Hot Coffee ☕️

A Coffee Shop Management System built in Go that provides APIs for managing menu items, orders, inventory, and generating sales reports. This project simulates the backend of a coffee shop, ensuring maintainability, scalability, and adherence to software architecture principles.

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Features

• Menu Management:
  • Add, retrieve, update, and delete menu items.
  • Validate ingredients against inventory before adding or updating menu items.
• Order Management:
  • Create, retrieve, update, and delete orders.
  • Close orders and update inventory upon fulfillment.
• Inventory Management:
  • Manage ingredients in inventory.
  • Ensure sufficient quantities of ingredients for menu items.
• Reports:
  • Total sales calculation.
  • Retrieve the most popular menu items.

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Architecture

The application follows a layered architecture for clean separation of concerns:

1. Handlers:
   • Responsible for handling HTTP requests and formatting responses.
2. Services:
   • Implements core business logic and communicates with the data access layer.
3. Repositories:
   • Reads and writes data to/from JSON files.

Folder Structure

hot-coffee/ 
├── cmd/ # Main application entry point 
│ └── main.go 
├── data/ # JSON storage files 
│ ├── inventory.json 
│ ├── menu_items.json 
│ └── orders.json 
├── internal/ # Application logic 
│ ├── dal/ # Data Access Layer (Repositories) 
│ ├── handler/ # HTTP Handlers 
│ ├── service/ # Business Logic Layer 
│ ├── utils/ # Utility functions (e.g., logging) 
│ └── logger.go # Logger configuration 
├── models/ # Data models 
│ ├── inventory_item.go 
│ ├── menu_item.go 
│ ├── order.go 
│ └── reports.go 
└── go.mod # Go module file

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APIs

Menu Management

Method	Endpoint	Description
POST	/menu	Add a new menu item.
GET	/menu	Retrieve all menu items.
GET	/menu/{id}	Retrieve a specific menu item.
PUT	/menu/{id}	Update a menu item.
DELETE	/menu/{id}	Delete a menu item.

Order Management

Method	Endpoint	Description
POST	/order	Create a new order.
GET	/order	Retrieve all orders.
GET	/order/{id}	Retrieve a specific order.
PUT	/order/{id}	Update an order.
DELETE	/order/{id}	Delete an order.
POST	/order/{id}/close	Close an order.

Inventory Management

Method	Endpoint	Description
POST	/inventory	Add a new inventory item.
GET	/inventory	Retrieve all inventory items.
GET	/inventory/{id}	Retrieve a specific item.
PUT	/inventory/{id}	Update an inventory item.
DELETE	/inventory/{id}	Delete an inventory item.

Reports

Method	Endpoint	Description
GET	/reports/total-sales	Retrieve total sales.
GET	/reports/popular-items	Retrieve popular items.

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Configuration

• Port Configuration: Set the API listening port using the --port flag (default: 8080).
• Data Directory: Specify the directory for JSON storage files using the --dir flag (default: data/).

Example:

./hot-coffee --port=8080 --dir=storage/

Logging

The application uses Go's log/slog package for logging:

• Logs significant events (e.g., adding a new menu item, processing orders).
• Logs errors with detailed context for easier debugging.
• Logs are stored in a central logging file located in the internal folder.

Logging Levels

• Info: General application events.
• Warning: Non-critical issues, such as invalid data format.
• Error: Critical issues that may prevent certain operations.

Example logging usage in code:

internal.Logger.Info("Menu item added successfully", "menuItemID", menuItem.ID)
internal.Logger.Warn("Unsupported Media Type", "expected", "application/json", "received", r.Header.Get("Content-type"))
internal.Logger.Error("Failed to decode request body", "error", err)

Error Handling

• Input Validation: Ensures all inputs meet requirements (e.g., JSON format, required fields).
• HTTP Status Codes:
  • 200 OK for successful GET requests.
  • 201 Created for successful POST requests.
  • 400 Bad Request for invalid input.
  • 404 Not Found for missing resources.
  • 500 Internal Server Error for unexpected errors.

Error responses are sent as JSON with descriptive messages. Utility functions handle error responses consistently.

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