import json


class InputError(Exception):
    def __str__(self):
        return '请根据提示输入正确的数字'

class StuSys:
    def __init__(self, sys_name):
        self.sys_name = sys_name

    def show_home(self):
        return """
    ======================================
            欢迎来到%s学生管理系统

            ◆ 1.登              录
            ◆ 2.注              册
            ◆ 3.退              出
    ======================================""" % self.sys_name


    def start_sys(self):
        flag = 1
        while flag:
            print(self.show_home())
            choice1 = int(input('请选择（1-3）：'))
            if choice1 == 1:
                StuSys.login_in()
            elif choice1 == 2:
                StuSys.register()
            elif choice1 == 3:
                break
            else:
                raise InputError




  @classmethod
  def login_in(cls):
        """登录"""
        while True:
            account = input('请输入账号:')
            password = input('请输入密码:')
            stu = {'account': account, 'password': password}
            with open('students.txt', 'r', encoding='utf-8') as f:
                students = json.load(f)
            stu_accounts = []
            for student in students:
                if student['account'] == account:
                    if student['password'] ==password:
                        input('登陆成功')
                        return 
                    else:
                        input('登录失败！密码错误！')
                        return
                else:
                    input('登录失败！账号不存在！')
                    return

            @classmethod
        def register(cls):
        """注册"""
        while True:
            flag = 0
            account = input('请输入账号:')
            password = input('请输入密码:')
            stu = {'account': account, 'password': password}
            with open('students.txt', 'r', encoding='utf-8') as f:
                students = json.load(f)
            for student in students:
                if student['account'] == account:
                    input('账号已存在，请按下任意键重新输入账号')
                    flag = 1
                    break
            if flag:
                continue
            else:
                students.append(stu)
                with open('students.txt', 'w', encoding='utf-8') as f:
                    json.dump(students, f)
                    input('注册成功！ 请按下任意键返回上一层')
                    break





def main():
    c1 = StuSys('千峰')
    c1.start_sys()


if __name__ == '__main__':
    main()