from datetime import datetime, timezone

from sqlalchemy import DateTime, ForeignKey, Index, Integer, Text, UniqueConstraint
from sqlalchemy.dialects.postgresql import JSONB
from sqlalchemy.orm import Mapped, mapped_column

from fabledassistant.models import Base


class WeatherCache(Base):
    __tablename__ = "weather_cache"

    id: Mapped[int] = mapped_column(primary_key=True)
    user_id: Mapped[int] = mapped_column(Integer, ForeignKey("users.id", ondelete="CASCADE"))
    # Unique key per location, e.g. "home", "work", or "event:<uid>"
    location_key: Mapped[str] = mapped_column(Text)
    location_label: Mapped[str] = mapped_column(Text, default="")
    # Current 7-day forecast from Open-Meteo (raw JSON)
    forecast_json: Mapped[dict | None] = mapped_column(JSONB, nullable=True)
    # Previous forecast — used to detect changes between fetches
    previous_json: Mapped[dict | None] = mapped_column(JSONB, nullable=True)
    fetched_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), default=lambda: datetime.now(timezone.utc)
    )

    __table_args__ = (
        UniqueConstraint("user_id", "location_key", name="uq_weather_cache_user_location"),
        Index("ix_weather_cache_user_id", "user_id"),
    )

    def to_dict(self) -> dict:
        return {
            "id": self.id,
            "location_key": self.location_key,
            "location_label": self.location_label,
            "forecast_json": self.forecast_json,
            "fetched_at": self.fetched_at.isoformat(),
        }