"""In-memory Repository: M0 default, and the reference fake for tests.

Single-process only (fine for one Gradio app); durable backends (SQLite local,
Supabase Postgres on the Space) land in M3.
"""

from tutor.domain.models import Attempt, Learner


class InMemoryRepository:
    def __init__(self) -> None:
        self._learners: dict[str, Learner] = {}
        self._attempts: dict[str, Attempt] = {}

    async def save_learner(self, learner: Learner) -> None:
        self._learners[learner.id] = learner

    async def get_learner(self, learner_id: str) -> Learner | None:
        return self._learners.get(learner_id)

    async def save_attempt(self, attempt: Attempt) -> None:
        self._attempts[attempt.id] = attempt

    async def list_attempts(self, learner_id: str) -> list[Attempt]:
        attempts = [a for a in self._attempts.values() if a.learner_id == learner_id]
        return sorted(attempts, key=lambda a: a.created_at)