export const dynamic = "force-dynamic";
import getDb from '@/lib/db';
import { getUserFromRequest, unauthorizedResponse } from '@/lib/auth';
import { v4 as uuidv4 } from 'uuid';
import path from 'path';
import fs from 'fs';

// POST /api/upload - 上传文件附件
export async function POST(request) {
  try {
    const user = getUserFromRequest(request);
    if (!user) return unauthorizedResponse();

    const formData = await request.formData();
    const file = formData.get('file');
    const contract_id = formData.get('contract_id');

    if (!file) {
      return Response.json(
        { error: '请选择要上传的文件' },
        { status: 400 }
      );
    }

    if (!contract_id) {
      return Response.json(
        { error: '请指定合同ID' },
        { status: 400 }
      );
    }

    // 确保上传目录存在
    const uploadDir = path.join(process.cwd(), 'public', 'uploads', 'attachments');
    if (!fs.existsSync(uploadDir)) {
      fs.mkdirSync(uploadDir, { recursive: true });
    }

    // 生成唯一文件名
    const ext = path.extname(file.name) || '';
    const fileName = `${uuidv4()}${ext}`;
    const filePath = path.join(uploadDir, fileName);

    // 保存文件
    const buffer = Buffer.from(await file.arrayBuffer());
    fs.writeFileSync(filePath, buffer);

    // 相对于 public 的路径
    const publicPath = `/api/upload?file=${fileName}`;

    // 插入附件记录
    const db = await getDb();
    const result = db.prepare(
      'INSERT INTO contract_attachments (contract_id, file_name, file_path, file_size) VALUES (?, ?, ?, ?)'
    ).run(contract_id, file.name, publicPath, buffer.length);

    const attachment = db.prepare('SELECT * FROM contract_attachments WHERE id = ?').get(result.lastInsertRowid);

    return Response.json(attachment, { status: 201 });
  } catch (error) {
    console.error('上传文件失败:', error);
    return Response.json(
      { error: '服务器内部错误' },
      { status: 500 }
    );
  }
}

// GET /api/upload - 动态读取并服务已上传的文件（规避 Next.js 静态文件缓存导致的 404）
export async function GET(request) {
  try {
    const user = getUserFromRequest(request);
    if (!user) return unauthorizedResponse();

    const { searchParams } = new URL(request.url);
    const file = searchParams.get('file');
    if (!file) {
      return Response.json(
        { error: '缺少文件名' },
        { status: 400 }
      );
    }

    // 过滤路径，防止路径穿越安全漏洞
    const cleanFile = path.basename(file);
    const filePath = path.join(process.cwd(), 'public', 'uploads', 'attachments', cleanFile);

    if (!fs.existsSync(filePath)) {
      return Response.json(
        { error: '文件不存在' },
        { status: 404 }
      );
    }

    const buffer = fs.readFileSync(filePath);
    const ext = path.extname(cleanFile).toLowerCase();

    // 映射 Content-Type
    let contentType = 'application/octet-stream';
    if (ext === '.png') contentType = 'image/png';
    else if (ext === '.jpg' || ext === '.jpeg') contentType = 'image/jpeg';
    else if (ext === '.gif') contentType = 'image/gif';
    else if (ext === '.webp') contentType = 'image/webp';
    else if (ext === '.bmp') contentType = 'image/bmp';
    else if (ext === '.pdf') contentType = 'application/pdf';
    else if (ext === '.xlsx') contentType = 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet';
    else if (ext === '.xls') contentType = 'application/vnd.ms-excel';
    else if (ext === '.docx') contentType = 'application/vnd.openxmlformats-officedocument.wordprocessingml.document';
    else if (ext === '.txt') contentType = 'text/plain; charset=utf-8';
    else if (ext === '.csv') contentType = 'text/csv; charset=utf-8';
    else if (ext === '.json') contentType = 'application/json; charset=utf-8';

    return new Response(buffer, {
      headers: {
        'Content-Type': contentType,
        'Content-Length': buffer.length.toString(),
        'Content-Disposition': `inline; filename="${encodeURIComponent(cleanFile)}"`,
        'Cache-Control': 'public, max-age=31536000, immutable'
      }
    });
  } catch (error) {
    console.error('获取文件失败:', error);
    return Response.json(
      { error: '服务器内部错误' },
      { status: 500 }
    );
  }
}