"""Launch a legacy-command pack: start the existing console and wait for it."""
from __future__ import annotations

import subprocess
import time
import urllib.request
from pathlib import Path

from .pack import Pack


def repo_root(pack: Pack) -> Path:
    """runbooks/<dir>/pack.yaml -> repository root."""
    return pack.path.resolve().parents[2]


def wait_ready(url: str, timeout: float = 30.0) -> bool:
    end = time.monotonic() + timeout
    while time.monotonic() < end:
        try:
            with urllib.request.urlopen(url, timeout=2):
                return True
        except Exception:
            time.sleep(0.3)
    return False


def launch(pack: Pack, timeout: float = 30.0) -> subprocess.Popen:
    """Start the console in the owning repo. Caller owns the returned process."""
    if pack.data.get("engine") != "legacy-command":
        raise ValueError("not a legacy-command pack")
    spec = pack.data["legacy"]
    cwd = (repo_root(pack) / spec.get("cwd", ".")).resolve()
    if repo_root(pack) not in [cwd, *cwd.parents]:
        raise ValueError("legacy.cwd escapes the owning repository")
    proc = subprocess.Popen(spec["command"], cwd=cwd)
    url = spec.get("url")
    if url and not wait_ready(url, timeout):
        proc.terminate()
        raise TimeoutError(f"{url} did not answer within {timeout}s")
    return proc