/******************************************************************************

 * Project:  PROJ

 * Purpose:  SQLite3 related utilities

 * Author:   Even Rouault, <even.rouault at spatialys.com>

 *

 ******************************************************************************

 * Copyright (c) 2019, 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.

 *****************************************************************************/

#ifdef __GNUC__

#pragma GCC diagnostic push

#pragma GCC diagnostic ignored "-Weffc++"

#endif

#include "sqlite3_utils.hpp"

#ifdef __GNUC__

#pragma GCC diagnostic pop

#endif

#ifdef EMBED_RESOURCE_FILES

#include "memvfs.h"

#endif

#include <cstdlib>

#include <cstring>

#include <sstream> // std::ostringstream

NS_PROJ_START

// ---------------------------------------------------------------------------

pj_sqlite3_vfs::~pj_sqlite3_vfs() = default;

// ---------------------------------------------------------------------------

SQLite3VFS::SQLite3VFS(pj_sqlite3_vfs *vfs) : vfs_(vfs) {}

// ---------------------------------------------------------------------------

SQLite3VFS::~SQLite3VFS() {

    if (vfs_) {

        sqlite3_vfs_unregister(&(vfs_->base));

        delete vfs_;

    }

}

// ---------------------------------------------------------------------------

const char *SQLite3VFS::name() const { return vfs_->namePtr.c_str(); }

// ---------------------------------------------------------------------------

typedef int (*ClosePtr)(sqlite3_file *);

// ---------------------------------------------------------------------------

static int VFSClose(sqlite3_file *file) {

    sqlite3_vfs *defaultVFS = sqlite3_vfs_find(nullptr);

    assert(defaultVFS);

    ClosePtr defaultClosePtr;

    std::memcpy(&defaultClosePtr,

                reinterpret_cast<char *>(file) + defaultVFS->szOsFile,

                sizeof(ClosePtr));

    void *methods = const_cast<sqlite3_io_methods *>(file->pMethods);

    int ret = defaultClosePtr(file);

    std::free(methods);

    return ret;

}

// ---------------------------------------------------------------------------

static int VSFNoOpLockUnlockSync(sqlite3_file *, int) { return SQLITE_OK; }

// ---------------------------------------------------------------------------

namespace {

struct pj_sqlite3_customvfs_appdata {

    sqlite3_vfs *defaultVFS = nullptr;

    bool fakeSync = false;

    bool fakeLock = false;

};

struct pj_sqlite3_customvfs : public pj_sqlite3_vfs {

    ~pj_sqlite3_customvfs() override {

        delete static_cast<pj_sqlite3_customvfs_appdata *>(base.pAppData);

        base.pAppData = nullptr;

    }

};

} // namespace

static int VFSCustomOpen(sqlite3_vfs *vfs, const char *name, sqlite3_file *file,

                         int flags, int *outFlags) {

    pj_sqlite3_customvfs_appdata *appdata =

        static_cast<pj_sqlite3_customvfs_appdata *>(vfs->pAppData);

    sqlite3_vfs *defaultVFS = appdata->defaultVFS;

    int ret = defaultVFS->xOpen(defaultVFS, name, file, flags, outFlags);

    if (ret == SQLITE_OK) {

        ClosePtr defaultClosePtr = file->pMethods->xClose;

        assert(defaultClosePtr);

        sqlite3_io_methods *methods = static_cast<sqlite3_io_methods *>(

            std::malloc(sizeof(sqlite3_io_methods)));

        if (!methods) {

            file->pMethods->xClose(file);

            return SQLITE_NOMEM;

        }

        memcpy(methods, file->pMethods, sizeof(sqlite3_io_methods));

        methods->xClose = VFSClose;

        if (appdata->fakeSync) {

            // Disable xSync because it can be significantly slow and we don't

            // need

            // that level of data integrity guarantee for the cache.

            methods->xSync = VSFNoOpLockUnlockSync;

        }

        if (appdata->fakeLock) {

            methods->xLock = VSFNoOpLockUnlockSync;

            methods->xUnlock = VSFNoOpLockUnlockSync;

        }

        file->pMethods = methods;

        // Save original xClose pointer at end of file structure

        std::memcpy(reinterpret_cast<char *>(file) + defaultVFS->szOsFile,

                    &defaultClosePtr, sizeof(ClosePtr));

    }

    return ret;

}

// ---------------------------------------------------------------------------

static int VFSCustomAccess(sqlite3_vfs *vfs, const char *zName, int flags,

                           int *pResOut) {

    sqlite3_vfs *defaultVFS = static_cast<sqlite3_vfs *>(vfs->pAppData);

    // Do not bother stat'ing for journal or wal files

    if (std::strstr(zName, "-journal") || std::strstr(zName, "-wal")) {

        *pResOut = false;

        return SQLITE_OK;

    }

    return defaultVFS->xAccess(defaultVFS, zName, flags, pResOut);

}

// ---------------------------------------------------------------------------

// SQLite3 logging infrastructure

static void projSqlite3LogCallback(void *, int iErrCode, const char *zMsg) {

    fprintf(stderr, "SQLite3 message: (code %d) %s\n", iErrCode, zMsg);

}

namespace {

struct InstallSqliteLogger {

    InstallSqliteLogger() {

        if (getenv("PROJ_LOG_SQLITE3") != nullptr) {

            sqlite3_config(SQLITE_CONFIG_LOG, projSqlite3LogCallback, nullptr);

        }

    }

    static InstallSqliteLogger &GetSingleton() {

        static InstallSqliteLogger installSqliteLogger;

        return installSqliteLogger;

    }

};

} // namespace

// ---------------------------------------------------------------------------

std::unique_ptr<SQLite3VFS> SQLite3VFS::create(bool fakeSync, bool fakeLock,

                                               bool skipStatJournalAndWAL) {

    // Install SQLite3 logger if PROJ_LOG_SQLITE3 env var is defined

    InstallSqliteLogger::GetSingleton();

    // Call to sqlite3_initialize() is normally not needed, except for

    // people building SQLite3 with -DSQLITE_OMIT_AUTOINIT

    sqlite3_initialize();

    sqlite3_vfs *defaultVFS = sqlite3_vfs_find(nullptr);

    assert(defaultVFS);

    auto vfs = new pj_sqlite3_customvfs();

    auto vfsUnique = std::unique_ptr<SQLite3VFS>(new SQLite3VFS(vfs));

    std::ostringstream buffer;

    buffer << vfs;

    vfs->namePtr = buffer.str();

    vfs->base.iVersion = 1;

    vfs->base.szOsFile = defaultVFS->szOsFile + sizeof(ClosePtr);

    vfs->base.mxPathname = defaultVFS->mxPathname;

    vfs->base.zName = vfs->namePtr.c_str();

    pj_sqlite3_customvfs_appdata *appdata = new pj_sqlite3_customvfs_appdata;

    appdata->fakeSync = fakeSync;

    appdata->fakeLock = fakeLock;

    appdata->defaultVFS = defaultVFS;

    vfs->base.pAppData = appdata;

    vfs->base.xOpen = VFSCustomOpen;

    vfs->base.xDelete = defaultVFS->xDelete;

    vfs->base.xAccess =

        skipStatJournalAndWAL ? VFSCustomAccess : defaultVFS->xAccess;

    vfs->base.xFullPathname = defaultVFS->xFullPathname;

    vfs->base.xDlOpen = defaultVFS->xDlOpen;

    vfs->base.xDlError = defaultVFS->xDlError;

    vfs->base.xDlSym = defaultVFS->xDlSym;

    vfs->base.xDlClose = defaultVFS->xDlClose;

    vfs->base.xRandomness = defaultVFS->xRandomness;

    vfs->base.xSleep = defaultVFS->xSleep;

    vfs->base.xCurrentTime = defaultVFS->xCurrentTime;

    vfs->base.xGetLastError = defaultVFS->xGetLastError;

    vfs->base.xCurrentTimeInt64 = defaultVFS->xCurrentTimeInt64;

    if (sqlite3_vfs_register(&(vfs->base), false) == SQLITE_OK) {

        return vfsUnique;

    }

    delete vfsUnique->vfs_;

    vfsUnique->vfs_ = nullptr;

    return nullptr;

}

// ---------------------------------------------------------------------------

#ifdef EMBED_RESOURCE_FILES

struct pj_sqlite3_memvfs : public pj_sqlite3_vfs {

    ~pj_sqlite3_memvfs() override;

};

pj_sqlite3_memvfs::~pj_sqlite3_memvfs() {

    pj_sqlite3_memvfs_deallocate_user_data(&base);

}

/* static */

std::unique_ptr<SQLite3VFS> SQLite3VFS::createMem(const void *membuffer,

                                                  size_t bufferSize) {

    // Install SQLite3 logger if PROJ_LOG_SQLITE3 env var is defined

    InstallSqliteLogger::GetSingleton();

    // Call to sqlite3_initialize() is normally not needed, except for

    // people building SQLite3 with -DSQLITE_OMIT_AUTOINIT

    sqlite3_initialize();

    auto vfs = new pj_sqlite3_memvfs();

    auto vfsUnique = std::unique_ptr<SQLite3VFS>(new SQLite3VFS(vfs));

    std::ostringstream buffer;

    buffer << vfs;

    vfs->namePtr = buffer.str();

    if (pj_sqlite3_memvfs_init(&(vfs->base), vfs->namePtr.c_str(), membuffer,

                               bufferSize) == SQLITE_OK) {

        return vfsUnique;

    }

    delete vfsUnique->vfs_;

    vfsUnique->vfs_ = nullptr;

    return nullptr;

}

#endif

// ---------------------------------------------------------------------------

SQLiteStatement::SQLiteStatement(sqlite3_stmt *hStmtIn) : hStmt(hStmtIn) {}

// ---------------------------------------------------------------------------

NS_PROJ_END