"""成绩表（需求 2.2）：一个学生 N 次考核，一对多。

红线预警：录入分数低于及格线时 flag=1，并往学生备注里追加一条提醒，
统计模块的"多次不及格"直接按 flag 聚合，不用每次临时算阈值。
"""

from __future__ import annotations

from datetime import date
from decimal import Decimal

from sqlalchemy import Date, ForeignKey, Numeric, SmallInteger, String, UniqueConstraint
from sqlalchemy.orm import Mapped, mapped_column, relationship

from app.model.base import Base, SoftDeleteMixin, TimestampMixin
from app.model.constants import ScoreFlag


class Score(Base, TimestampMixin, SoftDeleteMixin):
    __tablename__ = "score"
    __table_args__ = (
        UniqueConstraint("stu_id", "exam_seq", name="uk_score_stu_seq"),
        {"comment": "学生考核成绩表"},
    )

    id: Mapped[int] = mapped_column(primary_key=True, autoincrement=True)
    stu_id: Mapped[int] = mapped_column(ForeignKey("student.id"), nullable=False, index=True, comment="学生ID")
    exam_seq: Mapped[int] = mapped_column(SmallInteger, nullable=False, index=True, comment="考核序次（第几次考核）")
    exam_name: Mapped[str | None] = mapped_column(String(50), comment="考核名称，如 阶段一考试")
    exam_date: Mapped[date | None] = mapped_column(Date, comment="考核日期")
    score: Mapped[Decimal] = mapped_column(Numeric(5, 2), nullable=False, comment="成绩")
    flag: Mapped[int] = mapped_column(
        SmallInteger, default=int(ScoreFlag.NORMAL), nullable=False, index=True,
        comment="预警标记 0=正常 1=低于红线需重点关注",
    )
    remark: Mapped[str | None] = mapped_column(String(255), comment="备注")

    student: Mapped["Student"] = relationship(back_populates="scores", lazy="joined")  # noqa: F821

    # ---------------- 出参派生字段 ----------------
    @property
    def is_warning(self) -> bool:
        return self.flag == int(ScoreFlag.WARNING)

    @property
    def student_name(self) -> str | None:
        return self.student.name if self.student else None

    @property
    def class_name(self) -> str | None:
        return self.student.class_name if self.student else None