<?php
    error_reporting(E_ALL ^ E_DEPRECATED);
    mysqli_report(MYSQLI_REPORT_OFF);
    include "../include/variables.php";
    include "../include/functions.php";
    include "../include/errors.php";
    include "../include/getip.php";
    $PHP_SELF=$_SERVER['PHP_SELF'];
    if (isset($_SERVER['HTTP_ACCEPT_ENCODING']) && substr_count($_SERVER['HTTP_ACCEPT_ENCODING'], 'gzip')) {
        if (ob_get_length()) ob_end_clean();
        ob_start("ob_gzhandler");
    }
    else ob_start();
    if(!empty($_GET['sid']) && gettype($_GET['sid']) == "string" && $_GET['sid']!= session_id()) {
    session_id($_GET['sid']);
    }
    if (!empty($_SERVER['HTTPS'])) {
        $session_options = array(
            "secure" => true,
            "SameSite" => "None"
        );
        session_set_cookie_params($session_options);
    }
    session_start();
    include "../include/iplog.php";

    function avg($a,$b) {
        return ($a+$b)/2;
    }
    
    list($usec, $sec) = explode(' ', microtime());
    mt_srand($usec*1000000);
    
    $width=100;
    $height=30;
    $image=imagecreatetruecolor($width, $height);
    // Add Random noise
    for ($i = 0; $i < $width; $i++) {
        for ($j = 0; $j < $height; $j++) {
            $color = imagecolorallocate($image, mt_rand(0,127), mt_rand(0,127), mt_rand(0,127));
            imagesetpixel($image, $i, $j, $color);
        }
    }
    // Add Random lines
    for ($i = 0; $i < mt_rand(0,255); $i++) {
        $x1=mt_rand(0,$width);
        $x2=mt_rand(0,$width);
        $y1=mt_rand(0,$height);
        $y2=mt_rand(0,$height);
        $color = imagecolorallocatealpha($image, mt_rand(0,255), mt_rand(0,255), mt_rand(0,255), mt_rand(0,127));
        imageline($image, $x1, $y1, $x2, $y2, $color);
    }
    $rand_str=random_string(mt_rand(3,6));
    $agent=!empty($_SERVER['HTTP_USER_AGENT'])?$_SERVER['HTTP_USER_AGENT']:"";
    $agent_whitelist[]="Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/534+ (KHTML, like Gecko) BingPreview/1.0b";
    $whitelisted=false;
    if (isset($agent_whitelist) && in_array($agent, $agent_whitelist)) {
        $whitelisted=true;
    }
    $show_captcha = false;
    $logmsg="";
    if (!isset($_GET['cid']) || gettype($_GET['cid']) != "string"){
        $_SESSION['image_value'] = md5($rand_str);
        $show_captcha = true;
    } else {
        if (!isset($_SESSION['data']) || !is_array($_SESSION['data'])) {
            //$logmsg="No data entry in session";
        } elseif (!isset($_SESSION['data'][$_GET['cid']]) || !is_array($_SESSION['data'][$_GET['cid']])) {
            $logmsg="Unknown captcha id";
        } elseif (empty($_SESSION['data'][$_GET['cid']]["ip"])) {
            $logmsg="Captcha id w/o ip address";
        } elseif ($_SESSION['data'][$_GET['cid']]["ip"] != $ip) {
            $logmsg="Bad ip address (Captcha generated on ".$_SESSION['data'][$_GET['cid']]["ip"].")";
        } elseif ($_SESSION['data'][$_GET['cid']]["agent"] != $agent) {
            $logmsg="Bad user agent (Captcha generated on ".$_SESSION['data'][$_GET['cid']]["ip"]." with ".$_SESSION['data'][$_GET['cid']]["agent"]." User Agent)";
        } else {
            $show_captcha = true;
        }
    }
    if ($whitelisted) {
        if (!empty($logmsg)) $logmsg=$logmsg." (Whitelisted)";
        if (!$show_captcha) $show_captcha=true;
    }
    if ($show_captcha) {
        if (isset($_GET['cid']) && gettype($_GET['cid']) == "string") {
            $_SESSION['data'][$_GET['cid']]["captcha"] = md5($rand_str);
            $cid=$_GET['cid'];
        }
        //srand(time(NULL));
        $red=mt_rand(192,255);
        $green=mt_rand(192,255);
        $blue=mt_rand(192,255);
        $color = ImageColorAllocate($image, $red, $green, $blue);
        //imagestring($image, 5, 12, 4, $rand_str, $color);
        $angle=mt_rand(-8,8);
        $size= mt_rand(14,15);
        $box = imageftbbox($size, $angle, '../fonts/pala.ttf', $rand_str);
        $x_left=avg($box[0],$box[6]);
        $x_right=avg($box[2],$box[4]);
        $text_width = $x_right - $x_left;
        $y_top=avg($box[7],$box[5]);
        $y_bottom=avg($box[1],$box[3]);
        $text_height = $y_bottom - $y_top;
        $x=(($width-$text_width)/2); //x: left=0
        $y=($height-$text_height/2); //y: bottom=width
        imagettftext ($image, $size, $angle , $x, $y, $color , '../fonts/pala.ttf' , $rand_str);
    } else {
        header ($_SERVER['SERVER_PROTOCOL']." 403 Forbidden");
        if ($logmsg)  {
            $file=fopen("$prefix/logs/captcha.txt", "a");
            $msg= getinfo().(!empty($_SERVER['HTTP_USER_AGENT'])?("\nUser Agent: ".$_SERVER['HTTP_USER_AGENT']):"")."\n$logmsg".(!empty($dbg)?"\n$dbg":"")."\n\n";
            fwrite($file, $msg); fclose($file);
        }
    }
    
    // Add Random noise with alpha
    for ($i = 0; $i < $width; $i++) {
        for ($j = 0; $j < $height; $j++) {
            $color = imagecolorallocatealpha($image, mt_rand(0,255), mt_rand(0,255), mt_rand(0,255), mt_rand(95,127));
            imagesetpixel($image, $i, $j, $color);
        }
    }
    if ($show_captcha) {
        // Add Random lines
        for ($i = 0; $i < mt_rand(0,255); $i++) {
            $x1=mt_rand(0,$width);
            $x2=mt_rand(0,$width);
            $y1=mt_rand(0,$height);
            $y2=mt_rand(0,$height);
            $color = imagecolorallocatealpha($image, mt_rand(0,255), mt_rand(0,255), mt_rand(0,255), mt_rand(63,127));
            imageline($image, $x1, $y1, $x2, $y2, $color);
        }
    }
    ob_start();
    header('Content-type: image/jpeg');
    header("Content-Disposition: inline; filename=".(isset($cid)?$cid:"random").".jpg");
    //header ("Expires: ");
    //header ("Pragma: ");
    imagejpeg($image);
    header("Content-length: " . ob_get_length());
    ob_end_flush();
    imagedestroy($image);

?>