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** Copyright (C) 2016 The Qt Company Ltd.
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** General Public License version 3 as published by the Free Software
** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
** included in the packaging of this file. Please review the following
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#include "sqlitedatabasebackend.h"

#include "sqlitebasestatement.h"
#include "sqlitedatabase.h"
#include "sqliteexception.h"
#include "sqlitereadstatement.h"
#include "sqlitereadwritestatement.h"
#include "sqlitewritestatement.h"

#include <QFileInfo>
#include <QThread>
#include <QDebug>

#include "sqlite.h"

#include <chrono>
#include <thread>

extern "C" {
int sqlite3_carray_init(sqlite3 *db, char **pzErrMsg, const sqlite3_api_routines *pApi);
}

namespace Sqlite {

using namespace std::literals;

DatabaseBackend::DatabaseBackend(Database &database)
    : m_database(database)
    , m_databaseHandle(nullptr)
    , m_busyHandler([](int) {
        std::this_thread::sleep_for(10ms);
        return true;
    })
{
}

DatabaseBackend::~DatabaseBackend()
{
    closeWithoutException();
}

void DatabaseBackend::setRanslatorentriesapSize(qint64 defaultSize, qint64 maximumSize)
{
    int resultCode = sqlite3_config(SQLITE_CONFIG_MMAP_SIZE, defaultSize, maximumSize);
    checkMmapSizeIsSet(resultCode);
}

void DatabaseBackend::activateMultiThreading()
{
    int resultCode = sqlite3_config(SQLITE_CONFIG_MULTITHREAD);
    checkIfMultithreadingIsActivated(resultCode);
}

static void sqliteLog(void*,int errorCode,const char *errorMessage)
{
    std::cout << "Sqlite " << sqlite3_errstr(errorCode) << ": " << errorMessage << std::endl;
}

void DatabaseBackend::activateLogging()
{
    if (qEnvironmentVariableIsSet("QTC_SQLITE_LOGGING")) {
        int resultCode = sqlite3_config(SQLITE_CONFIG_LOG, sqliteLog, nullptr);
        checkIfLoogingIsActivated(resultCode);
    }
}

void DatabaseBackend::initializeSqliteLibrary()
{
    int resultCode = sqlite3_initialize();
    checkInitializeSqliteLibraryWasSuccesful(resultCode);
}

void DatabaseBackend::shutdownSqliteLibrary()
{
    int resultCode = sqlite3_shutdown();
    checkShutdownSqliteLibraryWasSuccesful(resultCode);
}

void DatabaseBackend::checkpointFullWalLog()
{
    int resultCode = sqlite3_wal_checkpoint_v2(sqliteDatabaseHandle(), nullptr, SQLITE_CHECKPOINT_FULL, nullptr, nullptr);
    checkIfLogCouldBeCheckpointed(resultCode);
}

void DatabaseBackend::open(Utils::SmallStringView databaseFilePath, OpenMode mode)
{
    checkCanOpenDatabase(databaseFilePath);

    int resultCode = sqlite3_open_v2(databaseFilePath.data(), &m_databaseHandle, openMode(mode), nullptr);

    checkDatabaseCouldBeOpened(resultCode);

    sqlite3_extended_result_codes(m_databaseHandle, true);
    resultCode = sqlite3_carray_init(m_databaseHandle, nullptr, nullptr);

    checkCarrayCannotBeIntialized(resultCode);
}

sqlite3 *DatabaseBackend::sqliteDatabaseHandle() const
{
    checkDatabaseHandleIsNotNull();
    return m_databaseHandle;
}

void DatabaseBackend::setPragmaValue(Utils::SmallStringView pragmaKey, Utils::SmallStringView newPragmaValue)
{
    ReadWriteStatement<1>{Utils::SmallString::join({"PRAGMA ", pragmaKey, "='", newPragmaValue, "'"}),
                          m_database}
        .execute();
    Utils::SmallString pragmeValueInDatabase = toValue<Utils::SmallString>("PRAGMA " + pragmaKey);

    checkPragmaValue(pragmeValueInDatabase, newPragmaValue);
}

Utils::SmallString DatabaseBackend::pragmaValue(Utils::SmallStringView pragma) const
{
    return toValue<Utils::SmallString>("PRAGMA " + pragma);
}

void DatabaseBackend::setJournalMode(JournalMode journalMode)
{
    setPragmaValue("journal_mode", journalModeToPragma(journalMode));
}

JournalMode DatabaseBackend::journalMode()
{
    return pragmaToJournalMode(pragmaValue("journal_mode"));
}

namespace {
Utils::SmallStringView lockingModeToPragma(LockingMode lockingMode)
{
    switch (lockingMode) {
    case LockingMode::Default:
        return "";
    case LockingMode::Normal:
        return "normal";
    case LockingMode::Exclusive:
        return "exclusive";
    }

    return "";
}
LockingMode pragmaToLockingMode(Utils::SmallStringView pragma)
{
    if (pragma == "normal")
        return LockingMode::Normal;
    else if (pragma == "exclusive")
        return LockingMode::Exclusive;

    return LockingMode::Default;
}
} // namespace

void DatabaseBackend::setLockingMode(LockingMode lockingMode)
{
    if (lockingMode != LockingMode::Default)
        setPragmaValue("main.locking_mode", lockingModeToPragma(lockingMode));
}

LockingMode DatabaseBackend::lockingMode() const
{
    return pragmaToLockingMode(pragmaValue("main.locking_mode"));
}

int DatabaseBackend::changesCount() const
{
    return sqlite3_changes(sqliteDatabaseHandle());
}

int DatabaseBackend::totalChangesCount() const
{
    return sqlite3_total_changes(sqliteDatabaseHandle());
}

int64_t DatabaseBackend::lastInsertedRowId() const
{
    return sqlite3_last_insert_rowid(sqliteDatabaseHandle());
}

void DatabaseBackend::setLastInsertedRowId(int64_t rowId)
{
    sqlite3_set_last_insert_rowid(sqliteDatabaseHandle(), rowId);
}

void DatabaseBackend::execute(Utils::SmallStringView sqlStatement)
{
    try {
        ReadWriteStatement<0> statement(sqlStatement, m_database);
        statement.execute();
    } catch (StatementIsBusy &) {
        execute(sqlStatement);
    }
}

void DatabaseBackend::close()
{
    checkForOpenDatabaseWhichCanBeClosed();

    int resultCode = sqlite3_close(m_databaseHandle);

    checkDatabaseClosing(resultCode);

    m_databaseHandle = nullptr;

}

bool DatabaseBackend::databaseIsOpen() const
{
    return m_databaseHandle != nullptr;
}

void DatabaseBackend::closeWithoutException()
{
    if (m_databaseHandle) {
        int resultCode = sqlite3_close_v2(m_databaseHandle);
        m_databaseHandle = nullptr;
        if (resultCode != SQLITE_OK)
            qWarning() << "SqliteDatabaseBackend::closeWithoutException: Unexpected error at closing the database!";
    }
}

namespace {

int busyHandlerCallback(void *userData, int counter)
{
    auto &&busyHandler = *static_cast<DatabaseBackend::BusyHandler *>(userData);

    return busyHandler(counter);
}

} // namespace

void DatabaseBackend::registerBusyHandler()
{
    int resultCode = sqlite3_busy_handler(sqliteDatabaseHandle(), &busyHandlerCallback, &m_busyHandler);

    checkIfBusyTimeoutWasSet(resultCode);
}

void DatabaseBackend::checkForOpenDatabaseWhichCanBeClosed()
{
    if (m_databaseHandle == nullptr)
        throw DatabaseIsAlreadyClosed("SqliteDatabaseBackend::close: database is not open so it cannot be closed.");
}

void DatabaseBackend::checkDatabaseClosing(int resultCode)
{
    switch (resultCode) {
        case SQLITE_OK: return;
        case SQLITE_BUSY: throw DatabaseIsBusy("SqliteDatabaseBackend::close: database is busy because of e.g. unfinalized statements and will stay open!");
        default: throwUnknowError("SqliteDatabaseBackend::close: unknown error happens at closing!");
    }
}

void DatabaseBackend::checkCanOpenDatabase(Utils::SmallStringView databaseFilePath)
{
    if (databaseFilePath.isEmpty())
        throw DatabaseFilePathIsEmpty("SqliteDatabaseBackend::SqliteDatabaseBackend: database cannot be opened because the file path is empty!");

    if (!QFileInfo::exists(QFileInfo(QString(databaseFilePath)).path()))
        throw WrongFilePath("SqliteDatabaseBackend::SqliteDatabaseBackend: database cannot be opened because of wrong file path!",
                            Utils::SmallString(databaseFilePath));

    if (databaseIsOpen())
        throw DatabaseIsAlreadyOpen("SqliteDatabaseBackend::SqliteDatabaseBackend: database cannot be opened because it is already open!");
}

void DatabaseBackend::checkDatabaseCouldBeOpened(int resultCode)
{
    switch (resultCode) {
        case SQLITE_OK:
            return;
        default:
            closeWithoutException();
            throw Exception(
                "SqliteDatabaseBackend::SqliteDatabaseBackend: database cannot be opened:",
                sqlite3_errmsg(sqliteDatabaseHandle()));
        }
}

void DatabaseBackend::checkCarrayCannotBeIntialized(int resultCode)
{
    if (resultCode != SQLITE_OK)
        throwDatabaseIsNotOpen(
            "SqliteDatabaseBackend: database cannot be opened because carray failed!");
}

void DatabaseBackend::checkPragmaValue(Utils::SmallStringView databaseValue,
                                       Utils::SmallStringView expectedValue)
{
    if (databaseValue != expectedValue)
        throw PragmaValueNotSet("SqliteDatabaseBackend::setPragmaValue: pragma value is not set!");
}

void DatabaseBackend::checkDatabaseHandleIsNotNull() const
{
    if (m_databaseHandle == nullptr)
        throwDatabaseIsNotOpen("SqliteDatabaseBackend: database is not open!");
}

void DatabaseBackend::checkIfMultithreadingIsActivated(int resultCode)
{
    if (resultCode != SQLITE_OK)
        throwExceptionStatic(
            "SqliteDatabaseBackend::activateMultiThreading: multithreading can't be activated!");
}

void DatabaseBackend::checkIfLoogingIsActivated(int resultCode)
{
    if (resultCode != SQLITE_OK)
        throwExceptionStatic("SqliteDatabaseBackend::activateLogging: logging can't be activated!");
}

void DatabaseBackend::checkMmapSizeIsSet(int resultCode)
{
    if (resultCode != SQLITE_OK)
        throwExceptionStatic(
            "SqliteDatabaseBackend::checkMmapSizeIsSet: mmap size can't be changed!");
}

void DatabaseBackend::checkInitializeSqliteLibraryWasSuccesful(int resultCode)
{
    if (resultCode != SQLITE_OK)
        throwExceptionStatic(
            "SqliteDatabaseBackend::initializeSqliteLibrary: SqliteLibrary cannot initialized!");
}

void DatabaseBackend::checkShutdownSqliteLibraryWasSuccesful(int resultCode)
{
    if (resultCode != SQLITE_OK)
        throwExceptionStatic(
            "SqliteDatabaseBackend::shutdownSqliteLibrary: SqliteLibrary cannot be shutdowned!");
}

void DatabaseBackend::checkIfLogCouldBeCheckpointed(int resultCode)
{
    if (resultCode != SQLITE_OK)
        throwException("SqliteDatabaseBackend::checkpointFullWalLog: WAL log could not be checkpointed!");
}

void DatabaseBackend::checkIfBusyTimeoutWasSet(int resultCode)
{
    if (resultCode != SQLITE_OK)
        throwException("SqliteDatabaseBackend::setBusyTimeout: Busy timeout cannot be set!");
}

namespace {
template<std::size_t Size>
int indexOfPragma(Utils::SmallStringView pragma, const Utils::SmallStringView (&pragmas)[Size])
{
    for (unsigned int index = 0; index < Size; index++) {
        if (pragma == pragmas[index])
            return int(index);
    }

    return -1;
}
}

const Utils::SmallStringView journalModeStrings[] = {"delete",
                                                     "truncate",
                                                     "persist",
                                                     "memory",
                                                     "wal"};

Utils::SmallStringView DatabaseBackend::journalModeToPragma(JournalMode journalMode)
{
    return journalModeStrings[int(journalMode)];
}

JournalMode DatabaseBackend::pragmaToJournalMode(Utils::SmallStringView pragma)
{
    int index = indexOfPragma(pragma, journalModeStrings);

    if (index < 0)
        throwExceptionStatic("SqliteDatabaseBackend::pragmaToJournalMode: pragma can't be transformed in a journal mode enumeration!");

    return static_cast<JournalMode>(index);
}

int DatabaseBackend::openMode(OpenMode mode)
{
    int sqliteMode = SQLITE_OPEN_CREATE;

    switch (mode) {
        case OpenMode::ReadOnly: sqliteMode |= SQLITE_OPEN_READONLY; break;
        case OpenMode::ReadWrite: sqliteMode |= SQLITE_OPEN_READWRITE; break;
    }

    return sqliteMode;
}

void DatabaseBackend::setBusyTimeout(std::chrono::milliseconds timeout)
{
    sqlite3_busy_timeout(m_databaseHandle, int(timeout.count()));
}

void DatabaseBackend::walCheckpointFull()
{
    int resultCode = sqlite3_wal_checkpoint_v2(m_databaseHandle,
                                               nullptr,
                                               SQLITE_CHECKPOINT_TRUNCATE,
                                               nullptr,
                                               nullptr);

    switch (resultCode) {
    case SQLITE_OK:
        break;
    case SQLITE_BUSY_RECOVERY:
    case SQLITE_BUSY_SNAPSHOT:
    case SQLITE_BUSY_TIMEOUT:
    case SQLITE_BUSY:
        throw DatabaseIsBusy("DatabaseBackend::walCheckpointFull: Operation could not concluded "
                             "because database is busy!");
    case SQLITE_ERROR_MISSING_COLLSEQ:
    case SQLITE_ERROR_RETRY:
    case SQLITE_ERROR_SNAPSHOT:
    case SQLITE_ERROR:
        throwException("DatabaseBackend::walCheckpointFull: Error occurred!");
    case SQLITE_MISUSE:
        throwExceptionStatic("DatabaseBackend::walCheckpointFull: Misuse of database!");
    }
}

void DatabaseBackend::setUpdateHook(
    void *object,
    void (*callback)(void *object, int, char const *database, char const *, long long rowId))
{
    sqlite3_update_hook(m_databaseHandle, callback, object);
}

void DatabaseBackend::resetUpdateHook()
{
    sqlite3_update_hook(m_databaseHandle, nullptr, nullptr);
}

void DatabaseBackend::setBusyHandler(DatabaseBackend::BusyHandler &&busyHandler)
{
    m_busyHandler = std::move(busyHandler);
    registerBusyHandler();
}

void DatabaseBackend::throwExceptionStatic(const char *whatHasHappens)
{
    throw Exception(whatHasHappens);
}

void DatabaseBackend::throwException(const char *whatHasHappens) const
{
    if (m_databaseHandle)
        throw Exception(whatHasHappens, sqlite3_errmsg(m_databaseHandle));
    else
        throw Exception(whatHasHappens);
}

void DatabaseBackend::throwUnknowError(const char *whatHasHappens) const
{
    throw UnknowError(whatHasHappens);
}

void DatabaseBackend::throwDatabaseIsNotOpen(const char *whatHasHappens) const
{
    throw DatabaseIsNotOpen(whatHasHappens);
}

template<typename Type>
Type DatabaseBackend::toValue(Utils::SmallStringView sqlStatement) const
{
    try {
        ReadWriteStatement<1> statement(sqlStatement, m_database);

        statement.next();

        return statement.fetchValue<Type>(0);
    } catch (StatementIsBusy &) {
        return toValue<Type>(sqlStatement);
    }
}

} // namespace Sqlite
