{
  "$schema": "https://ui.shadcn.com/schema/registry-item.json",
  "name": "cart-provider",
  "title": "Cart Provider",
  "description": "Optional, backend-agnostic cart state. A CartProvider context and useCart hook that add lines, merge duplicate variants, update quantities, and compute the subtotal. Sync to your backend through onLinesChange.",
  "registryDependencies": [
    "https://lumo-www.vercel.app/r/lib.json"
  ],
  "files": [
    {
      "path": "packages/core/src/components/lumo/cart-provider.tsx",
      "content": "\"use client\"\r\n\r\nimport * as React from \"react\"\r\nimport type { CartLine, Money, Product, Variant } from \"@/lib/lumo/types\"\r\nimport { addMoney, multiplyMoney, zeroMoney } from \"@/lib/lumo/money\"\r\n\r\n/** The product fields a cart line needs to display itself. */\r\nexport type CartProductRef = Pick<Product, \"id\" | \"handle\" | \"title\" | \"images\">\r\n\r\nexport interface CartContextValue {\r\n  lines: CartLine[]\r\n  subtotal: Money\r\n  totalQuantity: number\r\n  currency: string\r\n  isOpen: boolean\r\n  addLine: (product: CartProductRef, variant: Variant, quantity?: number) => void\r\n  removeLine: (lineId: string) => void\r\n  updateQuantity: (lineId: string, quantity: number) => void\r\n  clear: () => void\r\n  setOpen: (open: boolean) => void\r\n  openCart: () => void\r\n  closeCart: () => void\r\n}\r\n\r\nconst CartContext = React.createContext<CartContextValue | null>(null)\r\n\r\nfunction lineTotalFor(variant: Variant, quantity: number): Money {\r\n  return multiplyMoney(variant.price, quantity)\r\n}\r\n\r\nfunction computeSubtotal(lines: CartLine[], currency: string): Money {\r\n  if (lines.length === 0) {\r\n    return zeroMoney(currency)\r\n  }\r\n  return addMoney(...lines.map((line) => line.lineTotal))\r\n}\r\n\r\nexport interface CartProviderProps {\r\n  children: React.ReactNode\r\n  /** Currency used while the cart is empty. Defaults to 'USD'. */\r\n  currency?: string\r\n  /** Initial lines, for hydrating from storage or a backend. */\r\n  initialLines?: CartLine[]\r\n  /** Fired whenever the lines change, for syncing to your backend. */\r\n  onLinesChange?: (lines: CartLine[]) => void\r\n}\r\n\r\n/**\r\n * Optional, backend-agnostic cart state. Lumo components are presentational by\r\n * default; opt into this provider when you want client-side cart state and sync\r\n * changes to your backend through `onLinesChange`.\r\n */\r\nexport function CartProvider({\r\n  children,\r\n  currency = \"USD\",\r\n  initialLines = [],\r\n  onLinesChange,\r\n}: CartProviderProps) {\r\n  const [lines, setLines] = React.useState<CartLine[]>(initialLines)\r\n  const [isOpen, setIsOpen] = React.useState(false)\r\n\r\n  const isFirstRender = React.useRef(true)\r\n  React.useEffect(() => {\r\n    if (isFirstRender.current) {\r\n      isFirstRender.current = false\r\n      return\r\n    }\r\n    onLinesChange?.(lines)\r\n  }, [lines, onLinesChange])\r\n\r\n  const addLine = React.useCallback(\r\n    (product: CartProductRef, variant: Variant, quantity = 1) => {\r\n      setLines((prev) => {\r\n        const existing = prev.find((line) => line.variant.id === variant.id)\r\n        if (existing) {\r\n          return prev.map((line) =>\r\n            line.variant.id === variant.id\r\n              ? {\r\n                  ...line,\r\n                  quantity: line.quantity + quantity,\r\n                  lineTotal: lineTotalFor(variant, line.quantity + quantity),\r\n                }\r\n              : line\r\n          )\r\n        }\r\n        return [\r\n          ...prev,\r\n          {\r\n            id: variant.id,\r\n            variant,\r\n            product,\r\n            quantity,\r\n            lineTotal: lineTotalFor(variant, quantity),\r\n          },\r\n        ]\r\n      })\r\n    },\r\n    []\r\n  )\r\n\r\n  const removeLine = React.useCallback((lineId: string) => {\r\n    setLines((prev) => prev.filter((line) => line.id !== lineId))\r\n  }, [])\r\n\r\n  const updateQuantity = React.useCallback((lineId: string, quantity: number) => {\r\n    setLines((prev) => {\r\n      if (quantity <= 0) {\r\n        return prev.filter((line) => line.id !== lineId)\r\n      }\r\n      return prev.map((line) =>\r\n        line.id === lineId\r\n          ? { ...line, quantity, lineTotal: lineTotalFor(line.variant, quantity) }\r\n          : line\r\n      )\r\n    })\r\n  }, [])\r\n\r\n  const clear = React.useCallback(() => setLines([]), [])\r\n  const openCart = React.useCallback(() => setIsOpen(true), [])\r\n  const closeCart = React.useCallback(() => setIsOpen(false), [])\r\n\r\n  const value = React.useMemo<CartContextValue>(() => {\r\n    const activeCurrency = lines[0]?.variant.price.currency ?? currency\r\n    return {\r\n      lines,\r\n      subtotal: computeSubtotal(lines, activeCurrency),\r\n      totalQuantity: lines.reduce((total, line) => total + line.quantity, 0),\r\n      currency: activeCurrency,\r\n      isOpen,\r\n      addLine,\r\n      removeLine,\r\n      updateQuantity,\r\n      clear,\r\n      setOpen: setIsOpen,\r\n      openCart,\r\n      closeCart,\r\n    }\r\n  }, [lines, currency, isOpen, addLine, removeLine, updateQuantity, clear, openCart, closeCart])\r\n\r\n  return <CartContext.Provider value={value}>{children}</CartContext.Provider>\r\n}\r\n\r\n/** Read the cart state. Must be used within a `CartProvider`. */\r\nexport function useCart(): CartContextValue {\r\n  const context = React.useContext(CartContext)\r\n  if (!context) {\r\n    throw new Error(\"useCart must be used within a <CartProvider>\")\r\n  }\r\n  return context\r\n}\r\n",
      "type": "registry:hook",
      "target": "components/lumo/cart-provider.tsx"
    }
  ],
  "type": "registry:hook"
}