/******************************************************************************
 * Project:  OGR
 * Purpose:  OGRGMLASDriver implementation
 * Author:   Even Rouault, <even dot rouault at spatialys dot com>
 *
 * Initial development funded by the European Earth observation programme
 * Copernicus
 *
 ******************************************************************************
 * Copyright (c) 2016, Even Rouault, <even dot rouault at spatialys dot com>
 *
 * SPDX-License-Identifier: MIT
 ****************************************************************************/

#include "ogr_gmlas.h"

#include "cpl_http.h"

#include <time.h>

/************************************************************************/
/*                         GMLASXLinkResolver()                         */
/************************************************************************/

GMLASXLinkResolver::GMLASXLinkResolver()
    : m_nMaxRAMCacheSize(
          atoi(CPLGetConfigOption("GMLAS_XLINK_RAM_CACHE_SIZE", "10000000")))
{
}

/************************************************************************/
/*                             SetConf()                                */
/************************************************************************/

void GMLASXLinkResolver::SetConf(const GMLASXLinkResolutionConf &oConf)
{
    m_oConf = oConf;
    SetCacheDirectory(m_oConf.m_osCacheDirectory);
}

/************************************************************************/
/*                          FetchRawContent()                           */
/************************************************************************/

CPLString GMLASXLinkResolver::FetchRawContent(const CPLString &osURL,
                                              const char *pszHeaders)
{
    char **papszOptions = nullptr;
    if (m_oConf.m_nMaxGlobalResolutionTime > 0 &&
        m_nGlobalResolutionTime > m_oConf.m_nMaxGlobalResolutionTime)
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "Maximum global resolution time has been reached. "
                 "No remote resource will be fetched");
        return CPLString();
    }
    if (m_oConf.m_nTimeOut > 0 || m_oConf.m_nMaxGlobalResolutionTime > 0)
    {
        int nTimeout = m_oConf.m_nTimeOut;
        if (m_oConf.m_nTimeOut > 0 && m_oConf.m_nMaxGlobalResolutionTime > 0)
        {
            // Select the minimum between the individual timeout and the
            // remaining time granted by the max global resolution time.
            int nRemaining =
                m_oConf.m_nMaxGlobalResolutionTime - m_nGlobalResolutionTime;
            if (nRemaining < nTimeout)
                nTimeout = nRemaining;
        }
        else if (m_oConf.m_nMaxGlobalResolutionTime > 0)
        {
            nTimeout =
                m_oConf.m_nMaxGlobalResolutionTime - m_nGlobalResolutionTime;
        }
        papszOptions = CSLSetNameValue(papszOptions, "TIMEOUT",
                                       CPLSPrintf("%d", nTimeout));
    }
    if (m_oConf.m_nMaxFileSize > 0)
    {
        papszOptions =
            CSLSetNameValue(papszOptions, "MAX_FILE_SIZE",
                            CPLSPrintf("%d", m_oConf.m_nMaxFileSize));
    }
    if (!m_oConf.m_osProxyServerPort.empty())
    {
        papszOptions =
            CSLSetNameValue(papszOptions, "PROXY", m_oConf.m_osProxyServerPort);
    }
    if (!m_oConf.m_osProxyUserPassword.empty())
    {
        papszOptions = CSLSetNameValue(papszOptions, "PROXYUSERPWD",
                                       m_oConf.m_osProxyUserPassword);
    }
    if (!m_oConf.m_osProxyAuth.empty())
    {
        papszOptions =
            CSLSetNameValue(papszOptions, "PROXYAUTH", m_oConf.m_osProxyAuth);
    }
    if (pszHeaders != nullptr)
    {
        papszOptions = CSLSetNameValue(papszOptions, "HEADERS", pszHeaders);
    }
    time_t nTimeStart = time(nullptr);
    CPLHTTPResult *psResult = CPLHTTPFetch(osURL, papszOptions);
    time_t nTimeStop = time(nullptr);
    m_nGlobalResolutionTime += static_cast<int>(nTimeStop - nTimeStart);
    CSLDestroy(papszOptions);
    if (psResult == nullptr)
        return CPLString();

    if (psResult->nStatus != 0 || psResult->pabyData == nullptr)
    {
        CPLHTTPDestroyResult(psResult);
        return CPLString();
    }

    CPLString osResult;
    osResult.assign(reinterpret_cast<char *>(psResult->pabyData),
                    psResult->nDataLen);
    CPLHTTPDestroyResult(psResult);
    return osResult;
}

/************************************************************************/
/*                           GetRawContent()                            */
/************************************************************************/

CPLString GMLASXLinkResolver::GetRawContent(const CPLString &osURL,
                                            const char *pszHeaders,
                                            bool bAllowRemoteDownload,
                                            bool bCacheResults)
{
    bool bDiskCacheAvailable = false;
    if (!m_osCacheDirectory.empty() && RecursivelyCreateDirectoryIfNeeded())
    {
        bDiskCacheAvailable = true;

        CPLString osCachedFileName(GetCachedFilename(osURL));
        VSILFILE *fp = nullptr;
        if (!m_bRefresh || m_aoSetRefreshedFiles.find(osCachedFileName) !=
                               m_aoSetRefreshedFiles.end())
        {
            fp = VSIFOpenL(osCachedFileName, "rb");
        }
        if (fp != nullptr)
        {
            CPLDebug("GMLAS", "Use cached %s", osCachedFileName.c_str());
            GByte *pabyRet = nullptr;
            vsi_l_offset nSize = 0;
            CPLString osContent;
            if (VSIIngestFile(fp, nullptr, &pabyRet, &nSize, -1))
            {
                osContent.assign(reinterpret_cast<const char *>(pabyRet),
                                 static_cast<size_t>(nSize));
            }
            VSIFree(pabyRet);
            VSIFCloseL(fp);
            return osContent;
        }
        else if (bAllowRemoteDownload)
        {
            if (m_bRefresh)
                m_aoSetRefreshedFiles.insert(osCachedFileName);
        }
        else
        {
            CPLDebug("GMLAS",
                     "Could not find locally cached %s, and not allowed to"
                     "download it",
                     osURL.c_str());
            return CPLString();
        }
    }

    // Check memory cache first
    {
        const auto oIter = m_oMapURLToContent.find(osURL);
        if (oIter != m_oMapURLToContent.end())
            return oIter->second;
    }

    const CPLString osContent(FetchRawContent(osURL, pszHeaders));
    // Cache to disk if possible
    if (bDiskCacheAvailable && bCacheResults && !osContent.empty())
    {
        CPLString osCachedFileName(GetCachedFilename(osURL));
        CPLString osTmpfilename(osCachedFileName + ".tmp");
        VSILFILE *fpTemp = VSIFOpenL(osTmpfilename, "wb");
        if (fpTemp != nullptr)
        {
            const bool bSuccess =
                VSIFWriteL(osContent.data(), osContent.size(), 1, fpTemp) == 1;
            VSIFCloseL(fpTemp);
            if (bSuccess)
                VSIRename(osTmpfilename, osCachedFileName);
        }
    }
    // Otherwise to RAM
    else if (!osContent.empty() && osContent.size() < m_nMaxRAMCacheSize)
    {
        // If cache is going to be saturated, evict larger objects first
        while (osContent.size() + m_nCurrentRAMCacheSize > m_nMaxRAMCacheSize)
        {
            std::map<size_t, std::vector<CPLString>>::reverse_iterator oIter =
                m_oMapFileSizeToURLs.rbegin();
            const size_t nSizeToEvict = oIter->first;
            m_nCurrentRAMCacheSize -= nSizeToEvict;
            const CPLString osURLToEvict(oIter->second.front());
            m_oMapURLToContent.erase(osURLToEvict);
            oIter->second.erase(oIter->second.begin());
            if (oIter->second.empty())
                m_oMapFileSizeToURLs.erase(nSizeToEvict);
        }
        m_oMapURLToContent[osURL] = osContent;
        m_oMapFileSizeToURLs[osContent.size()].push_back(osURL);
        m_nCurrentRAMCacheSize += osContent.size();
    }
    return osContent;
}

/************************************************************************/
/*                     IsRawContentResolutionEnabled()                  */
/************************************************************************/

bool GMLASXLinkResolver::IsRawContentResolutionEnabled() const
{
    return m_oConf.m_bDefaultResolutionEnabled &&
           m_oConf.m_eDefaultResolutionMode ==
               GMLASXLinkResolutionConf::RawContent;
}

/************************************************************************/
/*                      GetMatchingResolutionRule()                      */
/************************************************************************/

int GMLASXLinkResolver::GetMatchingResolutionRule(const CPLString &osURL) const
{
    for (size_t i = 0; i < m_oConf.m_aoURLSpecificRules.size(); ++i)
    {
        if (osURL.compare(0,
                          m_oConf.m_aoURLSpecificRules[i].m_osURLPrefix.size(),
                          m_oConf.m_aoURLSpecificRules[i].m_osURLPrefix) == 0)
        {
            return static_cast<int>(i);
        }
    }

    // No match
    return -1;
}

/************************************************************************/
/*                           GetRawContent()                            */
/************************************************************************/

CPLString GMLASXLinkResolver::GetRawContent(const CPLString &osURL)
{
    return GetRawContent(osURL, nullptr, m_oConf.m_bDefaultAllowRemoteDownload,
                         m_oConf.m_bDefaultCacheResults);
}

/************************************************************************/
/*                         GetRawContentForRule()                       */
/************************************************************************/

CPLString GMLASXLinkResolver::GetRawContentForRule(const CPLString &osURL,
                                                   int nIdxRule)
{
    const GMLASXLinkResolutionConf::URLSpecificResolution &oRule(
        m_oConf.m_aoURLSpecificRules[nIdxRule]);

    CPLString osHeaders;
    for (size_t i = 0; i < oRule.m_aosNameValueHTTPHeaders.size(); ++i)
    {
        if (!osHeaders.empty())
            osHeaders += "\r\n";
        osHeaders += oRule.m_aosNameValueHTTPHeaders[i].first;
        osHeaders += ": ";
        osHeaders += oRule.m_aosNameValueHTTPHeaders[i].second;
    }
    return GetRawContent(osURL, osHeaders.empty() ? nullptr : osHeaders.c_str(),
                         oRule.m_bAllowRemoteDownload, oRule.m_bCacheResults);
}