From 83a25c6c34bcebc69772861e222d31665a0585df Mon Sep 17 00:00:00 2001
From: tequ <git@tequ.dev>
Date: Tue, 8 Jul 2025 01:31:55 +0900
Subject: [PATCH] HookCanEmit (#22)

---
 .../src/enums/definitions.json                | 10 +++++++
 packages/xahau/src/models/common/xahau.ts     |  4 +++
 .../xahau/src/models/transactions/setHook.ts  |  7 ++++-
 packages/xahau/src/utils/hooks.ts             | 10 +++++++
 packages/xahau/src/utils/index.ts             |  8 ++++-
 packages/xahau/test/models/setHook.test.ts    | 30 ++++++++++++++++++-
 6 files changed, 66 insertions(+), 3 deletions(-)

diff --git a/packages/xahau-binary-codec/src/enums/definitions.json b/packages/xahau-binary-codec/src/enums/definitions.json
index c8e98c42..2c88bfad 100644
--- a/packages/xahau-binary-codec/src/enums/definitions.json
+++ b/packages/xahau-binary-codec/src/enums/definitions.json
@@ -1478,6 +1478,16 @@
         "type": "Hash256"
       }
     ],
+    [
+      "HookCanEmit",
+      {
+        "nth": 96,
+        "isVLEncoded": false,
+        "isSerialized": true,
+        "isSigningField": true,
+        "type": "Hash256"
+      }
+    ],
     [
       "Amount",
       {
diff --git a/packages/xahau/src/models/common/xahau.ts b/packages/xahau/src/models/common/xahau.ts
index 0de6e708..ebcdf676 100644
--- a/packages/xahau/src/models/common/xahau.ts
+++ b/packages/xahau/src/models/common/xahau.ts
@@ -63,6 +63,10 @@ export interface Hook {
      * The transactions that triggers the hook. Represented as a 256Hash
      */
     HookOn?: string
+    /**
+     * The transactions that can emit from the hook. Represented as a 256Hash
+     */
+    HookCanEmit?: string
     /**
      * The namespace of the hook.
      */
diff --git a/packages/xahau/src/models/transactions/setHook.ts b/packages/xahau/src/models/transactions/setHook.ts
index d6a48bff..57eb3811 100644
--- a/packages/xahau/src/models/transactions/setHook.ts
+++ b/packages/xahau/src/models/transactions/setHook.ts
@@ -66,12 +66,17 @@ export function validateSetHook(tx: Record<string, unknown>): void {
   for (const hook of tx.Hooks) {
     // eslint-disable-next-line @typescript-eslint/consistent-type-assertions -- Should be a Hook
     const hookObject = hook as Hook
-    const { HookOn, HookNamespace } = hookObject.Hook
+    const { HookOn, HookCanEmit, HookNamespace } = hookObject.Hook
     if (HookOn !== undefined && !HEX_REGEX.test(HookOn)) {
       throw new ValidationError(
         `SetHook: HookOn in Hook must be a 256-bit (32-byte) hexadecimal value`,
       )
     }
+    if (HookCanEmit !== undefined && !HEX_REGEX.test(HookCanEmit)) {
+      throw new ValidationError(
+        `SetHook: HookCanEmit in Hook must be a 256-bit (32-byte) hexadecimal value`,
+      )
+    }
     if (HookNamespace !== undefined && !HEX_REGEX.test(HookNamespace)) {
       throw new ValidationError(
         `SetHook: HookNamespace in Hook must be a 256-bit (32-byte) hexadecimal value`,
diff --git a/packages/xahau/src/utils/hooks.ts b/packages/xahau/src/utils/hooks.ts
index efefc111..7a432dd8 100644
--- a/packages/xahau/src/utils/hooks.ts
+++ b/packages/xahau/src/utils/hooks.ts
@@ -55,6 +55,16 @@ export function calculateHookOn(arr: Array<keyof TTS>): string {
   return hash.toUpperCase()
 }
 
+/**
+ * Calculate the hook can emit
+ *
+ * @param arr - array of transaction types
+ * @returns the hook can emit
+ */
+export function calculateHookCanEmit(arr: Array<keyof TTS>): string {
+  return calculateHookOn(arr)
+}
+
 function isHex(value: string): boolean {
   return /^[0-9A-F]+$/iu.test(value)
 }
diff --git a/packages/xahau/src/utils/index.ts b/packages/xahau/src/utils/index.ts
index 64b4c22f..777969bf 100644
--- a/packages/xahau/src/utils/index.ts
+++ b/packages/xahau/src/utils/index.ts
@@ -46,7 +46,12 @@ import {
   hashPaymentChannel,
   hashURIToken,
 } from './hashes'
-import { calculateHookOn, hexHookParameters, TTS } from './hooks'
+import {
+  calculateHookOn,
+  calculateHookCanEmit,
+  hexHookParameters,
+  TTS,
+} from './hooks'
 import {
   percentToTransferRate,
   decimalToTransferRate,
@@ -227,6 +232,7 @@ export {
   encodeForSigning,
   encodeForSigningClaim,
   calculateHookOn,
+  calculateHookCanEmit,
   hexHookParameters,
   TTS,
 }
diff --git a/packages/xahau/test/models/setHook.test.ts b/packages/xahau/test/models/setHook.test.ts
index 3ebb8d82..ff7b23b1 100644
--- a/packages/xahau/test/models/setHook.test.ts
+++ b/packages/xahau/test/models/setHook.test.ts
@@ -9,7 +9,7 @@ import { validateSetHook } from '../../src/models/transactions/setHook'
  * Providing runtime verification testing for each specific transaction type.
  */
 describe('SetHook', function () {
-  let setHookTx
+  let setHookTx: any
 
   beforeEach(function () {
     setHookTx = {
@@ -24,6 +24,8 @@ describe('SetHook', function () {
               '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',
             HookOn:
               'FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFBFFFF7',
+            HookCanEmit:
+              'FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFBFFFF7',
             Flags: 1,
             HookApiVersion: 0,
             HookNamespace:
@@ -114,6 +116,32 @@ describe('SetHook', function () {
     assert.throws(() => validate(setHookTx), ValidationError, errorMessage)
   })
 
+  it(`throws w/ invalid HookCanEmit in Hooks`, function () {
+    setHookTx.Hooks = [
+      {
+        Hook: {
+          CreateCode:
+            '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',
+          HookOn:
+            'FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFBFFFF7',
+          HookCanEmit: '',
+          Flags: 1,
+          HookApiVersion: 0,
+          HookNamespace:
+            '4FF9961269BF7630D32E15276569C94470174A5DA79FA567C0F62251AA9A36B9',
+        },
+      },
+    ]
+    const errorMessage =
+      'SetHook: HookCanEmit in Hook must be a 256-bit (32-byte) hexadecimal value'
+    assert.throws(
+      () => validateSetHook(setHookTx),
+      ValidationError,
+      errorMessage,
+    )
+    assert.throws(() => validate(setHookTx), ValidationError, errorMessage)
+  })
+
   it(`throws w/ invalid HookNamespace in Hooks`, function () {
     setHookTx.SignerQuorum = 2
     setHookTx.Hooks = [