from sqlalchemy import or_, select
from sqlalchemy.orm import Session, selectinload

from app.models.knowledge import KnowledgeChunk


class KnowledgeRepository:
    """知识库仓储：负责评分参考指南的轻量检索。"""

    def __init__(self, db: Session) -> None:
        self.db = db

    def search_chunks(
        self,
        department_id: int,
        task_type: str,
        keywords: list[str],
        limit: int = 5,
    ) -> list[KnowledgeChunk]:
        """知识检索：按科室、任务类型和关键词检索知识片段。"""
        stmt = (
            select(KnowledgeChunk)
            .options(selectinload(KnowledgeChunk.document))
            .where(KnowledgeChunk.is_active.is_(True))
            .where(or_(KnowledgeChunk.department_id == department_id, KnowledgeChunk.department_id.is_(None)))
            .where(or_(KnowledgeChunk.task_type == task_type, KnowledgeChunk.task_type.is_(None)))
        )

        keyword_clauses = [KnowledgeChunk.chunk_text.contains(keyword) for keyword in keywords if keyword]
        if keyword_clauses:
            stmt = stmt.where(or_(*keyword_clauses))

        stmt = stmt.order_by(KnowledgeChunk.weight.desc(), KnowledgeChunk.id.asc()).limit(limit)
        return list(self.db.scalars(stmt).all())