/******************************************************************************
 *
 * Project:  OpenGIS Simple Features Reference Implementation
 * Purpose:  Implements SQLite VFS
 * Author:   Even Rouault, <even dot rouault at spatialys.com>

 ******************************************************************************
 * Copyright (c) 2011-2012, Even Rouault <even dot rouault at spatialys.com>
 *
 * SPDX-License-Identifier: MIT
 ****************************************************************************/

#include "cpl_port.h"
#include "ogr_sqlite.h"

#include <cstdio>
#include <cstdlib>
#include <cstring>

#include "cpl_conv.h"
#include "cpl_error.h"
#include "cpl_string.h"
#include "cpl_vsi.h"
#include "ogrsqlitevfs.h"

#ifdef DEBUG_IO
#define DEBUG_ONLY
#else
#define DEBUG_ONLY CPL_UNUSED
#endif

// #define DEBUG_IO 1

typedef struct
{
    char szVFSName[64];
    sqlite3_vfs *pDefaultVFS;
    pfnNotifyFileOpenedType pfn;
    void *pfnUserData;
} OGRSQLiteVFSAppDataStruct;

#define GET_UNDERLYING_VFS(pVFS)                                               \
    static_cast<OGRSQLiteVFSAppDataStruct *>(pVFS->pAppData)->pDefaultVFS

typedef struct
{
    const struct sqlite3_io_methods *pMethods;
    VSILFILE *fp;
    int bDeleteOnClose;
    char *pszFilename;
} OGRSQLiteFileStruct;

static int OGRSQLiteIOClose(sqlite3_file *pFile)
{
    OGRSQLiteFileStruct *pMyFile =
        reinterpret_cast<OGRSQLiteFileStruct *>(pFile);
#ifdef DEBUG_IO
    CPLDebug("SQLITE", "OGRSQLiteIOClose(%p (%s))", pMyFile->fp,
             pMyFile->pszFilename);
#endif
    VSIFCloseL(pMyFile->fp);
    if (pMyFile->bDeleteOnClose)
        VSIUnlink(pMyFile->pszFilename);
    CPLFree(pMyFile->pszFilename);
    return SQLITE_OK;
}

static int OGRSQLiteIORead(sqlite3_file *pFile, void *pBuffer, int iAmt,
                           sqlite3_int64 iOfst)
{
    OGRSQLiteFileStruct *pMyFile =
        reinterpret_cast<OGRSQLiteFileStruct *>(pFile);
    VSIFSeekL(pMyFile->fp, static_cast<vsi_l_offset>(iOfst), SEEK_SET);
    int nRead = static_cast<int>(VSIFReadL(pBuffer, 1, iAmt, pMyFile->fp));
#ifdef DEBUG_IO
    CPLDebug("SQLITE", "OGRSQLiteIORead(%p, %d, %d) = %d", pMyFile->fp, iAmt,
             static_cast<int>(iOfst), nRead);
#endif
    if (nRead < iAmt)
    {
        memset(static_cast<char *>(pBuffer) + nRead, 0, iAmt - nRead);
        return SQLITE_IOERR_SHORT_READ;
    }
    return SQLITE_OK;
}

static int OGRSQLiteIOWrite(sqlite3_file *pFile, const void *pBuffer, int iAmt,
                            sqlite3_int64 iOfst)
{
    OGRSQLiteFileStruct *pMyFile =
        reinterpret_cast<OGRSQLiteFileStruct *>(pFile);
    VSIFSeekL(pMyFile->fp, static_cast<vsi_l_offset>(iOfst), SEEK_SET);
    int nWritten = static_cast<int>(VSIFWriteL(pBuffer, 1, iAmt, pMyFile->fp));
#ifdef DEBUG_IO
    CPLDebug("SQLITE", "OGRSQLiteIOWrite(%p, %d, %d) = %d", pMyFile->fp, iAmt,
             static_cast<int>(iOfst), nWritten);
#endif
    if (nWritten < iAmt)
    {
        return SQLITE_IOERR_WRITE;
    }
    return SQLITE_OK;
}

static int OGRSQLiteIOTruncate(sqlite3_file *pFile, sqlite3_int64 size)
{
    OGRSQLiteFileStruct *pMyFile =
        reinterpret_cast<OGRSQLiteFileStruct *>(pFile);
#ifdef DEBUG_IO
    CPLDebug("SQLITE", "OGRSQLiteIOTruncate(%p, " CPL_FRMT_GIB ")", pMyFile->fp,
             size);
#endif
    int nRet = VSIFTruncateL(pMyFile->fp, size);
    return (nRet == 0) ? SQLITE_OK : SQLITE_IOERR_TRUNCATE;
}

static int OGRSQLiteIOSync(DEBUG_ONLY sqlite3_file *pFile, DEBUG_ONLY int flags)
{
#ifdef DEBUG_IO
    OGRSQLiteFileStruct *pMyFile =
        reinterpret_cast<OGRSQLiteFileStruct *>(pFile);
    CPLDebug("SQLITE", "OGRSQLiteIOSync(%p, %d)", pMyFile->fp, flags);
#endif
    return SQLITE_OK;
}

static int OGRSQLiteIOFileSize(sqlite3_file *pFile, sqlite3_int64 *pSize)
{
    OGRSQLiteFileStruct *pMyFile =
        reinterpret_cast<OGRSQLiteFileStruct *>(pFile);
    vsi_l_offset nCurOffset = VSIFTellL(pMyFile->fp);
    VSIFSeekL(pMyFile->fp, 0, SEEK_END);
    *pSize = VSIFTellL(pMyFile->fp);
    VSIFSeekL(pMyFile->fp, nCurOffset, SEEK_SET);
#ifdef DEBUG_IO
    CPLDebug("SQLITE", "OGRSQLiteIOFileSize(%p) = " CPL_FRMT_GIB, pMyFile->fp,
             *pSize);
#endif
    return SQLITE_OK;
}

static int OGRSQLiteIOLock(DEBUG_ONLY sqlite3_file *pFile, DEBUG_ONLY int flags)
{
#ifdef DEBUG_IO
    OGRSQLiteFileStruct *pMyFile =
        reinterpret_cast<OGRSQLiteFileStruct *>(pFile);
    CPLDebug("SQLITE", "OGRSQLiteIOLock(%p)", pMyFile->fp);
#endif
    return SQLITE_OK;
}

static int OGRSQLiteIOUnlock(DEBUG_ONLY sqlite3_file *pFile,
                             DEBUG_ONLY int flags)
{
#ifdef DEBUG_IO
    OGRSQLiteFileStruct *pMyFile =
        reinterpret_cast<OGRSQLiteFileStruct *>(pFile);
    CPLDebug("SQLITE", "OGRSQLiteIOUnlock(%p)", pMyFile->fp);
#endif
    return SQLITE_OK;
}

static int OGRSQLiteIOCheckReservedLock(DEBUG_ONLY sqlite3_file *pFile,
                                        DEBUG_ONLY int *pResOut)
{
#ifdef DEBUG_IO
    OGRSQLiteFileStruct *pMyFile =
        reinterpret_cast<OGRSQLiteFileStruct *>(pFile);
    CPLDebug("SQLITE", "OGRSQLiteIOCheckReservedLock(%p)", pMyFile->fp);
#endif
    *pResOut = 0;
    return SQLITE_OK;
}

static int OGRSQLiteIOFileControl(DEBUG_ONLY sqlite3_file *pFile,
                                  DEBUG_ONLY int op, DEBUG_ONLY void *pArg)
{
#ifdef DEBUG_IO
    OGRSQLiteFileStruct *pMyFile =
        reinterpret_cast<OGRSQLiteFileStruct *>(pFile);
    CPLDebug("SQLITE", "OGRSQLiteIOFileControl(%p, %d)", pMyFile->fp, op);
#endif
    return SQLITE_NOTFOUND;
}

static int OGRSQLiteIOSectorSize(DEBUG_ONLY sqlite3_file *pFile)
{
#ifdef DEBUG_IO
    OGRSQLiteFileStruct *pMyFile =
        reinterpret_cast<OGRSQLiteFileStruct *>(pFile);
    CPLDebug("SQLITE", "OGRSQLiteIOSectorSize(%p)", pMyFile->fp);
#endif
    return 0;
}

static int OGRSQLiteIODeviceCharacteristics(DEBUG_ONLY sqlite3_file *pFile)
{
#ifdef DEBUG_IO
    OGRSQLiteFileStruct *pMyFile =
        reinterpret_cast<OGRSQLiteFileStruct *>(pFile);
    CPLDebug("SQLITE", "OGRSQLiteIODeviceCharacteristics(%p)", pMyFile->fp);
#endif
    return 0;
}

static const sqlite3_io_methods OGRSQLiteIOMethods = {
    1,
    OGRSQLiteIOClose,
    OGRSQLiteIORead,
    OGRSQLiteIOWrite,
    OGRSQLiteIOTruncate,
    OGRSQLiteIOSync,
    OGRSQLiteIOFileSize,
    OGRSQLiteIOLock,
    OGRSQLiteIOUnlock,
    OGRSQLiteIOCheckReservedLock,
    OGRSQLiteIOFileControl,
    OGRSQLiteIOSectorSize,
    OGRSQLiteIODeviceCharacteristics,
    nullptr,  // xShmMap
    nullptr,  // xShmLock
    nullptr,  // xShmBarrier
    nullptr,  // xShmUnmap
    nullptr,  // xFetch
    nullptr,  // xUnfetch
};

static int OGRSQLiteVFSOpen(sqlite3_vfs *pVFS, const char *zNameIn,
                            sqlite3_file *pFile, int flags, int *pOutFlags)
{
#ifdef DEBUG_IO
    CPLDebug("SQLITE", "OGRSQLiteVFSOpen(%s, %d)", zNameIn ? zNameIn : "(null)",
             flags);
#endif

    OGRSQLiteVFSAppDataStruct *pAppData =
        static_cast<OGRSQLiteVFSAppDataStruct *>(pVFS->pAppData);

    const std::string osName(
        zNameIn ? zNameIn : VSIMemGenerateHiddenFilename("sqlitevfs"));

    OGRSQLiteFileStruct *pMyFile =
        reinterpret_cast<OGRSQLiteFileStruct *>(pFile);
    pMyFile->pMethods = nullptr;
    pMyFile->bDeleteOnClose = FALSE;
    pMyFile->pszFilename = nullptr;
    if (flags & SQLITE_OPEN_READONLY)
        pMyFile->fp = VSIFOpenL(osName.c_str(), "rb");
    else if (flags & SQLITE_OPEN_CREATE)
    {
        VSIStatBufL sStatBufL;
        if (VSIStatExL(osName.c_str(), &sStatBufL, VSI_STAT_EXISTS_FLAG) == 0)
            pMyFile->fp = VSIFOpenL(osName.c_str(), "rb+");
        else
            pMyFile->fp = VSIFOpenL(osName.c_str(), "wb+");
    }
    else if (flags & SQLITE_OPEN_READWRITE)
        pMyFile->fp = VSIFOpenL(osName.c_str(), "rb+");
    else
        pMyFile->fp = nullptr;

    if (pMyFile->fp == nullptr)
        return SQLITE_CANTOPEN;

#ifdef DEBUG_IO
    CPLDebug("SQLITE", "OGRSQLiteVFSOpen() = %p", pMyFile->fp);
#endif

    pfnNotifyFileOpenedType pfn = pAppData->pfn;
    if (pfn)
    {
        pfn(pAppData->pfnUserData, osName.c_str(), pMyFile->fp);
    }

    pMyFile->pMethods = &OGRSQLiteIOMethods;
    pMyFile->bDeleteOnClose = (flags & SQLITE_OPEN_DELETEONCLOSE);
    pMyFile->pszFilename = CPLStrdup(osName.c_str());

    if (pOutFlags != nullptr)
        *pOutFlags = flags;

    return SQLITE_OK;
}

static int OGRSQLiteVFSDelete(DEBUG_ONLY sqlite3_vfs *pVFS, const char *zName,
                              int DEBUG_ONLY syncDir)
{
#ifdef DEBUG_IO
    CPLDebug("SQLITE", "OGRSQLiteVFSDelete(%s)", zName);
#endif
    VSIUnlink(zName);
    return SQLITE_OK;
}

static int OGRSQLiteVFSAccess(DEBUG_ONLY sqlite3_vfs *pVFS, const char *zName,
                              int flags, int *pResOut)
{
#ifdef DEBUG_IO
    CPLDebug("SQLITE", "OGRSQLiteVFSAccess(%s, %d)", zName, flags);
#endif
    VSIStatBufL sStatBufL;
    int nRet;  // TODO(schwehr): Cleanup nRet and pResOut.  bools?
    if (flags == SQLITE_ACCESS_EXISTS)
    {
        /* Do not try to check the presence of a journal or a wal on /vsicurl !
         */
        if ((STARTS_WITH(zName, "/vsicurl/") ||
             STARTS_WITH(zName, "/vsitar/") ||
             STARTS_WITH(zName, "/vsizip/")) &&
            ((strlen(zName) > strlen("-journal") &&
              strcmp(zName + strlen(zName) - strlen("-journal"), "-journal") ==
                  0) ||
             (strlen(zName) > strlen("-wal") &&
              strcmp(zName + strlen(zName) - strlen("-wal"), "-wal") == 0)))
        {
            nRet = -1;
        }
        else
        {
            nRet = VSIStatExL(zName, &sStatBufL, VSI_STAT_EXISTS_FLAG);
        }
    }
    else if (flags == SQLITE_ACCESS_READ)
    {
        VSILFILE *fp = VSIFOpenL(zName, "rb");
        nRet = fp ? 0 : -1;
        if (fp)
            VSIFCloseL(fp);
    }
    else if (flags == SQLITE_ACCESS_READWRITE)
    {
        VSILFILE *fp = VSIFOpenL(zName, "rb+");
        nRet = fp ? 0 : -1;
        if (fp)
            VSIFCloseL(fp);
    }
    else
    {
        nRet = -1;
    }
    *pResOut = (nRet == 0);
    return SQLITE_OK;
}

static int OGRSQLiteVFSFullPathname(sqlite3_vfs *pVFS, const char *zName,
                                    int nOut, char *zOut)
{
    sqlite3_vfs *pUnderlyingVFS = GET_UNDERLYING_VFS(pVFS);
#ifdef DEBUG_IO
    CPLDebug("SQLITE", "OGRSQLiteVFSFullPathname(%s)", zName);
#endif
    if (zName[0] == '/')
    {
        if (static_cast<int>(strlen(zName)) >= nOut)
        {
            // The +8 comes from the fact that sqlite3 does this check as
            // it needs to be able to append .journal to the filename
            CPLError(CE_Failure, CPLE_AppDefined,
                     "Maximum pathname length reserved for SQLite3 VFS "
                     "isn't large enough. Try raising "
                     "OGR_SQLITE_VFS_MAXPATHNAME to at least %d",
                     static_cast<int>(strlen(zName)) + 8);
            return SQLITE_CANTOPEN;
        }
        strncpy(zOut, zName, nOut);
        zOut[nOut - 1] = '\0';
        return SQLITE_OK;
    }
    return pUnderlyingVFS->xFullPathname(pUnderlyingVFS, zName, nOut, zOut);
}

static void *OGRSQLiteVFSDlOpen(sqlite3_vfs *pVFS, const char *zFilename)
{
    sqlite3_vfs *pUnderlyingVFS = GET_UNDERLYING_VFS(pVFS);
    // CPLDebug("SQLITE", "OGRSQLiteVFSDlOpen(%s)", zFilename);
    return pUnderlyingVFS->xDlOpen(pUnderlyingVFS, zFilename);
}

static void OGRSQLiteVFSDlError(sqlite3_vfs *pVFS, int nByte, char *zErrMsg)
{
    sqlite3_vfs *pUnderlyingVFS = GET_UNDERLYING_VFS(pVFS);
    // CPLDebug("SQLITE", "OGRSQLiteVFSDlError()");
    pUnderlyingVFS->xDlError(pUnderlyingVFS, nByte, zErrMsg);
}

static void (*OGRSQLiteVFSDlSym(sqlite3_vfs *pVFS, void *pHandle,
                                const char *zSymbol))(void)
{
    sqlite3_vfs *pUnderlyingVFS = GET_UNDERLYING_VFS(pVFS);
    // CPLDebug("SQLITE", "OGRSQLiteVFSDlSym(%s)", zSymbol);
    return pUnderlyingVFS->xDlSym(pUnderlyingVFS, pHandle, zSymbol);
}

static void OGRSQLiteVFSDlClose(sqlite3_vfs *pVFS, void *pHandle)
{
    sqlite3_vfs *pUnderlyingVFS = GET_UNDERLYING_VFS(pVFS);
    // CPLDebug("SQLITE", "OGRSQLiteVFSDlClose(%p)", pHandle);
    pUnderlyingVFS->xDlClose(pUnderlyingVFS, pHandle);
}

static int OGRSQLiteVFSRandomness(sqlite3_vfs *pVFS, int nByte, char *zOut)
{
    sqlite3_vfs *pUnderlyingVFS = GET_UNDERLYING_VFS(pVFS);
    // CPLDebug("SQLITE", "OGRSQLiteVFSRandomness()");
    return pUnderlyingVFS->xRandomness(pUnderlyingVFS, nByte, zOut);
}

static int OGRSQLiteVFSSleep(sqlite3_vfs *pVFS, int microseconds)
{
    sqlite3_vfs *pUnderlyingVFS = GET_UNDERLYING_VFS(pVFS);
    // CPLDebug("SQLITE", "OGRSQLiteVFSSleep()");
    return pUnderlyingVFS->xSleep(pUnderlyingVFS, microseconds);
}

// Derived for sqlite3.c implementation of unixCurrentTime64 and
// winCurrentTime64
#ifdef _WIN32
#include <windows.h>

static int OGRSQLiteVFSCurrentTimeInt64(sqlite3_vfs * /*pVFS*/,
                                        sqlite3_int64 *piNow)
{
    FILETIME ft;
    constexpr sqlite3_int64 winFiletimeEpoch =
        23058135 * static_cast<sqlite3_int64>(8640000);
    constexpr sqlite3_int64 max32BitValue =
        static_cast<sqlite3_int64>(2000000000) +
        static_cast<sqlite3_int64>(2000000000) +
        static_cast<sqlite3_int64>(294967296);

#if defined(_WIN32_WCE)
    SYSTEMTIME time;
    GetSystemTime(&time);
    /* if SystemTimeToFileTime() fails, it returns zero. */
    if (!SystemTimeToFileTime(&time, &ft))
    {
        return SQLITE_ERROR;
    }
#else
    GetSystemTimeAsFileTime(&ft);
#endif
    *piNow = winFiletimeEpoch +
             ((static_cast<sqlite3_int64>(ft.dwHighDateTime) * max32BitValue) +
              static_cast<sqlite3_int64>(ft.dwLowDateTime)) /
                 static_cast<sqlite3_int64>(10000);
    return SQLITE_OK;
}
#else
#include <sys/time.h>

static int OGRSQLiteVFSCurrentTimeInt64(sqlite3_vfs * /*pVFS*/,
                                        sqlite3_int64 *piNow)
{
    struct timeval sNow;
    constexpr sqlite3_int64 unixEpoch =
        24405875 * static_cast<sqlite3_int64>(8640000);
    (void)gettimeofday(&sNow, nullptr); /* Cannot fail given valid arguments */
    *piNow = unixEpoch + 1000 * static_cast<sqlite3_int64>(sNow.tv_sec) +
             sNow.tv_usec / 1000;

    return SQLITE_OK;
}
#endif

static int OGRSQLiteVFSCurrentTime(sqlite3_vfs * /*pVFS*/, double *p1)
{
    sqlite3_int64 i = 0;
    int rc = OGRSQLiteVFSCurrentTimeInt64(nullptr, &i);
    *p1 = i / 86400000.0;
    return rc;
}

static int OGRSQLiteVFSGetLastError(sqlite3_vfs *pVFS, int p1, char *p2)
{
    sqlite3_vfs *pUnderlyingVFS = GET_UNDERLYING_VFS(pVFS);
    // CPLDebug("SQLITE", "OGRSQLiteVFSGetLastError()");
    return pUnderlyingVFS->xGetLastError(pUnderlyingVFS, p1, p2);
}

sqlite3_vfs *OGRSQLiteCreateVFS(pfnNotifyFileOpenedType pfn, void *pfnUserData)
{
    sqlite3_vfs *pDefaultVFS = sqlite3_vfs_find(nullptr);
    sqlite3_vfs *pMyVFS =
        static_cast<sqlite3_vfs *>(CPLCalloc(1, sizeof(sqlite3_vfs)));

    OGRSQLiteVFSAppDataStruct *pVFSAppData =
        static_cast<OGRSQLiteVFSAppDataStruct *>(
            CPLCalloc(1, sizeof(OGRSQLiteVFSAppDataStruct)));
    char szPtr[32];
    snprintf(szPtr, sizeof(szPtr), "%p", pVFSAppData);
    snprintf(pVFSAppData->szVFSName, sizeof(pVFSAppData->szVFSName),
             "OGRSQLITEVFS_%s", szPtr);
    pVFSAppData->pDefaultVFS = pDefaultVFS;
    pVFSAppData->pfn = pfn;
    pVFSAppData->pfnUserData = pfnUserData;

    pMyVFS->iVersion = 2;
    pMyVFS->szOsFile = sizeof(OGRSQLiteFileStruct);
    // must be large enough to hold potentially very long names like
    // /vsicurl/.... with AWS S3 security tokens
    pMyVFS->mxPathname =
        atoi(CPLGetConfigOption("OGR_SQLITE_VFS_MAXPATHNAME", "2048"));
    pMyVFS->zName = pVFSAppData->szVFSName;
    pMyVFS->pAppData = pVFSAppData;
    pMyVFS->xOpen = OGRSQLiteVFSOpen;
    pMyVFS->xDelete = OGRSQLiteVFSDelete;
    pMyVFS->xAccess = OGRSQLiteVFSAccess;
    pMyVFS->xFullPathname = OGRSQLiteVFSFullPathname;
    pMyVFS->xDlOpen = OGRSQLiteVFSDlOpen;
    pMyVFS->xDlError = OGRSQLiteVFSDlError;
    pMyVFS->xDlSym = OGRSQLiteVFSDlSym;
    pMyVFS->xDlClose = OGRSQLiteVFSDlClose;
    pMyVFS->xRandomness = OGRSQLiteVFSRandomness;
    pMyVFS->xSleep = OGRSQLiteVFSSleep;
    pMyVFS->xCurrentTime = OGRSQLiteVFSCurrentTime;
    pMyVFS->xGetLastError = OGRSQLiteVFSGetLastError;
    pMyVFS->xCurrentTimeInt64 = OGRSQLiteVFSCurrentTimeInt64;

    return pMyVFS;
}