Food Delivery

// Food delivery platform: restaurants, menus, customers, couriers,
// orders with line items, and a timestamped order-status audit log.
// Uses a GeoPoint struct (f64 latitude/longitude) for geographic coordinates.
// Provenance: Synthetic (modeled after the standard food delivery design pattern)

struct GeoPoint {
  latitude: f64
  longitude: f64
}

// Order lifecycle states — a closed set, so a declared enum (stored as a 1-byte
// discriminant, serialized as the variant name) is a better fit than a string.
enum OrderStatus {
  Placed,
  Confirmed,
  Preparing,
  Ready,
  PickedUp,
  Delivered,
  Cancelled,
}

Restaurant {
  id: +uuid
  name: &string @length(1, 200)
  phone: string?
  email: string? @email
  location: GeoPoint
  rating: f64? @min(0) @max(5)
  is_active: bool
  menus: [Menu]
  orders: [Order]
  created_at: +timestamp
}

Menu {
  id: +uuid
  restaurant: *Restaurant
  name: string @length(1, 100)
  is_active: bool
  items: [MenuItem]
  created_at: +timestamp
}

MenuItem {
  id: +uuid
  menu: *Menu
  name: string @length(1, 100)
  description: string?
  // price in minor currency units (cents)
  price: i64 @min(0)
  is_available: bool
  created_at: +timestamp
}

Customer {
  id: +uuid
  first_name: string @length(1, 50)
  last_name: string @length(1, 50)
  email: &string @email
  phone: string?
  delivery_location: GeoPoint?
  orders: [Order]
  created_at: +timestamp
}

Courier {
  id: +uuid
  first_name: string @length(1, 50)
  last_name: string @length(1, 50)
  email: &string @email
  phone: string
  current_location: GeoPoint?
  is_available: bool
  orders: [Order]
  created_at: +timestamp
}

// courier is optional — assigned after placement
Order {
  id: +uuid
  customer: *Customer
  restaurant: *Restaurant
  courier: ?Courier
  status: ^OrderStatus
  placed_at: +timestamp
  delivery_location: GeoPoint?
  // total_amount in minor currency units (cents)
  total_amount: i64 @min(0)
  items: [OrderItem]
  status_events: [OrderStatusEvent]
  created_at: +timestamp
  @index(customer, placed_at)
  @index(restaurant, placed_at)
}

// Explicit join model: Order <-> MenuItem with quantity and price-at-order-time.
OrderItem {
  id: +uuid
  order: *Order
  menu_item: *MenuItem
  quantity: u32 @min(1)
  // unit_price captured at order time (immutable snapshot)
  unit_price: i64 @min(0)
  created_at: +timestamp
  @index(order, menu_item)
}

// Append-only audit log for order lifecycle transitions.
OrderStatusEvent {
  id: +uuid
  order: *Order
  status: OrderStatus
  note: string?
  changed_at: +timestamp
  @index(order, changed_at)
}