import json
import os
from typing import Dict, Any


class StudentDataAccess:
    def __init__(self, file_path: str = 'student_data.json'):
        self.file_path = file_path

    def load_data(self) -> Dict[str, Any]:
        """从文件加载所有学生数据"""
        try:
            if os.path.exists(self.file_path):
                with open(self.file_path, 'r', encoding='utf-8') as f:
                    return json.load(f)
            return {}
        except Exception as e:
            raise Exception(f"加载数据时出错: {e}")

    def save_data(self, data: Dict[str, Any]) -> bool:
        """保存所有学生数据到文件"""
        try:
            with open(self.file_path, 'w', encoding='utf-8') as f:
                json.dump(data, f, ensure_ascii=False, indent=4)
            return True
        except Exception as e:
            raise Exception(f"保存数据时出错: {e}")

    def get_student(self, student_id: str) -> Dict[str, Any]:
        """根据学号获取单个学生信息"""
        data = self.load_data()
        return data.get(student_id)

    def get_all_students(self) -> Dict[str, Any]:
        """获取所有学生信息"""
        return self.load_data()

    def add_student(self, student_id: str, student_info: Dict[str, Any]) -> bool:
        """添加新学生"""
        data = self.load_data()
        if student_id in data:
            raise Exception("该学号已存在！")
        data[student_id] = student_info
        return self.save_data(data)

    def update_student(self, student_id: str, student_info: Dict[str, Any]) -> bool:
        """更新学生信息"""
        data = self.load_data()
        if student_id not in data:
            raise Exception("该学号不存在！")
        data[student_id] = student_info
        return self.save_data(data)

    def delete_student(self, student_id: str) -> bool:
        """删除学生"""
        data = self.load_data()
        if student_id not in data:
            raise Exception("该学号不存在！")
        del data[student_id]
        return self.save_data(data)