import fs from "fs";
import os from "os";
import path from "path";

export function projectRoot(): string {
  const fromDir = path.resolve(__dirname, "..");
  if (fs.existsSync(path.join(fromDir, "package.json"))) {
    return fromDir;
  }
  return process.cwd();
}

export function binDir(): string {
  return path.join(projectRoot(), "bin");
}

export function exeName(base: string): string {
  return process.platform === "win32" ? `${base}.exe` : base;
}

export function runnerPath(kind: "cpu" | "metal" | "cuda"): string | null {
  const names: Record<typeof kind, string> = {
    cpu: "med_cpu",
    metal: "med_gpu",
    cuda: "med_cuda",
  };
  const p = path.join(binDir(), exeName(names[kind]));
  return fs.existsSync(p) ? p : null;
}

export function metalShaderPath(): string {
  return path.join(projectRoot(), "native", "metal", "des_bruteforce.metal");
}

export function defaultMedPath(): string {
  const root = projectRoot();
  try {
    const match = fs.readdirSync(root).find((name) => name.toLowerCase().endsWith(".med"));
    if (match) {
      return path.join(root, match);
    }
  } catch {
    /* ignore */
  }
  return "";
}

export function defaultOutDir(): string {
  return path.join(projectRoot(), "decoded", "bruteforce");
}

export function cpuCoreCount(): number {
  return Math.max(1, os.cpus().length);
}