/**
 * Cloud storage plugins for Orthanc
 * Copyright (C) 2020-2021 Osimis S.A., Belgium
 *
 * This program is free software: you can redistribute it and/or
 * modify it under the terms of the GNU Affero General Public License
 * as published by the Free Software Foundation, either version 3 of
 * the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 **/

#if GOOGLE_STORAGE_PLUGIN==1
#include "../Google/GoogleStoragePlugin.h"
#define StoragePluginFactory GoogleStoragePluginFactory
#elif AZURE_STORAGE_PLUGIN==1
#include "../Azure/AzureBlobStoragePlugin.h"
#define StoragePluginFactory AzureBlobStoragePluginFactory
#elif AWS_STORAGE_PLUGIN==1
#include "../Aws/AwsS3StoragePlugin.h"
#define StoragePluginFactory AwsS3StoragePluginFactory
#else
#pragma message(error  "define a plugin")
#endif

#include <string.h>
#include <stdio.h>
#include <string>

#include <iostream>
#include <boost/filesystem.hpp>
#include <boost/filesystem/fstream.hpp>

#include "../Common/EncryptionHelpers.h"
#include "../Common/EncryptionConfigurator.h"

#include <Logging.h>
#include <SystemToolbox.h>

static std::unique_ptr<IStoragePlugin> plugin;

static std::unique_ptr<EncryptionHelpers> crypto;
static bool cryptoEnabled = false;
static std::string fileSystemRootPath;
static bool migrationFromFileSystemEnabled = false;
static std::string objectsRootPath;


static OrthancPluginErrorCode StorageCreate(const char* uuid,
                                            const void* content,
                                            int64_t size,
                                            OrthancPluginContentType type)
{
  try
  {
    std::unique_ptr<IStoragePlugin::IWriter> writer(plugin->GetWriterForObject(uuid, type, cryptoEnabled));

    if (cryptoEnabled)
    {
      std::string encryptedFile;

      try
      {
        crypto->Encrypt(encryptedFile, (const char*)content, size);
      }
      catch (EncryptionException& ex)
      {
        OrthancPlugins::LogError(std::string(StoragePluginFactory::GetStoragePluginName()) + ": error while encrypting object " + std::string(uuid) + ": " + ex.what());
        return OrthancPluginErrorCode_StorageAreaPlugin;
      }

      writer->Write(encryptedFile.data(), encryptedFile.size());
    }
    else
    {
      writer->Write(reinterpret_cast<const char*>(content), size);
    }
  }
  catch (StoragePluginException& ex)
  {
    OrthancPlugins::LogError(std::string(StoragePluginFactory::GetStoragePluginName()) + ": error while creating object " + std::string(uuid) + ": " + ex.what());
    return OrthancPluginErrorCode_StorageAreaPlugin;
  }

  return OrthancPluginErrorCode_Success;
}


static OrthancPluginErrorCode StorageReadRange(OrthancPluginMemoryBuffer64* target, // Memory buffer where to store the content of the range.  The memory buffer is allocated and freed by Orthanc. The length of the range of interest corresponds to the size of this buffer.
                                               const char* uuid,
                                               OrthancPluginContentType type,
                                               uint64_t rangeStart)
{
  assert(!cryptoEnabled);

  try
  {
    std::unique_ptr<IStoragePlugin::IReader> reader(plugin->GetReaderForObject(uuid, type, cryptoEnabled));
    reader->ReadRange(reinterpret_cast<char*>(target->data), target->size, rangeStart);
  }
  catch (StoragePluginException& ex)
  {
    if (migrationFromFileSystemEnabled)
    {
      try
      {
        OrthancPlugins::LogWarning(std::string(StoragePluginFactory::GetStoragePluginName()) + ": error while reading object " + std::string(uuid) + ": " + ex.what() + ", will now try to read it from legacy orthanc storage");
        std::string path = BaseStoragePlugin::GetOrthancFileSystemPath(uuid, fileSystemRootPath);

        std::string stringBuffer;
        Orthanc::SystemToolbox::ReadFileRange(stringBuffer, path, rangeStart, rangeStart + target->size, true);

        memcpy(target->data, stringBuffer.data(), stringBuffer.size());

        return OrthancPluginErrorCode_Success;
      }
      catch(Orthanc::OrthancException& e)
      {
        OrthancPlugins::LogError(std::string(StoragePluginFactory::GetStoragePluginName()) + ": error while reading object " + std::string(uuid) + ": " + std::string(e.What()));
        return OrthancPluginErrorCode_StorageAreaPlugin;
      }
    }
  }
  return OrthancPluginErrorCode_Success;
}


static OrthancPluginErrorCode StorageReadWhole(OrthancPluginMemoryBuffer64* target, // Memory buffer where to store the content of the file. It must be allocated by the plugin using OrthancPluginCreateMemoryBuffer64(). The core of Orthanc will free it.
                                               const char* uuid,
                                               OrthancPluginContentType type)
{
  try
  {
    std::unique_ptr<IStoragePlugin::IReader> reader(plugin->GetReaderForObject(uuid, type, cryptoEnabled));

    size_t fileSize = reader->GetSize();
    size_t size;

    if (cryptoEnabled)
    {
      size = fileSize - crypto->OVERHEAD_SIZE;
    }
    else
    {
      size = fileSize;
    }

    if (size <= 0)
    {
      OrthancPlugins::LogError(std::string(StoragePluginFactory::GetStoragePluginName()) + ": error while reading object " + std::string(uuid) + ", size of file is too small: " + boost::lexical_cast<std::string>(fileSize) + " bytes");
      return OrthancPluginErrorCode_StorageAreaPlugin;
    }

    if (OrthancPluginCreateMemoryBuffer64(OrthancPlugins::GetGlobalContext(), target, size) != OrthancPluginErrorCode_Success)
    {
      OrthancPlugins::LogError(std::string(StoragePluginFactory::GetStoragePluginName()) + ": error while reading object " + std::string(uuid) + ", cannot allocate memory of size " + boost::lexical_cast<std::string>(size) + " bytes");
      return OrthancPluginErrorCode_StorageAreaPlugin;
    }

    if (cryptoEnabled)
    {
      std::vector<char> encrypted(fileSize);
      reader->ReadWhole(encrypted.data(), fileSize);

      try
      {
        crypto->Decrypt(reinterpret_cast<char*>(target->data), encrypted.data(), fileSize);
      }
      catch (EncryptionException& ex)
      {
        OrthancPlugins::LogError(std::string(StoragePluginFactory::GetStoragePluginName()) + ": error while decrypting object " + std::string(uuid) + ": " + ex.what());
        return OrthancPluginErrorCode_StorageAreaPlugin;
      }
    }
    else
    {
      reader->ReadWhole(reinterpret_cast<char*>(target->data), fileSize);
    }
  }
  catch (StoragePluginException& ex)
  {
    if (migrationFromFileSystemEnabled)
    {
      try
      {
        OrthancPlugins::LogWarning(std::string(StoragePluginFactory::GetStoragePluginName()) + ": error while reading object " + std::string(uuid) + ": " + ex.what() + ", will now try to read it from legacy orthanc storage");
        std::string path = BaseStoragePlugin::GetOrthancFileSystemPath(uuid, fileSystemRootPath);

        std::string stringBuffer;
        Orthanc::SystemToolbox::ReadFile(stringBuffer, path);

        if (OrthancPluginCreateMemoryBuffer64(OrthancPlugins::GetGlobalContext(), target, stringBuffer.size()) != OrthancPluginErrorCode_Success)
        {
          OrthancPlugins::LogError(std::string(StoragePluginFactory::GetStoragePluginName()) + ": error while reading object " + std::string(uuid) + ", cannot allocate memory of size " + boost::lexical_cast<std::string>(stringBuffer.size()) + " bytes");
          return OrthancPluginErrorCode_StorageAreaPlugin;
        }

        memcpy(target->data, stringBuffer.data(), stringBuffer.size());

        return OrthancPluginErrorCode_Success;
      }
      catch(Orthanc::OrthancException& e)
      {
        OrthancPlugins::LogError(std::string(StoragePluginFactory::GetStoragePluginName()) + ": error while reading object " + std::string(uuid) + ": " + std::string(e.What()));
        return OrthancPluginErrorCode_StorageAreaPlugin;
      }
    }
    else
    {
      OrthancPlugins::LogError(std::string(StoragePluginFactory::GetStoragePluginName()) + ": error while reading object " + std::string(uuid) + ": " + ex.what());
      return OrthancPluginErrorCode_StorageAreaPlugin;
    }
  }

  return OrthancPluginErrorCode_Success;
}

static OrthancPluginErrorCode StorageReadWholeLegacy(void** content,
                                                     int64_t* size,
                                                     const char* uuid,
                                                     OrthancPluginContentType type)
{
  OrthancPluginMemoryBuffer64* buffer = nullptr;
  OrthancPluginErrorCode result = StorageReadWhole(buffer, uuid, type);  // allocates the buffer but Orthanc won't delete it -> to delete ourselves

  if (buffer != nullptr)
  {
    *size = buffer->size;
    memcpy(*content, buffer->data, buffer->size);
    OrthancPluginFreeMemoryBuffer64(OrthancPlugins::GetGlobalContext(), buffer);
  }

  return result;
}


static OrthancPluginErrorCode StorageRemove(const char* uuid,
                                            OrthancPluginContentType type)
{
  try
  {
    plugin->DeleteObject(uuid, type, cryptoEnabled);
  }
  catch (StoragePluginException& ex)
  {
    if (migrationFromFileSystemEnabled)
    {
      try
      {
        OrthancPlugins::LogWarning(std::string(StoragePluginFactory::GetStoragePluginName()) + ": error while deleting object " + std::string(uuid) + ": " + ex.what() + ", will now try to delete it from legacy orthanc storage");
        namespace fs = boost::filesystem;

        fs::path path = BaseStoragePlugin::GetOrthancFileSystemPath(uuid, fileSystemRootPath);

        try
        {
          fs::remove(path);
        }
        catch (...)
        {
          // Ignore the error
        }

        // Remove the two parent directories, ignoring the error code if
        // these directories are not empty

        try
        {
          boost::system::error_code err;
          fs::remove(path.parent_path(), err);
          fs::remove(path.parent_path().parent_path(), err);
        }
        catch (...)
        {
          // Ignore the error
        }

        return OrthancPluginErrorCode_Success;
      }
      catch(Orthanc::OrthancException& e)
      {
        OrthancPlugins::LogError(std::string(StoragePluginFactory::GetStoragePluginName()) + ": error while deleting object " + std::string(uuid) + ": " + std::string(e.What()));
        return OrthancPluginErrorCode_StorageAreaPlugin;
      }
    }
    else
    {
      OrthancPlugins::LogError(std::string(StoragePluginFactory::GetStoragePluginName()) + ": error while deleting object " + std::string(uuid) + ": " + ex.what());
      return OrthancPluginErrorCode_StorageAreaPlugin;
    }
  }

  return OrthancPluginErrorCode_Success;
}


extern "C"
{
  ORTHANC_PLUGINS_API int32_t OrthancPluginInitialize(OrthancPluginContext* context)
  {
    OrthancPlugins::SetGlobalContext(context);

    Orthanc::Logging::InitializePluginContext(context);

    OrthancPlugins::OrthancConfiguration orthancConfig;

    OrthancPlugins::LogWarning(std::string(StoragePluginFactory::GetStoragePluginName()) + " plugin is initializing");

    /* Check the version of the Orthanc core */
    if (OrthancPluginCheckVersion(context) == 0)
    {
      char info[1024];
      sprintf(info, "Your version of Orthanc (%s) must be above %d.%d.%d to run this plugin",
              context->orthancVersion,
              ORTHANC_PLUGINS_MINIMAL_MAJOR_NUMBER,
              ORTHANC_PLUGINS_MINIMAL_MINOR_NUMBER,
              ORTHANC_PLUGINS_MINIMAL_REVISION_NUMBER);
      OrthancPlugins::LogError(info);
      return -1;
    }

    try
    {
      plugin.reset(StoragePluginFactory::CreateStoragePlugin(orthancConfig));

      if (plugin.get() == nullptr)
      {
        return -1;
      }

      const char* pluginSectionName = plugin->GetConfigurationSectionName();
      static const char* const ENCRYPTION_SECTION = "StorageEncryption";

      if (orthancConfig.IsSection(pluginSectionName))
      {
        OrthancPlugins::OrthancConfiguration pluginSection;
        orthancConfig.GetSection(pluginSection, pluginSectionName);

        migrationFromFileSystemEnabled = pluginSection.GetBooleanValue("MigrationFromFileSystemEnabled", false);

        if (migrationFromFileSystemEnabled)
        {
          fileSystemRootPath = orthancConfig.GetStringValue("StorageDirectory", "OrthancStorageNotDefined");
          OrthancPlugins::LogWarning(std::string(StoragePluginFactory::GetStoragePluginName()) + ": migration from file system enabled, source: " + fileSystemRootPath);
        }

        objectsRootPath = pluginSection.GetStringValue("RootPath", std::string());

        if (objectsRootPath.size() >= 1 && objectsRootPath[0] == '/')
        {
          OrthancPlugins::LogError(std::string(StoragePluginFactory::GetStoragePluginName()) + ": The RootPath shall not start with a '/': " + objectsRootPath);
          return -1;
        }

        plugin->SetRootPath(objectsRootPath);

        if (pluginSection.IsSection(ENCRYPTION_SECTION))
        {
          OrthancPlugins::OrthancConfiguration cryptoSection;
          pluginSection.GetSection(cryptoSection, ENCRYPTION_SECTION);

          crypto.reset(EncryptionConfigurator::CreateEncryptionHelpers(cryptoSection));
          cryptoEnabled = crypto.get() != nullptr;
        }

        if (cryptoEnabled)
        {
          OrthancPlugins::LogWarning(std::string(StoragePluginFactory::GetStoragePluginName()) + ": client-side encryption is enabled");
        }
        else
        {
          OrthancPlugins::LogWarning(std::string(StoragePluginFactory::GetStoragePluginName()) + ": client-side encryption is disabled");
        }
      }

      if (cryptoEnabled)
      {
        // with encrypted file, we do not want to support ReadRange.  Therefore, we register the old interface
        OrthancPluginRegisterStorageArea(context, StorageCreate, StorageReadWholeLegacy, StorageRemove);
      }
      else
      {
        OrthancPluginRegisterStorageArea2(context, StorageCreate, StorageReadWhole, StorageReadRange, StorageRemove);
      }
    }
    catch (Orthanc::OrthancException& e)
    {
      LOG(ERROR) << "Exception while creating the object storage plugin: " << e.What();
      return -1;
    }

    return 0;
  }


  ORTHANC_PLUGINS_API void OrthancPluginFinalize()
  {
    OrthancPlugins::LogWarning(std::string(StoragePluginFactory::GetStoragePluginName()) + " plugin is finalizing");
  }


  ORTHANC_PLUGINS_API const char* OrthancPluginGetName()
  {
    return StoragePluginFactory::GetStoragePluginName();
  }


  ORTHANC_PLUGINS_API const char* OrthancPluginGetVersion()
  {
    return PLUGIN_VERSION;
  }
}