"""Memory system evaluation helpers."""

from __future__ import annotations

from typing import Any

from plane_mode_scholar.storage.sqlite_store import SQLiteStore


def evaluate_memory_health(store: SQLiteStore | None = None) -> dict[str, Any]:
    store = store or SQLiteStore()
    active = store.list_memories(status="active")
    archived = store.list_memories(status="archived")
    expired = store.list_memories(status="expired")

    canonical_forms = [m.canonical_form for m in active if m.canonical_form]
    duplicate_rate = 1 - (len(set(canonical_forms)) / len(canonical_forms)) if canonical_forms else 0.0

    stale = [m for m in active if m.confidence < 0.4]
    stale_rate = len(stale) / len(active) if active else 0.0

    return {
        "active_count": len(active),
        "archived_count": len(archived),
        "expired_count": len(expired),
        "duplicate_rate": round(duplicate_rate, 3),
        "stale_rate": round(stale_rate, 3),
        "type_distribution": _type_distribution(active),
    }


def _type_distribution(memories: list) -> dict[str, int]:
    dist: dict[str, int] = {}
    for m in memories:
        dist[m.type.value] = dist.get(m.type.value, 0) + 1
    return dist