From 9a85aaa109b6acbba8d548c13359577abb9be1ba Mon Sep 17 00:00:00 2001
From: Ildar Gumirov <ildaruz@users.noreply.github.com>
Date: Wed, 29 Nov 2023 20:27:36 +0100
Subject: [PATCH] fix: nftoken taxon calculation (#2590)

Fix taxon calculation for NFTokenID

### Context of Change

If NFToken taxon or serial is too big to be handled as number it could be calculated wrong.
---
 packages/xrpl/HISTORY.md                      |  3 ++
 packages/xrpl/src/utils/parseNFTokenID.ts     | 12 +++++++-
 .../xrpl/test/utils/parseNFTokenID.test.ts    | 30 +++++++++++++++++++
 3 files changed, 44 insertions(+), 1 deletion(-)

diff --git a/packages/xrpl/HISTORY.md b/packages/xrpl/HISTORY.md
index bcb40447..5b016387 100644
--- a/packages/xrpl/HISTORY.md
+++ b/packages/xrpl/HISTORY.md
@@ -12,6 +12,9 @@ Subscribe to [the **xrpl-announce** mailing list](https://groups.google.com/g/xr
 ### Added
 * Support for `server_definitions` RPC
 
+### Fixed
+* Fix parseNFTokenID to return the correct taxon if large serial and (or) taxon were used
+
 ## 2.13.0 (2023-10-18)
 
 ### Fixed
diff --git a/packages/xrpl/src/utils/parseNFTokenID.ts b/packages/xrpl/src/utils/parseNFTokenID.ts
index 3c253d15..0419b4f1 100644
--- a/packages/xrpl/src/utils/parseNFTokenID.ts
+++ b/packages/xrpl/src/utils/parseNFTokenID.ts
@@ -24,7 +24,17 @@ import { XrplError } from '../errors'
  */
 function unscrambleTaxon(taxon: number, tokenSeq: number): number {
   /* eslint-disable no-bitwise -- XOR is part of the encode/decode scheme. */
-  return (taxon ^ (384160001 * tokenSeq + 2459)) % 4294967296
+  const seed = 384160001
+  const increment = 2459
+  const max = 4294967296
+
+  const scramble = new BigNumber(seed)
+    .multipliedBy(tokenSeq)
+    .modulo(max)
+    .plus(increment)
+    .modulo(max)
+    .toNumber()
+  return (taxon ^ scramble) >>> 0
   /* eslint-enable no-bitwise */
 }
 
diff --git a/packages/xrpl/test/utils/parseNFTokenID.test.ts b/packages/xrpl/test/utils/parseNFTokenID.test.ts
index f2f9cfb7..c265700b 100644
--- a/packages/xrpl/test/utils/parseNFTokenID.test.ts
+++ b/packages/xrpl/test/utils/parseNFTokenID.test.ts
@@ -19,6 +19,36 @@ describe('parseNFTokenID', function () {
     assertResultMatch(result, expected)
   })
 
+  it('decode a valid NFTokenID with big taxon', function () {
+    const nftokenID =
+      '000000005EC8BC31F0415E5DD4A8AAAC3718249F8F27323C2EEE87B80000001E'
+    const result = parseNFTokenID(nftokenID)
+    const expected = {
+      NFTokenID: nftokenID,
+      Flags: 0,
+      TransferFee: 0,
+      Issuer: 'r9ewzMXVRAD9CjZQ6LTQ4P21vUUucDuqd4',
+      Taxon: 2147483649,
+      Sequence: 30,
+    }
+    assertResultMatch(result, expected)
+  })
+
+  it('decode a valid NFTokenID with big sequence', function () {
+    const nftokenID =
+      '00081388BE9E48FA0E6C95A3E970EB9503E3D3967E8DF95041FED82604D933AB'
+    const result = parseNFTokenID(nftokenID)
+    const expected = {
+      NFTokenID: nftokenID,
+      Flags: 8,
+      TransferFee: 5000,
+      Issuer: 'rJ4urHeGPr69TsC9TY9u8N965AdD7S3XEY',
+      Taxon: 96,
+      Sequence: 81343403,
+    }
+    assertResultMatch(result, expected)
+  })
+
   it('fail when given invalid NFTokenID', function () {
     assert.throws(() => {
       parseNFTokenID('ABCD')