lmexif-sniffer

import * as fs from "node:fs";
import * as path from "node:path";

/** Resolve *relative* under *root*, rejecting traversal outside *root* (Python resolve_under_root). */
export function resolveUnderRoot(rootAbs: string, relative: string): string {
  const root = path.resolve(rootAbs);
  const candidate = path.resolve(path.join(root, relative));
  const rel = path.relative(root, candidate);
  if (rel.startsWith("..") || path.isAbsolute(rel)) {
    throw new Error(`Path escapes data directory: ${JSON.stringify(relative)}`);
  }
  return candidate;
}

const RELATIVE_NAME_PATTERN = /^[\w./-]+$/;

export function validateRelativeName(name: string, label: string): void {
  const trimmed = name.trim();
  if (!trimmed) {
    throw new Error(`${label} cannot be empty`);
  }
  if (!RELATIVE_NAME_PATTERN.test(trimmed)) {
    throw new Error(
      `${label} may only contain letters, numbers, underscores, hyphens, dots, and slashes`,
    );
  }
  for (const part of trimmed.split(/[/\\]/)) {
    if (part === "..") {
      throw new Error(`${label} must not contain parent directory segments`);
    }
  }
}

export function configuredBaseDir(folderName: string): string {
  const raw = folderName.trim();
  if (!raw) {
    throw new Error(
      "Error: Directory not set. Configure Base Directory (folderName) in plugin settings.",
    );
  }
  const resolved = path.resolve(raw);
  if (!fs.existsSync(resolved) || !fs.statSync(resolved).isDirectory()) {
    throw new Error(`Error: Directory not set or does not exist (${resolved})`);
  }
  return resolved;
}