"""gpu-rent hold: pause idle-killer via hold-until file on the data volume."""

from __future__ import annotations

from datetime import datetime, timezone
from collections.abc import Callable

from gpu_rent.config import Config
from gpu_rent.errors import GpuRentError
from gpu_rent.ssh_ops import put_text, remote_exists, run_ssh

Log = Callable[[str], None]
HOLD_PATH = "/mnt/swarm_data/.gpu-rent-hold-until"


def _parse_until(value: str) -> int:
    text = value.strip()
    if text.isdigit():
        return int(text)
    try:
        dt = datetime.fromisoformat(text.replace("Z", "+00:00"))
    except ValueError as exc:
        raise GpuRentError(f"не разобрать --until {value!r}: нужен ISO или unix ts") from exc
    if dt.tzinfo is None:
        dt = dt.replace(tzinfo=timezone.utc)
    return int(dt.timestamp())


def set_hold(
    cfg: Config,
    host: str,
    *,
    minutes: int | None = None,
    until: str | None = None,
    log: Log | None = None,
) -> int:
    """Write hold-until unix ts. Default = now + IDLE_MINUTES."""
    if minutes is not None and until is not None:
        raise GpuRentError("укажи либо --minutes, либо --until, не оба")
    now = int(datetime.now(timezone.utc).timestamp())
    if until:
        ts = _parse_until(until)
    else:
        mins = minutes if minutes is not None else cfg.idle_minutes
        if mins <= 0:
            raise GpuRentError("--minutes должен быть > 0")
        ts = now + mins * 60
    if ts <= now:
        raise GpuRentError("hold уже в прошлом — увеличь время или используй --clear")
    put_text(cfg, host, HOLD_PATH, f"{ts}\n")
    # readable by ubuntu + root
    run_ssh(cfg, host, f"sudo -n chmod 644 {HOLD_PATH}", check=False)
    iso = datetime.fromtimestamp(ts, tz=timezone.utc).isoformat()
    if log:
        log(f"hold до {iso} (unix {ts})")
    return ts


def clear_hold(cfg: Config, host: str, log: Log | None = None) -> None:
    run_ssh(cfg, host, f"sudo -n rm -f {HOLD_PATH}", check=False)
    if log:
        log("hold снят")


def read_hold(cfg: Config, host: str) -> int | None:
    if not remote_exists(cfg, host, HOLD_PATH):
        return None
    raw = run_ssh(cfg, host, f"cat {HOLD_PATH}", check=False).strip()
    try:
        return int(float(raw.split()[0]))
    except (ValueError, IndexError):
        return None