import { execSync } from "child_process";
import fs from "fs";
import os from "os";
import path from "path";

export type BinaryName = "sling" | "atlas";

export interface BinaryInfo {
  path: string;
  version: string;
}

export function resolveBinary(name: BinaryName): string | null {
  try {
    const out = execSync(`which ${name}`, {
      encoding: "utf8",
      stdio: ["pipe", "pipe", "pipe"],
    })
      .trim()
      .split("\n")[0];
    if (out) return out;
  } catch {
    // not on PATH
  }
  if (name === "sling") {
    const fallback = path.join(os.homedir(), ".sling", "bin", "sling");
    if (fs.existsSync(fallback)) return fallback;
  }
  return null;
}

function probe(name: BinaryName): BinaryInfo | null {
  const binPath = resolveBinary(name);
  if (!binPath) return null;
  let version = "";
  try {
    version = execSync(
      name === "atlas" ? `"${binPath}" version` : `"${binPath}" --version`,
      { encoding: "utf8", timeout: 5000, stdio: ["pipe", "pipe", "pipe"] }
    )
      .trim()
      .split("\n")[0];
  } catch {
    // version probe failed; still report the path
  }
  return { path: binPath, version };
}

export function checkBinaries(): {
  sling: BinaryInfo | null;
  atlas: BinaryInfo | null;
} {
  return { sling: probe("sling"), atlas: probe("atlas") };
}