购物车功能

import os
import json

# 获取执行文件所在路径
current_path = os.path.dirname(__file__)
# 拼接db文件夹的路径
data_path = os.path.join(current_path, 'db')
if not os.path.exists(data_path):  # 没有文件夹
    os.mkdir(data_path)  # 创建文件

is_login = {'username': None}


def login_auth(func_name):
    def inner(*args, **kwargs):
        if is_login.get('username'):
            res = func_name(*args, **kwargs)
            return res
        else:
            print('请先登录')
            login()

    return inner


def register():
    # 获取用户名和密码，第二次输入密码
    username = input('username:').strip()
    password = input('password:').strip()
    second_pawd = input('second_pawd:').strip()
    # 比较密码两次是否一致
    if not password == second_pawd:
        print('两次密码不一致')
        return
    # 拼接用户数据文件路径
    file_path = os.path.join(data_path, f'{username}.json')
    # 检验用户名是否存在>>>:检验文件路径是否存在
    if os.path.isfile(file_path):  # 文件名存在用户就存在
        print('用户名已存在')
        return  # 结束函数运行
    # 初始化用户数据
    user_dict = {'username': username, 'password': password, 'balance': 15000, 'shop_car': {}}
    with open(file_path, 'w', encoding='utf8') as f:
        json.dump(user_dict, f, ensure_ascii=False)
    print(f'{username}注册成功')


def login():
    username = input('username:').strip()
    password = input('password:').strip()
    file_path = os.path.join(data_path, f'{username}.json')
    if not os.path.isfile(file_path):
        print('用户名不存在')
        return
    with open(file_path, 'r', encoding='utf8') as f:
        user_dict = json.load(f)
    if user_dict.get('password') == password:
        print('登录成功')
        # 修改全局变量
        is_login['username'] = username
    else:
        print('密码错误')


@login_auth
def add_shop_car():
    # 定义购物车数据(代码直接写死 也可以通过专门的商品文件便于后期维护更新)
    good_list = [
        ['挂壁面', 3],
        ['印度飞饼', 22],
        ['极品木瓜', 666],
        ['土耳其土豆', 999],
        ['伊拉克拌面', 1000],
        ['董卓戏张飞公仔', 2000],
        ['仿真玩偶', 10000]
    ]
    temp_shop_car = {}
    while True:
        for i, j in enumerate(good_list):
            print("商品编号:%s  |  商品名称:%s  |   商品单价:%s" % (i, j[0], j[1]))
        # 输入购买商品编号
        choice = input('请输入您想要购买的商品编号或者输入y退出添加>>>:').strip()
        # 想保存购物数据
        if choice == 'y':
            file_path = os.path.join(data_path, '%s.json' % is_login.get('username'))
            with open(file_path, 'r', encoding='utf8') as f:
                user_dict = json.load(f)
            # 修改购物车数据
            real_shop_car = user_dict.get('shop_car')
            for good_name in temp_shop_car:
                if good_name in real_shop_car:
                    real_shop_car[good_name][0] += temp_shop_car[good_name][0]
                else:
                    real_shop_car[good_name] = temp_shop_car[good_name]
            user_dict['shop_car'] = real_shop_car
            # 重新写入文件
            with open(file_path, 'w', encoding='utf8') as f:
                json.dump(user_dict, f, ensure_ascii=False)
            print('商品添加成功')
            break

        # 检验是否是纯数字
        if not choice.isdigit():
            print('必须输入纯数字')
            continue
        choice = int(choice)
        # 校验数字范围
        if not choice in range(len(good_list)):
            print('编号超出范围')
            continue
        # 获取用户想购买的商品数据
        target_good_list = good_list[choice]
        target_good_name = target_good_list[0]
        target_good_price = target_good_list[1]
        # 获取用户想要购买数量
        target_num = input('购买的数量：').strip()
        if target_num.isdigit():
            target_num = int(target_num)
            # 确定了商量和数量 添加购物车 但是要考虑用户还可能购买其他商品
            """临时购物车字典里面可能已经存在一些商品 也可能是第一次购买"""
            if target_good_name not in temp_shop_car:
                temp_shop_car[target_good_name] = [target_num, target_good_price]
            else:
                temp_shop_car[target_good_name][0] += target_num
        else:
            print('商品个数必须是纯数字')


@login_auth
def cler_shop():
    # 获取用户购物车数据
    file_path = os.path.join(data_path,'%s.json'%is_login.get('username'))
    # 获取购物车
    with open(file_path, 'r',encoding='utf8') as f:
        user_dict = json.load(f)
    shop_car = user_dict.get('shop_car')
    # 定义一个总价
    total_money = 0
    # 计算总价
    for good_num, good_price in shop_car.values():
        total_money += good_num * good_price
    balance = user_dict.get('balance')
    if balance > total_money:
        rest_money = balance - total_money
        user_dict['balance'] = rest_money
        user_dict['shop_car'] = {}
        with open(file_path,'w',encoding='utf8') as f:
            json.dump(user_dict,f,ensure_ascii=False)
        print(f'结算成功 今日消费{total_money} 余额{rest_money} 欢迎下次光临!!!')
    else:
        print('余额不够')




func_dict = {
    '1': register,
    '2': login,
    '3': add_shop_car,
    '4': cler_shop,
}
while True:
    print('''
    1.用户注册
    2.用户登录
    3.添加购物车
    4.结算购物车
    ''')
    choice = input('请输入功能编号：').strip()
    if choice in func_dict:
        func_name = func_dict.get(choice)
        func_name()
    else:
        print('功能编号不存在')