<?php

namespace app\admin\service;

use PhpOffice\PhpSpreadsheet\Spreadsheet;
use PhpOffice\PhpSpreadsheet\Writer\Xlsx;

class ExportService extends AdminBaseService
{
    /**
     * 导出 Excel
     * @param array $data 二维数组（含表头）
     * @param string $filename 导出文件名
     */
    public static function exportExcel(array $data, string $filename = '')
    {
        if (empty($data)) {
            throw new \Exception('导出数据不能为空');
        }

        $filename = $filename ?: '导出_' . date('Ymd_His') . '.xlsx';

        $spreadsheet = new Spreadsheet();
        $sheet = $spreadsheet->getActiveSheet();

        // 列号转字母函数
        $colIndexToLetter = function ($index) {
            $letters = '';
            while ($index >= 0) {
                $letters = chr($index % 26 + 65) . $letters;
                $index = intval($index / 26) - 1;
            }
            return $letters;
        };

        // 写入数据
        foreach ($data as $rowIndex => $row) {
            foreach ($row as $colIndex => $value) {
                $cell = $colIndexToLetter($colIndex) . ($rowIndex + 1); // 例如 A1, B1...
                $sheet->setCellValue($cell, $value);
            }
        }

        // 输出到浏览器
        header('Content-Type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet');
        header("Content-Disposition: attachment; filename=\"{$filename}\"");
        header('Cache-Control: max-age=0');

        $writer = new Xlsx($spreadsheet);
        $writer->save('php://output');
        exit;
    }

    /**
     * 导出 CSV
     * @param array $data 二维数组（含表头）
     * @param string $filename 导出文件名
     */
    public static function exportCsv(array $data, string $filename = '')
    {
        if (empty($data)) {
            throw new \Exception('导出数据不能为空');
        }

        $filename = $filename ?: '导出_' . date('Ymd_His') . '.csv';

        header('Content-Type: text/csv');
        header("Content-Disposition: attachment; filename={$filename}");

        $fp = fopen('php://output', 'w');
        fwrite($fp, chr(0xEF) . chr(0xBB) . chr(0xBF)); // 防止中文乱码

        foreach ($data as $row) {
            fputcsv($fp, $row);
        }

        fclose($fp);
        exit;
    }
}