@kaifronsdal/transcript-viewer/src/lib/client/utils/file-utils.ts

A web-based viewer for AI conversation transcripts with rollback support

// Helpers for path normalization and URL building used across components

/** Convert any Windows-style path separators to POSIX forward slashes */
export function toPosixPath(p: string): string {
  return p.replace(/\\/g, '/');
}

/** Build a transcript URL from a relative POSIX path, encoding each segment */
export function buildTranscriptUrl(relativePath: string): string {
  const safe = toPosixPath(relativePath || '');
  const segments = safe.split('/').filter(Boolean).map(encodeURIComponent);
  return `/transcript/${segments.join('/')}`;
}

/** Ensure a client-provided path is safe for splitting/URL usage */
export function normalizeClientFilePath(p: string | undefined | null): string | null {
  if (!p) return null;
  return toPosixPath(p);
}
/**
 * Client-side URL utilities - no Node.js path module dependency
 */

/**
 * Parse URL path segments into a clean file path (client-side)
 */
export function parseUrlPath(pathSegments: string[]): string {
  if (!pathSegments || pathSegments.length === 0) {
    throw new Error('Invalid path: empty path segments');
  }
  
  // Decode each segment
  const decodedSegments = pathSegments.map(segment => {
    try {
      return decodeURIComponent(segment);
    } catch (error) {
      throw new Error(`Invalid URL encoding in path segment: ${segment}`);
    }
  });
  
  // Join segments into a file path
  const filePath = decodedSegments.join('/');
  
  // Basic client-side validation aligned with server rules (server will still validate)
  if (!filePath || !filePath.endsWith('.json')) {
    throw new Error(`Invalid file path: ${filePath}`);
  }
  // Reject absolute paths
  if (filePath.startsWith('/')) {
    throw new Error('Invalid file path: must be relative, not absolute');
  }
  // Reject directory traversal attempts
  if (filePath.includes('../')) {
    throw new Error('Invalid file path: directory traversal is not allowed');
  }
  // Require transcript_ prefix on filename (matches server)
  const lastSlash = filePath.lastIndexOf('/')
  const filename = lastSlash >= 0 ? filePath.slice(lastSlash + 1) : filePath;
  if (!filename.startsWith('transcript_')) {
    throw new Error('Invalid file path: filename must start with "transcript_"');
  }
  
  return filePath;
}

/**
 * Generate a URL path for SvelteKit routing from a file path
 */
export function generateTranscriptUrl(filePath: string): string {
  if (!filePath) {
    throw new Error('Invalid file path: empty string');
  }
  
  // Split path into segments and encode each one
  const segments = filePath.split('/').map(segment => encodeURIComponent(segment));
  
  return `/transcript/${segments.join('/')}`;
}

/**
 * Extract directory name from file path (client-side version)
 */
export function extractDirectoryName(filePath: string): string {
  const lastSlashIndex = filePath.lastIndexOf('/');
  if (lastSlashIndex === -1) return 'root';
  return filePath.substring(0, lastSlashIndex);
}

/**
 * Extract filename without extension (client-side version)
 */
export function extractFilenameWithoutExtension(filePath: string): string {
  const filename = filePath.split('/').pop() || '';
  return filename.replace(/\.json$/, '');
}