ftdl/app/api/download/route.ts

// app/api/download/route.ts
import { NextResponse } from 'next/server';
import fs from 'fs';
import { RESOURCE_PATH } from '@/lib/constants';
import { validatePath } from '@/lib/fs-utils';

export async function GET(request: Request) {
  const { searchParams } = new URL(request.url);
  const project = searchParams.get('project');
  const version = searchParams.get('version');
  const filename = searchParams.get('filename');

  if (!project || !version || !filename) {
    return NextResponse.json(
      { error: 'Project, version, and filename parameters are required' },
      { status: 400 }
    );
  }

  // Validate the full path to prevent path traversal attacks
  const filePath = validatePath(RESOURCE_PATH, project, version, 'apks', filename);

  try {
    // Check if file exists
    if (!fs.existsSync(filePath)) {
      return NextResponse.json(
        { error: 'File not found' },
        { status: 404 }
      );
    }

    // Use streaming to avoid loading entire file into memory
    const fileStream = fs.createReadStream(filePath);
    const stat = await fs.promises.stat(filePath);

    return new NextResponse(fileStream as any, {
      headers: {
        'Content-Type': 'application/vnd.android.package-archive',
        'Content-Disposition': `attachment; filename="${encodeURIComponent(filename)}"`,
        'Content-Length': stat.size.toString(),
      },
    });
  } catch (error) {
    return NextResponse.json(
      { error: 'Failed to download file' },
      { status: 500 }
    );
  }
}