/**
 * @file Database.cpp
 * @ingroup SQLiteCpp
 * @brief Management of a SQLite Database Connection.
 *
 * Copyright (c) 2012-2025 Sebastien Rombauts (sebastien.rombauts@gmail.com)
 *
 * Distributed under the MIT License (MIT) (See accompanying file LICENSE.txt
 * or copy at http://opensource.org/licenses/MIT)
 */
#include <SQLiteCpp/Database.h>

#include <SQLiteCpp/Assertion.h>
#include <SQLiteCpp/Backup.h>
#include <SQLiteCpp/Exception.h>
#include <SQLiteCpp/Statement.h>

#include <sqlite3.h>
#include <fstream>
#include <string.h>

#ifndef SQLITE_DETERMINISTIC
#define SQLITE_DETERMINISTIC 0x800
#endif // SQLITE_DETERMINISTIC

namespace SQLite
{

const int OK = SQLITE_OK;
const int OPEN_READONLY = SQLITE_OPEN_READONLY;
const int OPEN_READWRITE = SQLITE_OPEN_READWRITE;
const int OPEN_CREATE = SQLITE_OPEN_CREATE;
const int OPEN_URI = SQLITE_OPEN_URI;
const int OPEN_MEMORY = SQLITE_OPEN_MEMORY;
const int OPEN_NOMUTEX = SQLITE_OPEN_NOMUTEX;
const int OPEN_FULLMUTEX = SQLITE_OPEN_FULLMUTEX;
const int OPEN_SHAREDCACHE = SQLITE_OPEN_SHAREDCACHE;
const int OPEN_PRIVATECACHE = SQLITE_OPEN_PRIVATECACHE;
// check if sqlite version is >= 3.31.0 and SQLITE_OPEN_NOFOLLOW is defined
#if SQLITE_VERSION_NUMBER >= 3031000 && defined(SQLITE_OPEN_NOFOLLOW)
const int OPEN_NOFOLLOW = SQLITE_OPEN_NOFOLLOW;
#else
const int OPEN_NOFOLLOW = 0;
#endif

const char* const VERSION = SQLITE_VERSION;
const int VERSION_NUMBER = SQLITE_VERSION_NUMBER;

// Return SQLite version string using runtime call to the compiled library
const char* getLibVersion() noexcept
{
 return sqlite3_libversion();
}

// Return SQLite version number using runtime call to the compiled library
int getLibVersionNumber() noexcept
{
 return sqlite3_libversion_number();
}


// Open the provided database UTF-8 filename with SQLite::OPEN_xxx provided flags.
Database::Database(const char* apFilename,
 const int aFlags /* = SQLite::OPEN_READONLY*/,
 const int aBusyTimeoutMs /* = 0 */,
 const char* apVfs /* = nullptr*/) :
 mFilename(apFilename)
{
 sqlite3* handle;
 const int ret = sqlite3_open_v2(apFilename, &handle, aFlags, apVfs);
 mSQLitePtr.reset(handle);
 if (SQLITE_OK != ret)
 {
 throw SQLite::Exception(handle, ret);
 }
 if (aBusyTimeoutMs > 0)
 {
 setBusyTimeout(aBusyTimeoutMs);
 }
}

// Deleter functor to use with smart pointers to close the SQLite database connection in an RAII fashion.
void Database::Deleter::operator()(sqlite3* apSQLite)
{
 const int ret = sqlite3_close(apSQLite); // Calling sqlite3_close() with a nullptr argument is a harmless no-op.

 // Avoid unreferenced variable warning when build in release mode
 (void) ret;

 // Only case of error is SQLITE_BUSY: "database is locked" (some statements are not finalized)
 // Never throw an exception in a destructor :
 SQLITECPP_ASSERT(SQLITE_OK == ret, "database is locked"); // See SQLITECPP_ENABLE_ASSERT_HANDLER
}

// Set a busy handler that sleeps for a specified amount of time when a table is locked.
void Database::setBusyTimeout(const int aBusyTimeoutMs)
{
 const int ret = sqlite3_busy_timeout(getHandle(), aBusyTimeoutMs);
 check(ret);
}

// Shortcut to execute one or multiple SQL statements without results (UPDATE, INSERT, ALTER, COMMIT, CREATE...).
// Return the number of changes.
int Database::exec(const char* apQueries)
{
 const int ret = tryExec(apQueries);
 check(ret);

 // Return the number of rows modified by those SQL statements (INSERT, UPDATE or DELETE only)
 return sqlite3_changes(getHandle());
}

int Database::tryExec(const char* apQueries) noexcept
{
 return sqlite3_exec(getHandle(), apQueries, nullptr, nullptr, nullptr);
}

// Shortcut to execute a one step query and fetch the first column of the result.
// WARNING: Be very careful with this dangerous method: you have to
// make a COPY OF THE result, else it will be destroy before the next line
// (when the underlying temporary Statement and Column objects are destroyed)
// this is an issue only for pointer type result (ie. char* and blob)
// (use the Column copy-constructor)
Column Database::execAndGet(const char* apQuery)
{
 Statement query(*this, apQuery);
 (void)query.executeStep(); // Can return false if no result, which will throw next line in getColumn()
 return query.getColumn(0);
}

// Shortcut to test if a table exists.
bool Database::tableExists(const char* apTableName) const
{
 Statement query(*this, "SELECT count(*) FROM sqlite_master WHERE type='table' AND name=?");
 query.bind(1, apTableName);
 (void)query.executeStep(); // Cannot return false, as the above query always return a result
 return (1 == query.getColumn(0).getInt());
}

// Get the rowid of the most recent successful INSERT into the database from the current connection.
int64_t Database::getLastInsertRowid() const noexcept
{
 return sqlite3_last_insert_rowid(getHandle());
}

// Get number of rows modified by last INSERT, UPDATE or DELETE statement (not DROP table).
int Database::getChanges() const noexcept
{
 return sqlite3_changes(getHandle());
}

// Get total number of rows modified by all INSERT, UPDATE or DELETE statement since connection.
int Database::getTotalChanges() const noexcept
{
 return sqlite3_total_changes(getHandle());
}

// Return the numeric result code for the most recent failed API call (if any).
int Database::getErrorCode() const noexcept
{
 return sqlite3_errcode(getHandle());
}

// Return the extended numeric result code for the most recent failed API call (if any).
int Database::getExtendedErrorCode() const noexcept
{
 return sqlite3_extended_errcode(getHandle());
}

// Return UTF-8 encoded English language explanation of the most recent failed API call (if any).
const char* Database::getErrorMsg() const noexcept
{
 return sqlite3_errmsg(getHandle());
}

// Attach a custom function to your sqlite database. Assumes UTF8 text representation.
// Parameter details can be found here: http://www.sqlite.org/c3ref/create_function.html
void Database::createFunction(const char* apFuncName,
 int aNbArg,
 bool abDeterministic,
 void* apApp,
 void (*apFunc)(sqlite3_context *, int, sqlite3_value **),
 void (*apStep)(sqlite3_context *, int, sqlite3_value **) /* = nullptr */,
 void (*apFinal)(sqlite3_context *) /* = nullptr */, // NOLINT(readability/casting)
 void (*apDestroy)(void *) /* = nullptr */)
{
 int textRep = SQLITE_UTF8;
 // optimization if deterministic function (e.g. of nondeterministic function random())
 if (abDeterministic)
 {
 textRep = textRep | SQLITE_DETERMINISTIC;
 }
 const int ret = sqlite3_create_function_v2(getHandle(), apFuncName, aNbArg, textRep,
 apApp, apFunc, apStep, apFinal, apDestroy);
 check(ret);
}

// Load an extension into the sqlite database. Only affects the current connection.
// Parameter details can be found here: http://www.sqlite.org/c3ref/load_extension.html
void Database::loadExtension(const char* apExtensionName, const char *apEntryPointName)
{
#ifdef SQLITE_OMIT_LOAD_EXTENSION
 // Unused
 (void)apExtensionName;
 (void)apEntryPointName;

 throw SQLite::Exception("sqlite extensions are disabled");
#else
#ifdef SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION // Since SQLite 3.13 (2016年05月18日):
 // Security warning:
 // It is recommended that the SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION method be used to enable only this interface.
 // The use of the sqlite3_enable_load_extension() interface should be avoided to keep the SQL load_extension()
 // disabled and prevent SQL injections from giving attackers access to extension loading capabilities.
 // (NOTE: not using nullptr: cannot pass object of non-POD type 'std::__1::nullptr_t' through variadic function)
 int ret = sqlite3_db_config(getHandle(), SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION, 1, NULL); // NOTE: not using nullptr
#else
 int ret = sqlite3_enable_load_extension(getHandle(), 1);
#endif
 check(ret);

 ret = sqlite3_load_extension(getHandle(), apExtensionName, apEntryPointName, 0);
 check(ret);
#endif
}

// Set the key for the current sqlite database instance.
void Database::key(const std::string& aKey) const
{
 int passLen = static_cast<int>(aKey.length());
#ifdef SQLITE_HAS_CODEC
 if (passLen > 0)
 {
 const int ret = sqlite3_key(getHandle(), aKey.c_str(), passLen);
 check(ret);
 }
#else // SQLITE_HAS_CODEC
 if (passLen > 0)
 {
 throw SQLite::Exception("No encryption support, recompile with SQLITE_HAS_CODEC to enable.");
 }
#endif // SQLITE_HAS_CODEC
}

// Reset the key for the current sqlite database instance.
void Database::rekey(const std::string& aNewKey) const
{
#ifdef SQLITE_HAS_CODEC
 int passLen = aNewKey.length();
 if (passLen > 0)
 {
 const int ret = sqlite3_rekey(getHandle(), aNewKey.c_str(), passLen);
 check(ret);
 }
 else
 {
 const int ret = sqlite3_rekey(getHandle(), nullptr, 0);
 check(ret);
 }
#else // SQLITE_HAS_CODEC
 static_cast<void>(aNewKey); // silence unused parameter warning
 throw SQLite::Exception("No encryption support, recompile with SQLITE_HAS_CODEC to enable.");
#endif // SQLITE_HAS_CODEC
}

// Test if a file contains an unencrypted database.
bool Database::isUnencrypted(const std::string& aFilename)
{
 if (aFilename.empty())
 {
 throw SQLite::Exception("Could not open database, the aFilename parameter was empty.");
 }

 std::ifstream fileBuffer(aFilename.c_str(), std::ios::in | std::ios::binary);
 char header[16];
 if (fileBuffer.is_open())
 {
 fileBuffer.seekg(0, std::ios::beg);
 fileBuffer.getline(header, 16);
 fileBuffer.close();
 }
 else
 {
 throw SQLite::Exception("Error opening file: " + aFilename);
 }

 return strncmp(header, "SQLite format 3000円", 16) == 0;
}

// Parse header data from a database.
Header Database::getHeaderInfo(const std::string& aFilename)
{
 Header h;
 unsigned char buf[100];
 char* pBuf = reinterpret_cast<char*>(&buf[0]);
 char* pHeaderStr = reinterpret_cast<char*>(&h.headerStr[0]);

 if (aFilename.empty())
 {
 throw SQLite::Exception("Filename parameter is empty");
 }

 {
 std::ifstream fileBuffer(aFilename.c_str(), std::ios::in | std::ios::binary);
 if (fileBuffer.is_open())
 {
 fileBuffer.seekg(0, std::ios::beg);
 fileBuffer.read(pBuf, 100);
 fileBuffer.close();
 if (fileBuffer.gcount() < 100)
 {
 throw SQLite::Exception("File " + aFilename + " is too short");
 }
 }
 else
 {
 throw SQLite::Exception("Error opening file " + aFilename);
 }
 }

 // If the "magic string" can't be found then header is invalid, corrupt or unreadable
 memcpy(pHeaderStr, pBuf, 16);
 pHeaderStr[15] = '0円';
 if (strncmp(pHeaderStr, "SQLite format 3", 15) != 0)
 {
 throw SQLite::Exception("Invalid or encrypted SQLite header in file " + aFilename);
 }

 h.pageSizeBytes = (buf[16] << 8) | buf[17];
 h.fileFormatWriteVersion = buf[18];
 h.fileFormatReadVersion = buf[19];
 h.reservedSpaceBytes = buf[20];
 h.maxEmbeddedPayloadFrac = buf[21];
 h.minEmbeddedPayloadFrac = buf[22];
 h.leafPayloadFrac = buf[23];

 h.fileChangeCounter =
 (buf[24] << 24) |
 (buf[25] << 16) |
 (buf[26] << 8) |
 (buf[27] << 0);

 h.databaseSizePages =
 (buf[28] << 24) |
 (buf[29] << 16) |
 (buf[30] << 8) |
 (buf[31] << 0);

 h.firstFreelistTrunkPage =
 (buf[32] << 24) |
 (buf[33] << 16) |
 (buf[34] << 8) |
 (buf[35] << 0);

 h.totalFreelistPages =
 (buf[36] << 24) |
 (buf[37] << 16) |
 (buf[38] << 8) |
 (buf[39] << 0);

 h.schemaCookie =
 (buf[40] << 24) |
 (buf[41] << 16) |
 (buf[42] << 8) |
 (buf[43] << 0);

 h.schemaFormatNumber =
 (buf[44] << 24) |
 (buf[45] << 16) |
 (buf[46] << 8) |
 (buf[47] << 0);

 h.defaultPageCacheSizeBytes =
 (buf[48] << 24) |
 (buf[49] << 16) |
 (buf[50] << 8) |
 (buf[51] << 0);

 h.largestBTreePageNumber =
 (buf[52] << 24) |
 (buf[53] << 16) |
 (buf[54] << 8) |
 (buf[55] << 0);

 h.databaseTextEncoding =
 (buf[56] << 24) |
 (buf[57] << 16) |
 (buf[58] << 8) |
 (buf[59] << 0);

 h.userVersion =
 (buf[60] << 24) |
 (buf[61] << 16) |
 (buf[62] << 8) |
 (buf[63] << 0);

 h.incrementalVaccumMode =
 (buf[64] << 24) |
 (buf[65] << 16) |
 (buf[66] << 8) |
 (buf[67] << 0);

 h.applicationId =
 (buf[68] << 24) |
 (buf[69] << 16) |
 (buf[70] << 8) |
 (buf[71] << 0);

 h.versionValidFor =
 (buf[92] << 24) |
 (buf[93] << 16) |
 (buf[94] << 8) |
 (buf[95] << 0);

 h.sqliteVersion =
 (buf[96] << 24) |
 (buf[97] << 16) |
 (buf[98] << 8) |
 (buf[99] << 0);

 return h;
}

void Database::backup(const char* apFilename, BackupType aType)
{
 // Open the database file identified by apFilename
 Database otherDatabase(apFilename, SQLite::OPEN_READWRITE | SQLite::OPEN_CREATE);

 // For a 'Save' operation, data is copied from the current Database to the other. A 'Load' is the reverse.
 Database& src = (aType == BackupType::Save ? *this : otherDatabase);
 Database& dest = (aType == BackupType::Save ? otherDatabase : *this);

 // Set up the backup procedure to copy between the "main" databases of each connection
 Backup bkp(dest, src);
 bkp.executeStep(); // Execute all steps at once

 // RAII Finish Backup an Close the other Database
}

} // namespace SQLite