import { readdir, stat } from "node:fs/promises";
import { join, dirname } from "node:path";
import { createRequire } from "node:module";

async function find(path: string, name: string): Promise<string | null> {
  for (const file of await readdir(path, { withFileTypes: true })) {
    if (file.isDirectory()) {
      const found = await find(join(file.parentPath, file.name), name);
      if (found) return found;
    } else if (file.isFile()) {
      if (file.name === name) return join(file.parentPath, file.name);
    }
  }
  return null;
}

async function isFile(path: string): Promise<boolean> {
  try {
    const st = await stat(path);
    return st.isFile();
  } catch {
    return false;
  }
}

async function getPackageJsonDir(path: string): Promise<string | null> {
  if (await isFile(join(path, "package.json"))) return path;
  const next = dirname(path);
  if (next === path) return null;
  return getPackageJsonDir(next);
}

export async function findNative(
  module: string,
  native: string
): Promise<string> {
  const path = await getPackageJsonDir(
    createRequire(import.meta.url).resolve(module)
  );
  if (!path) throw new Error(`Cannot find module directory for ${module}`);
  const file = await find(path, native);
  if (!file)
    throw new Error(
      `Cannot find native ${native} of package ${module} in ${path}`
    );
  return file;
}

export async function tryFindNative(
  module: string,
  native: string
): Promise<string | null> {
  try {
    return await findNative(module, native);
  } catch (e) {
    console.warn(e);
    return null;
  }
}

export async function findNatives(): Promise<typeof natives> {
  return {
    sqlite: await tryFindNative("better-sqlite3", "better_sqlite3.node"),
  };
}