"""HAProxy runtime socket adapter — stub for Plan 02."""

from __future__ import annotations

from dataclasses import dataclass


class HAProxyError(Exception):
    """Error communicating with HAProxy runtime socket."""


@dataclass
class SlotHealth:
    """Health status for a single HAProxy server slot."""

    status: str
    scur: int
    qcur: int


class HAProxyRuntime:
    """HAProxy runtime CLI adapter via Unix socket.

    Full implementation in Plan 02.
    """

    def __init__(self, socket_path: str, backend: str, slot_prefix: str) -> None:
        self._socket_path = socket_path
        self._backend = backend
        self._slot_prefix = slot_prefix

    def set_slot_addr(self, slot_id: str, ip: str, port: int = 22) -> None:
        """Update server address for a slot."""
        raise NotImplementedError

    def enable_slot(self, slot_id: str) -> None:
        """Enable a server slot."""
        raise NotImplementedError

    def disable_slot(self, slot_id: str) -> None:
        """Disable a server slot."""
        raise NotImplementedError

    def slot_is_up(self, slot_id: str) -> bool:
        """Return True when HAProxy health status is UP for slot."""
        raise NotImplementedError

    def slot_session_count(self, slot_id: str) -> int:
        """Return current active session count for slot."""
        raise NotImplementedError

    def read_slot_health(self) -> dict[str, SlotHealth]:
        """Return full stats snapshot for all slots."""
        raise NotImplementedError