import { readFileSync } from "node:fs";

export type Platform = "linux" | "macos" | "windows" | "wsl" | "other";
export type ProcVersionReader = () => string;

export function readProcVersionSync(): string {
  try {
    return readFileSync("/proc/version", "utf8");
  } catch {
    return "";
  }
}

export function isWsl(
  env: Readonly<Record<string, string | undefined>> = process.env,
  readProcVersion: ProcVersionReader = readProcVersionSync,
): boolean {
  if (env.WSL_DISTRO_NAME || env.WSL_INTEROP || env.WSLENV) return true;
  try {
    return /(?:microsoft|microsoft-standard)/iu.test(readProcVersion());
  } catch {
    return false;
  }
}

export function detectPlatform(
  platform: string = process.platform,
  env: Readonly<Record<string, string | undefined>> = process.env,
  readProcVersion: ProcVersionReader = readProcVersionSync,
): Platform {
  if (platform === "win32") return "windows";
  if (platform === "darwin") return "macos";
  if (platform === "linux") return isWsl(env, readProcVersion) ? "wsl" : "linux";
  return "other";
}