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)


FREQUENCIES = ["hourly", "daily", "weekly"]


class BackupSchedule(SQLModel, table=True):
    """An automatic, recurring backup of a local stack to a destination."""

    id: Optional[int] = Field(default=None, primary_key=True)
    stack_id: str
    destination_id: int
    frequency: str = "daily"  # one of FREQUENCIES
    hour: int = 3  # UTC, used for daily/weekly
    minute: int = 0
    weekday: int = 0  # 0=Mon .. 6=Sun, used for weekly
    include_volumes: bool = True
    stop_first: bool = True
    keep: int = 7  # retention: keep newest N for this stack on the dest (0 = all)
    enabled: bool = True
    last_run: Optional[datetime] = None
    last_status: Optional[str] = None  # "ok" | "error: ..."
    next_run: Optional[datetime] = None
    created_at: datetime = Field(default_factory=_now)


# --- API schemas ---


class ScheduleCreate(SQLModel):
    stack_id: str
    destination_id: int
    frequency: str = "daily"
    hour: int = 3
    minute: int = 0
    weekday: int = 0
    include_volumes: bool = True
    stop_first: bool = True
    keep: int = 7
    enabled: bool = True


class ScheduleUpdate(SQLModel):
    destination_id: Optional[int] = None
    frequency: Optional[str] = None
    hour: Optional[int] = None
    minute: Optional[int] = None
    weekday: Optional[int] = None
    include_volumes: Optional[bool] = None
    stop_first: Optional[bool] = None
    keep: Optional[int] = None
    enabled: Optional[bool] = None


class ScheduleRead(SQLModel):
    id: int
    stack_id: str
    destination_id: int
    destination_name: Optional[str]
    frequency: str
    hour: int
    minute: int
    weekday: int
    include_volumes: bool
    stop_first: bool
    keep: int
    enabled: bool
    last_run: Optional[datetime]
    last_status: Optional[str]
    next_run: Optional[datetime]
    created_at: datetime