/**
 * File Management API Endpoint
 * Agent 3: File Upload & Storage System
 *
 * GET /api/upload/[fileId] - Get file info or signed URL
 * DELETE /api/upload/[fileId] - Delete a file
 */

import type { NextApiRequest, NextApiResponse } from 'next';
import { getUploadService } from '../../../lib/storage';

interface FileResponse {
  success: boolean;
  signedUrl?: string;
  exists?: boolean;
  error?: string;
}

interface DeleteResponse {
  success: boolean;
  error?: string;
}

export default async function handler(
  req: NextApiRequest,
  res: NextApiResponse<FileResponse | DeleteResponse>
) {
  const { fileId } = req.query;

  if (!fileId || typeof fileId !== 'string') {
    return res.status(400).json({ success: false, error: 'File ID is required' });
  }

  // Decode the file key (it may be URL encoded)
  const fileKey = decodeURIComponent(fileId);

  const uploadService = getUploadService();

  switch (req.method) {
    case 'GET': {
      try {
        // Check if file exists
        const exists = await uploadService.exists(fileKey);

        if (!exists) {
          return res.status(404).json({
            success: false,
            exists: false,
            error: 'File not found',
          });
        }

        // Get expiration time from query params (default 1 hour)
        const expiresIn = parseInt(req.query.expiresIn as string) || 3600;

        // Get signed URL for private file access
        const signedUrl = await uploadService.getSignedUrl(fileKey, expiresIn);

        return res.status(200).json({
          success: true,
          exists: true,
          signedUrl,
        });
      } catch (error) {
        console.error('Get file error:', error);
        return res.status(500).json({
          success: false,
          error: error instanceof Error ? error.message : 'Internal server error',
        });
      }
    }

    case 'DELETE': {
      try {
        const deleted = await uploadService.delete(fileKey);

        if (!deleted) {
          return res.status(404).json({
            success: false,
            error: 'File not found or could not be deleted',
          });
        }

        return res.status(200).json({
          success: true,
        });
      } catch (error) {
        console.error('Delete file error:', error);
        return res.status(500).json({
          success: false,
          error: error instanceof Error ? error.message : 'Internal server error',
        });
      }
    }

    default:
      return res.status(405).json({ success: false, error: 'Method not allowed' });
  }
}