"""ORM models: a Game has many Snapshots. The full snapshot.json is stored verbatim in `data`
(JSON / JSONB); axis counts are denormalised for cheap listing. Diffing reads `data` back through
the existing ams.diff engine, so the DB never has to mirror the snapshot schema."""

from __future__ import annotations

from datetime import datetime, timezone

from sqlalchemy import ForeignKey, JSON, String, UniqueConstraint
from sqlalchemy.orm import Mapped, mapped_column, relationship

from .db import Base


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


class Game(Base):
    __tablename__ = "games"

    id: Mapped[int] = mapped_column(primary_key=True)
    name: Mapped[str] = mapped_column(String, unique=True, index=True)
    notes: Mapped[str | None] = mapped_column(String, default=None)

    snapshots: Mapped[list["Snapshot"]] = relationship(
        back_populates="game", cascade="all, delete-orphan")


class Snapshot(Base):
    __tablename__ = "snapshots"
    __table_args__ = (UniqueConstraint("sha256", name="uq_snapshot_sha256"),)

    id: Mapped[int] = mapped_column(primary_key=True)
    game_id: Mapped[int | None] = mapped_column(ForeignKey("games.id"), default=None, index=True)

    binary_name: Mapped[str] = mapped_column(String)
    sha256: Mapped[str] = mapped_column(String, index=True)
    engine: Mapped[str | None] = mapped_column(String, default=None)
    compiler: Mapped[str | None] = mapped_column(String, default=None)
    schema_version: Mapped[int | None] = mapped_column(default=None)

    n_types: Mapped[int] = mapped_column(default=0)
    n_methods: Mapped[int] = mapped_column(default=0)
    n_events: Mapped[int] = mapped_column(default=0)
    n_fields: Mapped[int] = mapped_column(default=0)

    created_at: Mapped[datetime] = mapped_column(default=_utcnow)
    data: Mapped[dict] = mapped_column(JSON)

    game: Mapped["Game | None"] = relationship(back_populates="snapshots")