/**
 * Runtime import helpers for lazy modules that may be loaded from file URLs or platform paths.
 * Windows paths need normalization before Node's ESM loader can import them safely.
 */
import { toSafeImportPath } from "./import-specifier.js";

/** Runtime-facing alias for import specifier normalization helpers. */
export { toSafeImportPath as toSafeRuntimeImportPath } from "./import-specifier.js";

/**
 * Resolves lazy runtime import parts against the caller's module URL or path.
 * Absolute normalized paths stay standalone; relative parts resolve against the normalized base.
 */
export function resolveRuntimeImportSpecifier(baseUrl: string, parts: readonly string[]): string {
  const joined = parts.join("");
  const safeJoined = toSafeImportPath(joined);
  // Absolute Windows paths and UNC shares become standalone file URLs instead
  // of being resolved relative to the caller's module URL.
  if (safeJoined !== joined) {
    return safeJoined;
  }
  return new URL(joined, toSafeImportPath(baseUrl)).href;
}

/**
 * Imports a lazy runtime module through the normalized runtime specifier.
 * The injectable importer keeps platform-specific specifier handling unit-testable.
 */
export async function importRuntimeModule<T>(
  baseUrl: string,
  parts: readonly string[],
  importModule: (specifier: string) => Promise<unknown> = (specifier) => import(specifier),
): Promise<T> {
  return (await importModule(resolveRuntimeImportSpecifier(baseUrl, parts))) as T;
}