/******************************************************************************
 *
 * Project:  CPL - Common Portability Library
 * Purpose:  Implement VSI large file api for Google Cloud Storage
 * Author:   Even Rouault, even.rouault at spatialys.com
 *
 ******************************************************************************
 * Copyright (c) 2010-2018, Even Rouault <even.rouault at spatialys.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 ****************************************************************************/

#include "cpl_port.h"
#include "cpl_http.h"
#include "cpl_minixml.h"
#include "cpl_vsil_curl_priv.h"
#include "cpl_vsil_curl_class.h"

#include <algorithm>
#include <set>
#include <map>
#include <memory>

#include "cpl_google_cloud.h"

CPL_CVSID("$Id: cpl_vsil_gs.cpp 07f0cbf27fd991e2767873940c8a30f1b7e13f82 2018-08-17 18:52:46 +0200 Even Rouault $")

#ifndef HAVE_CURL

void VSIInstallGSFileHandler( void )
{
    // Not supported.
}

#else

//! @cond Doxygen_Suppress
#ifndef DOXYGEN_SKIP

#define ENABLE_DEBUG 0

namespace cpl {

/************************************************************************/
/*                         VSIGSFSHandler                               */
/************************************************************************/

class VSIGSFSHandler final : public IVSIS3LikeFSHandler
{
    CPL_DISALLOW_COPY_ASSIGN(VSIGSFSHandler)

  protected:
    VSICurlHandle* CreateFileHandle( const char* pszFilename ) override;
    const char* GetDebugKey() const override { return "GS"; }

    CPLString GetFSPrefix() override { return "/vsigs/"; }
    CPLString GetURLFromFilename( const CPLString& osFilename ) override;

    IVSIS3LikeHandleHelper* CreateHandleHelper(
        const char* pszURI, bool bAllowNoObject) override;

    void ClearCache() override;

  public:
    VSIGSFSHandler() = default;
    ~VSIGSFSHandler() override;

    VSIVirtualHandle *Open( const char *pszFilename,
                            const char *pszAccess,
                            bool bSetError ) override;

    const char* GetOptions() override;

    char* GetSignedURL( const char* pszFilename, CSLConstList papszOptions ) override;
};

/************************************************************************/
/*                            VSIGSHandle                               */
/************************************************************************/

class VSIGSHandle final : public IVSIS3LikeHandle
{
    CPL_DISALLOW_COPY_ASSIGN(VSIGSHandle)

    VSIGSHandleHelper* m_poHandleHelper = nullptr;

  protected:
    struct curl_slist* GetCurlHeaders( const CPLString& osVerb,
        const struct curl_slist* psExistingHeaders ) override;

  public:
    VSIGSHandle( VSIGSFSHandler* poFS, const char* pszFilename,
                 VSIGSHandleHelper* poHandleHelper);
    ~VSIGSHandle() override;
};

/************************************************************************/
/*                          ~VSIGSFSHandler()                           */
/************************************************************************/

VSIGSFSHandler::~VSIGSFSHandler()
{
    VSICurlFilesystemHandler::ClearCache();
    VSIGSHandleHelper::CleanMutex();
}

/************************************************************************/
/*                            ClearCache()                              */
/************************************************************************/

void VSIGSFSHandler::ClearCache()
{
    VSICurlFilesystemHandler::ClearCache();

    VSIGSHandleHelper::ClearCache();
}

/************************************************************************/
/*                          CreateFileHandle()                          */
/************************************************************************/

VSICurlHandle* VSIGSFSHandler::CreateFileHandle(const char* pszFilename)
{
    VSIGSHandleHelper* poHandleHelper =
        VSIGSHandleHelper::BuildFromURI( pszFilename + GetFSPrefix().size(),
                                         GetFSPrefix() );
    if( poHandleHelper == nullptr )
        return nullptr;
    return new VSIGSHandle(this, pszFilename, poHandleHelper);
}

/************************************************************************/
/*                                Open()                                */
/************************************************************************/

VSIVirtualHandle* VSIGSFSHandler::Open( const char *pszFilename,
                                        const char *pszAccess,
                                        bool bSetError)
{
    if( !STARTS_WITH_CI(pszFilename, GetFSPrefix()) )
        return nullptr;

    if( strchr(pszAccess, 'w') != nullptr || strchr(pszAccess, 'a') != nullptr )
    {
        VSIGSHandleHelper* poHandleHelper =
            VSIGSHandleHelper::BuildFromURI(pszFilename + GetFSPrefix().size(),
                                            GetFSPrefix().c_str());
        if( poHandleHelper == nullptr )
            return nullptr;
        VSIS3WriteHandle* poHandle =
            new VSIS3WriteHandle(this, pszFilename, poHandleHelper, true);
        if( !poHandle->IsOK() )
        {
            delete poHandle;
            poHandle = nullptr;
        }
        return poHandle;
    }

    return
        VSICurlFilesystemHandler::Open(pszFilename, pszAccess, bSetError);
}

/************************************************************************/
/*                           GetOptions()                               */
/************************************************************************/

const char* VSIGSFSHandler::GetOptions()
{
    static CPLString osOptions(
        CPLString("<Options>") +
    "  <Option name='GS_SECRET_ACCESS_KEY' type='string' "
        "description='Secret access key. To use with GS_ACCESS_KEY_ID'/>"
    "  <Option name='GS_ACCESS_KEY_ID' type='string' "
        "description='Access key id'/>"
    "  <Option name='GS_OAUTH2_REFRESH_TOKEN' type='string' "
        "description='OAuth2 refresh token. For OAuth2 client authentication. "
        "To use with GS_OAUTH2_CLIENT_ID and GS_OAUTH2_CLIENT_SECRET'/>"
    "  <Option name='GS_OAUTH2_CLIENT_ID' type='string' "
        "description='OAuth2 client id for OAuth2 client authentication'/>"
    "  <Option name='GS_OAUTH2_CLIENT_SECRET' type='string' "
        "description='OAuth2 client secret for OAuth2 client authentication'/>"
    "  <Option name='GS_OAUTH2_PRIVATE_KEY' type='string' "
        "description='Private key for OAuth2 service account authentication. "
        "To use with GS_OAUTH2_CLIENT_EMAIL'/>"
    "  <Option name='GS_OAUTH2_PRIVATE_KEY_FILE' type='string' "
        "description='Filename that contains private key for OAuth2 service "
        "account authentication. "
        "To use with GS_OAUTH2_CLIENT_EMAIL'/>"
    "  <Option name='GS_OAUTH2_CLIENT_EMAIL' type='string' "
        "description='Client email to use with OAuth2 service account "
        "authentication'/>"
    "  <Option name='GS_OAUTH2_SCOPE' type='string' "
        "description='OAuth2 authorization scope' "
        "default='https://www.googleapis.com/auth/devstorage.read_write'/>"
    "  <Option name='CPL_MACHINE_IS_GCE' type='boolean' "
        "description='Whether the current machine is a Google Compute Engine "
        "instance' default='NO'/>"
    "  <Option name='CPL_GCE_CHECK_LOCAL_FILES' type='boolean' "
        "description='Whether to check system logs to determine "
        "if current machine is a GCE instance' default='YES'/>"
        "description='Filename that contains AWS configuration' "
        "default='~/.aws/config'/>"
    "  <Option name='CPL_GS_CREDENTIALS_FILE' type='string' "
        "description='Filename that contains Google Storage credentials' "
        "default='~/.boto'/>" +
        VSICurlFilesystemHandler::GetOptionsStatic() +
        "</Options>");
    return osOptions.c_str();
}

/************************************************************************/
/*                           GetSignedURL()                             */
/************************************************************************/

char* VSIGSFSHandler::GetSignedURL(const char* pszFilename, CSLConstList papszOptions )
{
    if( !STARTS_WITH_CI(pszFilename, GetFSPrefix()) )
        return nullptr;

    VSIGSHandleHelper* poHandleHelper =
        VSIGSHandleHelper::BuildFromURI(pszFilename + GetFSPrefix().size(),
                                        GetFSPrefix().c_str(),
                                        papszOptions);
    if( poHandleHelper == nullptr )
    {
        return nullptr;
    }

    CPLString osRet(poHandleHelper->GetSignedURL(papszOptions));

    delete poHandleHelper;
    return osRet.empty() ? nullptr : CPLStrdup(osRet);
}

/************************************************************************/
/*                          GetURLFromFilename()                         */
/************************************************************************/

CPLString VSIGSFSHandler::GetURLFromFilename( const CPLString& osFilename )
{
    CPLString osFilenameWithoutPrefix = osFilename.substr(GetFSPrefix().size());
    VSIGSHandleHelper* poHandleHelper =
        VSIGSHandleHelper::BuildFromURI( osFilenameWithoutPrefix, GetFSPrefix() );
    if( poHandleHelper == nullptr )
        return CPLString();
    CPLString osURL( poHandleHelper->GetURL() );
    delete poHandleHelper;
    return osURL;
}

/************************************************************************/
/*                          CreateHandleHelper()                        */
/************************************************************************/

IVSIS3LikeHandleHelper* VSIGSFSHandler::CreateHandleHelper(const char* pszURI,
                                                           bool)
{
    return VSIGSHandleHelper::BuildFromURI(pszURI, GetFSPrefix().c_str());
}

/************************************************************************/
/*                             VSIGSHandle()                            */
/************************************************************************/

VSIGSHandle::VSIGSHandle( VSIGSFSHandler* poFSIn,
                          const char* pszFilename,
                          VSIGSHandleHelper* poHandleHelper ) :
        IVSIS3LikeHandle(poFSIn, pszFilename, poHandleHelper->GetURL()),
        m_poHandleHelper(poHandleHelper)
{
}

/************************************************************************/
/*                            ~VSIGSHandle()                            */
/************************************************************************/

VSIGSHandle::~VSIGSHandle()
{
    delete m_poHandleHelper;
}


/************************************************************************/
/*                          GetCurlHeaders()                            */
/************************************************************************/

struct curl_slist* VSIGSHandle::GetCurlHeaders( const CPLString& osVerb,
                                const struct curl_slist* psExistingHeaders )
{
    return m_poHandleHelper->GetCurlHeaders( osVerb, psExistingHeaders );
}

} /* end of namespace cpl */


#endif // DOXYGEN_SKIP
//! @endcond

/************************************************************************/
/*                      VSIInstallGSFileHandler()                       */
/************************************************************************/

/**
 * \brief Install /vsigs/ Google Cloud Storage file system handler
 * (requires libcurl)
 *
 * @see <a href="gdal_virtual_file_systems.html#gdal_virtual_file_systems_vsigs">/vsigs/ documentation</a>
 *
 * @since GDAL 2.2
 */

void VSIInstallGSFileHandler( void )
{
    VSIFileManager::InstallHandler( "/vsigs/", new cpl::VSIGSFSHandler );
}

#endif /* HAVE_CURL */