternal(receiver, emitter, dicomCache_, rootDirectory_,
                          dynamic_cast<const ParseDicomFromFileCommand&>(command));
              break;

            case IOracleCommand::Type_ParseDicomFromWado:
              RunInternal(receiver, emitter, dicomCache_, orthanc_,
                          dynamic_cast<const ParseDicomFromWadoCommand&>(command));
              break;

            default:
              throw Orthanc::OrthancException(Orthanc::ErrorCode_InternalError);
          }            
          break;
#else
          throw Orthanc::OrthancException(Orthanc::ErrorCode_NotImplemented,
                                          "DCMTK must be enabled to parse DICOM files");
#endif

        default:
          throw Orthanc::OrthancException(Orthanc::ErrorCode_NotImplemented);
      }
    }
    catch (Orthanc::OrthancException& e)
    {
      LOG(ERROR) << "Exception within the oracle: " << e.What();
      error = e.GetErrorCode();
    }
    catch (...)
    {
      LOG(ERROR) << "Threaded exception within the oracle";
      error = Orthanc::ErrorCode_InternalError;
    }

    if (error != Orthanc::ErrorCode_Success)
    {
      OracleCommandExceptionMessage message(command, error);
      emitter.EmitMessage(receiver, message);
    }
  }
}