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

from app.models.source_case import CaseBase, CaseExamItem, TeachingCase, TraditionalCase


class CaseRepository:
    """病例只读仓储：读取已发布病例、模式扩展数据和固定检查项目。"""

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

    def list_active_cases(
        self,
        department_id: int | None = None,
        training_type: str | None = None,
        mode: str | None = None,
    ) -> list[CaseBase]:
        """病例列表：从 case_base 读取已发布病例，并按模式匹配扩展表。"""
        normalized_mode = "practice" if mode == "novice" else mode
        stmt = (
            select(CaseBase)
            .options(selectinload(CaseBase.traditional_case), selectinload(CaseBase.teaching_case))
            .where(CaseBase.status == 1, CaseBase.publish_status == 1)
        )
        if department_id:
            stmt = stmt.where(CaseBase.department_id == department_id)
        if training_type:
            stmt = stmt.where(CaseBase.case_type == training_type)
        if normalized_mode == "practice":
            stmt = stmt.where(exists().where(TraditionalCase.case_id == CaseBase.id))
        if normalized_mode == "teaching":
            stmt = stmt.where(exists().where(TeachingCase.case_id == CaseBase.id))
        return list(self.db.scalars(stmt.order_by(CaseBase.id.desc())).all())

    def get_active_case(self, case_id: int) -> CaseBase | None:
        """病例详情：读取病例主表及训练所需的扩展表、评分规则和检查项目。"""
        stmt = (
            select(CaseBase)
            .options(
                selectinload(CaseBase.traditional_case),
                selectinload(CaseBase.teaching_case),
                selectinload(CaseBase.scoring_rules),
                selectinload(CaseBase.exam_items),
            )
            .where(CaseBase.id == case_id, CaseBase.status == 1, CaseBase.publish_status == 1)
        )
        return self.db.scalar(stmt)

    def get_exam_items(self, case_id: int) -> list[CaseExamItem]:
        """检查项目：读取当前病例下全部可申请检查检验项目。"""
        stmt = select(CaseExamItem).where(CaseExamItem.case_id == case_id).order_by(CaseExamItem.display_order)
        return list(self.db.scalars(stmt).all())

    def get_exam_item(self, case_id: int, item_code: str) -> CaseExamItem | None:
        """检查结果：按病例和项目编码读取数据库中的固定结果。"""
        stmt = select(CaseExamItem).where(CaseExamItem.case_id == case_id, CaseExamItem.item_code == item_code)
        return self.db.scalar(stmt)