<?php
/**
 * Simple SQL class
 *
 * $Id$
 *
 * @author gERD Schaufelberger <gerd@schaufelberger.de>
 * @package Wombat
 * @subpackage db
 */

WBClass::load('WBLog');

/**
 * Simple SQL class
 *
 * Allows to connect and query MySQL DB
 *
 * @version 0.4.0
 * @package Wombat
 * @subpackage db
 */
class WBDatasource_SQL extends WBStdClass
{
    /**
     * Id of current database connection
     * @var string
     */
    protected $dbcId = null;

    /**
     * Bufferd DB connections
     * @var array
     */
    static protected $dbcs =   array();

    /**
     * Logger
     * @var WBLog
     */
    protected $log;

    /**
     * Config
     *
     * Holds configuration variables:
     * - dbconfig
     * - host
     * - user
     * - database
     * - password
     * - driver
     * - port
     *
     * @var array
     */
    protected $config  =   array(
                                    'dbconfig'  =>  '',
                                    'driver'    =>  'MySQL',
                                    'port'      =>  3306,
                                    'host'      =>  null,
                                    'user'      =>  null,
                                    'password'  =>  null,
                                    'database'  =>  null,
                                    );

    /**
     * Constructor
     *
     * Parameter:
     * - "dbconfig": name of database configuration file
     * - "driver": db driver (MySQL) like MySQL or Postgres
     * - "port": db port to connect (3306)
     * - "host": database
     * - "database": database
     * - "user": db user
     * - "password": db user's password
     *
     * @param array $parameter
     */
    public function __construct( $parameter = array() )
    {
        $this->log   =  WBLog::start(__CLASS__);

        // get config either from parameter or file
        /** @var WBConfig */
        $conf        =	WBClass::create( 'WBConfig' );
        if (empty($parameter['dbconfig'])) {
            $parameter['dbconfig']  =   'config';
        }

        // load from db config file
        $conf->load($parameter['dbconfig']);
        $parameter  =   array_merge($conf->get('db', array()), $parameter);

        // override default configuration with parameter
        foreach ($this->config as $k => $v) {
            if (!empty($parameter[$k])) {
                $this->config[$k]   =   $parameter[$k];
            }
        }

        // verify config
        foreach (array('driver', 'port', 'host', 'database', 'user', 'password') as $k) {
            if (empty($this->config[$k])) {
                WBClass::load('WBException_Argument');
                throw new WBException_Argument('Invalid parameter set to connect DB. Parameter driver (MySQL), port (3306), host, database, user, password must not be empty.', 7, __CLASS__);
            }
        }
    }

    /**
     * disconnect from database
     *
     */
    public function __destruct()
    {
        if( !$this->dbcId ) {
            return;
        }

        // decrese reference counter and disconnect
        --self::$dbcs[$this->dbcId]['count'];

        $log    =   array(
                'action'    =>  'diconnect',
                'connection'=>  'keep',
                'id'        =>  $this->dbcId,
                'refcount'  =>  self::$dbcs[$this->dbcId]['count']
            );

        if( self::$dbcs[$this->dbcId]['count'] > 0 ) {
            $this->log->notice( $log );
            return;
        }

        $log['connection']  =   'close';
        $this->log->notice( $log );

        self::$dbcs[$this->dbcId]['dbc']->close();
    }

    /**
    * connect to databse
    *
    * dynamicly connect to mysql database. Each connection is buffered to avoid
    * multiple connection to the same databse. This implies, that there can be
    * be only one connection per user, host and databse.
    *
    * @todo switch on caching
    * @return mysqli
    */
    public function connect()
    {
        // only once
        if( $this->dbcId ) {
            return self::$dbcs[$this->dbcId]['dbc'];
        }

        // allow only one instance per host, database and user
        $id =   $this->getId();

        if( isset( self::$dbcs[$id] ) && self::$dbcs[$id]['count'] > 0 ) {
            ++self::$dbcs[$id]['count'];
            $this->dbcId   =   $id;

            $log    =   array(
                'action'    =>  'connect',
                'connection'=>  'old',
                'id'        =>  $this->dbcId,
                'refcount'  =>  self::$dbcs[$this->dbcId]['count']
            );
            $this->log->notice( $log );
            return self::$dbcs[$this->dbcId]['dbc'];
        }

        $dbc =   new mysqli( $this->config['host'], $this->config['user'], $this->config['password'], $this->config['database'], $this->config['port'] );
        if( mysqli_connect_errno() ) {
            WBClass::load( 'WBException_Datasource' );
            throw new WBException_Datasource( 'Could not connect to database', 1, __CLASS__ );
            return false;
        }
        $dbc->set_charset( 'utf8' );

        // buffer
        self::$dbcs[$id]   =   array(
                            'dbc'   =>  $dbc,
                            'count' =>  1
                    );
        $this->dbcId   =   $id;

        $log    =   array(
                'action'    =>  'connect',
                'connection'=>  'new',
                'id'        =>  $this->dbcId,
                'refcount'  =>  1
            );
        $this->log->notice( $log );
        return self::$dbcs[$this->dbcId]['dbc'];
    }

    /**
     * receive connection id
     *
     * Create connection id using current config
     *
     * @return string
     */
    public function getId()
    {
        $id =   $this->config['host'] . '_'
                . $this->config['user'] . '_'
                . $this->config['database'];
        return $id;
    }

   /**
    * Quote anything for SQL
    *
    * @param mixed $value
    * @param bool $like whether the quote should be done for LIKE
    * @return string
    */
    public function quote($value, $like = false)
    {
        if ($like) {
            $dbc        =   $this->connect();
            $value      =   $dbc->real_escape_string($value);
            $replace    =   array(
                   '\\\\'   =>  '\\\\\\\\',
                   '%'      =>  '\\%',
                   '_'      =>  '\\_'
                );
            return str_replace(array_keys($replace), array_values($replace), $value);

        }

        // integer values are just OK
        if (is_int($value)) {
            return $value;
        }

        if (is_double($value) || is_float($value)) {
            return sprintf('%F', $value);
        }

        if (is_string($value) && preg_match('/^\d+$/', $value)) {
            // convert leading zero values to string
            if (preg_match('/^0+/', $value)) {
                return '"' . $value . '"';
            }
            return $value;
        }

        if (is_bool($value)) {
            return $value ? '1' : '0';
        }

        if (is_null($value)) {
            return 'NULL';
        }

        $dbc    =   $this->connect();
        return  "'" . $dbc->real_escape_string($value) . "'";
    }

   /**
    * execute query string
    *
    * Connects to database and execute query
    *
    * @param string $query
    * @return mysqli_result
    */
    public function query($q)
    {
        $dbc    =   $this->connect();
        $log    =   array(
                'action'    =>  'query',
                'id'        =>  $this->dbcId,
                'query'     =>  $q,
            );

        $res    =   $dbc->query($q);
        if (!$res) {
            $log['error']   =   $dbc->error;
            $this->log->err($log);
            WBClass::load( 'WBException_Datasource' );
            throw new WBException_Datasource('Database query failed! ' . $q, 2, __CLASS__);
        }

        // choose log level
        if (0 == strncmp('SELECT ', $q, 6)) {
            $this->log->notice($log);
        }
        else {
            $this->log->warn($log);
        }

        return $res;
    }
}