"""演化候选数据访问。"""

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

from app.models.evolution import EvolutionCandidate


async def add_candidates(session: AsyncSession, candidates: list[EvolutionCandidate]) -> None:
    session.add_all(candidates)
    await session.flush()


async def get_candidate(session: AsyncSession, candidate_id: str) -> EvolutionCandidate | None:
    return await session.get(EvolutionCandidate, candidate_id)


async def list_candidates(
    session: AsyncSession,
    character_id: str,
    *,
    status: str | None = None,
    candidate_type: str | None = None,
    page: int = 1,
    page_size: int = 20,
) -> tuple[list[EvolutionCandidate], int]:
    conditions = [EvolutionCandidate.character_id == character_id]
    if status is not None:
        conditions.append(EvolutionCandidate.status == status)
    if candidate_type is not None:
        conditions.append(EvolutionCandidate.type == candidate_type)
    total = (
        await session.execute(
            select(func.count()).select_from(EvolutionCandidate).where(*conditions)
        )
    ).scalar_one()
    items_result = await session.execute(
        select(EvolutionCandidate)
        .where(*conditions)
        .order_by(EvolutionCandidate.created_at.desc())
        .offset(max(page - 1, 0) * page_size)
        .limit(page_size)
    )
    return list(items_result.scalars().all()), int(total or 0)