import { NextResponse } from 'next/server';
import { getServerSession } from 'next-auth';
import { authOptions } from '@/app/api/auth/[...nextauth]/route';
import { S3Client, ListBucketsCommand, ListObjectsV2Command } from '@aws-sdk/client-s3';
import { createUserFolderStructure, listUserObjects } from '@/lib/s3';

// Import the configured S3 client and bucket name from lib/s3.ts
import { s3Client as configuredS3Client } from '@/lib/s3';

// Get bucket name from environment
const S3_BUCKET_NAME = process.env.MINIO_AWS_S3_UPLOAD_BUCKET_NAME || 'pages';

// Cache for folder lists
const folderCache = new Map<string, { folders: string[], timestamp: number }>();
const CACHE_TTL = 5 * 60 * 1000; // 5 minutes

export async function GET() {
  try {
    const session = await getServerSession(authOptions);
    if (!session?.user?.id) {
      return NextResponse.json({ error: 'Unauthorized' }, { status: 401 });
    }

    const userId = session.user.id;

    // Check if we have cached folders for this user
    const cachedData = folderCache.get(userId);
    if (cachedData && (Date.now() - cachedData.timestamp < CACHE_TTL)) {
      console.log(`Returning cached folders for user ${userId}:`, cachedData.folders);
      return NextResponse.json({
        status: 'ready',
        folders: cachedData.folders
      });
    }

    // Check S3 connectivity using the configured client
    try {
      // Simple check by listing buckets
      await configuredS3Client.send(new ListBucketsCommand({}));
    } catch (error) {
      console.error('S3 connectivity check failed:', error);
      return NextResponse.json({
        error: 'S3 storage service is not accessible',
        status: 'error'
      }, { status: 503 });
    }

    // Direct approach - list all folders under the user prefix
    try {
      const prefix = `user-${userId}/`;
      
      // List all objects with this prefix to find folders
      const command = new ListObjectsV2Command({
        Bucket: S3_BUCKET_NAME,
        Prefix: prefix,
        Delimiter: '/'
      });
      
      const response = await configuredS3Client.send(command);
      
      // CommonPrefixes contains the folder paths
      const userPrefixes = response.CommonPrefixes || [];
      
      // Extract folder names from prefixes (e.g., "user-123/notes/" → "Notes")
      let userFolders = userPrefixes
        .map(prefix => prefix.Prefix?.split('/')[1])
        .filter(Boolean) as string[];
      
      console.log(`Found ${userFolders.length} folders for user ${userId}:`, userFolders);
      
      // If no folders found, create the standard structure
      if (userFolders.length === 0) {
        console.log(`No folders found for user ${userId}, creating standard structure`);
        await createUserFolderStructure(userId);
        userFolders = ['notes', 'diary', 'health', 'contacts'];
      }

      // Convert to Pascal case for backwards compatibility with NextCloud
      const formattedFolders = userFolders.map(folder => 
        folder.charAt(0).toUpperCase() + folder.slice(1)
      );

      console.log(`Returning formatted folders for user ${userId}:`, formattedFolders);
      
      // Update cache
      folderCache.set(userId, {
        folders: formattedFolders,
        timestamp: Date.now()
      });

      return NextResponse.json({
        status: 'ready',
        folders: formattedFolders
      });
    } catch (error) {
      console.error('Error fetching user folders:', error);
      return NextResponse.json({
        error: 'Failed to fetch folders',
        status: 'error'
      }, { status: 500 });
    }
  } catch (error) {
    console.error('Error in storage status check:', error);
    return NextResponse.json({
      error: 'Internal server error',
      status: 'error'
    }, { status: 500 });
  }
}