from datetime import datetime

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

from app.models.training import SessionOrder, SessionSubmission, TrainingSession


class SessionRepository:
    """会话仓储：负责训练会话、检查申请和诊断治疗提交数据。"""

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

    def create_session(self, session: TrainingSession) -> TrainingSession:
        """会话创建：保存训练会话主记录。"""
        self.db.add(session)
        self.db.flush()
        return session

    def get_owned_session(self, session_id: int, user_id: str) -> TrainingSession | None:
        """会话归属校验：根据 session_id 和 user_id 查询会话。"""
        stmt = (
            select(TrainingSession)
            .options(
                selectinload(TrainingSession.case),
                selectinload(TrainingSession.orders),
                selectinload(TrainingSession.submission),
            )
            .where(TrainingSession.id == session_id, TrainingSession.user_id == user_id)
        )
        return self.db.scalar(stmt)

    def update_status(self, session: TrainingSession, status: str) -> TrainingSession:
        """状态流转：更新训练会话阶段状态。"""
        session.status = status
        if status == "diagnosis":
            session.inquiry_completed_at = datetime.utcnow()
        if status == "completed":
            session.completed_at = datetime.utcnow()
        self.db.flush()
        return session

    def create_order(self, order: SessionOrder) -> SessionOrder:
        """检查申请保存：保存用户申请过的检查检验结果。"""
        self.db.add(order)
        self.db.flush()
        return order

    def get_order_by_item(self, session_id: int, item_code: str) -> SessionOrder | None:
        """检查申请读取：按会话和检查编码获取已申请结果，用于幂等返回。"""
        stmt = select(SessionOrder).where(
            SessionOrder.session_id == session_id,
            SessionOrder.item_code == item_code,
        )
        return self.db.scalar(stmt)

    def get_submission(self, session_id: int) -> SessionSubmission | None:
        """提交读取：获取当前会话的诊断治疗提交记录。"""
        stmt = select(SessionSubmission).where(SessionSubmission.session_id == session_id)
        return self.db.scalar(stmt)

    def upsert_submission(self, submission: SessionSubmission) -> SessionSubmission:
        """诊断治疗保存：创建或更新当前会话的提交记录。"""
        self.db.add(submission)
        self.db.flush()
        return submission