/**
 * Orthanc - A Lightweight, RESTful DICOM Store
 * 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 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 "OrthancRestApi.h"

#include "../../../OrthancFramework/Sources/Compression/GzipCompressor.h"
#include "../../../OrthancFramework/Sources/DicomFormat/DicomImageInformation.h"
#include "../../../OrthancFramework/Sources/DicomParsing/DicomWebJsonVisitor.h"
#include "../../../OrthancFramework/Sources/DicomParsing/FromDcmtkBridge.h"
#include "../../../OrthancFramework/Sources/DicomParsing/Internals/DicomImageDecoder.h"
#include "../../../OrthancFramework/Sources/HttpServer/HttpContentNegociation.h"
#include "../../../OrthancFramework/Sources/Images/Image.h"
#include "../../../OrthancFramework/Sources/Images/ImageProcessing.h"
#include "../../../OrthancFramework/Sources/Logging.h"
#include "../../../OrthancFramework/Sources/MultiThreading/Semaphore.h"

#include "../OrthancConfiguration.h"
#include "../Search/DatabaseLookup.h"
#include "../ServerContext.h"
#include "../ServerToolbox.h"
#include "../SliceOrdering.h"

#include "../../Plugins/Engine/OrthancPlugins.h"

// This "include" is mandatory for Release builds using Linux Standard Base
#include <boost/math/special_functions/round.hpp>


/**
 * This semaphore is used to limit the number of concurrent HTTP
 * requests on CPU-intensive routes of the REST API, in order to
 * prevent exhaustion of resources (new in Orthanc 1.7.0).
 **/
static Orthanc::Semaphore throttlingSemaphore_(4);  // TODO => PARAMETER?


namespace Orthanc
{
  static void AnswerDicomAsJson(RestApiCall& call,
                                const Json::Value& dicom,
                                DicomToJsonFormat mode)
  {
    if (mode != DicomToJsonFormat_Full)
    {
      Json::Value simplified;
      Toolbox::SimplifyDicomAsJson(simplified, dicom, mode);
      call.GetOutput().AnswerJson(simplified);
    }
    else
    {
      call.GetOutput().AnswerJson(dicom);
    }
  }


  static DicomToJsonFormat GetDicomFormat(const RestApiGetCall& call)
  {
    if (call.HasArgument("simplify"))
    {
      return DicomToJsonFormat_Human;
    }
    else if (call.HasArgument("short"))
    {
      return DicomToJsonFormat_Short;
    }
    else
    {
      return DicomToJsonFormat_Full;
    }
  }


  static void AnswerDicomAsJson(RestApiGetCall& call,
                                const Json::Value& dicom)
  {
    AnswerDicomAsJson(call, dicom, GetDicomFormat(call));
  }


  static void ParseSetOfTags(std::set<DicomTag>& target,
                             const RestApiGetCall& call,
                             const std::string& argument)
  {
    target.clear();

    if (call.HasArgument(argument))
    {
      std::vector<std::string> tags;
      Toolbox::TokenizeString(tags, call.GetArgument(argument, ""), ',');

      for (size_t i = 0; i < tags.size(); i++)
      {
        target.insert(FromDcmtkBridge::ParseTag(tags[i]));
      }
    }
  }


  // List all the patients, studies, series or instances ----------------------
 
  static void AnswerListOfResources(RestApiOutput& output,
                                    ServerIndex& index,
                                    const std::list<std::string>& resources,
                                    ResourceType level,
                                    bool expand)
  {
    Json::Value answer = Json::arrayValue;

    for (std::list<std::string>::const_iterator
           resource = resources.begin(); resource != resources.end(); ++resource)
    {
      if (expand)
      {
        Json::Value item;
        if (index.LookupResource(item, *resource, level))
        {
          answer.append(item);
        }
      }
      else
      {
        answer.append(*resource);
      }
    }

    output.AnswerJson(answer);
  }


  template <enum ResourceType resourceType>
  static void ListResources(RestApiGetCall& call)
  {
    if (call.IsDocumentation())
    {
      const std::string resources = GetResourceTypeText(resourceType, true /* plural */, false /* lower case */);
      call.GetDocumentation()
        .SetTag(GetResourceTypeText(resourceType, true /* plural */, true /* upper case */))
        .SetSummary("List the available " + resources)
        .SetDescription("List the Orthanc identifiers of all the available DICOM " + resources)
        .SetHttpGetArgument("limit", RestApiCallDocumentation::Type_Number, "Limit the number of results", false)
        .SetHttpGetArgument("since", RestApiCallDocumentation::Type_Number, "Show only the resources since the provided index", false)
        .SetHttpGetArgument("expand", RestApiCallDocumentation::Type_String,
                            "If present, retrieve detailed information about the individual " + resources, false)
        .AddAnswerType(MimeType_Json, "JSON array containing either the Orthanc identifiers, or detailed information "
                       "about the reported " + resources + " (if `expand` argument is provided)")
        .SetHttpGetSample("https://demo.orthanc-server.com/" + resources + "?since=0&limit=2", true);
      return;
    }
    
    ServerIndex& index = OrthancRestApi::GetIndex(call);

    std::list<std::string> result;

    if (call.HasArgument("limit") ||
        call.HasArgument("since"))
    {
      if (!call.HasArgument("limit"))
      {
        throw OrthancException(ErrorCode_BadRequest,
                               "Missing \"limit\" argument for GET request against: " +
                               call.FlattenUri());
      }

      if (!call.HasArgument("since"))
      {
        throw OrthancException(ErrorCode_BadRequest,
                               "Missing \"since\" argument for GET request against: " +
                               call.FlattenUri());
      }

      size_t since = boost::lexical_cast<size_t>(call.GetArgument("since", ""));
      size_t limit = boost::lexical_cast<size_t>(call.GetArgument("limit", ""));
      index.GetAllUuids(result, resourceType, since, limit);
    }
    else
    {
      index.GetAllUuids(result, resourceType);
    }


    AnswerListOfResources(call.GetOutput(), index, result, resourceType, call.HasArgument("expand"));
  }



  static std::string GetDocumentationSampleResource(ResourceType type)
  {
    switch (type)
    {
      case Orthanc::ResourceType_Instance:
        return "https://demo.orthanc-server.com/instances/d94d9a03-3003b047-a4affc69-322313b2-680530a2";
        break;
        
      case Orthanc::ResourceType_Series:
        return "https://demo.orthanc-server.com/series/37836232-d13a2350-fa1dedc5-962b31aa-010f8e52";
        break;
        
      case Orthanc::ResourceType_Study:
        return "https://demo.orthanc-server.com/studies/27f7126f-4f66fb14-03f4081b-f9341db2-53925988";
        break;
        
      case Orthanc::ResourceType_Patient:
        return "https://demo.orthanc-server.com/patients/46e6332c-677825b6-202fcf7c-f787bc5f-7b07c382";
        break;
        
      default:
        throw OrthancException(ErrorCode_ParameterOutOfRange);
    }
  }
  

  template <enum ResourceType resourceType>
  static void GetSingleResource(RestApiGetCall& call)
  {
    if (call.IsDocumentation())
    {
      const std::string resource = GetResourceTypeText(resourceType, false /* plural */, false /* lower case */);
      call.GetDocumentation()
        .SetTag(GetResourceTypeText(resourceType, true /* plural */, true /* upper case */))
        .SetSummary("Get information about some " + resource)
        .SetDescription("Get detailed information about the DICOM " + resource + " of interest whose Orthanc identifier is provided in the URL")
        .SetUriArgument("id", "Orthanc identifier of the " + resource + " of interest")
        .AddAnswerType(MimeType_Json, "Information about the DICOM " + resource)
        .SetHttpGetSample(GetDocumentationSampleResource(resourceType), true);
      return;
    }
    
    Json::Value result;
    if (OrthancRestApi::GetIndex(call).LookupResource(result, call.GetUriComponent("id", ""), resourceType))
    {
      call.GetOutput().AnswerJson(result);
    }
  }

  template <enum ResourceType resourceType>
  static void DeleteSingleResource(RestApiDeleteCall& call)
  {
    if (call.IsDocumentation())
    {
      const std::string resource = GetResourceTypeText(resourceType, false /* plural */, false /* lower case */);
      call.GetDocumentation()
        .SetTag(GetResourceTypeText(resourceType, true /* plural */, true /* upper case */))
        .SetSummary("Delete some " + resource)
        .SetDescription("Delete the DICOM " + resource + " of interest whose Orthanc identifier is provided in the URL")
        .SetUriArgument("id", "Orthanc identifier of the " + resource + " of interest");
      return;
    }

    Json::Value result;
    if (OrthancRestApi::GetContext(call).DeleteResource(result, call.GetUriComponent("id", ""), resourceType))
    {
      call.GetOutput().AnswerJson(result);
    }
  }


  // Get information about a single patient -----------------------------------
 
  static void IsProtectedPatient(RestApiGetCall& call)
  {
    if (call.IsDocumentation())
    {
      call.GetDocumentation()
        .SetTag("Patients")
        .SetSummary("Is the patient protected against recycling?")
        .SetUriArgument("id", "Orthanc identifier of the patient of interest")
        .AddAnswerType(MimeType_PlainText, "`1` if protected, `0` if not protected");
      return;
    }
    
    std::string publicId = call.GetUriComponent("id", "");
    bool isProtected = OrthancRestApi::GetIndex(call).IsProtectedPatient(publicId);
    call.GetOutput().AnswerBuffer(isProtected ? "1" : "0", MimeType_PlainText);
  }


  static void SetPatientProtection(RestApiPutCall& call)
  {
    if (call.IsDocumentation())
    {
      call.GetDocumentation()
        .SetTag("Patients")
        .SetSummary("Protect one patient against recycling")
        .SetDescription("Check out configuration options `MaximumStorageSize` and `MaximumPatientCount`")
        .SetUriArgument("id", "Orthanc identifier of the patient of interest");
      return;
    }
    
    ServerContext& context = OrthancRestApi::GetContext(call);

    std::string publicId = call.GetUriComponent("id", "");

    std::string body;
    call.BodyToString(body);
    body = Toolbox::StripSpaces(body);

    if (body == "0")
    {
      context.GetIndex().SetProtectedPatient(publicId, false);
      call.GetOutput().AnswerBuffer("", MimeType_PlainText);
    }
    else if (body == "1")
    {
      context.GetIndex().SetProtectedPatient(publicId, true);
      call.GetOutput().AnswerBuffer("", MimeType_PlainText);
    }
    else
    {
      // Bad request
    }
  }


  // Get information about a single instance ----------------------------------
 
  static void GetInstanceFile(RestApiGetCall& call)
  {
    if (call.IsDocumentation())
    {
      call.GetDocumentation()
        .SetTag("Instances")
        .SetSummary("Download DICOM")
        .SetDescription("Download one DICOM instance")
        .SetUriArgument("id", "Orthanc identifier of the DICOM instance of interest")
        .SetHttpHeader("Accept", "This HTTP header can be set to retrieve the DICOM instance in DICOMweb format")
        .AddAnswerType(MimeType_Dicom, "The DICOM instance")
        .AddAnswerType(MimeType_DicomWebJson, "The DICOM instance, in DICOMweb JSON format")
        .AddAnswerType(MimeType_DicomWebXml, "The DICOM instance, in DICOMweb XML format");
      return;
    }

    ServerContext& context = OrthancRestApi::GetContext(call);

    std::string publicId = call.GetUriComponent("id", "");

    HttpToolbox::Arguments::const_iterator accept = call.GetHttpHeaders().find("accept");
    if (accept != call.GetHttpHeaders().end())
    {
      // New in Orthanc 1.5.4
      try
      {
        MimeType mime = StringToMimeType(accept->second.c_str());

        if (mime == MimeType_DicomWebJson ||
            mime == MimeType_DicomWebXml)
        {
          DicomWebJsonVisitor visitor;
          
          {
            ServerContext::DicomCacheLocker locker(OrthancRestApi::GetContext(call), publicId);
            locker.GetDicom().Apply(visitor);
          }

          if (mime == MimeType_DicomWebJson)
          {
            std::string s = visitor.GetResult().toStyledString();
            call.GetOutput().AnswerBuffer(s, MimeType_DicomWebJson);
          }
          else
          {
            std::string xml;
            visitor.FormatXml(xml);
            call.GetOutput().AnswerBuffer(xml, MimeType_DicomWebXml);
          }
          
          return;
        }
      }
      catch (OrthancException&)
      {
      }
    }

    context.AnswerAttachment(call.GetOutput(), publicId, FileContentType_Dicom);
  }


  static void ExportInstanceFile(RestApiPostCall& call)
  {
    ServerContext& context = OrthancRestApi::GetContext(call);

    std::string publicId = call.GetUriComponent("id", "");

    std::string dicom;
    context.ReadDicom(dicom, publicId);

    std::string target;
    call.BodyToString(target);
    SystemToolbox::WriteFile(dicom, target);

    call.GetOutput().AnswerBuffer("{}", MimeType_Json);
  }


  template <DicomToJsonFormat format>
  static void GetInstanceTags(RestApiGetCall& call)
  {
    if (call.IsDocumentation())
    {
      if (format == DicomToJsonFormat_Human)
      {
        call.GetDocumentation()
          .SetTag("Instances")
          .SetSummary("Get human-readable tags")
          .SetDescription("Get the DICOM tags in human-readable format")
          .SetUriArgument("id", "Orthanc identifier of the DICOM instance of interest")
          .AddAnswerType(MimeType_Json, "JSON object containing the DICOM tags and their associated value")
          .SetHttpGetSample("https://demo.orthanc-server.com/instances/7c92ce8e-bbf67ed2-ffa3b8c1-a3b35d94-7ff3ae26/simplified-tags", true);
        return;
      }
      else
      {
        throw OrthancException(ErrorCode_NotImplemented);
      }
    }

    ServerContext& context = OrthancRestApi::GetContext(call);

    std::string publicId = call.GetUriComponent("id", "");

    std::set<DicomTag> ignoreTagLength;
    ParseSetOfTags(ignoreTagLength, call, "ignore-length");
    
    if (format != DicomToJsonFormat_Full ||
        !ignoreTagLength.empty())
    {
      Json::Value full;
      context.ReadDicomAsJson(full, publicId, ignoreTagLength);
      AnswerDicomAsJson(call, full, format);
    }
    else
    {
      // This path allows one to avoid the JSON decoding if no
      // simplification is asked, and if no "ignore-length" argument
      // is present
      std::string full;
      context.ReadDicomAsJson(full, publicId);
      call.GetOutput().AnswerBuffer(full, MimeType_Json);
    }
  }


  static void GetInstanceTagsBis(RestApiGetCall& call)
  {
    if (call.IsDocumentation())
    {
      call.GetDocumentation()
        .SetTag("Instances")
        .SetSummary("Get DICOM tags")
        .SetDescription("Get the DICOM tags in the specified format. By default, the `full` format is used, which "
                        "combines hexadecimal tags with human-readable description.")
        .SetUriArgument("id", "Orthanc identifier of the DICOM instance of interest")
        .SetHttpGetArgument("simplify", RestApiCallDocumentation::Type_String,
                            "If present, report the DICOM tags in human-readable format "
                            "(same as the `/instances/{id}/simplified-tags` route)", false)
        .SetHttpGetArgument("short", RestApiCallDocumentation::Type_String,
                            "If present, report the DICOM tags indexed in hexadecimal format", false)
        .AddAnswerType(MimeType_Json, "JSON object containing the DICOM tags and their associated value")
        .SetHttpGetSample("https://demo.orthanc-server.com/instances/7c92ce8e-bbf67ed2-ffa3b8c1-a3b35d94-7ff3ae26/tags", true);      
      return;
    }

    switch (GetDicomFormat(call))
    {
      case DicomToJsonFormat_Human:
        GetInstanceTags<DicomToJsonFormat_Human>(call);
        break;

      case DicomToJsonFormat_Short:
        GetInstanceTags<DicomToJsonFormat_Short>(call);
        break;

      case DicomToJsonFormat_Full:
        GetInstanceTags<DicomToJsonFormat_Full>(call);
        break;

      default:
        throw OrthancException(ErrorCode_InternalError);
    }
  }

  
  static void ListFrames(RestApiGetCall& call)
  {
    std::string publicId = call.GetUriComponent("id", "");

    unsigned int numberOfFrames;
      
    {
      ServerContext::DicomCacheLocker locker(OrthancRestApi::GetContext(call), publicId);
      numberOfFrames = locker.GetDicom().GetFramesCount();
    }
    
    Json::Value result = Json::arrayValue;
    for (unsigned int i = 0; i < numberOfFrames; i++)
    {
      result.append(i);
    }
    
    call.GetOutput().AnswerJson(result);
  }


  namespace
  {
    class ImageToEncode
    {
    private:
      std::unique_ptr<ImageAccessor>&  image_;
      ImageExtractionMode            mode_;
      bool                           invert_;
      MimeType                       format_;
      std::string                    answer_;

    public:
      ImageToEncode(std::unique_ptr<ImageAccessor>& image,
                    ImageExtractionMode mode,
                    bool invert) :
        image_(image),
        mode_(mode),
        invert_(invert),
        format_(MimeType_Binary)
      {
      }

      void Answer(RestApiOutput& output)
      {
        output.AnswerBuffer(answer_, format_);
      }

      void EncodeUsingPng()
      {
        format_ = MimeType_Png;
        DicomImageDecoder::ExtractPngImage(answer_, image_, mode_, invert_);
      }

      void EncodeUsingPam()
      {
        format_ = MimeType_Pam;
        DicomImageDecoder::ExtractPamImage(answer_, image_, mode_, invert_);
      }

      void EncodeUsingJpeg(uint8_t quality)
      {
        format_ = MimeType_Jpeg;
        DicomImageDecoder::ExtractJpegImage(answer_, image_, mode_, invert_, quality);
      }
    };

    class EncodePng : public HttpContentNegociation::IHandler
    {
    private:
      ImageToEncode&  image_;

    public:
      explicit EncodePng(ImageToEncode& image) : image_(image)
      {
      }

      virtual void Handle(const std::string& type,
                          const std::string& subtype) ORTHANC_OVERRIDE
      {
        assert(type == "image");
        assert(subtype == "png");
        image_.EncodeUsingPng();
      }
    };

    class EncodePam : public HttpContentNegociation::IHandler
    {
    private:
      ImageToEncode&  image_;

    public:
      explicit EncodePam(ImageToEncode& image) : image_(image)
      {
      }

      virtual void Handle(const std::string& type,
                          const std::string& subtype) ORTHANC_OVERRIDE
      {
        assert(type == "image");
        assert(subtype == "x-portable-arbitrarymap");
        image_.EncodeUsingPam();
      }
    };

    class EncodeJpeg : public HttpContentNegociation::IHandler
    {
    private:
      ImageToEncode&  image_;
      unsigned int    quality_;

    public:
      EncodeJpeg(ImageToEncode& image,
                 const RestApiGetCall& call) :
        image_(image)
      {
        std::string v = call.GetArgument("quality", "90" /* default JPEG quality */);
        bool ok = false;

        try
        {
          quality_ = boost::lexical_cast<unsigned int>(v);
          ok = (quality_ >= 1 && quality_ <= 100);
        }
        catch (boost::bad_lexical_cast&)
        {
        }

        if (!ok)
        {
          throw OrthancException(
            ErrorCode_BadRequest,
            "Bad quality for a JPEG encoding (must be a number between 0 and 100): " + v);
        }
      }

      virtual void Handle(const std::string& type,
                          const std::string& subtype) ORTHANC_OVERRIDE
      {
        assert(type == "image");
        assert(subtype == "jpeg");
        image_.EncodeUsingJpeg(quality_);
      }
    };
  }


  namespace
  {
    class IDecodedFrameHandler : public boost::noncopyable
    {
    public:
      virtual ~IDecodedFrameHandler()
      {
      }

      virtual void Handle(RestApiGetCall& call,
                          std::unique_ptr<ImageAccessor>& decoded,
                          const DicomMap& dicom) = 0;

      virtual bool RequiresDicomTags() const = 0;

      static void Apply(RestApiGetCall& call,
                        IDecodedFrameHandler& handler,
                        ImageExtractionMode mode /* for generation of documentation */,
                        bool isRendered /* for generation of documentation */)
      {
        if (call.IsDocumentation())
        {
          std::string m;
          if (!isRendered)
          {
            switch (mode)
            {
              case ImageExtractionMode_Preview:
                m = "preview";
                break;
              case ImageExtractionMode_UInt8:
                m = "uint8";
                break;
              case ImageExtractionMode_UInt16:
                m = "uint16";
                break;
              case ImageExtractionMode_Int16:
                m = "int16";
                break;
              default:
                throw OrthancException(ErrorCode_ParameterOutOfRange);
            }
          }
          
          std::string description;
          std::string verb = (isRendered ? "Render" : "Decode");
          
          if (call.HasUriComponent("frame"))
          {
            description = verb + " one frame of interest from the given DICOM instance.";
            call.GetDocumentation()
              .SetSummary(verb + " a frame" + (m.empty() ? "" : " (" + m + ")"))
              .SetUriArgument("frame", RestApiCallDocumentation::Type_Number, "Index of the frame (starts at `0`)");
          }
          else
          {
            description = verb + " the first frame of the given DICOM instance.";
            call.GetDocumentation()
              .SetSummary(verb + " an image" + (m.empty() ? "" : " (" + m + ")"));
          }

          if (isRendered)
          {
            description += (" This function takes scaling into account (`RescaleSlope` and `RescaleIntercept` tags), "
                            "as well as the default windowing stored in the DICOM file (`WindowCenter` and `WindowWidth`tags), "
                            "and can be used to resize the resulting image. Color images are not affected by windowing.");
            call.GetDocumentation()
              .SetHttpGetArgument("window-center",RestApiCallDocumentation::Type_Number, "Windowing center", false)
              .SetHttpGetArgument("window-width",RestApiCallDocumentation::Type_Number, "Windowing width", false)
              .SetHttpGetArgument("width",RestApiCallDocumentation::Type_Number, "Width of the resized image", false)
              .SetHttpGetArgument("height",RestApiCallDocumentation::Type_Number, "Height of the resized image", false)
              .SetHttpGetArgument("smooth",RestApiCallDocumentation::Type_Boolean, "Whether to smooth image on resize", false);
          }
          else
          {
            switch (mode)
            {
              case ImageExtractionMode_Preview:
                description += " The full dynamic range of grayscale images is rescaled to the [0,255] range.";
                break;
              case ImageExtractionMode_UInt8:
                description += " Pixels of grayscale images are truncated to the [0,255] range.";
                break;
              case ImageExtractionMode_UInt16:
                description += " Pixels of grayscale images are truncated to the [0,65535] range.";
                break;
              case ImageExtractionMode_Int16:
                description += (" Pixels of grayscale images are truncated to the [-32768,32767] range. "
                                "Negative values must be interpreted according to two's complement.");
                break;
              default:
                throw OrthancException(ErrorCode_ParameterOutOfRange);
            }
          }
          
          call.GetDocumentation()
            .SetTag("Instances")
            .SetUriArgument("id", "Orthanc identifier of the DICOM instance of interest")
            .SetHttpGetArgument("quality", RestApiCallDocumentation::Type_Number, "Quality for JPEG images (between 1 and 100, defaults to 90)", false)
            .SetHttpHeader("Accept", "Format of the resulting image. Can be `image/png` (default), `image/jpeg` or `image/x-portable-arbitrarymap`")
            .AddAnswerType(MimeType_Png, "PNG image")
            .AddAnswerType(MimeType_Jpeg, "JPEG image")
            .AddAnswerType(MimeType_Pam, "PAM image (Portable Arbitrary Map)")
            .SetDescription(description);

          return;
        }
        
        ServerContext& context = OrthancRestApi::GetContext(call);

        std::string frameId = call.GetUriComponent("frame", "0");

        unsigned int frame;
        try
        {
          frame = boost::lexical_cast<unsigned int>(frameId);
        }
        catch (boost::bad_lexical_cast&)
        {
          return;
        }

        DicomMap dicom;
        std::unique_ptr<ImageAccessor> decoded;

        try
        {
          std::string publicId = call.GetUriComponent("id", "");

          decoded.reset(context.DecodeDicomFrame(publicId, frame));

          if (decoded.get() == NULL)
          {
            throw OrthancException(ErrorCode_NotImplemented,
                                   "Cannot decode DICOM instance with ID: " + publicId);
          }
          
          if (handler.RequiresDicomTags())
          {
            /**
             * Retrieve a summary of the DICOM tags, which is
             * necessary to deal with MONOCHROME1 photometric
             * interpretation, and with windowing parameters.
             **/ 
            ServerContext::DicomCacheLocker locker(context, publicId);
            OrthancConfiguration::DefaultExtractDicomSummary(dicom, locker.GetDicom());
          }
        }
        catch (OrthancException& e)
        {
          if (e.GetErrorCode() == ErrorCode_ParameterOutOfRange ||
              e.GetErrorCode() == ErrorCode_UnknownResource)
          {
            // The frame number is out of the range for this DICOM
            // instance, the resource is not existent
          }
          else
          {
            std::string root = "";
            for (size_t i = 1; i < call.GetFullUri().size(); i++)
            {
              root += "../";
            }

            call.GetOutput().Redirect(root + "app/images/unsupported.png");
          }
          return;
        }

        handler.Handle(call, decoded, dicom);
      }


      static void DefaultHandler(RestApiGetCall& call,
                                 std::unique_ptr<ImageAccessor>& decoded,
                                 ImageExtractionMode mode,
                                 bool invert)
      {
        ImageToEncode image(decoded, mode, invert);

        HttpContentNegociation negociation;
        EncodePng png(image);
        negociation.Register(MIME_PNG, png);

        EncodeJpeg jpeg(image, call);
        negociation.Register(MIME_JPEG, jpeg);

        EncodePam pam(image);
        negociation.Register(MIME_PAM, pam);

        if (negociation.Apply(call.GetHttpHeaders()))
        {
          image.Answer(call.GetOutput());
        }
      }
    };


    class GetImageHandler : public IDecodedFrameHandler
    {
    private:
      ImageExtractionMode mode_;

    public:
      explicit GetImageHandler(ImageExtractionMode mode) :
        mode_(mode)
      {
      }

      virtual void Handle(RestApiGetCall& call,
                          std::unique_ptr<ImageAccessor>& decoded,
                          const DicomMap& dicom) ORTHANC_OVERRIDE
      {
        bool invert = false;

        if (mode_ == ImageExtractionMode_Preview)
        {
          DicomImageInformation info(dicom);
          invert = (info.GetPhotometricInterpretation() == PhotometricInterpretation_Monochrome1);
        }

        DefaultHandler(call, decoded, mode_, invert);
      }

      virtual bool RequiresDicomTags() const ORTHANC_OVERRIDE
      {
        return mode_ == ImageExtractionMode_Preview;
      }
    };


    class RenderedFrameHandler : public IDecodedFrameHandler
    {
    private:
      static void GetDicomParameters(bool& invert,
                                     float& rescaleSlope,
                                     float& rescaleIntercept,
                                     float& windowWidth,
                                     float& windowCenter,
                                     const DicomMap& dicom)
      {
        DicomImageInformation info(dicom);

        invert = (info.GetPhotometricInterpretation() == PhotometricInterpretation_Monochrome1);

        rescaleSlope = 1.0f;
        rescaleIntercept = 0.0f;

        if (dicom.HasTag(Orthanc::DICOM_TAG_RESCALE_SLOPE) &&
            dicom.HasTag(Orthanc::DICOM_TAG_RESCALE_INTERCEPT))
        {
          dicom.ParseFloat(rescaleSlope, Orthanc::DICOM_TAG_RESCALE_SLOPE);
          dicom.ParseFloat(rescaleIntercept, Orthanc::DICOM_TAG_RESCALE_INTERCEPT);
        }

        windowWidth = static_cast<float>(1 << info.GetBitsStored()) * rescaleSlope;
        windowCenter = windowWidth / 2.0f + rescaleIntercept;

        if (dicom.HasTag(Orthanc::DICOM_TAG_WINDOW_CENTER) &&
            dicom.HasTag(Orthanc::DICOM_TAG_WINDOW_WIDTH))
        {
          dicom.ParseFirstFloat(windowCenter, Orthanc::DICOM_TAG_WINDOW_CENTER);
          dicom.ParseFirstFloat(windowWidth, Orthanc::DICOM_TAG_WINDOW_WIDTH);
        }
      }

      static void GetUserArguments(float& windowWidth /* inout */,
                                   float& windowCenter /* inout */,
                                   unsigned int& argWidth,
                                   unsigned int& argHeight,
                                   bool& smooth,
                                   const RestApiGetCall& call)
      {
        static const char* ARG_WINDOW_CENTER = "window-center";
        static const char* ARG_WINDOW_WIDTH = "window-width";
        static const char* ARG_WIDTH = "width";
        static const char* ARG_HEIGHT = "height";
        static const char* ARG_SMOOTH = "smooth";

        if (call.HasArgument(ARG_WINDOW_WIDTH))
        {
          try
          {
            windowWidth = boost::lexical_cast<float>(call.GetArgument(ARG_WINDOW_WIDTH, ""));
          }
          catch (boost::bad_lexical_cast&)
          {
            throw OrthancException(ErrorCode_ParameterOutOfRange,
                                   "Bad value for argument: " + std::string(ARG_WINDOW_WIDTH));
          }
        }

        if (call.HasArgument(ARG_WINDOW_CENTER))
        {
          try
          {
            windowCenter = boost::lexical_cast<float>(call.GetArgument(ARG_WINDOW_CENTER, ""));
          }
          catch (boost::bad_lexical_cast&)
          {
            throw OrthancException(ErrorCode_ParameterOutOfRange,
                                   "Bad value for argument: " + std::string(ARG_WINDOW_CENTER));
          }
        }

        argWidth = 0;
        argHeight = 0;

        if (call.HasArgument(ARG_WIDTH))
        {
          try
          {
            int tmp = boost::lexical_cast<int>(call.GetArgument(ARG_WIDTH, ""));
            if (tmp < 0)
            {
              throw OrthancException(ErrorCode_ParameterOutOfRange,
                                     "Argument cannot be negative: " + std::string(ARG_WIDTH));
            }
            else
            {
              argWidth = static_cast<unsigned int>(tmp);
            }
          }
          catch (boost::bad_lexical_cast&)
          {
            throw OrthancException(ErrorCode_ParameterOutOfRange,
                                   "Bad value for argument: " + std::string(ARG_WIDTH));
          }
        }

        if (call.HasArgument(ARG_HEIGHT))
        {
          try
          {
            int tmp = boost::lexical_cast<int>(call.GetArgument(ARG_HEIGHT, ""));
            if (tmp < 0)
            {
              throw OrthancException(ErrorCode_ParameterOutOfRange,
                                     "Argument cannot be negative: " + std::string(ARG_HEIGHT));
            }
            else
            {
              argHeight = static_cast<unsigned int>(tmp);
            }
          }
          catch (boost::bad_lexical_cast&)
          {
            throw OrthancException(ErrorCode_ParameterOutOfRange,
                                   "Bad value for argument: " + std::string(ARG_HEIGHT));
          }
        }

        smooth = false;

        if (call.HasArgument(ARG_SMOOTH))
        {
          std::string value = call.GetArgument(ARG_SMOOTH, "");
          if (value == "0" ||
              value == "false")
          {
            smooth = false;
          }
          else if (value == "1" ||
                   value == "true")
          {
            smooth = true;
          }
          else
          {
            throw OrthancException(ErrorCode_ParameterOutOfRange,
                                   "Argument must be Boolean: " + std::string(ARG_SMOOTH));
          }
        }        
      }
                                
      
    public:
      virtual void Handle(RestApiGetCall& call,
                          std::unique_ptr<ImageAccessor>& decoded,
                          const DicomMap& dicom) ORTHANC_OVERRIDE
      {
        bool invert;
        float rescaleSlope, rescaleIntercept, windowWidth, windowCenter;
        GetDicomParameters(invert, rescaleSlope, rescaleIntercept, windowWidth, windowCenter, dicom);

        unsigned int argWidth, argHeight;
        bool smooth;
        GetUserArguments(windowWidth, windowCenter, argWidth, argHeight, smooth, call);

        unsigned int targetWidth = decoded->GetWidth();
        unsigned int targetHeight = decoded->GetHeight();

        if (decoded->GetWidth() != 0 &&
            decoded->GetHeight() != 0)
        {
          float ratio = 1;

          if (argWidth != 0 &&
              argHeight != 0)
          {
            float ratioX = static_cast<float>(argWidth) / static_cast<float>(decoded->GetWidth());
            float ratioY = static_cast<float>(argHeight) / static_cast<float>(decoded->GetHeight());
            ratio = std::min(ratioX, ratioY);
          }
          else if (argWidth != 0)
          {
            ratio = static_cast<float>(argWidth) / static_cast<float>(decoded->GetWidth());
          }
          else if (argHeight != 0)
          {
            ratio = static_cast<float>(argHeight) / static_cast<float>(decoded->GetHeight());
          }
          
          targetWidth = boost::math::iround(ratio * static_cast<float>(decoded->GetWidth()));
          targetHeight = boost::math::iround(ratio * static_cast<float>(decoded->GetHeight()));
        }
        
        if (decoded->GetFormat() == PixelFormat_RGB24)
        {
          if (targetWidth == decoded->GetWidth() &&
              targetHeight == decoded->GetHeight())
          {
            DefaultHandler(call, decoded, ImageExtractionMode_Preview, false);
          }
          else
          {
            std::unique_ptr<ImageAccessor> resized(
              new Image(decoded->GetFormat(), targetWidth, targetHeight, false));
            
            if (smooth &&
                (targetWidth < decoded->GetWidth() ||
                 targetHeight < decoded->GetHeight()))
            {
              ImageProcessing::SmoothGaussian5x5(*decoded, false /* be fast, don't round */);
            }
            
            ImageProcessing::Resize(*resized, *decoded);
            DefaultHandler(call, resized, ImageExtractionMode_Preview, false);
          }
        }
        else
        {
          // Grayscale image: (1) convert to Float32, (2) apply
          // windowing to get a Grayscale8, (3) possibly resize

          Image converted(PixelFormat_Float32, decoded->GetWidth(), decoded->GetHeight(), false);
          ImageProcessing::Convert(converted, *decoded);

          // Avoid divisions by zero
          if (windowWidth <= 1.0f)
          {
            windowWidth = 1;
          }

          if (std::abs(rescaleSlope) <= 0.1f)
          {
            rescaleSlope = 0.1f;
          }

          const float scaling = 255.0f * rescaleSlope / windowWidth;
          const float offset = (rescaleIntercept - windowCenter + windowWidth / 2.0f) / rescaleSlope;

          std::unique_ptr<ImageAccessor> rescaled(new Image(PixelFormat_Grayscale8, decoded->GetWidth(), decoded->GetHeight(), false));
          ImageProcessing::ShiftScale(*rescaled, converted, offset, scaling, false);

          if (targetWidth == decoded->GetWidth() &&
              targetHeight == decoded->GetHeight())
          {
            DefaultHandler(call, rescaled, ImageExtractionMode_UInt8, invert);
          }
          else
          {
            std::unique_ptr<ImageAccessor> resized(
              new Image(PixelFormat_Grayscale8, targetWidth, targetHeight, false));
            
            if (smooth &&
                (targetWidth < decoded->GetWidth() ||
                 targetHeight < decoded->GetHeight()))
            {
              ImageProcessing::SmoothGaussian5x5(*rescaled, false /* be fast, don't round */);
            }
            
            ImageProcessing::Resize(*resized, *rescaled);
            DefaultHandler(call, resized, ImageExtractionMode_UInt8, invert);
          }
        }
      }

      virtual bool RequiresDicomTags() const ORTHANC_OVERRIDE
      {
        return true;
      }
    };
  }


  template <enum ImageExtractionMode mode>
  static void GetImage(RestApiGetCall& call)
  {
    Semaphore::Locker locker(throttlingSemaphore_);
        
    GetImageHandler handler(mode);
    IDecodedFrameHandler::Apply(call, handler, mode, false /* not rendered */);
  }


  static void GetRenderedFrame(RestApiGetCall& call)
  {
    Semaphore::Locker locker(throttlingSemaphore_);
        
    RenderedFrameHandler handler;
    IDecodedFrameHandler::Apply(call, handler, ImageExtractionMode_Preview /* arbitrary value */, true);
  }


  static void GetMatlabImage(RestApiGetCall& call)
  {
    Semaphore::Locker locker(throttlingSemaphore_);
        
    ServerContext& context = OrthancRestApi::GetContext(call);

    std::string frameId = call.GetUriComponent("frame", "0");

    unsigned int frame;
    try
    {
      frame = boost::lexical_cast<unsigned int>(frameId);
    }
    catch (boost::bad_lexical_cast&)
    {
      return;
    }

    std::string publicId = call.GetUriComponent("id", "");
    std::unique_ptr<ImageAccessor> decoded(context.DecodeDicomFrame(publicId, frame));

    if (decoded.get() == NULL)
    {
      throw OrthancException(ErrorCode_NotImplemented,
                             "Cannot decode DICOM instance with ID: " + publicId);
    }
    else
    {
      std::string result;
      decoded->ToMatlabString(result);
      call.GetOutput().AnswerBuffer(result, MimeType_PlainText);
    }
  }


  template <bool GzipCompression>
  static void GetRawFrame(RestApiGetCall& call)
  {
    if (call.IsDocumentation())
    {
      call.GetDocumentation()
        .SetTag("Instances")
        .SetSummary("Access raw frame" + std::string(GzipCompression ? " (compressed)" : ""))
        .SetDescription("Access the raw content of one individual frame of the DICOM instance of interest, "
                        "bypassing image decoding. This is notably useful to access the source files "
                        "in compressed transfer syntaxes." +
                        std::string(GzipCompression ? " The image is compressed using gzip" : ""))
        .SetUriArgument("frame", RestApiCallDocumentation::Type_Number, "Index of the frame (starts at `0`)");

      if (GzipCompression)
      {
        call.GetDocumentation().AddAnswerType(MimeType_Gzip, "The raw frame, compressed using gzip");
      }
      else
      {
        call.GetDocumentation().AddAnswerType(MimeType_Binary, "The raw frame");
      }
      return;
    }
    
    std::string frameId = call.GetUriComponent("frame", "0");

    unsigned int frame;
    try
    {
      frame = boost::lexical_cast<unsigned int>(frameId);
    }
    catch (boost::bad_lexical_cast&)
    {
      return;
    }

    std::string publicId = call.GetUriComponent("id", "");
    std::string raw;
    MimeType mime;

    {
      ServerContext::DicomCacheLocker locker(OrthancRestApi::GetContext(call), publicId);
      locker.GetDicom().GetRawFrame(raw, mime, frame);
    }

    if (GzipCompression)
    {
      GzipCompressor gzip;
      std::string compressed;
      gzip.Compress(compressed, raw.empty() ? NULL : raw.c_str(), raw.size());
      call.GetOutput().AnswerBuffer(compressed, MimeType_Gzip);
    }
    else
    {
      call.GetOutput().AnswerBuffer(raw, mime);
    }
  }


  static void GetResourceStatistics(RestApiGetCall& call)
  {
    static const uint64_t MEGA_BYTES = 1024 * 1024;

    std::string publicId = call.GetUriComponent("id", "");

    ResourceType type;
    uint64_t diskSize, uncompressedSize, dicomDiskSize, dicomUncompressedSize;
    unsigned int countStudies, countSeries, countInstances;
    OrthancRestApi::GetIndex(call).GetResourceStatistics(
      type, diskSize, uncompressedSize, countStudies, countSeries, 
      countInstances, dicomDiskSize, dicomUncompressedSize, publicId);

    Json::Value result = Json::objectValue;
    result["DiskSize"] = boost::lexical_cast<std::string>(diskSize);
    result["DiskSizeMB"] = static_cast<unsigned int>(diskSize / MEGA_BYTES);
    result["UncompressedSize"] = boost::lexical_cast<std::string>(uncompressedSize);
    result["UncompressedSizeMB"] = static_cast<unsigned int>(uncompressedSize / MEGA_BYTES);

    result["DicomDiskSize"] = boost::lexical_cast<std::string>(dicomDiskSize);
    result["DicomDiskSizeMB"] = static_cast<unsigned int>(dicomDiskSize / MEGA_BYTES);
    result["DicomUncompressedSize"] = boost::lexical_cast<std::string>(dicomUncompressedSize);
    result["DicomUncompressedSizeMB"] = static_cast<unsigned int>(dicomUncompressedSize / MEGA_BYTES);

    switch (type)
    {
      // Do NOT add "break" below this point!
      case ResourceType_Patient:
        result["CountStudies"] = countStudies;

      case ResourceType_Study:
        result["CountSeries"] = countSeries;

      case ResourceType_Series:
        result["CountInstances"] = countInstances;

      case ResourceType_Instance:
      default:
        break;
    }

    call.GetOutput().AnswerJson(result);
  }



  // Handling of metadata -----------------------------------------------------

  static void CheckValidResourceType(const RestApiCall& call)
  {
    const std::string resourceType = call.GetFullUri() [0];
    StringToResourceType(resourceType.c_str());
  }


  static void ListMetadata(RestApiGetCall& call)
  {
    CheckValidResourceType(call);
    
    std::string publicId = call.GetUriComponent("id", "");
    std::map<MetadataType, std::string> metadata;

    OrthancRestApi::GetIndex(call).GetAllMetadata(metadata, publicId);

    Json::Value result;

    if (call.HasArgument("expand"))
    {
      result = Json::objectValue;
      
      for (std::map<MetadataType, std::string>::const_iterator 
             it = metadata.begin(); it != metadata.end(); ++it)
      {
        std::string key = EnumerationToString(it->first);
        result[key] = it->second;
      }      
    }
    else
    {
      result = Json::arrayValue;
      
      for (std::map<MetadataType, std::string>::const_iterator 
             it = metadata.begin(); it != metadata.end(); ++it)
      {       
        result.append(EnumerationToString(it->first));
      }
    }

    call.GetOutput().AnswerJson(result);
  }


  static void GetMetadata(RestApiGetCall& call)
  {
    CheckValidResourceType(call);
    
    std::string publicId = call.GetUriComponent("id", "");
    std::string name = call.GetUriComponent("name", "");
    MetadataType metadata = StringToMetadata(name);

    std::string value;
    if (OrthancRestApi::GetIndex(call).LookupMetadata(value, publicId, metadata))
    {
      call.GetOutput().AnswerBuffer(value, MimeType_PlainText);
    }
  }


  static void DeleteMetadata(RestApiDeleteCall& call)
  {
    CheckValidResourceType(call);

    std::string publicId = call.GetUriComponent("id", "");
    std::string name = call.GetUriComponent("name", "");
    MetadataType metadata = StringToMetadata(name);

    if (IsUserMetadata(metadata))  // It is forbidden to modify internal metadata
    {      
      OrthancRestApi::GetIndex(call).DeleteMetadata(publicId, metadata);
      call.GetOutput().AnswerBuffer("", MimeType_PlainText);
    }
    else
    {
      call.GetOutput().SignalError(HttpStatus_403_Forbidden);
    }
  }


  static void SetMetadata(RestApiPutCall& call)
  {
    CheckValidResourceType(call);

    std::string publicId = call.GetUriComponent("id", "");
    std::string name = call.GetUriComponent("name", "");
    MetadataType metadata = StringToMetadata(name);

    std::string value;
    call.BodyToString(value);

    if (IsUserMetadata(metadata))  // It is forbidden to modify internal metadata
    {
      // It is forbidden to modify internal metadata
      OrthancRestApi::GetIndex(call).SetMetadata(publicId, metadata, value);
      call.GetOutput().AnswerBuffer("", MimeType_PlainText);
    }
    else
    {
      call.GetOutput().SignalError(HttpStatus_403_Forbidden);
    }
  }




  // Handling of attached files -----------------------------------------------

  static void ListAttachments(RestApiGetCall& call)
  {
    if (call.IsDocumentation())
    {
      ResourceType t = StringToResourceType(call.GetFullUri()[0].c_str());
      std::string r = GetResourceTypeText(t, false /* plural */, false /* upper case */);
      call.GetDocumentation()
        .SetTag(GetResourceTypeText(t, true /* plural */, true /* upper case */))
        .SetSummary("List attachments")
        .SetDescription("Get the list of attachments that are associated with the given " + r)
        .SetUriArgument("id", "Orthanc identifier of the " + r + " of interest")
        .AddAnswerType(MimeType_Json, "JSON array containing the names of the attachments")
        .SetHttpGetSample(GetDocumentationSampleResource(t) + "/attachments", true);
      return;
    }

    const std::string resourceType = call.GetFullUri() [0];
    const std::string publicId = call.GetUriComponent("id", "");
    std::list<FileContentType> attachments;
    OrthancRestApi::GetIndex(call).ListAvailableAttachments(attachments, publicId, StringToResourceType(resourceType.c_str()));

    Json::Value result = Json::arrayValue;

    for (std::list<FileContentType>::const_iterator 
           it = attachments.begin(); it != attachments.end(); ++it)
    {
      result.append(EnumerationToString(*it));
    }

    call.GetOutput().AnswerJson(result);
  }


  static bool GetAttachmentInfo(FileInfo& info, RestApiCall& call)
  {
    CheckValidResourceType(call);
 
    std::string publicId = call.GetUriComponent("id", "");
    std::string name = call.GetUriComponent("name", "");
    FileContentType contentType = StringToContentType(name);

    return OrthancRestApi::GetIndex(call).LookupAttachment(info, publicId, contentType);
  }


  static void GetAttachmentOperations(RestApiGetCall& call)
  {
    if (call.IsDocumentation())
    {
      ResourceType t = StringToResourceType(call.GetFullUri()[0].c_str());
      std::string r = GetResourceTypeText(t, false /* plural */, false /* upper case */);
      call.GetDocumentation()
        .SetTag("Other")
        .SetSummary("List of operations on attachments")
        .SetDescription("Get the list of operations that are available for attachments associated with the given " + r)
        .SetUriArgument("id", "Orthanc identifier of the " + r + " of interest")
        .SetUriArgument("name", "The name of the attachment")
        .AddAnswerType(MimeType_Json, "List of the available operations")
        .SetHttpGetSample("https://demo.orthanc-server.com/instances/d94d9a03-3003b047-a4affc69-322313b2-680530a2/attachments/dicom", true);
      return;
    }

    FileInfo info;
    if (GetAttachmentInfo(info, call))
    {
      Json::Value operations = Json::arrayValue;

      operations.append("compress");
      operations.append("compressed-data");

      if (info.GetCompressedMD5() != "")
      {
        operations.append("compressed-md5");
      }

      operations.append("compressed-size");
      operations.append("data");
      operations.append("is-compressed");

      if (info.GetUncompressedMD5() != "")
      {
        operations.append("md5");
      }

      operations.append("size");
      operations.append("uncompress");

      if (info.GetCompressedMD5() != "" &&
          info.GetUncompressedMD5() != "")
      {
        operations.append("verify-md5");
      }

      call.GetOutput().AnswerJson(operations);
    }
  }

  
  template <int uncompress>
  static void GetAttachmentData(RestApiGetCall& call)
  {
    if (call.IsDocumentation())
    {
      ResourceType t = StringToResourceType(call.GetFullUri()[0].c_str());
      std::string r = GetResourceTypeText(t, false /* plural */, false /* upper case */);
      call.GetDocumentation()
        .SetTag(GetResourceTypeText(t, true /* plural */, true /* upper case */))
        .SetSummary("Get attachment" + std::string(uncompress ? "" : " (no decompression)"))
        .SetDescription("Get the (binary) content of one attachment associated with the given " + r +
                        std::string(uncompress ? "" : ". The attachment will not be decompressed if `StorageCompression` if `true`."))
        .SetUriArgument("id", "Orthanc identifier of the " + r + " of interest")
        .SetUriArgument("name", "The name of the attachment")
        .AddAnswerType(MimeType_Binary, "The attachment");
      return;
    }

    ServerContext& context = OrthancRestApi::GetContext(call);

    CheckValidResourceType(call);
 
    std::string publicId = call.GetUriComponent("id", "");
    FileContentType type = StringToContentType(call.GetUriComponent("name", ""));

    if (uncompress)
    {
      context.AnswerAttachment(call.GetOutput(), publicId, type);
    }
    else
    {
      // Return the raw data (possibly compressed), as stored on the filesystem
      std::string content;
      context.ReadAttachment(content, publicId, type, false);
      call.GetOutput().AnswerBuffer(content, MimeType_Binary);
    }
  }


  static void GetAttachmentSize(RestApiGetCall& call)
  {
    if (call.IsDocumentation())
    {
      ResourceType t = StringToResourceType(call.GetFullUri()[0].c_str());
      std::string r = GetResourceTypeText(t, false /* plural */, false /* upper case */);
      call.GetDocumentation()
        .SetTag(GetResourceTypeText(t, true /* plural */, true /* upper case */))
        .SetSummary("Get size of attachment")
        .SetDescription("Get the size of one attachment associated with the given " + r)
        .SetUriArgument("id", "Orthanc identifier of the " + r + " of interest")
        .SetUriArgument("name", "The name of the attachment")
        .AddAnswerType(MimeType_PlainText, "The size of the attachment");
      return;
    }

    FileInfo info;
    if (GetAttachmentInfo(info, call))
    {
      call.GetOutput().AnswerBuffer(boost::lexical_cast<std::string>(info.GetUncompressedSize()), MimeType_PlainText);
    }
  }


  static void GetAttachmentCompressedSize(RestApiGetCall& call)
  {
    if (call.IsDocumentation())
    {
      ResourceType t = StringToResourceType(call.GetFullUri()[0].c_str());
      std::string r = GetResourceTypeText(t, false /* plural */, false /* upper case */);
      call.GetDocumentation()
        .SetTag(GetResourceTypeText(t, true /* plural */, true /* upper case */))
        .SetSummary("Get size of attachment on disk")
        .SetDescription("Get the size of one attachment associated with the given " + r + ", as stored on the disk. "
                        "This is different from `.../size` if `EnableStorage` is `true`.")
        .SetUriArgument("id", "Orthanc identifier of the " + r + " of interest")
        .SetUriArgument("name", "The name of the attachment")
        .AddAnswerType(MimeType_PlainText, "The size of the attachment, as stored on the disk");
      return;
    }

    FileInfo info;
    if (GetAttachmentInfo(info, call))
    {
      call.GetOutput().AnswerBuffer(boost::lexical_cast<std::string>(info.GetCompressedSize()), MimeType_PlainText);
    }
  }


  static void GetAttachmentMD5(RestApiGetCall& call)
  {
    if (call.IsDocumentation())
    {
      ResourceType t = StringToResourceType(call.GetFullUri()[0].c_str());
      std::string r = GetResourceTypeText(t, false /* plural */, false /* upper case */);
      call.GetDocumentation()
        .SetTag(GetResourceTypeText(t, true /* plural */, true /* upper case */))
        .SetSummary("Get MD5 of attachment")
        .SetDescription("Get the MD5 hash of one attachment associated with the given " + r)
        .SetUriArgument("id", "Orthanc identifier of the " + r + " of interest")
        .SetUriArgument("name", "The name of the attachment")
        .AddAnswerType(MimeType_PlainText, "The MD5 of the attachment");
      return;
    }

    FileInfo info;
    if (GetAttachmentInfo(info, call) &&
        info.GetUncompressedMD5() != "")
    {
      call.GetOutput().AnswerBuffer(boost::lexical_cast<std::string>(info.GetUncompressedMD5()), MimeType_PlainText);
    }
  }


  static void GetAttachmentCompressedMD5(RestApiGetCall& call)
  {
    if (call.IsDocumentation())
    {
      ResourceType t = StringToResourceType(call.GetFullUri()[0].c_str());
      std::string r = GetResourceTypeText(t, false /* plural */, false /* upper case */);
      call.GetDocumentation()
        .SetTag(GetResourceTypeText(t, true /* plural */, true /* upper case */))
        .SetSummary("Get MD5 of attachment on disk")
        .SetDescription("Get the MD5 hash of one attachment associated with the given " + r + ", as stored on the disk. "
                        "This is different from `.../md5` if `EnableStorage` is `true`.")
        .SetUriArgument("id", "Orthanc identifier of the " + r + " of interest")
        .SetUriArgument("name", "The name of the attachment")
        .AddAnswerType(MimeType_PlainText, "The MD5 of the attachment, as stored on the disk");
      return;
    }

    FileInfo info;
    if (GetAttachmentInfo(info, call) &&
        info.GetCompressedMD5() != "")
    {
      call.GetOutput().AnswerBuffer(boost::lexical_cast<std::string>(info.GetCompressedMD5()), MimeType_PlainText);
    }
  }


  static void VerifyAttachment(RestApiPostCall& call)
  {
    if (call.IsDocumentation())
    {
      ResourceType t = StringToResourceType(call.GetFullUri()[0].c_str());
      std::string r = GetResourceTypeText(t, false /* plural */, false /* upper case */);
      call.GetDocumentation()
        .SetTag(GetResourceTypeText(t, true /* plural */, true /* upper case */))
        .SetSummary("Verify attachment")
        .SetDescription("Verify that the attachment is not corrupted, by validating its MD5 hash")
        .SetUriArgument("id", "Orthanc identifier of the " + r + " of interest")
        .SetUriArgument("name", "The name of the attachment")
        .AddAnswerType(MimeType_Json, "On success, a valid JSON object is returned");
      return;
    }

    ServerContext& context = OrthancRestApi::GetContext(call);
    CheckValidResourceType(call);

    std::string publicId = call.GetUriComponent("id", "");
    std::string name = call.GetUriComponent("name", "");

    FileInfo info;
    if (!GetAttachmentInfo(info, call) ||
        info.GetCompressedMD5() == "" ||
        info.GetUncompressedMD5() == "")
    {
      // Inexistent resource, or no MD5 available
      return;
    }

    bool ok = false;

    // First check whether the compressed data is correctly stored in the disk
    std::string data;
    context.ReadAttachment(data, publicId, StringToContentType(name), false);

    std::string actualMD5;
    Toolbox::ComputeMD5(actualMD5, data);
    
    if (actualMD5 == info.GetCompressedMD5())
    {
      // The compressed data is OK. If a compression algorithm was
      // applied to it, now check the MD5 of the uncompressed data.
      if (info.GetCompressionType() == CompressionType_None)
      {
        ok = true;
      }
      else
      {
        context.ReadAttachment(data, publicId, StringToContentType(name), true);        
        Toolbox::ComputeMD5(actualMD5, data);
        ok = (actualMD5 == info.GetUncompressedMD5());
      }
    }

    if (ok)
    {
      CLOG(INFO, HTTP) << "The attachment " << name << " of resource " << publicId << " has the right MD5";
      call.GetOutput().AnswerBuffer("{}", MimeType_Json);
    }
    else
    {
      CLOG(INFO, HTTP) << "The attachment " << name << " of resource " << publicId << " has bad MD5!";
    }
  }


  static void UploadAttachment(RestApiPutCall& call)
  {
    ServerContext& context = OrthancRestApi::GetContext(call);
    CheckValidResourceType(call);
 
    std::string publicId = call.GetUriComponent("id", "");
    std::string name = call.GetUriComponent("name", "");

    FileContentType contentType = StringToContentType(name);
    if (IsUserContentType(contentType) &&  // It is forbidden to modify internal attachments
        context.AddAttachment(publicId, StringToContentType(name), call.GetBodyData(), call.GetBodySize()))
    {
      call.GetOutput().AnswerBuffer("{}", MimeType_Json);
    }
    else
    {
      call.GetOutput().SignalError(HttpStatus_403_Forbidden);
    }
  }


  static void DeleteAttachment(RestApiDeleteCall& call)
  {
    CheckValidResourceType(call);

    std::string publicId = call.GetUriComponent("id", "");
    std::string name = call.GetUriComponent("name", "");
    FileContentType contentType = StringToContentType(name);

    bool allowed;
    if (IsUserContentType(contentType))
    {
      allowed = true;
    }
    else
    {
      OrthancConfiguration::ReaderLock lock;

      if (lock.GetConfiguration().GetBooleanParameter("StoreDicom", true) &&
          contentType == FileContentType_DicomAsJson)
      {
        allowed = true;
      }
      else
      {
        // It is forbidden to delete internal attachments, except for
        // the "DICOM as JSON" summary as of Orthanc 1.2.0 (this summary
        // would be automatically reconstructed on the next GET call)
        allowed = false;
      }
    }

    if (allowed) 
    {
      OrthancRestApi::GetIndex(call).DeleteAttachment(publicId, contentType);
      call.GetOutput().AnswerBuffer("{}", MimeType_Json);
    }
    else
    {
      call.GetOutput().SignalError(HttpStatus_403_Forbidden);
    }
  }


  template <enum CompressionType compression>
  static void ChangeAttachmentCompression(RestApiPostCall& call)
  {
    CheckValidResourceType(call);

    std::string publicId = call.GetUriComponent("id", "");
    std::string name = call.GetUriComponent("name", "");
    FileContentType contentType = StringToContentType(name);

    OrthancRestApi::GetContext(call).ChangeAttachmentCompression(publicId, contentType, compression);
    call.GetOutput().AnswerBuffer("{}", MimeType_Json);
  }


  static void IsAttachmentCompressed(RestApiGetCall& call)
  {
    FileInfo info;
    if (GetAttachmentInfo(info, call))
    {
      std::string answer = (info.GetCompressionType() == CompressionType_None) ? "0" : "1";
      call.GetOutput().AnswerBuffer(answer, MimeType_PlainText);
    }
  }


  // Raw access to the DICOM tags of an instance ------------------------------

  static void GetRawContent(RestApiGetCall& call)
  {
    if (call.IsDocumentation())
    {
      call.GetDocumentation()
        .SetTag("Instances")
        .SetSummary("Get raw tag")
        .SetDescription("Get the raw content of one DICOM tag in the hierarchy of DICOM dataset")
        .SetUriArgument("id", "Orthanc identifier of the DICOM instance of interest")
        .SetUriArgument("...", "Path to the DICOM tag. This is the interleaving of one DICOM tag, possibly followed "
                        "by an index for sequences. Sequences are accessible as, for instance, `/0008-1140/1/0008-1150`")
        .AddAnswerType(MimeType_Binary, "The raw value of the tag of intereset "
                       "(binary data, whose memory layout depends on the underlying transfer syntax), "
                       "or JSON array containing the list of available tags if accessing a dataset");
      return;
    }

    std::string id = call.GetUriComponent("id", "");

    ServerContext::DicomCacheLocker locker(OrthancRestApi::GetContext(call), id);

    locker.GetDicom().SendPathValue(call.GetOutput(), call.GetTrailingUri());
  }



  static bool ExtractSharedTags(Json::Value& shared,
                                ServerContext& context,
                                const std::string& publicId)
  {
    // Retrieve all the instances of this patient/study/series
    typedef std::list<std::string> Instances;
    Instances instances;
    context.GetIndex().GetChildInstances(instances, publicId);  // (*)

    // Loop over the instances
    bool isFirst = true;
    shared = Json::objectValue;

    for (Instances::const_iterator it = instances.begin();
         it != instances.end(); ++it)
    {
      // Get the tags of the current instance, in the simplified format
      Json::Value tags;

      try
      {
        context.ReadDicomAsJson(tags, *it);
      }
      catch (OrthancException&)
      {
        // Race condition: This instance has been removed since
        // (*). Ignore this instance.
        continue;
      }

      if (tags.type() != Json::objectValue)
      {
        return false;   // Error
      }

      // Only keep the tags that are mapped to a string
      Json::Value::Members members = tags.getMemberNames();
      for (size_t i = 0; i < members.size(); i++)
      {
        const Json::Value& tag = tags[members[i]];
        if (tag.type() != Json::objectValue ||
            tag["Type"].type() != Json::stringValue ||
            tag["Type"].asString() != "String")
        {
          tags.removeMember(members[i]);
        }
      }

      if (isFirst)
      {
        // This is the first instance, keep its tags as such
        shared = tags;
        isFirst = false;
      }
      else
      {
        // Loop over all the members of the shared tags extracted so
        // far. If the value of one of these tags does not match its
        // value in the current instance, remove it.
        members = shared.getMemberNames();
        for (size_t i = 0; i < members.size(); i++)
        {
          if (!tags.isMember(members[i]) ||
              tags[members[i]]["Value"].asString() != shared[members[i]]["Value"].asString())
          {
            shared.removeMember(members[i]);
          }
        }
      }
    }

    return true;
  }


  static void GetSharedTags(RestApiGetCall& call)
  {
    ServerContext& context = OrthancRestApi::GetContext(call);
    std::string publicId = call.GetUriComponent("id", "");

    Json::Value sharedTags;
    if (ExtractSharedTags(sharedTags, context, publicId))
    {
      // Success: Send the value of the shared tags
      AnswerDicomAsJson(call, sharedTags);
    }
  }


  static void GetModuleInternal(RestApiGetCall& call,
                                ResourceType resourceType,
                                DicomModule module)
  {
    if (!((resourceType == ResourceType_Patient && module == DicomModule_Patient) ||
          (resourceType == ResourceType_Study && module == DicomModule_Patient) ||
          (resourceType == ResourceType_Study && module == DicomModule_Study) ||
          (resourceType == ResourceType_Series && module == DicomModule_Series) ||
          (resourceType == ResourceType_Instance && module == DicomModule_Instance) ||
          (resourceType == ResourceType_Instance && module == DicomModule_Image)))
    {
      throw OrthancException(ErrorCode_NotImplemented);
    }

    ServerContext& context = OrthancRestApi::GetContext(call);
    std::string publicId = call.GetUriComponent("id", "");

    std::set<DicomTag> ignoreTagLength;
    ParseSetOfTags(ignoreTagLength, call, "ignore-length");

    typedef std::set<DicomTag> ModuleTags;
    ModuleTags moduleTags;
    DicomTag::AddTagsForModule(moduleTags, module);

    Json::Value tags;

    if (resourceType != ResourceType_Instance)
    {
      // Retrieve all the instances of this patient/study/series
      typedef std::list<std::string> Instances;
      Instances instances;
      context.GetIndex().GetChildInstances(instances, publicId);

      if (instances.empty())
      {
        return;   // Error: No instance (should never happen)
      }

      // Select one child instance
      publicId = instances.front();
    }

    context.ReadDicomAsJson(tags, publicId, ignoreTagLength);
    
    // Filter the tags of the instance according to the module
    Json::Value result = Json::objectValue;
    for (ModuleTags::const_iterator tag = moduleTags.begin(); tag != moduleTags.end(); ++tag)
    {
      std::string s = tag->Format();
      if (tags.isMember(s))
      {
        result[s] = tags[s];
      }      
    }

    AnswerDicomAsJson(call, result);
  }
    


  template <enum ResourceType resourceType, 
            enum DicomModule module>
  static void GetModule(RestApiGetCall& call)
  {
    GetModuleInternal(call, resourceType, module);
  }


  namespace
  {
    typedef std::list< std::pair<ResourceType, std::string> >  LookupResults;
  }


  static void AccumulateLookupResults(LookupResults& result,
                                      ServerIndex& index,
                                      const DicomTag& tag,
                                      const std::string& value,
                                      ResourceType level)
  {
    std::vector<std::string> tmp;
    index.LookupIdentifierExact(tmp, level, tag, value);

    for (size_t i = 0; i < tmp.size(); i++)
    {
      result.push_back(std::make_pair(level, tmp[i]));
    }
  }


  static void Lookup(RestApiPostCall& call)
  {
    std::string tag;
    call.BodyToString(tag);

    LookupResults resources;
    ServerIndex& index = OrthancRestApi::GetIndex(call);
    AccumulateLookupResults(resources, index, DICOM_TAG_PATIENT_ID, tag, ResourceType_Patient);
    AccumulateLookupResults(resources, index, DICOM_TAG_STUDY_INSTANCE_UID, tag, ResourceType_Study);
    AccumulateLookupResults(resources, index, DICOM_TAG_SERIES_INSTANCE_UID, tag, ResourceType_Series);
    AccumulateLookupResults(resources, index, DICOM_TAG_SOP_INSTANCE_UID, tag, ResourceType_Instance);

    Json::Value result = Json::arrayValue;    
    for (LookupResults::const_iterator 
           it = resources.begin(); it != resources.end(); ++it)
    {     
      ResourceType type = it->first;
      const std::string& id = it->second;
      
      Json::Value item = Json::objectValue;
      item["Type"] = EnumerationToString(type);
      item["ID"] = id;
      item["Path"] = GetBasePath(type, id);
    
      result.append(item);
    }

    call.GetOutput().AnswerJson(result);
  }


  namespace 
  {
    class FindVisitor : public ServerContext::ILookupVisitor
    {
    private:
      bool                    isComplete_;
      std::list<std::string>  resources_;

    public:
      FindVisitor() :
        isComplete_(false)
      {
      }
      
      virtual bool IsDicomAsJsonNeeded() const ORTHANC_OVERRIDE
      {
        return false;   // (*)
      }
      
      virtual void MarkAsComplete() ORTHANC_OVERRIDE
      {
        isComplete_ = true;  // Unused information as of Orthanc 1.5.0
      }

      virtual void Visit(const std::string& publicId,
                         const std::string& instanceId   /* unused     */,
                         const DicomMap& mainDicomTags   /* unused     */,
                         const Json::Value* dicomAsJson  /* unused (*) */)  ORTHANC_OVERRIDE
      {
        resources_.push_back(publicId);
      }

      void Answer(RestApiOutput& output,
                  ServerIndex& index,
                  ResourceType level,
                  bool expand) const
      {
        AnswerListOfResources(output, index, resources_, level, expand);
      }
    };
  }


  static void Find(RestApiPostCall& call)
  {
    static const char* const KEY_CASE_SENSITIVE = "CaseSensitive";
    static const char* const KEY_EXPAND = "Expand";
    static const char* const KEY_LEVEL = "Level";
    static const char* const KEY_LIMIT = "Limit";
    static const char* const KEY_QUERY = "Query";
    static const char* const KEY_SINCE = "Since";

    ServerContext& context = OrthancRestApi::GetContext(call);

    Json::Value request;
    if (!call.ParseJsonRequest(request) ||
        request.type() != Json::objectValue)
    {
      throw OrthancException(ErrorCode_BadRequest, 
                             "The body must contain a JSON object");
    }
    else if (!request.isMember(KEY_LEVEL) ||
             request[KEY_LEVEL].type() != Json::stringValue)
    {
      throw OrthancException(ErrorCode_BadRequest, 
                             "Field \"" + std::string(KEY_LEVEL) + "\" is missing, or should be a string");
    }
    else if (!request.isMember(KEY_QUERY) &&
             request[KEY_QUERY].type() != Json::objectValue)
    {
      throw OrthancException(ErrorCode_BadRequest, 
                             "Field \"" + std::string(KEY_QUERY) + "\" is missing, or should be a JSON object");
    }
    else if (request.isMember(KEY_CASE_SENSITIVE) && 
             request[KEY_CASE_SENSITIVE].type() != Json::booleanValue)
    {
      throw OrthancException(ErrorCode_BadRequest, 
                             "Field \"" + std::string(KEY_CASE_SENSITIVE) + "\" should be a Boolean");
    }
    else if (request.isMember(KEY_LIMIT) && 
             request[KEY_LIMIT].type() != Json::intValue)
    {
      throw OrthancException(ErrorCode_BadRequest, 
                             "Field \"" + std::string(KEY_LIMIT) + "\" should be an integer");
    }
    else if (request.isMember(KEY_SINCE) &&
             request[KEY_SINCE].type() != Json::intValue)
    {
      throw OrthancException(ErrorCode_BadRequest, 
                             "Field \"" + std::string(KEY_SINCE) + "\" should be an integer");
    }
    else
    {
      bool expand = false;
      if (request.isMember(KEY_EXPAND))
      {
        expand = request[KEY_EXPAND].asBool();
      }

      bool caseSensitive = false;
      if (request.isMember(KEY_CASE_SENSITIVE))
      {
        caseSensitive = request[KEY_CASE_SENSITIVE].asBool();
      }

      size_t limit = 0;
      if (request.isMember(KEY_LIMIT))
      {
        int tmp = request[KEY_LIMIT].asInt();
        if (tmp < 0)
        {
          throw OrthancException(ErrorCode_ParameterOutOfRange,
                                 "Field \"" + std::string(KEY_LIMIT) + "\" should be a positive integer");
        }

        limit = static_cast<size_t>(tmp);
      }

      size_t since = 0;
      if (request.isMember(KEY_SINCE))
      {
        int tmp = request[KEY_SINCE].asInt();
        if (tmp < 0)
        {
          throw OrthancException(ErrorCode_ParameterOutOfRange,
                                 "Field \"" + std::string(KEY_SINCE) + "\" should be a positive integer");
        }

        since = static_cast<size_t>(tmp);
      }

      ResourceType level = StringToResourceType(request[KEY_LEVEL].asCString());

      DatabaseLookup query;

      Json::Value::Members members = request[KEY_QUERY].getMemberNames();
      for (size_t i = 0; i < members.size(); i++)
      {
        if (request[KEY_QUERY][members[i]].type() != Json::stringValue)
        {
          throw OrthancException(ErrorCode_BadRequest,
                                 "Tag \"" + members[i] + "\" should be associated with a string");
        }

        const std::string value = request[KEY_QUERY][members[i]].asString();

        if (!value.empty())
        {
          // An empty string corresponds to an universal constraint,
          // so we ignore it. This mimics the behavior of class
          // "OrthancFindRequestHandler"
          query.AddRestConstraint(FromDcmtkBridge::ParseTag(members[i]), 
                                  value, caseSensitive, true);
        }
      }

      FindVisitor visitor;
      context.Apply(visitor, query, level, since, limit);
      visitor.Answer(call.GetOutput(), context.GetIndex(), level, expand);
    }
  }


  template <enum ResourceType start, 
            enum ResourceType end>
  static void GetChildResources(RestApiGetCall& call)
  {
    ServerIndex& index = OrthancRestApi::GetIndex(call);

    std::list<std::string> a, b, c;
    a.push_back(call.GetUriComponent("id", ""));

    ResourceType type = start;
    while (type != end)
    {
      b.clear();

      for (std::list<std::string>::const_iterator
             it = a.begin(); it != a.end(); ++it)
      {
        index.GetChildren(c, *it);
        b.splice(b.begin(), c);
      }

      type = GetChildResourceType(type);

      a.clear();
      a.splice(a.begin(), b);
    }

    Json::Value result = Json::arrayValue;

    for (std::list<std::string>::const_iterator
           it = a.begin(); it != a.end(); ++it)
    {
      Json::Value item;

      if (OrthancRestApi::GetIndex(call).LookupResource(item, *it, end))
      {
        result.append(item);
      }
    }

    call.GetOutput().AnswerJson(result);
  }


  static void GetChildInstancesTags(RestApiGetCall& call)
  {
    ServerContext& context = OrthancRestApi::GetContext(call);
    std::string publicId = call.GetUriComponent("id", "");
    DicomToJsonFormat format = GetDicomFormat(call);

    std::set<DicomTag> ignoreTagLength;
    ParseSetOfTags(ignoreTagLength, call, "ignore-length");

    // Retrieve all the instances of this patient/study/series
    typedef std::list<std::string> Instances;
    Instances instances;

    context.GetIndex().GetChildInstances(instances, publicId);  // (*)

    Json::Value result = Json::objectValue;

    for (Instances::const_iterator it = instances.begin();
         it != instances.end(); ++it)
    {
      Json::Value full;
      context.ReadDicomAsJson(full, *it, ignoreTagLength);

      if (format != DicomToJsonFormat_Full)
      {
        Json::Value simplified;
        Toolbox::SimplifyDicomAsJson(simplified, full, format);
        result[*it] = simplified;
      }
      else
      {
        result[*it] = full;
      }
    }
    
    call.GetOutput().AnswerJson(result);
  }



  template <enum ResourceType start, 
            enum ResourceType end>
  static void GetParentResource(RestApiGetCall& call)
  {
    assert(start > end);

    ServerIndex& index = OrthancRestApi::GetIndex(call);
    
    std::string current = call.GetUriComponent("id", "");
    ResourceType currentType = start;
    while (currentType > end)
    {
      std::string parent;
      if (!index.LookupParent(parent, current))
      {
        // Error that could happen if the resource gets deleted by
        // another concurrent call
        return;
      }
      
      current = parent;
      currentType = GetParentResourceType(currentType);
    }

    assert(currentType == end);

    Json::Value result;
    if (index.LookupResource(result, current, end))
    {
      call.GetOutput().AnswerJson(result);
    }
  }


  static void ExtractPdf(RestApiGetCall& call)
  {
    if (call.IsDocumentation())
    {
      call.GetDocumentation()
        .SetTag("Instances")
        .SetSummary("Get embedded PDF")
        .SetDescription("Get the PDF file that is embedded in one DICOM instance. "
                        "If the DICOM instance doesn't contain the `EncapsulatedDocument` tag or if the "
                        "`MIMETypeOfEncapsulatedDocument` tag doesn't correspond to the PDF type, a `404` HTTP error is raised.")
        .SetUriArgument("id", "Orthanc identifier of the instance interest")
        .AddAnswerType(MimeType_Pdf, "PDF file");
      return;
    }

    const std::string id = call.GetUriComponent("id", "");
    std::string pdf;
    ServerContext::DicomCacheLocker locker(OrthancRestApi::GetContext(call), id);

    if (locker.GetDicom().ExtractPdf(pdf))
    {
      call.GetOutput().AnswerBuffer(pdf, MimeType_Pdf);
      return;
    }
  }


  static void OrderSlices(RestApiGetCall& call)
  {
    const std::string id = call.GetUriComponent("id", "");

    ServerIndex& index = OrthancRestApi::GetIndex(call);
    SliceOrdering ordering(index, id);

    Json::Value result;
    ordering.Format(result);
    call.GetOutput().AnswerJson(result);
  }


  static void GetInstanceHeader(RestApiGetCall& call)
  {
    if (call.IsDocumentation())
    {
      call.GetDocumentation()
        .SetTag("Instances")
        .SetSummary("Get DICOM meta-header")
        .SetDescription("Get the DICOM tags in the meta-header of the DICOM instance. By default, the `full` format is used, which "
                        "combines hexadecimal tags with human-readable description.")
        .SetUriArgument("id", "Orthanc identifier of the DICOM instance of interest")
        .SetHttpGetArgument("simplify", RestApiCallDocumentation::Type_String,
                            "If present, report the DICOM tags in human-readable format", false)
        .SetHttpGetArgument("short", RestApiCallDocumentation::Type_String,
                            "If present, report the DICOM tags indexed in hexadecimal format", false)
        .AddAnswerType(MimeType_Json, "JSON object containing the DICOM tags and their associated value")
        .SetHttpGetSample("https://demo.orthanc-server.com/instances/7c92ce8e-bbf67ed2-ffa3b8c1-a3b35d94-7ff3ae26/header", true);
      return;
    }

    ServerContext& context = OrthancRestApi::GetContext(call);

    std::string publicId = call.GetUriComponent("id", "");

    std::string dicomContent;
    context.ReadDicom(dicomContent, publicId);

    // TODO Consider using "DicomMap::ParseDicomMetaInformation()" to
    // speed up things here

    ParsedDicomFile dicom(dicomContent);

    Json::Value header;
    OrthancConfiguration::DefaultDicomHeaderToJson(header, dicom);

    AnswerDicomAsJson(call, header);
  }


  static void InvalidateTags(RestApiPostCall& call)
  {
    ServerIndex& index = OrthancRestApi::GetIndex(call);
    
    // Loop over the instances, grouping them by parent studies so as
    // to avoid large memory consumption
    std::list<std::string> studies;
    index.GetAllUuids(studies, ResourceType_Study);

    for (std::list<std::string>::const_iterator 
           study = studies.begin(); study != studies.end(); ++study)
    {
      std::list<std::string> instances;
      index.GetChildInstances(instances, *study);

      for (std::list<std::string>::const_iterator 
             instance = instances.begin(); instance != instances.end(); ++instance)
      {
        index.DeleteAttachment(*instance, FileContentType_DicomAsJson);
      }
    }

    call.GetOutput().AnswerBuffer("", MimeType_PlainText);
  }


  template <enum ResourceType type>
  static void ReconstructResource(RestApiPostCall& call)
  {
    ServerContext& context = OrthancRestApi::GetContext(call);
    ServerToolbox::ReconstructResource(context, call.GetUriComponent("id", ""));
    call.GetOutput().AnswerBuffer("", MimeType_PlainText);
  }


  static void ReconstructAllResources(RestApiPostCall& call)
  {
    ServerContext& context = OrthancRestApi::GetContext(call);

    std::list<std::string> studies;
    context.GetIndex().GetAllUuids(studies, ResourceType_Study);

    for (std::list<std::string>::const_iterator 
           study = studies.begin(); study != studies.end(); ++study)
    {
      ServerToolbox::ReconstructResource(context, *study);
    }
    
    call.GetOutput().AnswerBuffer("", MimeType_PlainText);
  }


  void OrthancRestApi::RegisterResources()
  {
    Register("/instances", ListResources<ResourceType_Instance>);
    Register("/patients", ListResources<ResourceType_Patient>);
    Register("/series", ListResources<ResourceType_Series>);
    Register("/studies", ListResources<ResourceType_Study>);

    Register("/instances/{id}", DeleteSingleResource<ResourceType_Instance>);
    Register("/instances/{id}", GetSingleResource<ResourceType_Instance>);
    Register("/patients/{id}", DeleteSingleResource<ResourceType_Patient>);
    Register("/patients/{id}", GetSingleResource<ResourceType_Patient>);
    Register("/series/{id}", DeleteSingleResource<ResourceType_Series>);
    Register("/series/{id}", GetSingleResource<ResourceType_Series>);
    Register("/studies/{id}", DeleteSingleResource<ResourceType_Study>);
    Register("/studies/{id}", GetSingleResource<ResourceType_Study>);

    Register("/instances/{id}/statistics", GetResourceStatistics);
    Register("/patients/{id}/statistics", GetResourceStatistics);
    Register("/studies/{id}/statistics", GetResourceStatistics);
    Register("/series/{id}/statistics", GetResourceStatistics);

    Register("/patients/{id}/shared-tags", GetSharedTags);
    Register("/series/{id}/shared-tags", GetSharedTags);
    Register("/studies/{id}/shared-tags", GetSharedTags);

    Register("/instances/{id}/module", GetModule<ResourceType_Instance, DicomModule_Instance>);
    Register("/patients/{id}/module", GetModule<ResourceType_Patient, DicomModule_Patient>);
    Register("/series/{id}/module", GetModule<ResourceType_Series, DicomModule_Series>);
    Register("/studies/{id}/module", GetModule<ResourceType_Study, DicomModule_Study>);
    Register("/studies/{id}/module-patient", GetModule<ResourceType_Study, DicomModule_Patient>);

    Register("/instances/{id}/file", GetInstanceFile);
    Register("/instances/{id}/export", ExportInstanceFile);
    Register("/instances/{id}/tags", GetInstanceTagsBis);
    Register("/instances/{id}/simplified-tags", GetInstanceTags<DicomToJsonFormat_Human>);
    Register("/instances/{id}/frames", ListFrames);

    Register("/instances/{id}/frames/{frame}/preview", GetImage<ImageExtractionMode_Preview>);
    Register("/instances/{id}/frames/{frame}/rendered", GetRenderedFrame);
    Register("/instances/{id}/frames/{frame}/image-uint8", GetImage<ImageExtractionMode_UInt8>);
    Register("/instances/{id}/frames/{frame}/image-uint16", GetImage<ImageExtractionMode_UInt16>);
    Register("/instances/{id}/frames/{frame}/image-int16", GetImage<ImageExtractionMode_Int16>);
    Register("/instances/{id}/frames/{frame}/matlab", GetMatlabImage);
    Register("/instances/{id}/frames/{frame}/raw", GetRawFrame<false>);
    Register("/instances/{id}/frames/{frame}/raw.gz", GetRawFrame<true>);
    Register("/instances/{id}/pdf", ExtractPdf);
    Register("/instances/{id}/preview", GetImage<ImageExtractionMode_Preview>);
    Register("/instances/{id}/rendered", GetRenderedFrame);
    Register("/instances/{id}/image-uint8", GetImage<ImageExtractionMode_UInt8>);
    Register("/instances/{id}/image-uint16", GetImage<ImageExtractionMode_UInt16>);
    Register("/instances/{id}/image-int16", GetImage<ImageExtractionMode_Int16>);
    Register("/instances/{id}/matlab", GetMatlabImage);
    Register("/instances/{id}/header", GetInstanceHeader);

    Register("/patients/{id}/protected", IsProtectedPatient);
    Register("/patients/{id}/protected", SetPatientProtection);

    std::vector<std::string> resourceTypes;
    resourceTypes.push_back("patients");
    resourceTypes.push_back("studies");
    resourceTypes.push_back("series");
    resourceTypes.push_back("instances");

    for (size_t i = 0; i < resourceTypes.size(); i++)
    {
      Register("/" + resourceTypes[i] + "/{id}/metadata", ListMetadata);
      Register("/" + resourceTypes[i] + "/{id}/metadata/{name}", DeleteMetadata);
      Register("/" + resourceTypes[i] + "/{id}/metadata/{name}", GetMetadata);
      Register("/" + resourceTypes[i] + "/{id}/metadata/{name}", SetMetadata);

      Register("/" + resourceTypes[i] + "/{id}/attachments", ListAttachments);
      Register("/" + resourceTypes[i] + "/{id}/attachments/{name}", DeleteAttachment);
      Register("/" + resourceTypes[i] + "/{id}/attachments/{name}", GetAttachmentOperations);
      Register("/" + resourceTypes[i] + "/{id}/attachments/{name}", UploadAttachment);
      Register("/" + resourceTypes[i] + "/{id}/attachments/{name}/compress", ChangeAttachmentCompression<CompressionType_ZlibWithSize>);
      Register("/" + resourceTypes[i] + "/{id}/attachments/{name}/compressed-data", GetAttachmentData<0>);
      Register("/" + resourceTypes[i] + "/{id}/attachments/{name}/compressed-md5", GetAttachmentCompressedMD5);
      Register("/" + resourceTypes[i] + "/{id}/attachments/{name}/compressed-size", GetAttachmentCompressedSize);
      Register("/" + resourceTypes[i] + "/{id}/attachments/{name}/data", GetAttachmentData<1>);
      Register("/" + resourceTypes[i] + "/{id}/attachments/{name}/is-compressed", IsAttachmentCompressed);
      Register("/" + resourceTypes[i] + "/{id}/attachments/{name}/md5", GetAttachmentMD5);
      Register("/" + resourceTypes[i] + "/{id}/attachments/{name}/size", GetAttachmentSize);
      Register("/" + resourceTypes[i] + "/{id}/attachments/{name}/uncompress", ChangeAttachmentCompression<CompressionType_None>);
      Register("/" + resourceTypes[i] + "/{id}/attachments/{name}/verify-md5", VerifyAttachment);
    }

    Register("/tools/invalidate-tags", InvalidateTags);
    Register("/tools/lookup", Lookup);
    Register("/tools/find", Find);

    Register("/patients/{id}/studies", GetChildResources<ResourceType_Patient, ResourceType_Study>);
    Register("/patients/{id}/series", GetChildResources<ResourceType_Patient, ResourceType_Series>);
    Register("/patients/{id}/instances", GetChildResources<ResourceType_Patient, ResourceType_Instance>);
    Register("/studies/{id}/series", GetChildResources<ResourceType_Study, ResourceType_Series>);
    Register("/studies/{id}/instances", GetChildResources<ResourceType_Study, ResourceType_Instance>);
    Register("/series/{id}/instances", GetChildResources<ResourceType_Series, ResourceType_Instance>);

    Register("/studies/{id}/patient", GetParentResource<ResourceType_Study, ResourceType_Patient>);
    Register("/series/{id}/patient", GetParentResource<ResourceType_Series, ResourceType_Patient>);
    Register("/series/{id}/study", GetParentResource<ResourceType_Series, ResourceType_Study>);
    Register("/instances/{id}/patient", GetParentResource<ResourceType_Instance, ResourceType_Patient>);
    Register("/instances/{id}/study", GetParentResource<ResourceType_Instance, ResourceType_Study>);
    Register("/instances/{id}/series", GetParentResource<ResourceType_Instance, ResourceType_Series>);

    Register("/patients/{id}/instances-tags", GetChildInstancesTags);
    Register("/studies/{id}/instances-tags", GetChildInstancesTags);
    Register("/series/{id}/instances-tags", GetChildInstancesTags);

    Register("/instances/{id}/content/*", GetRawContent);

    Register("/series/{id}/ordered-slices", OrderSlices);

    Register("/patients/{id}/reconstruct", ReconstructResource<ResourceType_Patient>);
    Register("/studies/{id}/reconstruct", ReconstructResource<ResourceType_Study>);
    Register("/series/{id}/reconstruct", ReconstructResource<ResourceType_Series>);
    Register("/instances/{id}/reconstruct", ReconstructResource<ResourceType_Instance>);
    Register("/tools/reconstruct", ReconstructAllResources);
  }
}