<?php
/**
 *  Kata-kana CAPTCHA
 *
 *  @since      2006.11.26
 *  @author     Nob Funaki <http://blog.zuzara.com/>
 *  @license    GNU Lesser General Public License (GNU LGPL)
 */
class KATAKANA_CAPTCHA
{
    /**
     *  表示されるカタカナ
     *  @var    string
     */
    private $textstring = '';

    /**
     *
     */
    public function __construct()
    {
        $this->create();
    }

    /**
     *
     */
    private function create()
    {
        $width = 150;
        $height = 40;
        $im = imagecreatetruecolor($width, $height);

        // Create some colors
        $white = imagecolorallocate($im, 255, 255, 255);
        $black = imagecolorallocate($im, 0, 0, 0);
        imagefilledrectangle($im, 0, 0, $width, $height, $white);

        $text = $this->generateKeyString();
        $font = dirname(__FILE__).'/fonts/ClownCharlie.TTF'; // @todo   フォント増やす

        imagettftext($im, 20, 0, 0, 30, $black, $font, $text);

        //  This code based on KCAPTCHA PROJECT VERSION 1.2.4
        //  Copyright by Kruglov Sergei, 2006
        //  www.captcha.ru, www.kruglov.ru
        //  @see    kcaptcha.php
        //  {{{
        $center = $width / 2;

        // periods
        $rand1 = mt_rand(750000,1200000)/10000000;
        $rand2 = mt_rand(750000,1200000)/10000000;
        $rand3 = mt_rand(750000,1200000)/10000000;
        $rand4 = mt_rand(750000,1200000)/10000000;
        // phases
        $rand5 = mt_rand(0,3141592)/500000;
        $rand6 = mt_rand(0,3141592)/500000;
        $rand7 = mt_rand(0,3141592)/500000;
        $rand8 = mt_rand(0,3141592)/500000;
        // amplitudes
        $rand9 = mt_rand(330,420)/110;
        $rand10 = mt_rand(330,450)/110;

        $foreground_color = array(mt_rand(0,100), mt_rand(0,100), mt_rand(0,100));
        $background_color = array(mt_rand(200,255), mt_rand(200,255), mt_rand(200,255));

        $img2 = imagecreatetruecolor($width, $height);
        $foreground = imagecolorallocate($img2, $foreground_color[0], $foreground_color[1], $foreground_color[2]);
        $background = imagecolorallocate($img2, $background_color[0], $background_color[1], $background_color[2]);

        for ($x = 0; $x < $width; $x++) {
            for ($y = 0; $y < $height; $y++) {
                $sx = $x + (sin($x*$rand1+$rand5) + sin($y*$rand3+$rand6)) * $rand9 - $width/2 + $center + 1;
                $sy = $y + (sin($x*$rand2+$rand7) + sin($y*$rand4+$rand8)) * $rand10;

                if ($sx < 0 || $sy < 0 || $sx >= $width-1 || $sy >= $height-1) {
                    $color    = 255;
                    $color_x  = 255;
                    $color_y  = 255;
                    $color_xy = 255;
                } else {
                    $color    = imagecolorat($im, $sx, $sy) & 0xFF;
                    $color_x  = imagecolorat($im, $sx+1, $sy) & 0xFF;
                    $color_y  = imagecolorat($im, $sx, $sy+1) & 0xFF;
                    $color_xy = imagecolorat($im, $sx+1, $sy+1) & 0xFF;
                }

                if ($color == 0 && $color_x == 0 && $color_y == 0 && $color_xy == 0) {
                    $newred   = $foreground_color[0];
                    $newgreen = $foreground_color[1];
                    $newblue  = $foreground_color[2];
                } else if ($color == 255 && $color_x == 255 && $color_y == 255 && $color_xy == 255) {
                    $newred   = $background_color[0];
                    $newgreen = $background_color[1];
                    $newblue  = $background_color[2];	
                } else {
                    $frsx=$sx-floor($sx);
                    $frsy=$sy-floor($sy);
                    $frsx1=1-$frsx;
                    $frsy1=1-$frsy;

                    $newcolor = ($color*$frsx1*$frsy1 + $color_x*$frsx*$frsy1 + $color_y*$frsx1*$frsy + $color_xy*$frsx*$frsy);

                    if ($newcolor > 255) {
                        $newcolor = 255;
                    }
                    $newcolor  = $newcolor/255;
                    $newcolor0 = 1-$newcolor;

                    $newred   = $newcolor0*$foreground_color[0]+$newcolor*$background_color[0];
                    $newgreen = $newcolor0*$foreground_color[1]+$newcolor*$background_color[1];
                    $newblue  = $newcolor0*$foreground_color[2]+$newcolor*$background_color[2];
                }

                imagesetpixel($img2, $x, $y, imagecolorallocate($img2, $newred, $newgreen, $newblue));
            }
        }
        //  }}} End KCAPTCHA code.

        header("Content-Type: image/x-png");
        imagepng($img2);
    }

    /**
     *  @param  void
     *  @return string
     */
    private function generateKeyString()
    {
        $convert_table = array(
            'a' => 'チ',
            'b' => 'コ',
            'e' => 'イ',
            'f' => 'ハ',
            'g' => 'キ',
            'j' => 'マ',
            'm' => 'モ',
            'n' => 'ミ',
            'o' => 'ラ',
            'p' => 'セ',
            'q' => 'タ',
            'r' => 'ス',
            's' => 'ト',
            't' => 'カ',
            'u' => 'ナ',
            'v' => 'ヒ',
            'w' => 'テ',
            'x' => 'サ',
            '1' => 'ヌ',
            '2' => 'フ',
            '3' => 'ア',
            '4' => 'ウ',
            '5' => 'エ',
            '6' => 'オ',
            '7' => 'ヤ',
            '8' => 'ユ',
            '9' => 'ヨ',
            '-' => 'ホ',
            '^' => 'ヘ',
            ';' => 'レ',
            ']' => 'ム',
            ',' => 'ネ',
            '.' => 'ル',
            '/' => 'メ',
            'A' => 'ヂ',
            'B' => 'ゴ',
            'F' => 'バ',
            'G' => 'ギ',
            'I' => 'ピ',
            'K' => 'ポ',
            'N' => 'ロ',
            'P' => 'ゼ',
            'Q' => 'ダ',
            'R' => 'ズ',
            'S' => 'ド',
            'T' => 'ガ',
            'U' => 'パ',
            'V' => 'ビ',
            'W' => 'デ',
            'X' => 'ザ',
            '!' => 'プ',
            '"' => 'ブ',
            '=' => 'ボ',
            '`' => 'ベ',
            '<' => 'ペ',
            '?' => 'ヴ',
            );
        //  @fixme  ノとレが隣とかダメそう
        $rand = array_rand($convert_table, 4);
        $text = '';
        $keys = '';
        foreach ($rand as $val) {
            $keys .= $val;
            $text .= $convert_table[$val];
        }
        $this->textstring = $text;
        return $keys;
    }

    /**
     *
     */
    public function getTextString()
    {
        return $this->textstring;
    }
}