File Service Integration

/**
 * Unified API for all file system operations
 */
interface FileService {
  /** Map of registered file system providers by scheme */
  readonly providers: Map<string, FileSystemProvider>;
  
  /** Register a file system provider for a URI scheme */
  registerProvider(scheme: string, provider: FileSystemProvider): Disposable;
  
  /** Get provider for a specific URI */
  getProvider(resource: URI): FileSystemProvider | undefined;
  
  /** Check if a provider exists for the URI scheme */
  hasProvider(resource: URI): boolean;
  
  /** Check provider capabilities for a resource */
  hasCapability(resource: URI, capability: FileSystemProviderCapabilities): boolean;
  
  /** Read file with automatic encoding detection and handling */
  readFile(resource: URI, options?: ReadEncodingOptions): Promise<FileContent>;
  
  /** Read file as stream with encoding handling */
  readFileStream(resource: URI, options?: ReadEncodingOptions): Promise<FileStreamContent>;
  
  /** Write file with encoding handling */
  writeFile(resource: URI, content: string | Uint8Array, options?: WriteFileOptions): Promise<FileStat>;
  
  /** Get file statistics */
  stat(resource: URI): Promise<FileStat>;
  
  /** List directory contents */
  readdir(resource: URI): Promise<FileStat[]>;
  
  /** Create directory */
  createFolder(resource: URI): Promise<FileStat>;
  
  /** Delete file or directory */
  delete(resource: URI, options?: DeleteFileOptions): Promise<void>;
  
  /** Move/rename file or directory */
  move(source: URI, target: URI, options?: MoveFileOptions): Promise<FileStat>;
  
  /** Copy file or directory */
  copy(source: URI, target: URI, options?: CopyFileOptions): Promise<FileStat>;
  
  /** File system change events */
  readonly onDidFilesChange: Event<FileChangesEvent>;
  
  /** File operation events */
  readonly onDidRunFileOperation: Event<FileOperationEvent>;
  
  /** Provider registration events */
  readonly onDidChangeFileSystemProviderRegistrations: Event<FileSystemProviderRegistrationEvent>;
}

/**
 * Text file content with encoding information
 */
interface TextFileContent {
  /** File resource URI */
  readonly resource: URI;
  
  /** Text content as string */
  readonly value: string;
  
  /** Character encoding used */
  readonly encoding: string;
  
  /** File statistics */
  readonly stat: FileStat;
  
  /** Version information */
  readonly version: FileResourceVersion;
}

/**
 * Streaming text file content
 */
interface TextFileStreamContent {
  /** File resource URI */
  readonly resource: URI;
  
  /** Text content as readable stream */
  readonly value: ReadableStream<string>;
  
  /** Character encoding used */
  readonly encoding: string;
  
  /** File statistics */
  readonly stat: FileStat;
  
  /** Version information */
  readonly version: FileResourceVersion;
}

/**
 * Read text file with encoding options
 */
interface ReadTextFileOptions extends ReadEncodingOptions {
  /** Accept text files over this size with confirmation */
  acceptTextOnly?: boolean;
  
  /** Maximum file size to read */
  limits?: {
    /** Maximum file size in bytes */
    size?: number;
  };
}

/**
 * Options for reading files with encoding
 */
interface ReadEncodingOptions {
  /** Override encoding detection */
  encoding?: string;
  
  /** Whether to auto-detect encoding */
  autoGuessEncoding?: boolean;
}

/**
 * Options for writing files
 */
interface WriteFileOptions extends WriteEncodingOptions {
  /** Create file if it doesn't exist */
  create?: boolean;
  
  /** Overwrite existing file */
  overwrite?: boolean;
  
  /** Unlock readonly files */
  unlock?: boolean;
  
  /** Atomic write operation */
  atomic?: boolean;
}

/**
 * Encoding options for writing
 */
interface WriteEncodingOptions {
  /** Character encoding to use */
  encoding?: string;
  
  /** Write BOM for UTF encodings */
  writeBOM?: boolean;
}

/**
 * Options for deleting files/directories
 */
interface DeleteFileOptions {
  /** Delete recursively for directories */
  recursive?: boolean;
  
  /** Move to trash instead of permanent deletion */
  useTrash?: boolean;
  
  /** Skip confirmation dialogs */
  skipConfirm?: boolean;
}

/**
 * Options for moving/renaming files
 */
interface MoveFileOptions {
  /** Overwrite existing target */
  overwrite?: boolean;
  
  /** Skip confirmation dialogs */
  skipConfirm?: boolean;
}

/**
 * Options for copying files
 */
interface CopyFileOptions {
  /** Overwrite existing target */
  overwrite?: boolean;
  
  /** Skip confirmation dialogs */
  skipConfirm?: boolean;
  
  /** Preserve original timestamps */
  preserveTimestamps?: boolean;
}

/**
 * Participant in file operations for validation or transformation
 */
interface FileOperationParticipant {
  /** Participate in file operation before execution */
  participate(
    files: SourceTargetPair[],
    operation: FileOperation,
    timeout: number,
    token: CancellationToken
  ): Promise<void>;
}

/**
 * Source and target pair for file operations
 */
interface SourceTargetPair {
  /** Source file URI */
  source?: URI;
  
  /** Target file URI */
  target: URI;
}

/**
 * Register file operation participant
 */
function registerFileOperationParticipant(participant: FileOperationParticipant): Disposable;

/**
 * File system provider registration event
 */
interface FileSystemProviderRegistrationEvent {
  /** URI scheme being registered/unregistered */
  readonly scheme: string;
  
  /** Provider instance (undefined for unregistration) */
  readonly provider?: FileSystemProvider;
  
  /** Whether this is a registration or unregistration */
  readonly added: boolean;
}

/**
 * Extended file service interface with text file operations
 */
interface FileService {
  /** Read text file with encoding detection and handling */
  readTextContent(resource: URI, options?: ReadTextFileOptions): Promise<TextFileContent>;
  
  /** Read text file as stream with encoding handling */
  readTextContentStream(resource: URI, options?: ReadTextFileOptions): Promise<TextFileStreamContent>;
  
  /** Write text content to file with encoding */
  writeTextContent(resource: URI, content: string, options?: WriteTextFileOptions): Promise<FileStatWithMetadata & { encoding: string }>;
  
  /** Create new text file with content */
  createTextFile(resource: URI, content?: string, options?: CreateTextFileOptions): Promise<FileStatWithMetadata>;
  
  /** Update text file with incremental changes */
  updateTextFile(resource: URI, changes: TextDocumentContentChangeEvent[], options: UpdateTextFileOptions): Promise<FileStatWithMetadata & { encoding: string }>;
}

/**
 * Text file content with encoding information
 */
interface TextFileContent extends BaseStatWithMetadata {
  /** Text content of the file */
  readonly value: string;
  
  /** Character encoding used */
  readonly encoding: string;
}

/**
 * Streaming text file content
 */
interface TextFileStreamContent extends BaseStatWithMetadata {
  /** Text content as readable stream */
  readonly value: ReadableStream<string>;
  
  /** Character encoding used */
  readonly encoding: string;
}

/**
 * Text file operation specific error
 */
class TextFileOperationError extends FileOperationError {
  constructor(
    message: string,
    public textFileOperationResult: TextFileOperationResult,
    options?: ReadTextFileOptions & WriteTextFileOptions
  );
}

enum TextFileOperationResult {
  FILE_IS_BINARY
}

/**
 * Options for text file operations
 */
interface ReadTextFileOptions extends ReadEncodingOptions, ReadFileOptions {
  /** Accept text files only, fail if binary */
  acceptTextOnly?: boolean;
}

interface CreateTextFileOptions extends WriteEncodingOptions, CreateFileOptions {}

interface WriteTextFileOptions extends WriteEncodingOptions, WriteFileOptions {}

interface UpdateTextFileOptions extends WriteEncodingOptions, WriteFileOptions {
  /** Encoding used when reading the file */
  readEncoding: string;
}

interface WriteEncodingOptions {
  /** Encoding to use when writing */
  encoding?: string;
  
  /** Enforce encoding without BOM detection */
  overwriteEncoding?: boolean;
}

/**
 * File upload service with progress tracking
 */
interface FileUploadService {
  /** Event fired when files are uploaded */
  readonly onDidUpload: Event<string[]>;
  
  /** Maximum concurrent uploads allowed */
  readonly maxConcurrentUploads: number;
  
  /** Upload files to target location */
  upload(targetUri: string | URI, params?: FileUploadParams): Promise<FileUploadResult>;
}

/**
 * File upload parameters and options
 */
interface FileUploadParams {
  /** Source data (drag-and-drop or file input) */
  source?: DataTransfer | CustomDataTransfer;
  
  /** Progress tracking options */
  progress?: FileUploadProgressParams;
  
  /** Callback when upload completes */
  onDidUpload?: (uri: string) => void;
  
  /** Keep files in temporary directory */
  leaveInTemp?: boolean;
}

interface FileUploadProgressParams {
  /** Progress display text */
  text: string;
}

interface FileUploadResult {
  /** Array of uploaded file URIs */
  uploaded: string[];
}

/**
 * Upload endpoint and URL constants
 */
const HTTP_FILE_UPLOAD_PATH = '/file-upload';
const HTTP_UPLOAD_URL: string;

/**
 * File download service
 */
interface FileDownloadService {
  /** Download files or directories */
  download(uris: URI[], options?: DownloadOptions): Promise<void>;
  
  /** Cancel ongoing download */
  cancelDownload(id: string): Promise<void>;
}

/**
 * Download operation options
 */
interface DownloadOptions {
  /** Copy download link to clipboard instead of downloading */
  readonly copyLink?: boolean;
}

/**
 * Download data structure
 */
interface FileDownloadData {
  /** Array of file URIs to download */
  readonly uris: string[];
}

import { 
  FileService, TextFileContent, FileUploadService, 
  FileDownloadService 
} from "@theia/filesystem/lib/browser";
import { URI } from "@theia/core/lib/common/uri";

// Get file service instance
const fileService = container.get(FileService);

// Basic file operations
const fileUri = URI.parse('file:///workspace/readme.txt');

// Read file with encoding detection
const content = await fileService.readFile(fileUri);
console.log(`Content: ${content.value.toString()}`);
console.log(`Encoding: ${content.encoding}`);
console.log(`Size: ${content.stat.size} bytes`);

// Read file with specific encoding
const contentUtf16 = await fileService.readFile(fileUri, { 
  encoding: 'utf16le' 
});

// Write file with encoding
await fileService.writeFile(
  URI.parse('file:///workspace/output.txt'),
  'Hello, World!',
  { 
    encoding: 'utf8',
    create: true,
    overwrite: true
  }
);

// Stream reading for large files
const streamContent = await fileService.readFileStream(fileUri);
const reader = streamContent.value.getReader();

try {
  while (true) {
    const { done, value } = await reader.read();
    if (done) break;
    console.log('Chunk:', value);
  }
} finally {
  reader.releaseLock();
}

// Directory operations
const dirUri = URI.parse('file:///workspace/src');

// List directory contents
const entries = await fileService.readdir(dirUri);
for (const entry of entries) {
  console.log(`${entry.name}: ${entry.isFile ? 'file' : 'directory'}`);
}

// Create directory
const newDirUri = URI.parse('file:///workspace/new-folder');
await fileService.createFolder(newDirUri);

// File operations
const sourceUri = URI.parse('file:///workspace/source.txt');
const targetUri = URI.parse('file:///workspace/target.txt');

// Copy file
await fileService.copy(sourceUri, targetUri, { 
  overwrite: true,
  preserveTimestamps: true 
});

// Move/rename file
await fileService.move(sourceUri, URI.parse('file:///workspace/renamed.txt'), {
  overwrite: false
});

// Delete file
await fileService.delete(targetUri, { 
  useTrash: true 
});

// Event handling
fileService.onDidFilesChange(event => {
  console.log(`${event.changes.length} files changed`);
  
  for (const change of event.changes) {
    console.log(`${FileChangeType[change.type]}: ${change.resource.toString()}`);
  }
});

fileService.onDidRunFileOperation(event => {
  console.log(`Operation: ${FileOperation[event.operation]}`);
  console.log(`Target: ${event.target.toString()}`);
  if (event.source) {
    console.log(`Source: ${event.source.toString()}`);
  }
});

// Provider management
const customProvider = new CustomFileSystemProvider();
const disposable = fileService.registerProvider('custom', customProvider);

// Check provider capabilities
const hasWriteCapability = fileService.hasCapability(
  URI.parse('custom://example'),
  FileSystemProviderCapabilities.FileReadWrite
);

// Get specific provider
const provider = fileService.getProvider(URI.parse('file:///example'));
if (provider) {
  // Direct provider operations
  const stat = await provider.stat(URI.parse('file:///example'));
}

// Cleanup
disposable.dispose();

// Custom file operation participant
class ValidationParticipant implements FileOperationParticipant {
  
  async participate(
    files: SourceTargetPair[],
    operation: FileOperation,
    timeout: number,
    token: CancellationToken
  ): Promise<void> {
    
    for (const { source, target } of files) {
      // Validate operation
      if (operation === FileOperation.DELETE && target.path.includes('important')) {
        throw new Error('Cannot delete important files');
      }
      
      // Transform paths
      if (operation === FileOperation.CREATE && source) {
        // Custom logic for file creation
      }
    }
  }
}

// Register participant
const participant = new ValidationParticipant();
const disposable = registerFileOperationParticipant(participant);

// Batch operations
const files = [
  URI.parse('file:///file1.txt'),
  URI.parse('file:///file2.txt'),
  URI.parse('file:///file3.txt')
];

// Read multiple files in parallel
const contents = await Promise.all(
  files.map(uri => fileService.readFile(uri))
);

// Write multiple files with same options
const writeOptions = { encoding: 'utf8', create: true };
await Promise.all(
  contents.map((content, index) => 
    fileService.writeFile(
      URI.parse(`file:///output${index}.txt`),
      content.value.toString().toUpperCase(),
      writeOptions
    )
  )
);

// Complex file operations with error handling
async function safeFileOperation(uri: URI) {
  try {
    // Check if provider exists
    if (!fileService.hasProvider(uri)) {
      throw new Error(`No provider for scheme: ${uri.scheme}`);
    }
    
    // Check capabilities
    if (!fileService.hasCapability(uri, FileSystemProviderCapabilities.FileReadWrite)) {
      throw new Error('Provider does not support read/write operations');
    }
    
    // Perform operation
    const content = await fileService.readFile(uri);
    return content;
    
  } catch (error) {
    console.error(`File operation failed for ${uri.toString()}:`, error);
    throw error;
  }
}