<?php
/**
 * 验证码类（PHP 8.0 兼容版 - 无需字体文件版）
 * 用于生成图片验证码，不依赖外部 ttf 字体
 */
class ValidateCode {
    private $charset = 'abcdefghkmnprstuvwxyzABCDEFGHKMNPRSTUVWXYZ23456789'; //随机因子
    private $code;            //验证码
    private $codelen = 4;     //验证码长度
    private $width = 130;     //宽度
    private $height = 50;     //高度
    private $img;             //图片资源
    private $fontcolor;       //字体颜色

    //构造方法
    public function __construct() {
        // PHP 8.0 建议初始化变量
        $this->code = '';
    }

    //生成随机码
    private function createCode() {
        $_len = strlen($this->charset) - 1;
        for ($i = 0; $i < $this->codelen; $i++) {
            $this->code .= $this->charset[mt_rand(0, $_len)];
        }
    }

    //生成背景
    private function createBg() {
        $this->img = imagecreatetruecolor($this->width, $this->height);
        $color = imagecolorallocate($this->img, mt_rand(157, 255), mt_rand(157, 255), mt_rand(157, 255));
        imagefilledrectangle($this->img, 0, $this->height, $this->width, 0, $color);
    }

    //生成文字
    private function createFont() {    
        $_x = $this->width / $this->codelen;
        for ($i = 0; $i < $this->codelen; $i++) {
            $this->fontcolor = imagecolorallocate($this->img, mt_rand(0, 156), mt_rand(0, 156), mt_rand(0, 156));
            
            // --- 方案 B 核心修改：使用内置字体，不需要 ttf 文件 ---
            // 参数：图片资源, 字体大小(1-5), X坐标, Y坐标, 文字内容, 颜色
            imagestring($this->img, 5, $_x * $i + mt_rand(5, 10), mt_rand(8, 15), $this->code[$i], $this->fontcolor);
        }
    }

    //生成线条、雪花
    private function createLine() {
        //线条
        for ($i = 0; $i < 6; $i++) {
            $color = imagecolorallocate($this->img, mt_rand(0, 156), mt_rand(0, 156), mt_rand(0, 156));
            imageline($this->img, mt_rand(0, $this->width), mt_rand(0, $this->height), mt_rand(0, $this->width), mt_rand(0, $this->height), $color);
        }
        //雪花
        for ($i = 0; $i < 100; $i++) {
            $color = imagecolorallocate($this->img, mt_rand(200, 255), mt_rand(200, 255), mt_rand(200, 255));
            imagestring($this->img, mt_rand(1, 5), mt_rand(0, $this->width), mt_rand(0, $this->height), '*', $color);
        }
    }

    //输出
    private function outPut() {
        header('Content-type:image/png');
        imagepng($this->img);
        imagedestroy($this->img);
    }

    //对外生成
    public function doimg() {
        $this->createBg();
        $this->createCode();
        $this->createLine();
        $this->createFont();
        $this->outPut();
    }

    //获取验证码
    public function getCode() {
        return strtolower($this->code);
    }
}
?>
