from datetime import date
from typing import Optional, List
from dal.student_dal_json import StudentDAL
from model import Student


class StudentBLL:
    def __init__(self, dal: StudentDAL):
        self.dal = dal

    def add_student(self, student: Student) -> bool:
        if self.dal.check_student_exists(student.sid):
            raise ValueError(f"学生 ID {student.sid} 已存在。")
        if not student.is_valid:
            raise ValueError(f"学生数据校验不通过。错误信息：{student.get_errors()}")
        return self.dal.add_student(student)

    def delete_student(self, sid: str) -> bool:
        if not self.dal.check_student_exists(sid):
            raise ValueError(f"学生 ID {sid} 不存在。")
        return self.dal.delete_student(sid)

    def delete_student_by_id_number(self, id_number: str) -> bool:
        student = self.dal.find_student_by_id_number(id_number)
        if not student:
            raise ValueError(f"身份证号为 {id_number} 的学生不存在。")
        return self.dal.delete_student_by_id_number(id_number)

    def update_student(self, sid: str, student: Student) -> bool:
        if not self.dal.check_student_exists(sid):
            raise ValueError(f"学生 ID {sid} 不存在。")
        if not student.is_valid:
            raise ValueError(f"学生数据校验不通过。错误信息：{student.get_errors()}")
        return self.dal.update_student(sid, student)

    def update_student_partial(self, sid: str, name: Optional[str] = None, height: Optional[int] = None,
                               birth_date: Optional[date] = None, enrollment_date: Optional[date] = None,
                               class_name: Optional[str] = None, major: Optional[str] = None,
                               phone: Optional[str] = None, email: Optional[str] = None) -> bool:
        if not self.dal.check_student_exists(sid):
            raise ValueError(f"学生 ID {sid} 不存在。")
        return self.dal.update_student_partial(sid, name, height, birth_date, enrollment_date,
                                               class_name, major, phone, email)

    def get_student_by_id(self, sid: str) -> Optional[Student]:
        return self.dal.find_student_by_sid(sid)

    def find_student_by_id_number(self, id_number: str) -> Optional[Student]:
        return self.dal.find_student_by_id_number(id_number)

    def get_students_by_name(self, name: str) -> List[Student]:
        return self.dal.find_students_by_name(name)

    def get_students_by_class(self, class_name: str) -> List[Student]:
        return self.dal.find_students_by_class_name(class_name)

    def get_students_by_major(self, major: str) -> List[Student]:
        return self.dal.find_students_by_major(major)

    def get_all_students(self) -> List[Student]:
        return self.dal.get_all_students()

    def count_students_by_major(self):
        """统计各专业学生人数"""
        return self.dal.count_students_by_major()

    def calculate_average_height_weight(self, group_by='major'):
        """计算平均身高/体重（按班级或专业）"""
        return self.dal.calculate_average_height_weight(group_by)

    def calculate_gender_ratio(self):
        """统计性别比例"""
        return self.dal.calculate_gender_ratio()