feat: create_order instruction (SOL canonical currency)

app/src/app/listing/[pk]/page.tsx

@@ -1,19 +1,30 @@
 'use client'
 
-import { use } from 'react'
+import { use, useState } from 'react'
 import { useRouter } from 'next/navigation'
 import { useWallet, useKitTransactionSigner } from '@solana/connector/react'
 import { ListingDetail } from '@/components/ListingDetail'
 import { useTx } from '@/hooks/useTx'
-import { getCloseListingInstruction } from '@solisting/sdk'
+import { useListing } from '@/hooks/useListing'
+import {
+  getCloseListingInstruction,
+  getCreateOrderInstructionAsync,
+  findOrderPda,
+  deriveEscrowId,
+} from '@solisting/sdk'
+import { DESCRO_PROGRAM_ADDRESS } from '@descro/sdk'
 import type { Address } from '@solisting/sdk'
 
+const SYSTEM_PROGRAM = '11111111111111111111111111111111' as Address<'11111111111111111111111111111111'>
+
 export default function ListingPage({ params }: { params: Promise<{ pk: string }> }) {
   const { pk } = use(params)
   const router = useRouter()
   const { account } = useWallet()
   const { signer } = useKitTransactionSigner()
   const sendTx = useTx()
+  const { data: listing } = useListing(pk as Address)
+  const [orderLoading, setOrderLoading] = useState(false)
 
   async function handleClose() {
     if (!signer) return
@@ -22,13 +33,47 @@ export default function ListingPage({ params }: { params: Promise<{ pk: string }
     router.push('/listings')
   }
 
+  async function handlePlaceOrder() {
+    if (!signer || !account || !listing) return
+    setOrderLoading(true)
+    try {
+      const orderId = BigInt(Date.now())
+      const [orderPda] = await findOrderPda(pk as Address, account as Address, orderId)
+      const escrowId = deriveEscrowId(orderPda)
+
+      const ix = await getCreateOrderInstructionAsync({
+        buyer: signer,
+        seller: listing.data.seller,
+        listingAccount: pk as Address,
+        canonicalOracle: SYSTEM_PROGRAM,
+        targetOracle: SYSTEM_PROGRAM,
+        descroProgram: DESCRO_PROGRAM_ADDRESS,
+        orderId,
+        escrowId,
+        resolver: account as Address,
+        paymentCurrency: { __kind: 'Sol' },
+        expectedAmount: listing.data.price,
+        maxSlippageBps: 0,
+      })
+      await sendTx(
+        [ix as never],
+        [['listing', pk], ['orders', pk]],
+        'create_order',
+      )
+    } catch (err) {
+      console.error('create_order failed:', err)
+    } finally {
+      setOrderLoading(false)
+    }
+  }
+
   return (
     <ListingDetail
       pk={pk as Address}
       walletAddress={account ?? null}
       onUpdate={() => router.push(`/listing/create?edit=${pk}`)}
       onClose={handleClose}
-      onPlaceOrder={() => {}}
+      onPlaceOrder={orderLoading ? undefined : handlePlaceOrder}
     />
   )
 }