"""记忆数据访问。"""

from sqlalchemy import func, select
from sqlalchemy.ext.asyncio import AsyncSession

from app.models.memory import Memory


async def get_memory(session: AsyncSession, memory_id: str) -> Memory | None:
    return await session.get(Memory, memory_id)


async def list_memories(
    session: AsyncSession,
    character_id: str,
    *,
    memory_type: str | None = None,
    source: str | None = None,
    page: int,
    page_size: int,
    active_only: bool = True,
) -> tuple[list[Memory], int]:
    conditions = [Memory.character_id == character_id]
    if active_only:
        conditions.append(Memory.status == "active")
        conditions.append(Memory.deleted_at.is_(None))
    if memory_type is not None:
        conditions.append(Memory.type == memory_type)
    if source is not None:
        conditions.append(Memory.source == source)
    total_result = await session.execute(
        select(func.count()).select_from(Memory).where(*conditions)
    )
    total = int(total_result.scalar_one())
    result = await session.execute(
        select(Memory)
        .where(*conditions)
        .order_by(Memory.importance.desc(), Memory.updated_at.desc())
        .offset((page - 1) * page_size)
        .limit(page_size)
    )
    return list(result.scalars().all()), total


async def list_injectable_memories(
    session: AsyncSession, character_id: str, *, limit: int
) -> list[Memory]:
    result = await session.execute(
        select(Memory)
        .where(
            Memory.character_id == character_id,
            Memory.status == "active",
            Memory.deleted_at.is_(None),
        )
        .order_by(Memory.importance.desc(), Memory.updated_at.desc())
        .limit(limit)
    )
    return list(result.scalars().all())


async def get_memories_by_ids(
    session: AsyncSession, memory_ids: list[str]
) -> list[Memory]:
    """按 ID 列表批量获取记忆（按重要性降序排序，而非 ID 传入顺序）。"""
    result = await session.execute(
        select(Memory).where(
            Memory.id.in_(memory_ids),
            Memory.status == "active",
            Memory.deleted_at.is_(None),
        )
        .order_by(Memory.importance.desc(), Memory.updated_at.desc())
    )
    return list(result.scalars().all())