import fsSync from "node:fs";
import path from "node:path";
import { openBoundaryFileSync } from "./boundary-file-read.js";

export function expectedIntegrityForUpdate(
  spec: string | undefined,
  integrity: string | undefined,
): string | undefined {
  if (!integrity || !spec) {
    return undefined;
  }
  const value = spec.trim();
  if (!value) {
    return undefined;
  }
  const at = value.lastIndexOf("@");
  if (at <= 0 || at >= value.length - 1) {
    return undefined;
  }
  const version = value.slice(at + 1).trim();
  if (!/^v?\d+\.\d+\.\d+(?:-[0-9A-Za-z.-]+)?(?:\+[0-9A-Za-z.-]+)?$/.test(version)) {
    return undefined;
  }
  return integrity;
}

export async function readInstalledPackageVersion(dir: string): Promise<string | undefined> {
  const manifestPath = path.join(dir, "package.json");
  const opened = openBoundaryFileSync({
    absolutePath: manifestPath,
    rootPath: dir,
    boundaryLabel: "installed package directory",
  });
  if (!opened.ok) {
    return undefined;
  }
  try {
    const raw = fsSync.readFileSync(opened.fd, "utf-8");
    const parsed = JSON.parse(raw) as { version?: unknown };
    return typeof parsed.version === "string" ? parsed.version : undefined;
  } catch {
    return undefined;
  } finally {
    fsSync.closeSync(opened.fd);
  }
}