/**
 * multer 文件上传配置
 */
import multer from 'multer';
import path from 'path';
import fs from 'fs';
import { fileURLToPath } from 'url';

const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);

const uploadsDir = path.resolve(__dirname, '..', 'uploads');
if (!fs.existsSync(uploadsDir)) {
  fs.mkdirSync(uploadsDir, { recursive: true });
}

const storage = multer.diskStorage({
  destination: (_req, _file, cb) => {
    cb(null, uploadsDir);
  },
  filename: (_req, file, cb) => {
    const ext = path.extname(file.originalname).toLowerCase() || '.jpg';
    const unique = `${Date.now()}_${Math.round(Math.random() * 1e6)}${ext}`;
    cb(null, unique);
  },
});

const allowedMime = new Set([
  'image/jpeg',
  'image/png',
  'image/gif',
  'image/webp',
  'image/avif',
]);

export const upload = multer({
  storage,
  limits: {
    fileSize: 20 * 1024 * 1024, // 20MB / 单图
    files: 30, // 最多 30 张
  },
  fileFilter: (_req, file, cb) => {
    if (allowedMime.has(file.mimetype)) {
      cb(null, true);
    } else {
      cb(new Error(`不支持的文件类型: ${file.mimetype}`));
    }
  },
});

export const UPLOADS_DIR = uploadsDir;