py设计一个超市进销存管理系统

好的，一个超市进销存管理系统主要包括以下模块：

1. 商品管理模块：包括添加商品、修改商品、删除商品、查询商品等操作；
2. 库存管理模块：包括商品入库、商品出库、库存查询等操作；
3. 销售管理模块：包括销售记录、销售统计等操作；
4. 用户管理模块：包括添加用户、修改用户、删除用户、查询用户等操作；
5. 权限管理模块：包括用户权限分配、角色管理等操作。

下面是一个简单的示例代码：

import json

class Product:
    def __init__(self, pid, name, price, quantity):
        self.id = pid
        self.name = name
        self.price = price
        self.quantity = quantity
        
    def __str__(self):
        return f'{self.id}\t{self.name}\t{self.price}\t{self.quantity}'

class Inventory:
    def __init__(self, filename):
        self.filename = filename
        self.products = []
        self.load()
        
    def load(self):
        try:
            with open(self.filename, 'r') as f:
                data = json.load(f)
                for p in data:
                    product = Product(p['id'], p['name'], p['price'], p['quantity'])
                    self.products.append(product)
        except FileNotFoundError:
            pass
        
    def save(self):
        with open(self.filename, 'w') as f:
            data = []
            for p in self.products:
                data.append({'id': p.id, 'name': p.name, 'price': p.price, 'quantity': p.quantity})
            json.dump(data, f)
            
    def add_product(self, product):
        self.products.append(product)
        self.save()
        
    def remove_product(self, pid):
        for p in self.products:
            if p.id == pid:
                self.products.remove(p)
                self.save()
                return True
        return False
        
    def update_product(self, pid, name, price, quantity):
        for p in self.products:
            if p.id == pid:
                p.name = name
                p.price = price
                p.quantity = quantity
                self.save()
                return True
        return False
        
    def search_product(self, pid=None, name=None):
        result = []
        for p in self.products:
            if pid and p.id == pid:
                result.append(p)
            elif name and p.name == name:
                result.append(p)
        return result
        
    def get_all_products(self):
        return self.products
        
    def add_quantity(self, pid, quantity):
        for p in self.products:
            if p.id == pid:
                p.quantity += quantity
                self.save()
                return True
        return False
        
    def remove_quantity(self, pid, quantity):
        for p in self.products:
            if p.id == pid:
                if p.quantity >= quantity:
                    p.quantity -= quantity
                    self.save()
                    return True
                else:
                    return False
        return False
        
class Sale:
    def __init__(self, pid, quantity, total):
        self.pid = pid
        self.quantity = quantity
        self.total = total
        
    def __str__(self):
        return f'{self.pid}\t{self.quantity}\t{self.total}'
        
class SalesRecord:
    def __init__(self, filename):
        self.filename = filename
        self.sales = []
        self.load()
        
    def load(self):
        try:
            with open(self.filename, 'r') as f:
                data = json.load(f)
                for s in data:
                    sale = Sale(s['pid'], s['quantity'], s['total'])
                    self.sales.append(sale)
        except FileNotFoundError:
            pass
        
    def save(self):
        with open(self.filename, 'w') as f:
            data = []
            for s in self.sales:
                data.append({'pid': s.pid, 'quantity': s.quantity, 'total': s.total})
            json.dump(data, f)
            
    def add_sale(self, sale):
        self.sales.append(sale)
        self.save()
        
    def get_sales(self):
        return self.sales
        
    def get_total_sales(self):
        total = 0
        for s in self.sales:
            total += s.total
        return total
        
class User:
    def __init__(self, username, password, role):
        self.username = username
        self.password = password
        self.role = role
        
    def __str__(self):
        return f'{self.username}\t{self.role}'
        
class UserManager:
    def __init__(self, filename):
        self.filename = filename
        self.users = []
        self.load()
        
    def load(self):
        try:
            with open(self.filename, 'r') as f:
                data = json.load(f)
                for u in data:
                    user = User(u['username'], u['password'], u['role'])
                    self.users.append(user)
        except FileNotFoundError:
            pass
        
    def save(self):
        with open(self.filename, 'w') as f:
            data = []
            for u in self.users:
                data.append({'username': u.username, 'password': u.password, 'role': u.role})
            json.dump(data, f)
            
    def add_user(self, user):
        self.users.append(user)
        self.save()
        
    def remove_user(self, username):
        for u in self.users:
            if u.username == username:
                self.users.remove(u)
                self.save()
                return True
        return False
        
    def update_user(self, username, password, role):
        for u in self.users:
            if u.username == username:
                u.password = password
                u.role = role
                self.save()
                return True
        return False
        
    def search_user(self, username=None):
        result = []
        for u in self.users:
            if username and u.username == username:
                result.append(u)
        return result
        
    def get_all_users(self):
        return self.users
        
class Role:
    ADMIN = 'admin'
    CASHIER = 'cashier'

class Supermarket:
    def __init__(self):
        self.inventory = Inventory('inventory.json')
        self.sales = SalesRecord('sales.json')
        self.users = UserManager('users.json')
        self.current_user = None
        
    def login(self, username, password):
        users = self.users.search_user(username)
        if users:
            user = users[0]
            if user.password == password:
                self.current_user = user
                return True
        return False
        
    def logout(self):
        self.current_user = None
        
    def is_admin(self):
        return self.current_user and self.current_user.role == Role.ADMIN
        
    def add_product(self, pid, name, price, quantity):
        product = Product(pid, name, price, quantity)
        self.inventory.add_product(product)
        
    def remove_product(self, pid):
        if self.inventory.remove_product(pid):
            self.sales.sales = [s for s in self.sales.sales if s.pid != pid]
        
    def update_product(self, pid, name, price, quantity):
        self.inventory.update_product(pid, name, price, quantity)
        
    def search_product(self, pid=None, name=None):
        return self.inventory.search_product(pid, name)
        
    def get_all_products(self):
        return self.inventory.get_all_products()
        
    def add_quantity(self, pid, quantity):
        if self.inventory.add_quantity(pid, quantity):
            product = self.search_product(pid=pid)[0]
            total = product.price * quantity
            sale = Sale(pid, quantity, total)
            self.sales.add_sale(sale)
        
    def remove_quantity(self, pid, quantity):
        if self.inventory.remove_quantity(pid, quantity):
            product = self.search_product(pid=pid)[0]
            total = product.price * quantity
            sale = Sale(pid, quantity, total)
            self.sales.add_sale(sale)
        
    def get_sales(self):
        return self.sales.get_sales()
        
    def get_total_sales(self):
        return self.sales.get_total_sales()
        
    def add_user(self, username, password, role):
        user = User(username, password, role)
        self.users.add_user(user)
        
    def remove_user(self, username):
        self.users.remove_user(username)
        
    def update_user(self, username, password, role):
        self.users.update_user(username, password, role)
        
    def search_user(self, username=None):
        return self.users.search_user(username)
        
    def get_all_users(self):
        return self.users.get_all_users()

上面的代码中，我们定义了 `Product`、`Inventory`、`Sale`、`SalesRecord`、`User`、`UserManager`、`Supermarket` 等类来实现超市进销存管理系统的各项操作，其中：

- `Product` 类表示商品信息，包括商品编号、商品名称、商品单价和库存数量；
- `Inventory` 类表示库存管理模块，包括添加商品、删除商品、修改商品、查询商品、商品入库、商品出库等操作；
- `Sale` 类表示销售记录，包括商品编号、销售数量和销售总额；
- `SalesRecord` 类表示销售管理模块，包括销售记录和销售统计等操作；
- `User` 类表示用户信息，包括用户名、密码和角色；
- `UserManager` 类表示用户管理模块，包括添加用户、删除用户、修改用户、查询用户等操作；
- `Supermarket` 类表示超市进销存管理系统，包括系统登录、系统登出、商品管理、库存管理、销售管理、用户管理等操作。

我们可以通过以下代码来测试上面的超市进销存管理系统：

# 创建一个超市进销存管理系统
supermarket = Supermarket()

# 添加商品
supermarket.add_product('001', '可乐', 2.5, 100)
supermarket.add_product('002', '薯片', 3.0, 200)
supermarket.add_product('003', '巧克力', 5.0, 150)

# 查询商品
print('所有商品：')
for p in supermarket.get_all_products():
    print(p)
print()

print('查询商品：')
for p in supermarket.search_product(name='可乐'):
    print(p)
print()

# 商品入库
supermarket.add_quantity('001', 50)

# 商品出库
supermarket.remove_quantity('002', 100)

# 查询销售记录
print('销售记录：')
for s in supermarket.get_sales():
    print(s)
print()

# 查询销售总额
print(f'销售总额：{supermarket.get_total_sales()}')
print()

# 添加用户
supermarket.add_user('admin', 'admin123', Role.ADMIN)
supermarket.add_user('cashier', 'cashier123', Role.CASHIER)

# 查询用户
print('所有用户：')
for u in supermarket.get_all_users():
    print(u)
print()

print('查询用户：')
for u in supermarket.search_user(username='admin'):
    print(u)
print()

# 修改用户
supermarket.update_user('admin', 'admin456', Role.CASHIER)

# 删除用户
supermarket.remove_user('cashier')