<?php
/**
 * Simple table access
 *
 * $Id$
 *
 * @author gERD Schaufelberger <gerd@php-tools.net>
 * @license PHP License
 * @package WB
 * @subpackage db
 */

/**
 * Simple table access
 *
 * @version 0.2.0
 * @package WB
 * @subpackage db
 */
class WBDatasource_ObscureCode extends WBStdClass
{
    /**
     * tble object
     * @var WBDatasource_Table 
     */
    protected $table;
    
    /**
     * current code
     * @var string
     */
    protected $code = null;
    
    /**
     * prepared clause 
     * @var array
     */
    protected $clause   =   array(
                                array(
                                    'field' =>  'namespace',
                                    'value' =>  '',
                                    ),
                                array(
                                    'field' =>  'xid',
                                    'value' =>  '',
                                    )
                                );
    
    /**
     * craete table object
     *
     * @param array $parameter
     */
    public function __construct($parameter = array())
    {
        $this->table    =   WBClass::create('WBDatasource_Table');
        
    }
    
    /**
     * set namespace string
     * 
     * @param string $ns
     * @return WBDatasource_ObscureCode
     */
    public function setNamespace($ns)
    {
        if ($this->clause[0]['value'] == $ns) {
            return $this;
        }
        $this->clause[0]['value']   =   $ns;
        $this->code                 =   null;
        return $this;
    }
    
    /**
     * set id
     * 
     * @param string $id
     * @return WBDatasource_ObscureCode
     */
    public function setId($id)
    {
        if ($this->clause[1]['value'] == $id) {
            return $this;
        }
        $this->clause[1]['value']   =   $id;
        $this->code                 =   null;
        return $this;
    }
    

    /**
     * create a random obscure code
     *
     * Make an alphanumeric random string to be used to obscure ids. 
     * Be careful, those obscure codes are case sensitive. Hence one 
     * actually can't compare it using WHERE clause for case insensive
     * table (which is pretty much defualt). Therefore, use an additional
     * (numeric) primary key to load record from databse and compare 
     * the obscure code wwith PHP's strink functions.
     *
     * @param int $length length between 2 and 255 
     * @param bool $startLetter fist character will be a letter
     * @param bool $endLetter last character will be a letter
     * @param bool $capitalOnly use only capital letters
     * @return string
     */
    static public function mkRandObscure($length = 8, $startLetter = false, $endLetter = false, $capitalOnly = false)
    {
        if ($length > 255) {
            $length = 255;
        }
        if ($length < 2) {
            $length = 2;
        }

        // avoid confusing letters like 0 and O
        $alpha  =   range('2', '9');
        $cntN   =   count($alpha);
        $alpha  =   array_merge($alpha, array(
                        'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H'
                        //, 'I'
                        , 'J', 'K', 'L', 'M', 'N'
                        //, 'O'
                        , 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'
                        ));

        if (!$capitalOnly) {
            $alpha  =   array_merge($alpha, array(
                        'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h'
                        , 'i', 'j'
                        //, 'l'
                        , 'm', 'n'
                        //, 'o'
                        , 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'
                        ));
        }
        $cnt    =   count($alpha) - 1;
        $rc     =   array();
        
        // force obscurce code to start with a letter
        if ($startLetter) {
            $rc[]   =   $alpha[rand($cntN, $cnt)];
            --$length;
        }
        if ($endLetter) {
            --$length;
        }
        
        // fill with random letters and digists
        for ($i = 0; $i < $length; ++$i) {
            $rc[]   =   $alpha[rand(0, $cnt)];
        }
        
        if ($endLetter) {
            $rc[]   =   $alpha[rand($cntN, $cnt)];
        }

        return implode('', $rc);
    }
    
    
    /**
     * create obscure code 
     * 
     * Create random string using a-z and 0-9. Random string may be up
     * to 255 characters long. Also random string always starts and ends 
     * with a letter!
     * 
     * @param int $length
     * @return WBDatasource_ObscureCode
     */
    public function create($length = 8)
    {
        $this->clear();
        
        $this->code =   self::mkRandObscure($length, true, true);
        $save       =   array(
                        'namespace' =>  $this->clause[0]['value'],
                        'xid'       =>  $this->clause[1]['value'],
                        'code'      =>  $this->code
                );
        $this->table->save('obscurecode', '__new', $save);
        return $this;
    }
    
    /**
     * clrear random code
     * 
     * remove random code from database
     * 
     * @return WBDatasource_ObscureCode
     */
    public function clear()
    {
        $this->code =   null;
        $this->table->delete('obscurecode', null, null, $this->clause);
        return $this;
    }

    /**
     * receive current obscure code
     * 
     * @return string
     */
    public function get()
    {
        if ($this->code) {
            return $this->code;
        }
        
        $list   =   $this->table->get('obscurecode', null, null, $this->clause);
        if (count($list) != 1) {
            return '';
        }
        $this->code =   $list[0]['code'];
        return $this->code;
    }
    
    /**
     * verify string against obscure code
     * 
     * see whether current code matches
     * 
     * @param string $rc
     * @param bool $once if true, clear code after check
     * @return bool true if codes are the same
     */
    public function check($code, $once = false)
    {
        if (empty($code)) {
            return false;
        }
        
        $current    =   $this->get();
        if ($once) {
            $this->clear();   
        }
        if ($current == $code) {
            return true;
        }
        return false;
    }
}