<?php
/*
simple credit card validator class
Author: slave@codegrunt.com / http://codegrunt.com

USAGE:

$cc=new CC;
$cc->ccnum="1234567890";
$cc->validate();

After validating you will have the following data:

$cc->status['type'] =  visa, mastercard, amex, discover, dinersclub, unknown
$cc->status['luhn'] = 0 (invalid), 1 (valid)

*/

class CC
{
    public $ccnum;
    public $status;
    public $allowed; // accepted card types

    function __construct()
    {
        $this->ccnum=''; // string
        $this->status=array('luhn'=>0,'type'=>'unknown'); // holds luhn and type check
        $this->allowed=array('visa','mastercard','amex','dinersclub','discover');
    }

    // see if card number passes mod10 check
    function check_luhn()
    {
        $tot=0;
        $y=0;
        for($x=strlen($this->ccnum)-1;$x>=0;$x-=2)
        {
            $tot+=$this->ccnum[$x];
            $y=$this->ccnum[$x-1]*2;
            $y>9 ? $tot+=1+$y%10 : $tot+=$y;
        }
        if($tot%10==0&&$tot>0) $this->status['luhn']=1;
        else $this->status['luhn']=0;
    }

    function validate()
    {
        $this->status['luhn']=0;
        $this->status['type']='unknown';
        foreach($this->allowed AS $check)
        {
            $this->{'check_'.$check}();
            if($this->status['type']!='unknown')
            {
                break;
            }
        }
        $this->check_luhn();
    }

    // individual card type checks

    function check_mastercard()
    {
        if(strlen($this->ccnum)==16)
        {
            $prefix=(int)substr($this->ccnum,0,2);
            if($prefix>50 && $prefix <56)
            {
                $this->status['type']='mastercard';
            }
        }
    }

    function check_visa()
    {
        if(strlen($this->ccnum)==13 || strlen($this->ccnum)==16)
        {
            if($this->ccnum[0]=='4')
            {
                $this->status['type']='visa';
            }
        }
    }

    function check_amex()
    {
        if(strlen($this->ccnum)==15)
        {
            $prefix=(int)substr($this->ccnum,0,2);
            if($prefix==34 || $prefix==37)
            {
                $this->status['type']='amex';
            }
        }
    }

    function check_dinersclub()
    {
        if(strlen($this->ccnum)==14)
        {
            $prefix=(int)substr($this->ccnum,0,3);
            if($prefix>299 || $prefix<306)
            {
                $this->status['type']='dinersclub';
            }
            else if($prefix-300==36 || $prefix-300==38)
            {
                $this->status['type']='dinersclub';
            }
        }
    }

    function check_discover()
    {
        if(strlen($this->ccnum)==16)
        {
            if(substr($this->ccnum,0,4)=='6011')
            {
                $this->status['type']='discover';
            }
        }
    }
}
?>