Build a Restaurant Ordering API

Problem/Feature Description

A restaurant chain needs a backend API for their online ordering system. Build it using Spring Boot and Java.

Resources:

• MenuItem: { id, name, description, price, category, available }
• Order: { id, customerName, customerPhone, items: [{menuItemId, quantity, specialInstructions}], status, total, createdAt }

Endpoints:

• GET /api/menu -- list all menu items, support filtering by category query parameter
• GET /api/menu/{id} -- get a single menu item
• POST /api/menu -- add a menu item (name required, price > 0, category must be one of: appetizer, main, dessert, drink)
• PUT /api/menu/{id} -- update a menu item
• DELETE /api/menu/{id} -- remove a menu item (only if not referenced by pending orders)
• POST /api/orders -- place an order:
  • customerName and customerPhone are required
  • items array must be non-empty
  • each item must reference an existing, available menu item
  • quantity must be between 1 and 10
  • calculate and store the order total
• GET /api/orders/{id} -- get order details
• PATCH /api/orders/{id}/status -- update order status (valid transitions: pending -> preparing -> ready -> completed, or pending -> cancelled)

Business rules:

• Menu item names must be unique within a category
• An order cannot be modified once its status is "preparing" or beyond
• Phone number must match a simple pattern (at least 10 digits)

Seed the menu with 5-8 sample items. Use in-memory storage or H2.

Output Specification

Produce a complete Spring Boot project:

• src/main/java/com/example/ -- controller, service, model, and repository packages
• pom.xml or build.gradle -- with dependencies
• src/main/resources/application.properties -- configuration

You may create additional files as needed for a well-structured codebase.