from __future__ import annotations

from datetime import datetime, timezone
from typing import Optional

from sqlmodel import Field, SQLModel


def _now() -> datetime:
    return datetime.now(timezone.utc)


class AutoUpdate(SQLModel, table=True):
    """Per-stack auto-update policy (Watchtower-style).

    When the background image-update check finds a newer registry digest for one
    of the stack's images, the stack is either pulled + redeployed
    (``redeploy=True``) or merely notified about (``redeploy=False``).
    ``agent_id`` None = local host, otherwise a remote agent's stack.
    """

    id: Optional[int] = Field(default=None, primary_key=True)
    stack_id: str
    agent_id: Optional[int] = None
    enabled: bool = True
    redeploy: bool = True  # True = pull + up -d; False = notify only
    last_run: Optional[datetime] = None
    last_status: Optional[str] = None  # "updated" | "up-to-date" | "update-available" | "skipped" | "error"
    last_result: Optional[str] = None  # detail (stale images / error text)
    created_at: datetime = Field(default_factory=_now)


# --- API schemas ---


class AutoUpdateWrite(SQLModel):
    enabled: bool = True
    redeploy: bool = True


class AutoUpdateRead(SQLModel):
    id: Optional[int]
    stack_id: str
    agent_id: Optional[int]
    agent_name: Optional[str] = None
    enabled: bool
    redeploy: bool
    last_run: Optional[datetime]
    last_status: Optional[str]
    last_result: Optional[str]