"""班级表（需求 2.4）。"""

from __future__ import annotations

from datetime import date

from sqlalchemy import Date, ForeignKey, String, Text
from sqlalchemy.orm import Mapped, mapped_column, relationship

from app.model.assoc import class_teachers
from app.model.base import Base, SoftDeleteMixin, TimestampMixin
from app.model.constants import CLASS_STATUS_TEXT, ClassStatus


class Clazz(Base, TimestampMixin, SoftDeleteMixin):
    __tablename__ = "clazz"
    __table_args__ = {"comment": "班级表"}

    id: Mapped[int] = mapped_column(primary_key=True, autoincrement=True)
    class_no: Mapped[str] = mapped_column(String(30), unique=True, nullable=False, comment="班级编号，如 JAVA2401")
    name: Mapped[str] = mapped_column(String(50), nullable=False, index=True, comment="班级名称")
    direction: Mapped[str | None] = mapped_column(String(50), comment="班级方向，如 Java 就业班")
    open_date: Mapped[date | None] = mapped_column(Date, comment="开课时间")
    close_date: Mapped[date | None] = mapped_column(Date, comment="结课时间")
    classroom: Mapped[str | None] = mapped_column(String(30), comment="教室")
    capacity: Mapped[int | None] = mapped_column(default=40, comment="计划招生人数")
    status: Mapped[int] = mapped_column(default=int(ClassStatus.RUNNING), nullable=False, comment="班级状态 1=在读 2=已结课 3=已解散")

    head_teacher_id: Mapped[int | None] = mapped_column(ForeignKey("teacher.id"), comment="班主任（老师）")
    advisor_id: Mapped[int | None] = mapped_column(ForeignKey("advisor.id"), comment="带班顾问")

    description: Mapped[str | None] = mapped_column(Text, comment="班级说明")

    # ---------------- 关系 ----------------
    head_teacher: Mapped["Teacher"] = relationship(lazy="joined", foreign_keys=[head_teacher_id])  # noqa: F821
    advisor: Mapped["Advisor"] = relationship(lazy="joined")  # noqa: F821
    teachers: Mapped[list["Teacher"]] = relationship(  # noqa: F821
        secondary=class_teachers,
        back_populates="classes",
        lazy="selectin",
    )
    # viewonly：人数统计走 DAO 的聚合查询，这个关系只在班级详情里用来展开学生
    students: Mapped[list["Student"]] = relationship(  # noqa: F821
        back_populates="klass",
        viewonly=True,
        lazy="select",
    )

    # ---------------- 出参派生字段 ----------------
    @property
    def status_text(self) -> str:
        return CLASS_STATUS_TEXT.get(self.status, "未知")

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

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

    @property
    def teacher_names(self) -> list[str]:
        return [t.name for t in self.teachers if t.is_del == 0]

    @property
    def teacher_ids(self) -> list[int]:
        return [t.id for t in self.teachers if t.is_del == 0]