# -*- coding: utf-8 -*-
import json
import os

DATA_FILE = 'students.json'

def load_students():
    """从文件加载学生数据"""
    if os.path.exists(DATA_FILE):
        with open(DATA_FILE, 'r', encoding='utf-8') as f:
            return json.load(f)
    return []

def save_students(students):
    """保存学生数据到文件"""
    with open(DATA_FILE, 'w', encoding='utf-8') as f:
        json.dump(students, f, ensure_ascii=False, indent=2)

def input_student_info():
    """输入学生信息并验证"""
    name = input("请输入姓名：").strip()
    while not name:
        print("姓名不能为空！")
        name = input("请输入姓名：").strip()

    gender = input("请输入性别（男/女）：").strip()
    while gender not in ['男', '女']:
        print("性别输入错误，请重新输入！")
        gender = input("请输入性别（男/女）：").strip()

    class_name = input("请输入班级：").strip()
    while not class_name:
        print("班级不能为空！")
        class_name = input("请输入班级：").strip()

    phone = input("请输入电话号码：").strip()
    while not (phone.isdigit() and len(phone) >= 7):
        print("电话号码必须为数字且至少7位！")
        phone = input("请输入电话号码：").strip()

    return {
        'name': name,
        'gender': gender,
        'class': class_name,
        'phone': phone
    }

def add_student(students):
    """添加学生"""
    student = input_student_info()
    students.append(student)
    print(f"学生 {student['name']} 添加成功！")

def delete_student(students):
    """删除学生"""
    name = input("请输入要删除的学生姓名：").strip()
    found = [s for s in students if s['name'] == name]
    
    if not found:
        print("未找到该学生！")
        return
    
    for s in found:
        students.remove(s)
    
    print(f"已删除 {len(found)} 个名为 {name} 的学生")

def search_student(students):
    """查询学生"""
    keyword = input("请输入查询关键字（姓名或班级）：").strip()
    results = []
    
    for s in students:
        if keyword in s['name'] or keyword in s['class']:
            results.append(s)
    
    if not results:
        print("未找到匹配的学生！")
        return
    
    print("\n查询结果：")
    for i, student in enumerate(results, 1):
        print(f"{i}. 姓名：{student['name']}")
        print(f"   性别：{student['gender']}")
        print(f"   班级：{student['class']}")
        print(f"   电话：{student['phone']}\n")

def show_menu():
    """显示主菜单"""
    print("\n学生通讯录管理系统")
    print("1. 添加学生")
    print("2. 删除学生")
    print("3. 查询学生")
    print("4. 退出系统")

def main():
    students = load_students()
    
    while True:
        show_menu()
        choice = input("请选择操作（1-4）：").strip()
        
        if choice == '1':
            add_student(students)
        elif choice == '2':
            delete_student(students)
        elif choice == '3':
            search_student(students)
        elif choice == '4':
            save_students(students)
            print("系统已退出，数据已保存！")
            break
        else:
            print("输入无效，请重新输入！")

if __name__ == '__main__':
    main()