refactor(order): rewrite store around state machine transitions

store/wallet.ts

@@ -9,6 +9,7 @@ interface WalletState {
   topUp: (amount: number) => void
   withdraw: (amount: number) => void
   deductBalance: (orderId: string, amount: number) => boolean
+  refundPayment: (orderId: string, amount: number) => boolean
   addIncome: (orderId: string, amount: number) => void
   addTransaction: (transaction: WalletTransaction) => void
 }
@@ -76,6 +77,38 @@ export const useWalletStore = create<WalletState>((set, get) => ({
     }))
     return true
   },
+  refundPayment: (orderId, amount) => {
+    if (!Number.isFinite(amount) || amount <= 0) return false
+
+    const state = get()
+    const paid = state.transactions.some(
+      (transaction) => transaction.type === "payment" && transaction.description.includes(orderId),
+    )
+    const refunded = state.transactions.some(
+      (transaction) => transaction.type === "refund" && transaction.description.includes(orderId),
+    )
+
+    if (!paid || refunded) {
+      return false
+    }
+
+    const now = new Date().toISOString()
+    set((prev) => ({
+      balance: prev.balance + amount,
+      transactions: [
+        {
+          id: generateId("tx"),
+          type: "refund",
+          amount,
+          description: `订单 ${orderId} 退款`,
+          createdAt: now,
+        },
+        ...prev.transactions,
+      ],
+    }))
+
+    return true
+  },
   addIncome: (orderId, amount) => {
     if (!Number.isFinite(amount) || amount <= 0) return