import fs from "node:fs/promises";
import path from "node:path";

export async function resolveWorkspacePath(root, project = ".") {
  if (typeof project !== "string" || project.includes("\0")) {
    throw new Error("Invalid project path");
  }
  const rootReal = await fs.realpath(root);
  const candidate = path.resolve(rootReal, project || ".");
  const candidateReal = await fs.realpath(candidate);
  if (candidateReal !== rootReal && !candidateReal.startsWith(`${rootReal}${path.sep}`)) {
    throw new Error("Project must be below /workspace");
  }
  const stat = await fs.stat(candidateReal);
  if (!stat.isDirectory()) throw new Error("Project is not a directory");
  return candidateReal;
}

export async function listProjects(root) {
  const rootReal = await fs.realpath(root);
  const entries = await fs.readdir(rootReal, { withFileTypes: true });
  return entries
    .filter((entry) => entry.isDirectory() && !entry.name.startsWith("."))
    .map((entry) => entry.name)
    .sort((a, b) => a.localeCompare(b));
}