From 103ea31f50d337cc8619e54471eab5670a137d2d Mon Sep 17 00:00:00 2001
From: Alex Li <github@alexv525.com>
Date: Sun, 29 Sep 2024 10:30:02 +0800
Subject: [PATCH] =?UTF-8?q?=F0=9F=90=9B=20Ignores=20empty=20subaccount=20a?=
 =?UTF-8?q?nd=20fixes=20checksum=20output?=
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---
 lib/principal/principal.dart  | 21 +++++++++++++--------
 test/principal/principal.dart |  9 +++++++++
 2 files changed, 22 insertions(+), 8 deletions(-)

diff --git a/lib/principal/principal.dart b/lib/principal/principal.dart
index 333bbdd1..a94971e7 100644
--- a/lib/principal/principal.dart
+++ b/lib/principal/principal.dart
@@ -14,11 +14,16 @@ const _suffixAnonymous = 4;
 const _maxLengthInBytes = 29;
 const _typeOpaque = 1;
 
+final _emptySubAccount = Uint8List(32);
+
 class Principal {
-  const Principal(
+  Principal(
     this.principal, {
-    this.subAccount,
-  }) : assert(subAccount == null || subAccount.length == 32);
+    Uint8List? subAccount,
+  })  : assert(subAccount == null || subAccount.length == 32),
+        subAccount = subAccount != null && subAccount.eq(_emptySubAccount)
+            ? null
+            : subAccount;
 
   factory Principal.selfAuthenticating(Uint8List publicKey) {
     final sha = sha224Hash(publicKey.buffer);
@@ -130,7 +135,7 @@ class Principal {
   final Uint8List? subAccount;
 
   Principal newSubAccount(Uint8List? subAccount) {
-    if (subAccount == null) {
+    if (subAccount == null || subAccount.eq(_emptySubAccount)) {
       return this;
     }
     if (this.subAccount == null || !this.subAccount!.eq(subAccount)) {
@@ -160,10 +165,6 @@ class Principal {
     }
     final buffer = StringBuffer(matches.map((e) => e.group(0)).join('-'));
     if (subAccount != null) {
-      final checksum = base32Encode(
-        _getChecksum(Uint8List.fromList(principal + subAccount!).buffer),
-      );
-      buffer.write('-$checksum');
       final subAccountHex = subAccount!.toHex();
       int nonZeroStart = 0;
       while (nonZeroStart < subAccountHex.length) {
@@ -173,6 +174,10 @@ class Principal {
         nonZeroStart++;
       }
       if (nonZeroStart != subAccountHex.length) {
+        final checksum = base32Encode(
+          _getChecksum(Uint8List.fromList(principal + subAccount!).buffer),
+        );
+        buffer.write('-$checksum');
         buffer.write('.');
         buffer.write(subAccountHex.replaceRange(0, nonZeroStart, ''));
       }
diff --git a/test/principal/principal.dart b/test/principal/principal.dart
index 97e6f62d..e45a06d2 100644
--- a/test/principal/principal.dart
+++ b/test/principal/principal.dart
@@ -1,3 +1,5 @@
+import 'dart:typed_data';
+
 import 'package:agent_dart/principal/principal.dart';
 import 'package:flutter_test/flutter_test.dart';
 
@@ -85,6 +87,13 @@ void principalTest() {
       'z4s7u-byaaa-aaaao-a3paa-cai-l435n4y'
       '.1de15338bedf41b306d4ef5615d1f94fd7b0474b9255690cbe78d2309f02',
     );
+    expect(
+      Principal(
+        Uint8List.fromList([0, 0, 0, 0, 0, 224, 17, 26, 1, 1]),
+        subAccount: Uint8List(32),
+      ).toText(),
+      'lrllq-iqaaa-aaaah-acena-cai',
+    );
   });
 
   test('errors out on invalid checksums', () {