/**
 * Orthanc - A Lightweight, RESTful DICOM Store
 * Copyright (C) 2012-2016 Sebastien Jodogne, Medical Physics
 * Department, University Hospital of Liege, Belgium
 * Copyright (C) 2017-2023 Osimis S.A., Belgium
 * Copyright (C) 2024-2024 Orthanc Team SRL, Belgium
 * Copyright (C) 2021-2024 Sebastien Jodogne, ICTEAM UCLouvain, 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.
 * 
 * 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 "../ServerContext.h"

namespace Orthanc
{
  // Changes API --------------------------------------------------------------
  static const unsigned int DEFAULT_LIMIT = 100;
  static const int64_t DEFAULT_TO = -1;
 
  static void GetSinceToAndLimit(int64_t& since,
                                 int64_t& to,
                                 unsigned int& limit,
                                 bool& last,
                                 const RestApiGetCall& call)
  {
    if (call.HasArgument("last"))
    {
      last = true;
      return;
    }

    last = false;

    try
    {
      since = boost::lexical_cast<int64_t>(call.GetArgument("since", "0"));
      to = boost::lexical_cast<int64_t>(call.GetArgument("to", boost::lexical_cast<std::string>(DEFAULT_TO)));
      limit = boost::lexical_cast<unsigned int>(call.GetArgument("limit", boost::lexical_cast<std::string>(DEFAULT_LIMIT)));
    }
    catch (boost::bad_lexical_cast&)
    {
      since = 0;
      to = DEFAULT_TO;
      limit = DEFAULT_LIMIT;
      return;
    }
  }

  static void GetChanges(RestApiGetCall& call)
  {
    if (call.IsDocumentation())
    {
      call.GetDocumentation()
        .SetTag("Tracking changes")
        .SetSummary("List changes")
        .SetDescription("Whenever Orthanc receives a new DICOM instance, this event is recorded in the so-called _Changes Log_. This enables remote scripts to react to the arrival of new DICOM resources. A typical application is auto-routing, where an external script waits for a new DICOM instance to arrive into Orthanc, then forward this instance to another modality.")
        .SetHttpGetArgument("last", RestApiCallDocumentation::Type_Number, "Request only the last change id (this argument must be used alone)", false)
        .SetHttpGetArgument("limit", RestApiCallDocumentation::Type_Number, "Limit the number of results", false)
        .SetHttpGetArgument("since", RestApiCallDocumentation::Type_Number, "Show only the resources since the provided index excluded", false)
        .SetHttpGetArgument("to", RestApiCallDocumentation::Type_Number, "Show only the resources till the provided index included (only available if your DB backend supports ExtendedChanges)", false)
        .SetHttpGetArgument("type", RestApiCallDocumentation::Type_String, "Show only the changes of the provided type (only available if your DB backend supports ExtendedChanges)", false)
        .AddAnswerType(MimeType_Json, "The list of changes")
        .SetAnswerField("Changes", RestApiCallDocumentation::Type_JsonListOfObjects, "The individual changes")
        .SetAnswerField("Done", RestApiCallDocumentation::Type_Boolean,
                        "Whether the last reported change is the last of the full history.")
        .SetAnswerField("Last", RestApiCallDocumentation::Type_Number,
                        "The index of the last reported change, can be used for the `since` argument in subsequent calls to this route")
        .SetAnswerField("First", RestApiCallDocumentation::Type_Number,
                        "The index of the first reported change, its value-1 can be used for the `to` argument in subsequent calls to this route when browsing the changes in reverse order")
        .SetHttpGetSample("https://orthanc.uclouvain.be/demo/changes?since=0&limit=2", true);
      return;
    }
    
    ServerContext& context = OrthancRestApi::GetContext(call);

    int64_t since, to;
    ChangeType filterType = ChangeType_INTERNAL_All;

    unsigned int limit;
    bool last;
    GetSinceToAndLimit(since, to, limit, last, call);

    std::string filterArgument = call.GetArgument("type", "all");
    if (filterArgument != "all" && filterArgument != "All")
    {
      filterType = StringToChangeType(filterArgument);
    }

    Json::Value result;
    if (last)
    {
      context.GetIndex().GetLastChange(result);
    }
    else if (context.GetIndex().HasExtendedChanges())
    {
      context.GetIndex().GetChangesExtended(result, since, to, limit, filterType);
    }
    else
    {
      if (filterType != ChangeType_INTERNAL_All)
      {
        throw OrthancException(ErrorCode_ParameterOutOfRange, "CAPABILITIES: Trying to filter changes while the Database backend does not support it (requires a DB backend with support for ExtendedChanges)");
      }

      if (to != DEFAULT_TO)
      {
        throw OrthancException(ErrorCode_ParameterOutOfRange, "CAPABILITIES: Trying to use the 'to' parameter in /changes while the Database backend does not support it (requires a DB backend with support for ExtendedChanges)");
      }

      context.GetIndex().GetChanges(result, since, limit);
    }

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


  static void DeleteChanges(RestApiDeleteCall& call)
  {
    if (call.IsDocumentation())
    {
      call.GetDocumentation()
        .SetTag("Tracking changes")
        .SetSummary("Clear changes")
        .SetDescription("Clear the full history stored in the changes log");
      return;
    }

    OrthancRestApi::GetIndex(call).DeleteChanges();
    call.GetOutput().AnswerBuffer("", MimeType_PlainText);
  }


  // Exports API --------------------------------------------------------------
 
  static void GetExports(RestApiGetCall& call)
  {
    if (call.IsDocumentation())
    {
      call.GetDocumentation()
        .SetTag("Tracking changes")
        .SetSummary("List exports")
        .SetDescription("For medical traceability, Orthanc can be configured to store a log of all the resources "
                        "that have been exported to remote modalities. In auto-routing scenarios, it is important "
                        "to prevent this log to grow indefinitely as incoming instances are routed. You can either "
                        "disable this logging by setting the option `LogExportedResources` to `false` in the "
                        "configuration file, or periodically clear this log by `DELETE`-ing this URI. This route "
                        "might be removed in future versions of Orthanc.")
        .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)
        .AddAnswerType(MimeType_Json, "The list of exports");
      return;
    }

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

    int64_t since, to;
    unsigned int limit;
    bool last;
    GetSinceToAndLimit(since, to, limit, last, call);

    Json::Value result;
    if (last)
    {
      context.GetIndex().GetLastExportedResource(result);
    }
    else
    {
      context.GetIndex().GetExportedResources(result, since, limit);
    }

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


  static void DeleteExports(RestApiDeleteCall& call)
  {
    if (call.IsDocumentation())
    {
      call.GetDocumentation()
        .SetTag("Tracking changes")
        .SetSummary("Clear exports")
        .SetDescription("Clear the full history stored in the exports log");
      return;
    }

    OrthancRestApi::GetIndex(call).DeleteExportedResources();
    call.GetOutput().AnswerBuffer("", MimeType_PlainText);
  }
  

  void OrthancRestApi::RegisterChanges()
  {
    Register("/changes", GetChanges);
    Register("/changes", DeleteChanges);
    Register("/exports", GetExports);
    Register("/exports", DeleteExports);
  }
}