<?php
/**
 * Store reference to something else
 *
 * $Id$
 *
 * @author gERD Schaufelberger <gerd@php-tools.net>
 * @license PHP License
 * @package WB
 * @subpackage db
 */

/**
 * Store reference to something else
 *
 * Manage storage of something for anything related to other tables. Hence, this allows
 * to comment or ratings blog entries as well as users or uploaded files
 *
 * @version 0.2.0
 * @package WB
 * @subpackage db
 */
class WBDatasource_XReference extends WBStdClass
{
    /**
     * table object
     * @var WBDatasource_Table
     */
    protected $table;

    /**
     * prepared clause
     * @var array
     */
    protected $clause   =   array(
                                array(
                                    'field' =>  'namespace',
                                    'value' =>  '',
                                    ),
                                array(
                                    'field' =>  'xid',
                                    'value' =>  '',
                                    )
                                );

    /**
     * config loader
     * @var array
     */
    static protected $conf = array(
                                'default'       =>  array(),
                                'namespaces'    =>  array()
                                );

    /**
     * user id for comments
     * @var string
     */
    protected $uid  =   0;

    /**
     * list of user groups the current user is member of
     * @var array
     */
    protected $uGroups  =   array();

    /**
     * user table's primary key
     * @var string
     */
    protected $uPrimary;

    /**
     * static constructor helper
     *
     * Load configuration into static property and merge it with
     * default values.
     * @param array $defaultConfig
     * @param string $name
     */
    static protected function staticConstructLoader($defaultConfig, $name)
    {
        self::$conf =   $defaultConfig;

        $config   =   WBClass::create('WBConfig');
        $config->load($name);

        // default config
        $default    =   $config->get($name . '/default', array());
        if (!is_array($default)) {
            $default    =   array();
        }
        self::$conf['default'] =    array_merge(self::$conf['default'], $default);

        // merge namespace config with default values
        $namespaces =   $config->get($name . '/namespaces', array());
        if (!is_array($namespaces)) {
            $namespaces =   array();
        }

        foreach ($namespaces as $ns => $c) {
            if (empty($ns)) {
                continue;
            }
            if (!is_array($c)) {
                $c  =   array();
            }

            $c  =   array_merge(self::$conf['default'], $c);
            self::$conf['namespaces'][$ns]  =   $c;
        }
    }

    /**
     * craete table object
     *
     * @param array $parameter
     */
    public function __construct($parameter = array())
    {
        $this->table    =   WBClass::create('WBDatasource_Table');
        $this->uPrimary =   $this->table->getIdentifier('user');

        $this->uid      =   0;
        $this->uGroups  =   array();

        // act as user
        if (!isset($parameter['user']) || empty($parameter['user'])) {
            WBClass::load('WBUser');
            $user               =   WBUser::getCurrent();
            if ($user->isAuthenticated()) {
                $this->uid          =   $user->getId();
                $this->uGroups      =   $user->getGroups();
            }
            return;
        }

        $user   =   WBClass::create('WBUser');
        if (!$user->load($parameter['user'])) {
            return;
        }

        $this->uid      =   $user->getId();
        $this->uGroups  =   $user->getGroups();
    }

    /**
     * set namespace string
     *
     * @param string $ns
     * @return WBDatasource_Comment
     */
    public function setNamespace($ns)
    {
        if ($this->clause[0]['value'] == $ns) {
            return $this;
        }

        $this->xuid =   0;

        // verify namespace config
        if (!isset(self::$conf['namespaces'][$ns])) {
            WBClass::load('WBException_Config');
            throw new WBException_Config('Namespace "' . $ns . '" is not configured.', 1, __CLASS__);
        }

        // verify table
        $primary    =   $this->table->getIdentifier($ns);
        if (empty($primary)) {
            WBClass::load('WBException_Argument');
            throw new WBException_Argument('Namespace must be a table with primary key.', 1, __CLASS__);
        }

        $this->clause[0]['value']   =   $ns;
        return $this;
    }

    /**
     * get current namespace
     *
     * Namespace might be set explicitly or using by loading a special
     * comment by id
     *
     * @see getXid()
     * @see load()
     * @return string
     */
    public function getNamespace()
    {
        return $this->clause[0]['value'];
    }

    /**
     * set reference id
     *
     * @param string $id
     * @return WBDatasource_Comment
     */
    public function setXId($id)
    {
        if ($this->clause[1]['value'] == $id) {
            return $this;
        }
        $this->xuid =   0;

        // verify xid
        if (empty($this->clause[0]['value'])) {
            WBClass::load('WBException_Call');
            throw new WBException_Call('There is no namespace set, yet. Use setNamespace() first.', 1, __CLASS__);
        }
        $source =   $this->table->get($this->clause[0]['value'], $id);
        if (count($source) != 1) {
            WBClass::load('WBException_Argument');
            throw new WBException_Argument('Could not identify record from namespace using given XId (' . $id . ').', 2, __CLASS__);
        }

        $this->clause[1]['value']   =   $id;

        $source     =   array_shift($source);
        if (isset($source[$this->uPrimary])) {
            $this->xuid =   $source[$this->uPrimary];
        }
        return $this;
    }

    /**
     * get current xid
     *
     * Xid might be set explicitly or using by loading a special
     * comment by id
     *
     * @see getNamespace()
     * @see load()
     * @return string
     */
    public function getXid()
    {
        return $this->clause[1]['value'];
    }

    /**
     * reset namespace and xid
     *
     * @return WBDatasource_XReference
     */
    public function reset()
    {
        $this->xuid =   0;
        foreach ($this->clause as $i => $c) {
            $this->clause[$i]['value']  =   '';
        }
        return $this;
    }

}