import { S3Client, ListObjectsV2Command, GetObjectCommand, PutObjectCommand, DeleteObjectCommand } from '@aws-sdk/client-s3';
import { getSignedUrl } from '@aws-sdk/s3-request-presigner';

/**
 * S3/MinIO Configuration
 * 
 * IMPORTANT: Set these environment variables in your .env file:
 * 
 * MINIO_S3_UPLOAD_BUCKET_URL=https://your-minio-instance.com/
 * MINIO_AWS_REGION=your-region
 * MINIO_AWS_S3_UPLOAD_BUCKET_NAME=your-bucket-name
 * MINIO_ACCESS_KEY=your-access-key
 * MINIO_SECRET_KEY=your-secret-key
 * 
 * Alternative credentials (fallback):
 * AWS_ACCESS_KEY_ID=your-aws-access-key
 * AWS_SECRET_ACCESS_KEY=your-aws-secret-key
 */
export const S3_CONFIG = {
  endpoint: process.env.MINIO_S3_UPLOAD_BUCKET_URL,
  region: process.env.MINIO_AWS_REGION,
  bucket: process.env.MINIO_AWS_S3_UPLOAD_BUCKET_NAME,
  accessKey: process.env.MINIO_ACCESS_KEY || process.env.AWS_ACCESS_KEY_ID,
  secretKey: process.env.MINIO_SECRET_KEY || process.env.AWS_SECRET_ACCESS_KEY,
}

// Initialize S3 client with standard configuration
const s3Config = {
  region: S3_CONFIG.region,
  endpoint: S3_CONFIG.endpoint,
  forcePathStyle: true, // Required for MinIO
};

// Add credentials if available
if (S3_CONFIG.accessKey && S3_CONFIG.secretKey) {
  Object.assign(s3Config, {
    credentials: {
      accessKeyId: S3_CONFIG.accessKey,
      secretAccessKey: S3_CONFIG.secretKey
    }
  });
}

// Create S3 client
export const s3Client = new S3Client(s3Config);

// Check Minio connection on startup
(async () => {
  try {
    console.log('Testing Minio/S3 connection...');
    // Try a simple operation to test the connection
    const command = new ListObjectsV2Command({
      Bucket: S3_CONFIG.bucket,
      MaxKeys: 1
    });
    
    const response = await s3Client.send(command);
    console.log('Minio/S3 connection successful! Bucket exists and is accessible.');
    console.log(`Bucket details: ${S3_CONFIG.bucket}, contains ${response.KeyCount || 0} objects`);
  } catch (error) {
    console.error('CRITICAL ERROR: Failed to connect to Minio/S3 server!');
    console.error('File uploads will fail until this is resolved.');
    console.error('Error details:', error);
    console.error('Please check your S3/Minio configuration and server status.');
  }
})();

// Check for required environment variables
if (!S3_CONFIG.endpoint || !S3_CONFIG.bucket) {
  console.error('ERROR: Missing required S3 environment variables!');
  console.error('Please make sure your .env file contains:');
  console.error('- MINIO_S3_UPLOAD_BUCKET_URL');
  console.error('- MINIO_AWS_S3_UPLOAD_BUCKET_NAME');
  console.error('- MINIO_ACCESS_KEY or AWS_ACCESS_KEY_ID');
  console.error('- MINIO_SECRET_KEY or AWS_SECRET_ACCESS_KEY');
}

// Log configuration for debugging (without exposing credentials)
console.log('S3 Configuration:', {
  endpoint: S3_CONFIG.endpoint || 'MISSING!',
  region: S3_CONFIG.region || 'MISSING!',
  bucket: S3_CONFIG.bucket || 'MISSING!',
  hasAccessKey: !!S3_CONFIG.accessKey || 'MISSING!',
  hasSecretKey: !!S3_CONFIG.secretKey || 'MISSING!',
});

// Helper functions for S3 operations

// List objects in a "folder" for a specific user
export async function listUserObjects(userId: string, folder: string) {
  try {
    // Remove the 'pages/' prefix since it's already the bucket name
    const prefix = `user-${userId}/${folder}/`;
    console.log(`Listing objects with prefix: ${prefix}`);
    
    const command = new ListObjectsV2Command({
      Bucket: S3_CONFIG.bucket,
      Prefix: prefix,
      Delimiter: '/'
    });
    
    const response = await s3Client.send(command);
    
    // Transform S3 objects to match the expected format for the frontend
    // This ensures compatibility with existing NextCloud based components
    return response.Contents?.map(item => ({
      id: item.Key,
      title: item.Key?.split('/').pop()?.replace('.md', '') || '',
      lastModified: item.LastModified?.toISOString(),
      size: item.Size,
      type: 'file',
      mime: item.Key?.endsWith('.md') ? 'text/markdown' : 'application/octet-stream',
      etag: item.ETag
    }))
    // Filter out placeholder files and empty directory markers
    .filter(item => !item.title.startsWith('.placeholder') && item.title !== '')
    || [];
  } catch (error) {
    console.error('Error listing objects:', error);
    throw error;
  }
}

// Get object content
export async function getObjectContent(key: string) {
  try {
    const command = new GetObjectCommand({
      Bucket: S3_CONFIG.bucket,
      Key: key
    });
    
    const response = await s3Client.send(command);
    
    // Convert the stream to string
    return await response.Body?.transformToString();
  } catch (error) {
    console.error('Error getting object content:', error);
    throw error;
  }
}

// Put object (create or update a file)
export async function putObject(key: string, content: string | Buffer, contentType?: string) {
  try {
    console.log(`Attempting to upload to S3/Minio: ${key}`);
    
    if (!S3_CONFIG.bucket) {
      throw new Error('S3 bucket name is not configured');
    }
    
    const command = new PutObjectCommand({
      Bucket: S3_CONFIG.bucket,
      Key: key,
      Body: content,
      ContentType: contentType || (key.endsWith('.md') ? 'text/markdown' : 'text/plain')
    });
    
    console.log(`S3 PutObject request prepared for ${key}`);
    const response = await s3Client.send(command);
    console.log(`S3 PutObject successful for ${key}, ETag: ${response.ETag}`);
    
    return {
      id: key,
      title: key.split('/').pop()?.replace('.md', '') || '',
      lastModified: new Date().toISOString(),
      size: typeof content === 'string' ? content.length : content.length,
      type: 'file',
      mime: contentType || (key.endsWith('.md') ? 'text/markdown' : 'text/plain'),
      etag: response.ETag
    };
  } catch (error) {
    console.error(`Error putting object to S3/Minio (${key}):`, error);
    // Check for specific S3 errors
    if ((error as any)?.name === 'NoSuchBucket') {
      console.error(`Bucket "${S3_CONFIG.bucket}" does not exist. Please create it first.`);
    }
    throw error;
  }
}

// Delete object
export async function deleteObject(key: string) {
  try {
    const command = new DeleteObjectCommand({
      Bucket: S3_CONFIG.bucket,
      Key: key
    });
    
    await s3Client.send(command);
    return true;
  } catch (error) {
    console.error('Error deleting object:', error);
    throw error;
  }
}

// Create folder structure (In S3, folders are just prefix notations)
export async function createUserFolderStructure(userId: string) {
  try {
    console.log(`Creating folder structure for user: ${userId}`);
    
    // Define standard folders - use lowercase only for simplicity and consistency
    const folders = ['notes', 'diary', 'health', 'contacts'];
    
    // Create folders with placeholders
    const results = [];
    
    for (const folder of folders) {
      try {
        // Create the folder path (just a prefix in S3)
        // Remove the 'pages/' prefix since it's already the bucket name
        const key = `user-${userId}/${folder}/`;
        console.log(`Creating folder: ${key}`);
        await putObject(key, '', 'application/x-directory');
        
        // Create a placeholder file to ensure the folder exists and is visible
        const placeholderKey = `user-${userId}/${folder}/.placeholder`;
        await putObject(placeholderKey, 'Folder placeholder', 'text/plain');
        
        results.push(folder);
      } catch (error) {
        console.error(`Error creating folder ${folder}:`, error);
      }
    }
    
    console.log(`Successfully created ${results.length} folders for user ${userId}: ${results.join(', ')}`);
    return true;
  } catch (error) {
    console.error('Error creating folder structure:', error);
    throw error;
  }
}

// Generate pre-signed URL for direct browser upload (optional feature)
export async function generatePresignedUrl(key: string, expiresIn = 3600) {
  try {
    const command = new PutObjectCommand({
      Bucket: S3_CONFIG.bucket,
      Key: key
    });

    return await getSignedUrl(s3Client, command, { expiresIn });
  } catch (error) {
    console.error('Error generating presigned URL:', error);
    throw error;
  }
}

// Generate a public URL for a file stored in Minio/S3
export function getPublicUrl(filePath: string): string {
  if (!filePath) return '';
  if (filePath.startsWith('http')) return filePath; // Already a full URL
  
  console.log('Generating public URL for:', filePath);
  
  // Remove leading slash if present
  const cleanPath = filePath.startsWith('/') ? filePath.substring(1) : filePath;
  
  // Construct the full URL
  const endpoint = S3_CONFIG.endpoint?.replace(/\/$/, ''); // Remove trailing slash if present
  const bucket = S3_CONFIG.bucket;
  
  console.log('S3 Config for URL generation:', {
    endpoint,
    bucket,
    cleanPath
  });
  
  // Return original path if no endpoint is configured
  if (!endpoint) {
    console.warn('No S3/Minio endpoint configured, returning original path');
    return cleanPath;
  }
  
  // Construct and return the full URL
  const publicUrl = `${endpoint}/${bucket}/${cleanPath}`;
  console.log('Generated public URL:', publicUrl);
  return publicUrl;
}

// Test Minio connection - can be called from browser console
export async function testMinioConnection() {
  console.log('=== Testing Minio Connection ===');
  try {
    console.log('S3 Configuration:', {
      endpoint: S3_CONFIG.endpoint || 'MISSING!',
      region: S3_CONFIG.region || 'MISSING!',
      bucket: S3_CONFIG.bucket || 'MISSING!',
      hasAccessKey: !!S3_CONFIG.accessKey || 'MISSING!',
      hasSecretKey: !!S3_CONFIG.secretKey || 'MISSING!',
    });
    
    // Try a simple operation
    console.log('Attempting to list objects...');
    const command = new ListObjectsV2Command({
      Bucket: S3_CONFIG.bucket || '',
      MaxKeys: 5
    });
    
    const response = await s3Client.send(command);
    console.log('Connection successful!');
    console.log('Response:', response);
    
    const files = response.Contents || [];
    console.log(`Found ${files.length} files in bucket ${S3_CONFIG.bucket}:`);
    files.forEach((file, index) => {
      console.log(`  ${index + 1}. ${file.Key} (${file.Size} bytes)`);
    });
    
    console.log('=== Test completed successfully ===');
    return { success: true, files: files.map(f => f.Key) };
  } catch (error) {
    console.error('=== Test failed ===');
    console.error('Error details:', error);
    return { success: false, error };
  }
}

// Make testMinioConnection available globally if in browser
if (typeof window !== 'undefined') {
  (window as any).testMinioConnection = testMinioConnection;
  
  // Also expose the getPublicUrl function
  (window as any).getMinioUrl = getPublicUrl;
  
  console.log('Minio test utilities available. Run window.testMinioConnection() to test Minio connection.');
}