<?php
/**
 * @file dba_driver.php
 * @brief Some database related functions and database classes.
 *
 * This file contains the abstract database driver class dba_driver, the
 * database class DBA and some functions for working with databases.
 */

use Code\Lib\System;

/**
 * @brief Database classs with database factory method.
 *
 * The factory will return a database driver which is an implementation of the
 * abstract dba_driver class.
 */

class DBA
{

    public static $dba = null;
    public static $dbtype = null;
    public static $scheme = 'mysql';
    public static $logging = false;

    public static $install_script = 'schema_mysql.sql';
    public static $null_date = '0001-01-01 00:00:00';
    public static $utc_now = 'UTC_TIMESTAMP()';
    public static $tquot = "`";


    /**
     * @brief Returns the database driver object.
     *
     * @param string $server DB server name (or PDO dsn - e.g. mysqli:foobar.com;)
     * @param string $port DB port
     * @param string $user DB username
     * @param string $pass DB password
     * @param string $db database name
     * @param string $dbtype 0 for mysql, 1 for postgres
     * @param bool $install Defaults to false
     * @return null|dba_driver A database driver object (dba_pdo) or null if no driver found.
     */
    public static function dba_factory($server, $port, $user, $pass, $db, $dbtype, $install = false)
    {

        self::$dba = null;
        self::$dbtype = intval($dbtype);

        if (self::$dbtype == DBTYPE_POSTGRES) {
            if (!($port)) {
                $port = 5432;
            }

            self::$install_script = 'schema_postgres.sql';
            self::$utc_now = "now() at time zone 'UTC'";
            self::$tquot = '"';
            self::$scheme = 'pgsql';
        } else {
            // attempt to use the pdo driver compiled-in mysqli socket
            // if using 'localhost' with no port configured.
            // If this is wrong you'll need to set the socket path specifically
            // using a server name of 'mysql:unix_socket=/socket/path', setting /socket/path
            // as needed for your platform

            if ((!($port)) && ($server !== 'localhost')) {
                $port = 3306;
            }
        }

        require_once('include/dba/dba_pdo.php');
        self::$dba = new dba_pdo($server, self::$scheme, $port, $user, $pass, $db, $install);

        define('NULL_DATE', self::$null_date);
        define('ACTIVE_DBTYPE', self::$dbtype);
        define('TQUOT', self::$tquot);

        return self::$dba;
    }
}

/**
 * @brief Abstract database driver class.
 *
 * This class gets extended by the real database driver class. We used to have
 * dba_mysql, dba_mysqli or dba_postgres, but we moved to PDO and the only
 * implemented driver is dba_pdo.
 */
abstract class dba_driver
{
    // legacy behavior

    public $db;

    public $debug = 0;
    public $connected = false;
    public $error = false;

    /**
     * @brief Connect to the database.
     *
     * This abstract function needs to be implemented in the real driver.
     *
     * @param string $server DB server name
     * @param string $scheme DB scheme
     * @param string $port DB port
     * @param string $user DB username
     * @param string $pass DB password
     * @param string $db database name
     * @return bool
     */
    abstract public function connect($server, $scheme, $port, $user, $pass, $db);

    /**
     * @brief Perform a DB query with the SQL statement $sql.
     *
     * This abstract function needs to be implemented in the real driver.
     *
     * @param string $sql The SQL query to execute
     */
    abstract public function q($sql);

    /**
     * @brief Escape a string before being passed to a DB query.
     *
     * This abstract function needs to be implemented in the real driver.
     *
     * @param string $str The string to escape.
     */
    abstract public function escape($str);

    /**
     * @brief Close the database connection.
     *
     * This abstract function needs to be implemented in the real driver.
     */
    abstract public function close();

    /**
     * @brief Return text name for db driver
     *
     * This abstract function needs to be implemented in the real driver.
     */
    abstract public function getdriver();

    public function __construct($server, $scheme, $port, $user, $pass, $db, $install = false)
    {
        if (($install) && (!$this->install($server, $scheme, $port, $user, $pass, $db))) {
            return;
        }
        $this->connect($server, $scheme, $port, $user, $pass, $db);
    }

    public function get_null_date()
    {
        return DBA::$null_date;
    }

    public function get_install_script()
    {
        $platform_name = System::get_platform_name();
        if (file_exists('install/' . $platform_name . '/' . DBA::$install_script)) {
            return 'install/' . $platform_name . '/' . DBA::$install_script;
        }

        return 'install/' . DBA::$install_script;
    }

    public function get_table_quote()
    {
        return DBA::$tquot;
    }

    public function utcnow()
    {
        return DBA::$utc_now;
    }

    public function install($server, $scheme, $port, $user, $pass, $db)
    {
        if (!(strlen($server) && strlen($user))) {
            $this->connected = false;
            $this->db = null;
            return false;
        }

        if (strlen($server) && ($server !== 'localhost') && ($server !== '127.0.0.1') && (!strpbrk($server, ':;'))) {
            if (!z_dns_check($server)) {
                $this->error = sprintf(t('Cannot locate DNS info for database server \'%s\''), $server);
                $this->connected = false;
                $this->db = null;
                return false;
            }
        }

        return true;
    }

    /**
     * @brief Sets the database driver's debugging state.
     *
     * @param int $dbg 0 to disable debugging
     */
    public function dbg($dbg)
    {
        $this->debug = $dbg;
    }

    public function __destruct()
    {
        if ($this->db && $this->connected) {
            $this->close();
        }
    }

    public function quote_interval($txt)
    {
        return $txt;
    }

    public function optimize_table($table)
    {
        q('OPTIMIZE TABLE ' . $table);
    }

    public function concat($fld, $sep)
    {
        return 'GROUP_CONCAT(DISTINCT ' . $fld . ' SEPARATOR \'' . $sep . '\')';
    }

    public function escapebin($str)
    {
        return $this->escape($str);
    }

    public function unescapebin($str)
    {
        return $str;
    }
} // end abstract dba_driver class


//
// Procedural functions
//

function printable($s, $escape = true)
{
    $s = preg_replace("~([\x01-\x08\x0E-\x0F\x10-\x1F\x7F-\xFF])~", ".", $s);
    $s = str_replace("\x00", '.', $s);
    if ($escape) {
        $s = escape_tags($s);
    }

    return $s;
}

/**
 * @brief set database driver debugging state.
 *
 * @param int $state 0 to disable debugging
 */
function dbg($state)
{
    global $db;

    if (DBA::$dba) {
        DBA::$dba->dbg($state);
    }
}

/**
 * @brief Escape strings being passed to DB queries.
 *
 * Always escape strings being used in DB queries. This function returns the
 * escaped string. Integer DB parameters should all be proven integers by
 * wrapping with intval().
 *
 * @param string $str A string to pass to a DB query
 * @return string Return an escaped string of the value to pass to a DB query.
 */
function dbesc($str)
{

    if (is_null_date($str)) {
        $str = NULL_DATE;
    }

    if (DBA::$dba && DBA::$dba->connected) {
        return(DBA::$dba->escape($str));
    } else {
        return(str_replace("'", "\\'", $str));
    }
}
function dbescbin($str)
{
    return DBA::$dba->escapebin($str);
}

function dbunescbin($str)
{
    return DBA::$dba->unescapebin($str);
}

function dbescdate($date)
{
    if (is_null_date($date)) {
        return DBA::$dba->escape(NULL_DATE);
    }

    return DBA::$dba->escape($date);
}

function db_quoteinterval($txt)
{
    return DBA::$dba->quote_interval($txt);
}

function dbesc_identifier($str)
{
    return DBA::$dba->escape_identifier($str);
}

function db_utcnow()
{
    return DBA::$dba->utcnow();
}

function db_optimizetable($table)
{
    DBA::$dba->optimize_table($table);
}

function db_concat($fld, $sep)
{
    return DBA::$dba->concat($fld, $sep);
}

function db_use_index($str)
{
    return DBA::$dba->use_index($str);
}

/**
 * @brief Execute a SQL query with printf style args.
 *
 * printf style arguments %s and %d are replaced with variable arguments, which
 * should each be appropriately dbesc() or intval().
 *
 * SELECT queries return an array of results or false if SQL or DB error. Other
 * queries return true if the command was successful or false if it wasn't.
 *
 * Example:
 * @code{.php}$r = q("SELECT * FROM %s WHERE `uid` = %d",
 *         'user', 1);@endcode
 *
 * @param string $sql The SQL query to execute
 * @return bool|array
 */
function q($sql)
{

    $args = func_get_args();
    array_shift($args);

    if (DBA::$dba && DBA::$dba->connected) {
        $stmt = vsprintf($sql, $args);
        if ($stmt === false) {
            db_logger('dba: vsprintf error: ' .
                print_r(debug_backtrace(DEBUG_BACKTRACE_PROVIDE_OBJECT, 1), true), LOGGER_NORMAL, LOG_CRIT);
        }
        if (DBA::$dba->debug) {
            db_logger('Sql: ' . $stmt, LOGGER_DEBUG, LOG_INFO);
        }

        return DBA::$dba->q($stmt);
    }

    /*
     * This will happen occasionally trying to store the
     * session data after abnormal program termination
     */

    db_logger('dba: no database: ' . print_r($args, true), LOGGER_NORMAL, LOG_CRIT);

    return false;
}

/**
 * @brief Raw DB query, no arguments.
 *
 * This function executes a raw DB query without any arguments.
 *
 * @param string $sql The SQL query to execute
 */
function dbq($sql)
{

    if (DBA::$dba && DBA::$dba->connected) {
        $ret = DBA::$dba->q($sql);
    } else {
        $ret = false;
    }

    return $ret;
}


// Caller is responsible for ensuring that any integer arguments to
// dbesc_array are actually integers and not malformed strings containing
// SQL injection vectors. All integer array elements should be specifically
// cast to int to avoid trouble.

function dbesc_array_cb(&$item, $key)
{
    if (is_string($item)) {
        if (is_null_date($item)) {
            $item = NULL_DATE;
        }
        $item = dbesc($item);
    }
}


function dbesc_array(&$arr)
{
    $bogus_key = false;
    if (is_array($arr) && count($arr)) {
        $matches = false;
        foreach ($arr as $k => $v) {
            if (preg_match('/([^a-zA-Z0-9\-\_\.])/', $k, $matches)) {
                logger('bogus key: ' . $k);
                $bogus_key = true;
            }
        }
        array_walk($arr, 'dbesc_array_cb');
        if ($bogus_key) {
            $arr['BOGUS.KEY'] = 1;
            return false;
        }
    }
    return true;
}

function db_getfunc($f)
{
    $lookup = array(
        'rand'=>array(
            DBTYPE_MYSQL=>'RAND()',
            DBTYPE_POSTGRES=>'RANDOM()'
        ),
        'utc_timestamp'=>array(
            DBTYPE_MYSQL=>'UTC_TIMESTAMP()',
            DBTYPE_POSTGRES=>"now() at time zone 'UTC'"
        ),
        'regexp'=>array(
            DBTYPE_MYSQL=>'REGEXP',
            DBTYPE_POSTGRES=>'~'
        ),
        '^'=>array(
            DBTYPE_MYSQL=>'^',
            DBTYPE_POSTGRES=>'#'
        )
    );
    $f = strtolower($f);
    if (isset($lookup[$f]) && isset($lookup[$f][ACTIVE_DBTYPE])) {
        return $lookup[$f][ACTIVE_DBTYPE];
    }

    db_logger('Unable to abstract DB function "'. $f . '" for dbtype ' . ACTIVE_DBTYPE, LOGGER_DEBUG, LOG_ERR);
    return $f;
}

function db_load_file($f)
{
    // db errors should get logged to the logfile
    $str = @file_get_contents($f);
    $arr = explode(';', $str);
    if ($arr) {
        foreach ($arr as $a) {
            if (strlen(trim($a))) {
                $r = dbq(trim($a));
            }
        }
    }
}


// The logger function may make DB calls internally to query the system logging parameters.
// This can cause a recursion if database debugging is enabled.
// So this function preserves the current database debugging state and then turns it off
// temporarily while doing the logger() call

function db_logger($s, $level = LOGGER_NORMAL, $syslog = LOG_INFO)
{

    if (DBA::$logging || ! DBA::$dba) {
        return;
    }

    $saved = DBA::$dba->debug;
    DBA::$dba->debug = false;
    DBA::$logging = true;
    logger($s, $level, $syslog);
    DBA::$logging = false;
    DBA::$dba->debug = $saved;
}


function db_columns($table)
{

    if ($table) {
        if (ACTIVE_DBTYPE === DBTYPE_POSTGRES) {
            $r = q(
                "SELECT column_name as field FROM information_schema.columns WHERE table_schema = 'public' AND table_name = '%s'",
                dbesc($table)
            );
            if ($r) {
                return ids_to_array($r, 'field');
            }
        } else {
            $r = q(
                "show columns in %s",
                dbesc($table)
            );
            if ($r) {
                return ids_to_array($r, 'Field');
            }
        }
    }

    return [];
}


function db_indexes($table)
{

    if ($table) {
        if (ACTIVE_DBTYPE === DBTYPE_POSTGRES) {
            $r = q(
                "SELECT indexname from pg_indexes where tablename = '%s'",
                dbesc($table)
            );
            if ($r) {
                return ids_to_array($r, 'indexname');
            }
        } else {
            $r = q(
                "show index from %s",
                dbesc($table)
            );
            if ($r) {
                return ids_to_array($r, 'Key_name');
            }
        }
    }

    return [];
}