<?php
/*
This file belongs to the Webinterface of schokokeks.org Hosting

Written by schokokeks.org Hosting, namely
  Bernd Wurst <bernd@schokokeks.org>
  Hanno Böck <hanno@schokokeks.org>

This code is published under a 0BSD license.

Nevertheless, in case you use a significant part of this code, we ask (but not require, see the license) that you keep the authors' names in place and return your changes to the public. We would be especially happy if you tell us what you're going to do with this code.
*/

require_once('inc/base.php');
require_once('inc/error.php');
require_once('inc/debug.php');


class DB extends PDO
{
    public function __construct()
    {
        $dsn = "mysql:host=".config('db_host', true);
        if (config('db_port', true)) {
            $dsn .= ';port='.config('db_port', true);
        }
        if (config('db_socket', true)) {
            $dsn = "mysql:unix_socket=".config('db_socket', true);
        }
        $username = config('db_user', true);
        $password = config('db_pass', true);
        parent::__construct($dsn, $username, $password, [PDO::ATTR_TIMEOUT => "30"]);
    }


    /*
      Wenn Parameter übergeben werden, werden Queries immer als Prepared statements übertragen
    */
    public function myquery($stmt, $params = null, $allowempty = false)
    {
        if (is_array($params)) {
            if (config("enable_debug") && !$allowempty) {
                foreach (array_values($params) as $p) {
                    if ($p === '') {
                        DEBUG("Potential bug, empty string found in database parameters");
                        warning("Potential bug, empty string found in database parameters");
                    }
                }
            }
            $response = parent::prepare($stmt);
            $response->execute($params);
            return $response;
        } else {
            if (strtoupper(substr($stmt, 0, 6)) == "INSERT" ||
          strtoupper(substr($stmt, 0, 7)) == "REPLACE" ||
          strpos(strtoupper($stmt), "WHERE") > 0) { // Das steht nie am Anfang
                $backtrace = debug_backtrace();
                $wherepart = substr(strtoupper($stmt), strpos(strtoupper($stmt), "WHERE"));
                if ((strpos($wherepart, '"') > 0 || strpos($wherepart, "'") > 0) && config("enable_debug")) {
                    warning("Possibly unsafe SQL statement in {$backtrace[1]['file']} line {$backtrace[1]['line']}:\n$stmt");
                }
            }
            return parent::query($stmt);
        }
    }
}


/* FIXME
   Das ist etwas unelegant. Soll nur übergangsweise verwendet werden bis alles auf prepared statements umgestellt ist
*/
function db_escape_string($string)
{
    if (config("enable_debug")) {
        $backtrace = debug_backtrace();
        warning("call to db_escape_string() in {$backtrace[0]['file']} line {$backtrace[0]['line']}");
    }
    global $_db;
    __ensure_connected();
    $quoted = $_db->quote($string);
    // entferne die quotes, damit wird es drop-in-Kompatibel zu db_escape_string()
    $ret = substr($quoted, 1, -1);
    return $ret;
}


function db_insert_id()
{
    global $_db;
    __ensure_connected();
    return $_db->lastInsertId();
}


function __ensure_connected()
{
    /*
      Dieses Kontrukt ist vermultich noch schlimmer als ein normales singleton
      aber es hilft uns in unserem prozeduralen Kontext
    */
    global $_db;
    if (! isset($_db)) {
        try {
            DEBUG("Neue Datenbankverbindung!");
            $_db = new DB();
            $_db->query("SET NAMES utf8mb4");
            $_db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
            $_db->setAttribute(PDO::ATTR_AUTOCOMMIT, true);
        } catch (PDOException $e) {
            global $debugmode;
            if ($debugmode) {
                die("MySQL-Fehler: ".$e->getMessage());
            } else {
                die("Fehler bei der Datenbankverbindung!");
            }
        }
    }
}


function db_query($stmt, $params = null, $allowempty = false)
{
    global $_db;
    __ensure_connected();
    $backtrace = debug_backtrace();
    DEBUG($backtrace[0]['file'].':'.$backtrace[0]['line'].': '.htmlspecialchars($stmt));
    if ($params) {
        DEBUG($params);
    }
    try {
        $result = $_db->myquery($stmt, $params, $allowempty);
        DEBUG('=> '.$result->rowCount().' rows');
    } catch (PDOException $e) {
        global $debugmode;
        if ($debugmode) {
            system_failure("MySQL-Fehler: ".$e->getMessage()."\nQuery:\n".$stmt."\nParameters:\n".print_r($params, true));
        } else {
            system_failure("Datenbankfehler");
        }
    }
    return $result;
}