namespace eq;
 use PhpOffice\PhpSpreadsheet\Spreadsheet;
 class Excel{
    /**
     * @description: 使用例子
     * @return {*}
     */    
    public static function demo()
    {
        $fields=[
            ['name'=>'名称','field'=>'name'],
            ['name'=>'性别','field'=>'sex']
        ];
        $list=[
            ['name'=>'张三','sex'=>'男'],
            ['name'=>'李四','sex'=>'女']
        ];
        $name='测试demo下载'.date('YmdHis');
        self::downXlsx($name,$fields,$list);
    }
    /**
     * @description: 下载Excel文档
     * @param {*} $name 生成文件名称
     * @param {*} $list 数据列表
     * @param {*} $fields 字段列表 [['name'=>'名称','field'=>'name'],['name'=>'手机','field'=>'phone']]
     * @return {*}
     */    
    public static function downXlsx($name, $fields = [], $list = [])
    {
        $spreadsheet = new Spreadsheet();
        $sheet = $spreadsheet->getActiveSheet();
        $letter_all=[];
        $letter=['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'];
        // 通过fields数量生成Excel A-Z
        $item=0;
        foreach($fields as $k => $v){
            if($item==26){
                $item=0;
            }
            $n=ceil(($k+1)/26);
            if($n==1){
                array_push($letter_all,$letter[$item]);
            }else{
                $n=$n-2;
                array_push($letter_all,$letter[$n].$letter[$item]);
            }
            $item++;
        }
        # 生成首行标题
        foreach($fields as $k => $v){
            $sheet->setCellValue($letter_all[$k].'1', $v['name']);
        }
        // 通过传入数据生成Excel
        foreach($list as $k => $v){
            foreach($fields as $kk => $vv){
                switch($vv['field']){
                    default:$value=$v[$vv['field']];;
                }
                $sheet->setCellValue($letter_all[$kk].($k+2), $value);
            }
        }
         $names = $name;
        //utf-8转unicode格式
        $name = iconv('UTF-8', 'UCS-2BE', $name);
        $len = strlen($name);
        $str = '';
        for ($i = 0; $i < $len - 1; $i = $i + 2) {
            $c = $name[$i];
            $c2 = $name[$i + 1];
            if (ord($c) > 0) {
                $str .= '\u' . base_convert(ord($c), 10, 16) . str_pad(base_convert(ord($c2), 10, 16), 2, 0, STR_PAD_LEFT);
            } else {
                $str .= '\u' . str_pad(base_convert(ord($c2), 10, 16), 4, 0, STR_PAD_LEFT);
            }
        }
//        header('Content-Type: application/vnd.ms-excel');
        header('Content-Type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet');
        header('Data-Type: binary');
        //前端导出数据根据这个unicode格式解析为中文
        header('Data-Filename: ' . $str);
        header('Content-Disposition: attachment;filename="' . $names . '.xlsx"');
        header('Cache-Control: max-age=0');
        header('Access-Control-Expose-Headers:Data-Type,Data-Filename');
        //header('Content-Type: application/vnd.ms-excel');
        //header('Content-Disposition: attachment;filename="' . $name . '.xlsx"');
        //header('Cache-Control: max-age=0');
        $writer = \PhpOffice\PhpSpreadsheet\IOFactory::createWriter($spreadsheet, 'Xlsx');
        $writer->save('php://output');
        exit;
    }
 }