import path from "node:path";
import fs from "node:fs";
import { fileURLToPath } from "node:url";

export const defaultMonorepoRoot = (): string => {
  const fromEnv = process.env.SMART_IDE_MONOREPO_ROOT?.trim();
  if (fromEnv) {
    return path.resolve(fromEnv);
  }
  const here = path.dirname(fileURLToPath(import.meta.url));
  return path.resolve(here, "..", "..", "..");
};

const extraPrefixes = (): string[] => {
  const raw = process.env.TOOLS_ALLOWED_PATH_PREFIXES?.trim();
  if (!raw) {
    return [];
  }
  return raw
    .split(",")
    .map((s) => path.resolve(s.trim()))
    .filter((s) => s.length > 0);
};

export const isPathAllowed = (absPath: string, monorepoRoot: string): boolean => {
  const norm = path.resolve(absPath);
  const roots = [path.resolve(monorepoRoot), ...extraPrefixes()];
  return roots.some((r) => norm === r || norm.startsWith(r + path.sep));
};

export const assertAllowedFile = (p: string, monorepoRoot: string): string => {
  const abs = path.resolve(p);
  if (!isPathAllowed(abs, monorepoRoot)) {
    throw new Error(`Path not allowed under SMART_IDE_MONOREPO_ROOT: ${abs}`);
  }
  if (!fs.existsSync(abs)) {
    throw new Error(`Path does not exist: ${abs}`);
  }
  return abs;
};

/** Output directory (may not exist yet); must resolve under an allowed root. */
export const assertAllowedDirPath = (p: string, monorepoRoot: string): string => {
  const abs = path.resolve(p);
  if (!isPathAllowed(abs, monorepoRoot)) {
    throw new Error(`Path not allowed under SMART_IDE_MONOREPO_ROOT: ${abs}`);
  }
  return abs;
};