<?php
// MariaDBConnection.php
// Created: 2021-04-30
// Updated: 2022-02-27

namespace Index\Data\MariaDB;

use mysqli;
use mysqli_sql_exception;
use InvalidArgumentException;
use RuntimeException;
use Index\AString;
use Index\Version;
use Index\Data\BeginTransactionFailedException;
use Index\Data\DataException;
use Index\Data\IDbConnection;
use Index\Data\IDbTransactions;
use Index\Data\CommitFailedException;
use Index\Data\ConnectionFailedException;
use Index\Data\ReleaseSavePointFailedException;
use Index\Data\RollbackFailedException;
use Index\Data\SavePointFailedException;
use Index\Data\QueryExecuteException;

/**
 * Represents a connection with a MariaDB or MySQL database server.
 */
class MariaDBConnection implements IDbConnection, IDbTransactions {
    /**
     * Refresh grant tables.
     *
     * @var int
     */
    public const REFRESH_GRANT = MYSQLI_REFRESH_GRANT;

    /**
     * Flushes logs, like the FLUSH LOGS; statement.
     *
     * @var int
     */
    public const REFRESH_LOG = MYSQLI_REFRESH_LOG;

    /**
     * Refresh tables, like the FLUSH TABLES; statement.
     *
     * @var int
     */
    public const REFRESH_TABLES = MYSQLI_REFRESH_TABLES;

    /**
     * Refreshes the hosts cache, like the FLUSH HOSTS; statement.
     *
     * @var int
     */
    public const REFRESH_HOSTS = MYSQLI_REFRESH_HOSTS;

    /**
     * Refresh the status variables, like the FLUSH STATUS; statement.
     *
     * @var int
     */
    public const REFRESH_STATUS = MYSQLI_REFRESH_STATUS;

    /**
     * Flushes the thread cache.
     *
     * @var int
     */
    public const REFRESH_THREADS = MYSQLI_REFRESH_THREADS;

    /**
     * Resets information about the master server and restarts on slave replication servers,
     *  like the RESET SLAVE; statement.
     *
     * @var int
     */
    public const REFRESH_SLAVE = MYSQLI_REFRESH_SLAVE;

    /**
     * Removes binary log files listed in the binary log index and truncates the index file
     *  on master replication servers, like the RESET MASTER; statement.
     */
    public const REFRESH_MASTER = MYSQLI_REFRESH_MASTER;

    private mysqli $connection;

    /**
     * Creates a new instance of MariaDBConnection.
     *
     * @param MariaDBConnectionInfo $connectionInfo Information about the connection.
     * @return MariaDBConnection A new instance of MariaDBConnection.
     */
    public function __construct(MariaDBConnectionInfo $connectionInfo) {
        mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);

        // I'm not sure if calling "new mysqli" without arguments is equivalent to this
        //  the documentation would suggest it's not and that it just pulls from the config
        //  nothing suggests otherwise too.
        // The output of mysqli_init is just an object anyway so we can safely use it instead
        //  but continue to use it as an object.
        $this->connection = mysqli_init();
        $this->connection->options(MYSQLI_OPT_LOCAL_INFILE, 0);

        if($connectionInfo->hasCharacterSet())
            $this->connection->options(MYSQLI_SET_CHARSET_NAME, $connectionInfo->getCharacterSet());

        if($connectionInfo->hasInitCommand())
            $this->connection->options(MYSQLI_INIT_COMMAND, $connectionInfo->getInitCommand());

        $flags = $connectionInfo->shouldUseCompression() ? MYSQLI_CLIENT_COMPRESS : 0;

        if($connectionInfo->isSecure()) {
            $flags |= MYSQLI_CLIENT_SSL;

            if($connectionInfo->shouldVerifyCertificate())
                $this->connection->options(MYSQLI_OPT_SSL_VERIFY_SERVER_CERT, 1);
            else
                $flags |= MYSQLI_CLIENT_SSL_DONT_VERIFY_SERVER_CERT;

            $this->connection->ssl_set(
                $connectionInfo->getKeyPath(),
                $connectionInfo->getCertificatePath(),
                $connectionInfo->getCertificateAuthorityPath(),
                $connectionInfo->getTrustedCertificatesPath(),
                $connectionInfo->getCipherAlgorithms()
            );
        }

        try {
            if($connectionInfo->isUnixSocket())
                $this->connection->real_connect(
                    '',
                    $connectionInfo->getUserName(),
                    $connectionInfo->getPassword(),
                    $connectionInfo->getDatabaseName(),
                    -1,
                    $connectionInfo->getSocketPath(),
                    $flags
                );
            else
                $this->connection->real_connect(
                    $connectionInfo->getHost(),
                    $connectionInfo->getUserName(),
                    $connectionInfo->getPassword(),
                    $connectionInfo->getDatabaseName(),
                    $connectionInfo->getPort(),
                    '',
                    $flags
                );
        } catch(mysqli_sql_exception $ex) {
            throw new ConnectionFailedException($ex->getMessage(), $ex->getCode(), $ex);
        }
    }

    /**
     * Gets the number of rows affected by the last operation.
     *
     * @return int|string Number of rows affected by the last operation.
     */
    public function getAffectedRows(): int|string {
        return $this->connection->affected_rows;
    }

    /**
     * Gets the name of the currently active character set.
     *
     * @return string Name of the character set.
     */
    public function getCharacterSet(): string {
        return $this->connection->character_set_name();
    }

    /**
     * Switch to a different character set.
     *
     * @param string $charSet Name of the new character set.
     * @throws InvalidArgumentException Switching to new character set failed.
     */
    public function setCharacterSet(string $charSet): void {
        if(!$this->connection->set_charset($charSet))
            throw new InvalidArgumentException('$charSet is not a supported character set.');
    }

    /**
     * Returns info about the currently character set and collation.
     *
     * @return MariaDBCharacterSetInfo Information about the character set.
     */
    public function getCharacterSetInfo(): MariaDBCharacterSetInfo {
        return new MariaDBCharacterSetInfo($this->connection->get_charset());
    }

    /**
     * Switches the connection to a different user and default database.
     *
     * @param string $userName New user name.
     * @param string $password New password.
     * @param string|null $database New default database.
     * @throws DataException If the user switch action failed.
     */
    public function switchUser(string $userName, string $password, string|null $database = null): void {
        if(!$this->connection->change_user($userName, $password, $database === null ? null : $database))
            throw new DataException($this->getLastErrorString(), $this->getLastErrorCode());
    }

    /**
     * Switches the default database for this connection.
     *
     * @param string $database New default database.
     * @throws DataException If the database switch failed.
     */
    public function switchDatabase(string $database): void {
        if(!$this->connection->select_db($database))
            throw new DataException($this->getLastErrorString(), $this->getLastErrorCode());
    }

    /**
     * Gets the version of the server.
     *
     * @return Version Version of the server.
     */
    public function getServerVersion(): Version {
        return MariaDBBackend::intToVersion($this->connection->server_version);
    }

    /**
     * Gets the last error code.
     *
     * @return int Last error code.
     */
    public function getLastErrorCode(): int {
        return $this->connection->errno;
    }

    /**
     * Gets the last error string.
     *
     * @return string Last error string.
     */
    public function getLastErrorString(): string {
        return $this->connection->error;
    }

    /**
     * Gets the current SQL State of the connection.
     *
     * @return string Current SQL State.
     */
    public function getSQLState(): string {
        return $this->connection->sqlstate;
    }

    /**
     * Gets a list of errors from the last command.
     *
     * @return array List of last errors.
     */
    public function getLastErrors(): array {
        return MariaDBWarning::fromLastErrors($this->connection->error_list);
    }

    /**
     * Gets the number of columns for the last query.
     *
     * @return int
     */
    public function getLastFieldCount(): int {
        return $this->connection->field_count;
    }

    /**
     * Gets list of warnings.
     *
     * The result of SHOW WARNINGS;
     *
     * @return array List of warnings.
     */
    public function getWarnings(): array {
        return MariaDBWarning::fromGetWarnings($this->connection->get_warnings());
    }

    /**
     * Returns the number of warnings for the last query.
     *
     * @return int Amount of warnings.
     */
    public function getWarningCount(): int {
        return $this->connection->warning_count;
    }

    public function getLastInsertId(): int|string {
        return $this->connection->insert_id;
    }

    /**
     * Sends a keep alive request to the server, or tries to reconnect if it has gone down.
     *
     * @return bool true if the keep alive was successful, false if the server is Gone.
     */
    public function ping(): bool {
        return $this->connection->ping();
    }

    /**
     * Runs various refresh operations, see the REFRESH_ constants for the flags.
     *
     * @param int $flags A bitset of REFRESH_ flags.
     */
    public function refresh(int $flags): void {
        $this->connection->refresh($flags);
    }

    public function setAutoCommit(bool $state): void {
        $this->connection->autocommit($state);
    }

    public function beginTransaction(): void {
        if(!$this->connection->begin_transaction())
            throw new BeginTransactionFailedException((string)$this->getLastErrorString(), $this->getLastErrorCode());
    }

    public function commit(): void {
        if(!$this->connection->commit())
            throw new CommitFailedException((string)$this->getLastErrorString(), $this->getLastErrorCode());
    }

    public function rollback(?string $name = null): void {
        if(!$this->connection->rollback(0, $name))
            throw new RollbackFailedException((string)$this->getLastErrorString(), $this->getLastErrorCode());
    }

    public function savePoint(string $name): void {
        if(!$this->connection->savepoint($name))
            throw new SavePointFailedException((string)$this->getLastErrorString(), $this->getLastErrorCode());
    }

    public function releaseSavePoint(string $name): void {
        if(!$this->connection->release_savepoint($name))
            throw new ReleaseSavePointFailedException((string)$this->getLastErrorString(), $this->getLastErrorCode());
    }

    /**
     * Gets the thread ID for the current connection.
     *
     * @return int Thread ID.
     */
    public function getThreadId(): int {
        return $this->connection->thread_id;
    }

    /**
     * Asks the server to kill a thread.
     *
     * @param int $threadId ID of the thread that should be killed.
     * @return bool true if the thread was killed, false if not.
     */
    public function killThread(int $threadId): bool {
        return $this->connection->kill($threadId);
    }

    /**
     * @return MariaDBStatement A database statement.
     */
    public function prepare(string $query): MariaDBStatement {
        $statement = $this->connection->prepare($query);
        if($statement === false)
            throw new QueryExecuteException($this->getLastErrorString(), $this->getLastErrorCode());
        return new MariaDBStatement($statement);
    }

    /**
     * @return MariaDBResult A database result.
     */
    public function query(string $query): MariaDBResult {
        $result = $this->connection->query($query, MYSQLI_STORE_RESULT);
        if($result === false)
            throw new QueryExecuteException($this->getLastErrorString(), $this->getLastErrorCode());
        // Yes, this always uses Native, for some reason the stupid limitation in libmysql only applies to preparing
        return new MariaDBResultNative($result);
    }

    public function execute(string $query): int|string {
        if(!$this->connection->real_query($query))
            throw new QueryExecuteException($this->getLastErrorString(), $this->getLastErrorCode());
        return $this->connection->affected_rows;
    }

    /**
     * Closes the connection and associated resources.
     */
    public function close(): void {
        $this->connection->close();
    }

    /**
     * Closes the connection and associated resources.
     */
    public function __destruct() {
        $this->close();
    }
}