import { execFile } from "node:child_process";
import { promisify } from "node:util";
import { basename } from "node:path";

export interface ProcessRow { pid: number; ppid: number; command: string }
export function parseProcesses(text: string): ProcessRow[] {
  return text.split("\n").flatMap(line => {
    const m = /^\s*(\d+)\s+(\d+)\s+(.+)$/.exec(line);
    return m ? [{ pid: Number(m[1]), ppid: Number(m[2]), command: m[3]!.trim() }] : [];
  });
}
export function externalCodexPresent(rows: ProcessRow[], managerPid: number): boolean {
  const children = new Set([managerPid]);
  let changed = true;
  while (changed) { changed = false; for (const row of rows) if (children.has(row.ppid) && !children.has(row.pid)) { children.add(row.pid); changed = true; } }
  return rows.some(r => !children.has(r.pid) && basename(r.command) === "codex");
}
export async function codexPresent(managerPid = process.pid): Promise<boolean> {
  const { stdout } = await promisify(execFile)("/bin/ps", ["-axo", "pid=,ppid=,comm="], { timeout: 5000, maxBuffer: 4 * 1024 * 1024 });
  return externalCodexPresent(parseProcesses(stdout), managerPid);
}