/**
 * Background bash job — spawns a `bash -c` subprocess and tracks its life.
 * Mirrors `apps/infrastructure/src/bgbash/job.rs`.
 */
import { spawn, type ChildProcess } from "node:child_process";
import { randomUUID } from "node:crypto";

/** A handle to a spawned background bash job. */
export class BashJob {
  readonly id: string;
  readonly command: string;
  private process: ChildProcess | null = null;
  private cancelled = false;
  private finished = false;

  constructor(command: string) {
    this.id = randomUUID();
    this.command = command;
  }

  /** Spawn the `bash -c` child process and begin tracking it. */
  start(): void {
    const child = spawn("bash", ["-c", this.command], {
      stdio: ["ignore", "pipe", "pipe"],
    });
    this.process = child;

    // Drain stdout/stderr so the process doesn't block on a full pipe, and
    // mark finished when it exits.
    child.stdout?.resume();
    child.stderr?.resume();
    child.on("exit", () => {
      this.finished = true;
    });
    child.on("error", () => {
      this.finished = true;
    });
  }

  /** Cancel the job: set the cancelled flag and kill the child process. */
  cancel(): void {
    this.cancelled = true;
    if (this.process && !this.finished) {
      try {
        this.process.kill("SIGKILL");
      } catch {
        /* already gone */
      }
    }
  }

  /** Whether the job is currently running. */
  isRunning(): boolean {
    if (this.cancelled || this.finished) return false;
    if (!this.process) return false;
    return this.process.exitCode === null && !this.finished;
  }
}

/** Spawn a background bash job and return its handle (node-side). */
export function spawnBashJob(command: string): BashJob {
  const job = new BashJob(command);
  job.start();
  return job;
}