Utilities

class CRC32C {
  constructor(initial?: number);
  
  // Methods
  update(data: Buffer | Uint8Array | string): CRC32C;
  digest(): Buffer;
  toString(encoding?: string): string;
  
  // Static methods
  static from(data: Buffer | Uint8Array | string): CRC32C;
  static calculate(data: Buffer | Uint8Array | string): Buffer;
}

// Basic usage
import { CRC32C } from '@google-cloud/storage';

// Calculate checksum for data
const data = Buffer.from('Hello, World!');
const checksum = CRC32C.from(data);
console.log('CRC32C:', checksum.toString('base64'));

// Incremental calculation
const crc = new CRC32C();
crc.update('Hello, ');
crc.update('World!');
const result = crc.digest();
console.log('CRC32C:', result.toString('base64'));

// One-shot calculation
const quickChecksum = CRC32C.calculate(data);
console.log('CRC32C:', quickChecksum.toString('base64'));

type CRC32CValidatorGenerator = () => CRC32C;

// Default validator generator
import { CRC32C_DEFAULT_VALIDATOR_GENERATOR } from '@google-cloud/storage';

const storage = new Storage({
  crc32cGenerator: CRC32C_DEFAULT_VALIDATOR_GENERATOR
});

// Custom validator generator
function customCRC32CGenerator(): CRC32C {
  return new CRC32C();
}

const storage = new Storage({
  crc32cGenerator: customCRC32CGenerator
});

// Validate file integrity during upload
const file = bucket.file('important-data.zip');

// Calculate local file checksum
const fs = require('fs');
const localData = fs.readFileSync('/local/important-data.zip');
const expectedChecksum = CRC32C.from(localData).toString('base64');

// Upload with validation
await file.save(localData, {
  validation: 'crc32c',
  metadata: {
    crc32c: expectedChecksum
  }
});

// Download with validation
const [downloadedData] = await file.download({
  validation: 'crc32c'
});

// Verify checksums match
const actualChecksum = CRC32C.from(downloadedData).toString('base64');
if (actualChecksum === expectedChecksum) {
  console.log('File integrity verified');
} else {
  console.error('File integrity check failed');
}

class HashStreamValidator extends Transform {
  constructor(options: HashStreamValidatorOptions);
  
  // Properties
  crc32c?: string;
  md5?: string;
  
  // Methods
  test(hash: 'crc32c' | 'md5', sum: string): boolean;
}

interface HashStreamValidatorOptions {
  crc32c?: boolean | string;
  md5?: boolean | string;
}

import { HashStreamValidator } from '@google-cloud/storage';

// Validate stream with expected checksums
const validator = new HashStreamValidator({
  crc32c: true,
  md5: true
});

// Stream file through validator
fs.createReadStream('/local/file.txt')
  .pipe(validator)
  .pipe(fs.createWriteStream('/local/validated-file.txt'))
  .on('finish', () => {
    console.log('CRC32C:', validator.crc32c);
    console.log('MD5:', validator.md5);
    
    // Test against expected values
    const crcValid = validator.test('crc32c', 'expected-crc32c-value');
    const md5Valid = validator.test('md5', 'expected-md5-value');
    
    console.log('CRC32C valid:', crcValid);
    console.log('MD5 valid:', md5Valid);
  });

// Upload with stream validation
function uploadWithValidation(localPath: string, file: File) {
  return new Promise<void>((resolve, reject) => {
    const validator = new HashStreamValidator({
      crc32c: true,
      md5: true
    });
    
    const readStream = fs.createReadStream(localPath);
    const writeStream = file.createWriteStream();
    
    readStream
      .pipe(validator)
      .pipe(writeStream)
      .on('error', reject)
      .on('finish', async () => {
        try {
          // Set metadata with calculated checksums
          await file.setMetadata({
            crc32c: validator.crc32c,
            md5Hash: validator.md5
          });
          
          console.log('Upload completed with validation');
          resolve();
        } catch (error) {
          reject(error);
        }
      });
  });
}

// Download with validation
function downloadWithValidation(file: File, localPath: string) {
  return new Promise<void>((resolve, reject) => {
    file.getMetadata()
      .then(([metadata]) => {
        const validator = new HashStreamValidator({
          crc32c: metadata.crc32c,
          md5: metadata.md5Hash
        });
        
        file.createReadStream()
          .pipe(validator)
          .pipe(fs.createWriteStream(localPath))
          .on('error', reject)
          .on('finish', () => {
            console.log('Download completed with validation');
            resolve();
          });
      })
      .catch(reject);
  });
}

class URLSigner {
  constructor(authClient: AuthClient, bucket: Bucket, file?: File);
  
  // Methods
  getSignedUrl(config: GetSignedUrlConfig): Promise<string>;
}

interface GetSignedUrlConfig {
  version: 'v2' | 'v4';
  action: 'read' | 'write' | 'delete' | 'resumable' | 'list';
  expires: string | number | Date;
  accessibleAt?: string | number | Date;
  virtualHostedStyle?: boolean;
  cname?: string;
  contentMd5?: string;
  contentType?: string;
  extensionHeaders?: { [key: string]: string };
  queryParams?: { [key: string]: string };
  responseDisposition?: string;
  responseType?: string;
  promptSaveAs?: string;
}

type GetSignedUrlResponse = [string]; // [signedUrl]
type GetSignedUrlCallback = (err: Error | null, url?: string) => void;

// Batch signed URL generation
async function generateBatchSignedUrls(files: File[], action: string, expires: Date) {
  const urlPromises = files.map(file => 
    file.getSignedUrl({
      version: 'v4',
      action: action as any,
      expires: expires
    })
  );
  
  const urls = await Promise.all(urlPromises);
  
  const result = files.map((file, index) => ({
    fileName: file.name,
    signedUrl: urls[index][0]
  }));
  
  return result;
}

// Time-limited upload URLs
async function generateTimeLimitedUploadUrls(fileNames: string[], bucket: Bucket) {
  const expires = Date.now() + 60 * 60 * 1000; // 1 hour
  
  const urlPromises = fileNames.map(fileName => {
    const file = bucket.file(fileName);
    return file.getSignedUrl({
      version: 'v4',
      action: 'write',
      expires: expires,
      contentType: 'application/octet-stream'
    });
  });
  
  const urls = await Promise.all(urlPromises);
  
  return fileNames.map((fileName, index) => ({
    fileName,
    uploadUrl: urls[index][0],
    expiresAt: new Date(expires)
  }));
}

// Conditional access URLs
async function generateConditionalUrls(file: File) {
  // URL valid only for specific IP ranges
  const restrictedUrl = await file.getSignedUrl({
    version: 'v4',
    action: 'read',
    expires: Date.now() + 3600000, // 1 hour
    extensionHeaders: {
      'x-goog-ip-range': '192.168.1.0/24'
    }
  });
  
  // URL with custom response headers
  const customHeaderUrl = await file.getSignedUrl({
    version: 'v4',
    action: 'read',
    expires: Date.now() + 3600000,
    responseDisposition: 'attachment; filename="download.pdf"',
    responseType: 'application/pdf'
  });
  
  return {
    restricted: restrictedUrl[0],
    customHeaders: customHeaderUrl[0]
  };
}

class Channel {
  constructor(storage: Storage, id: string, resourceId: string);
  
  // Properties
  id: string;
  resourceId: string;
  
  // Methods
  stop(): Promise<void>;
}

type StopCallback = (err: Error | null) => void;

// Create and manage channels
const channel = storage.channel('my-channel', 'resource-123');

// Stop channel (Promise)
await channel.stop();

// Stop channel (callback)
channel.stop((err) => {
  if (err) {
    console.error('Error stopping channel:', err);
  } else {
    console.log('Channel stopped successfully');
  }
});

class ChannelManager {
  private channels = new Map<string, Channel>();
  private storage: Storage;
  
  constructor(storage: Storage) {
    this.storage = storage;
  }
  
  async createChannel(bucket: Bucket, channelId: string, webhookUrl: string) {
    // Create watch channel
    const [channel] = await bucket.createChannel(channelId, {
      address: webhookUrl,
      type: 'web_hook'
    });
    
    // Track channel
    this.channels.set(channelId, channel);
    
    // Auto-stop after timeout
    setTimeout(async () => {
      await this.stopChannel(channelId);
    }, 24 * 60 * 60 * 1000); // 24 hours
    
    return channel;
  }
  
  async stopChannel(channelId: string) {
    const channel = this.channels.get(channelId);
    if (channel) {
      await channel.stop();
      this.channels.delete(channelId);
      console.log(`Channel ${channelId} stopped`);
    }
  }
  
  async stopAllChannels() {
    const stopPromises = Array.from(this.channels.values()).map(channel => channel.stop());
    await Promise.all(stopPromises);
    this.channels.clear();
    console.log('All channels stopped');
  }
  
  getActiveChannels() {
    return Array.from(this.channels.keys());
  }
}

// ApiError is exported from the common library
import { ApiError } from '@google-cloud/storage';

interface ApiErrorOptions {
  code?: number;
  message?: string;
  errors?: any[];
}

class ApiError extends Error {
  code?: number;
  errors?: any[];
  
  constructor(options?: ApiErrorOptions | string);
}

// Error handling utilities
class StorageErrorHandler {
  static isRetryable(error: Error): boolean {
    if (error instanceof ApiError) {
      // Retry on server errors and rate limiting
      return error.code >= 500 || error.code === 429 || error.code === 408;
    }
    return false;
  }
  
  static getErrorCategory(error: Error): string {
    if (error instanceof ApiError) {
      if (error.code === 400) return 'client-error';
      if (error.code === 401 || error.code === 403) return 'auth-error';
      if (error.code === 404) return 'not-found';
      if (error.code === 409) return 'conflict';
      if (error.code === 412) return 'precondition-failed';
      if (error.code === 429) return 'rate-limited';
      if (error.code >= 500) return 'server-error';
    }
    return 'unknown';
  }
  
  static async retryOperation<T>(
    operation: () => Promise<T>,
    maxRetries = 3,
    baseDelay = 1000
  ): Promise<T> {
    let lastError: Error;
    
    for (let attempt = 1; attempt <= maxRetries; attempt++) {
      try {
        return await operation();
      } catch (error) {
        lastError = error as Error;
        
        if (!this.isRetryable(lastError) || attempt === maxRetries) {
          throw lastError;
        }
        
        // Exponential backoff with jitter
        const delay = baseDelay * Math.pow(2, attempt - 1) + Math.random() * 1000;
        await new Promise(resolve => setTimeout(resolve, delay));
        
        console.warn(`Attempt ${attempt} failed, retrying in ${delay}ms:`, lastError.message);
      }
    }
    
    throw lastError!;
  }
}

// Utility functions for common operations
class StorageUtils {
  // Sanitize file names for Cloud Storage
  static sanitizeFileName(fileName: string): string {
    // Remove invalid characters
    return fileName
      .replace(/[<>:"/\\|?*]/g, '_')
      .replace(/\s+/g, '_')
      .toLowerCase();
  }
  
  // Generate unique file names
  static generateUniqueFileName(baseName: string, extension?: string): string {
    const timestamp = Date.now();
    const random = Math.random().toString(36).substring(2, 8);
    const ext = extension || '';
    return `${baseName}_${timestamp}_${random}${ext}`;
  }
  
  // Parse Cloud Storage URLs
  static parseStorageUrl(url: string): { bucket: string; object: string } | null {
    // Match gs://bucket/object or https://storage.googleapis.com/bucket/object
    const gsMatch = url.match(/^gs:\/\/([^\/]+)\/(.+)$/);
    if (gsMatch) {
      return { bucket: gsMatch[1], object: gsMatch[2] };
    }
    
    const httpsMatch = url.match(/^https:\/\/storage\.googleapis\.com\/([^\/]+)\/(.+)$/);
    if (httpsMatch) {
      return { bucket: httpsMatch[1], object: decodeURIComponent(httpsMatch[2]) };
    }
    
    return null;
  }
  
  // Build Cloud Storage URLs
  static buildStorageUrl(bucket: string, object: string, protocol: 'gs' | 'https' = 'gs'): string {
    if (protocol === 'gs') {
      return `gs://${bucket}/${object}`;
    } else {
      return `https://storage.googleapis.com/${bucket}/${encodeURIComponent(object)}`;
    }
  }
  
  // Extract metadata from file path
  static getFileInfo(filePath: string) {
    const path = require('path');
    const fs = require('fs');
    
    const stat = fs.statSync(filePath);
    const parsed = path.parse(filePath);
    
    return {
      name: parsed.name,
      extension: parsed.ext,
      size: stat.size,
      modified: stat.mtime,
      directory: parsed.dir,
      fullPath: filePath
    };
  }
}

// Batch utility for processing large numbers of operations
class BatchProcessor<T, R> {
  private batchSize: number;
  private concurrency: number;
  
  constructor(batchSize = 100, concurrency = 10) {
    this.batchSize = batchSize;
    this.concurrency = concurrency;
  }
  
  async processBatch<T, R>(
    items: T[],
    processor: (item: T) => Promise<R>
  ): Promise<Array<{ item: T; result?: R; error?: Error }>> {
    const results: Array<{ item: T; result?: R; error?: Error }> = [];
    
    // Split into batches
    for (let i = 0; i < items.length; i += this.batchSize) {
      const batch = items.slice(i, i + this.batchSize);
      
      // Process batch with concurrency limit
      const batchPromises = batch.map(async (item) => {
        try {
          const result = await processor(item);
          return { item, result };
        } catch (error) {
          return { item, error: error as Error };
        }
      });
      
      const batchResults = await this.limitConcurrency(batchPromises, this.concurrency);
      results.push(...batchResults);
      
      console.log(`Processed batch ${Math.floor(i / this.batchSize) + 1}/${Math.ceil(items.length / this.batchSize)}`);
    }
    
    return results;
  }
  
  private async limitConcurrency<T>(promises: Promise<T>[], limit: number): Promise<T[]> {
    const results: T[] = [];
    
    for (let i = 0; i < promises.length; i += limit) {
      const batch = promises.slice(i, i + limit);
      const batchResults = await Promise.all(batch);
      results.push(...batchResults);
    }
    
    return results;
  }
}

// Usage example
const processor = new BatchProcessor<string, File>(50, 5);

const filePaths = [/* array of file paths */];
const results = await processor.processBatch(filePaths, async (filePath) => {
  const [uploadResult] = await bucket.upload(filePath);
  return uploadResult;
});

// Process results
const successful = results.filter(r => r.result && !r.error);
const failed = results.filter(r => r.error);

console.log(`Success: ${successful.length}, Failed: ${failed.length}`);

// Metrics collection utilities
class StorageMetrics {
  private metrics = {
    uploads: 0,
    downloads: 0,
    deletes: 0,
    errors: 0,
    bytesUploaded: 0,
    bytesDownloaded: 0
  };
  
  recordUpload(bytes: number) {
    this.metrics.uploads++;
    this.metrics.bytesUploaded += bytes;
  }
  
  recordDownload(bytes: number) {
    this.metrics.downloads++;
    this.metrics.bytesDownloaded += bytes;
  }
  
  recordDelete() {
    this.metrics.deletes++;
  }
  
  recordError() {
    this.metrics.errors++;
  }
  
  getMetrics() {
    return { ...this.metrics };
  }
  
  reset() {
    Object.keys(this.metrics).forEach(key => {
      (this.metrics as any)[key] = 0;
    });
  }
  
  // Format bytes for display
  formatBytes(bytes: number): string {
    const units = ['B', 'KB', 'MB', 'GB', 'TB'];
    let size = bytes;
    let unitIndex = 0;
    
    while (size >= 1024 && unitIndex < units.length - 1) {
      size /= 1024;
      unitIndex++;
    }
    
    return `${size.toFixed(2)} ${units[unitIndex]}`;
  }
  
  getSummary() {
    return {
      operations: {
        uploads: this.metrics.uploads,
        downloads: this.metrics.downloads,
        deletes: this.metrics.deletes,
        errors: this.metrics.errors
      },
      bandwidth: {
        uploaded: this.formatBytes(this.metrics.bytesUploaded),
        downloaded: this.formatBytes(this.metrics.bytesDownloaded),
        total: this.formatBytes(this.metrics.bytesUploaded + this.metrics.bytesDownloaded)
      },
      errorRate: this.metrics.uploads + this.metrics.downloads > 0 
        ? (this.metrics.errors / (this.metrics.uploads + this.metrics.downloads) * 100).toFixed(2) + '%'
        : '0%'
    };
  }
}

// Global metrics instance
const storageMetrics = new StorageMetrics();

// Usage in operations
async function monitoredUpload(file: File, data: Buffer) {
  try {
    await file.save(data);
    storageMetrics.recordUpload(data.length);
  } catch (error) {
    storageMetrics.recordError();
    throw error;
  }
}

// Periodic reporting
setInterval(() => {
  console.log('Storage Metrics:', storageMetrics.getSummary());
}, 60000); // Every minute

// Type guards for runtime validation
class StorageTypeGuards {
  static isFile(obj: any): obj is File {
    return obj && typeof obj.save === 'function' && typeof obj.download === 'function';
  }
  
  static isBucket(obj: any): obj is Bucket {
    return obj && typeof obj.file === 'function' && typeof obj.upload === 'function';
  }
  
  static isStorage(obj: any): obj is Storage {
    return obj && typeof obj.bucket === 'function' && typeof obj.createBucket === 'function';
  }
  
  static isApiError(error: any): error is ApiError {
    return error instanceof ApiError || (error && typeof error.code === 'number');
  }
  
  // Validate storage configuration
  static validateStorageOptions(options: any): options is StorageOptions {
    if (!options || typeof options !== 'object') return false;
    
    if (options.projectId && typeof options.projectId !== 'string') return false;
    if (options.keyFilename && typeof options.keyFilename !== 'string') return false;
    if (options.apiEndpoint && typeof options.apiEndpoint !== 'string') return false;
    
    return true;
  }
  
  // Validate file metadata
  static validateFileMetadata(metadata: any): metadata is FileMetadata {
    if (!metadata || typeof metadata !== 'object') return false;
    
    if (metadata.contentType && typeof metadata.contentType !== 'string') return false;
    if (metadata.size && typeof metadata.size !== 'string') return false;
    if (metadata.generation && typeof metadata.generation !== 'string') return false;
    
    return true;
  }
}

// Storage class constants
export const STORAGE_CLASSES = {
  STANDARD: 'STANDARD',
  NEARLINE: 'NEARLINE', 
  COLDLINE: 'COLDLINE',
  ARCHIVE: 'ARCHIVE',
  DURABLE_REDUCED_AVAILABILITY: 'DURABLE_REDUCED_AVAILABILITY'
} as const;

// ACL constants
export const ACL_ROLES = {
  OWNER: 'OWNER',
  READER: 'READER', 
  WRITER: 'WRITER',
  FULL_CONTROL: 'FULL_CONTROL'
} as const;

export const ACL_ENTITIES = {
  ALL_USERS: 'allUsers',
  ALL_AUTHENTICATED_USERS: 'allAuthenticatedUsers'
} as const;

// HTTP methods for signed URLs
export const SIGNED_URL_ACTIONS = {
  READ: 'read',
  WRITE: 'write',
  DELETE: 'delete',
  RESUMABLE: 'resumable'
} as const;

// Event types for notifications
export const NOTIFICATION_EVENTS = {
  OBJECT_FINALIZE: 'OBJECT_FINALIZE',
  OBJECT_DELETE: 'OBJECT_DELETE', 
  OBJECT_METADATA_UPDATE: 'OBJECT_METADATA_UPDATE',
  OBJECT_ACL_UPDATE: 'OBJECT_ACL_UPDATE'
} as const;

// Usage
const bucket = storage.bucket('my-bucket');
await bucket.setStorageClass(STORAGE_CLASSES.COLDLINE);

await file.acl.add({
  entity: ACL_ENTITIES.ALL_USERS,
  role: ACL_ROLES.READER
});