From 4b6afe1db06cb03365369c4d3e58efc63c31c95b Mon Sep 17 00:00:00 2001
From: julian <julian@cypherstack.com>
Date: Mon, 29 May 2023 17:13:45 -0600
Subject: [PATCH] indicate loss of precision in displayed amounts

---
 lib/utilities/amount/amount_unit.dart       | 15 +++++++++++++++
 test/utilities/amount/amount_unit_test.dart | 18 ++++++++++++++----
 2 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/lib/utilities/amount/amount_unit.dart b/lib/utilities/amount/amount_unit.dart
index f418f5752..275352f53 100644
--- a/lib/utilities/amount/amount_unit.dart
+++ b/lib/utilities/amount/amount_unit.dart
@@ -134,6 +134,9 @@ extension AmountUnitExt on AmountUnit {
     // start building the return value with just the whole value
     String returnValue = wholeNumber.toString();
 
+    // if true and withUnitName is true, we will show "~" prepended on amount
+    bool didLosePrecision = false;
+
     // if any decimal places should be shown continue building the return value
     if (places > 0) {
       // get the fractional value
@@ -162,6 +165,13 @@ extension AmountUnitExt on AmountUnit {
       }
 
       if (remainder.length > actualDecimalPlaces) {
+        // check for loss of precision
+        final remainingRemainder =
+            BigInt.tryParse(remainder.substring(actualDecimalPlaces));
+        if (remainingRemainder != null) {
+          didLosePrecision = remainingRemainder > BigInt.zero;
+        }
+
         // trim unwanted trailing digits
         remainder = remainder.substring(0, actualDecimalPlaces);
       } else if (remainder.length < actualDecimalPlaces) {
@@ -190,6 +200,11 @@ extension AmountUnitExt on AmountUnit {
     if (tokenContract != null) {
       overrideUnit = unitForContract(tokenContract);
     }
+
+    if (didLosePrecision) {
+      returnValue = "~$returnValue";
+    }
+
     return "$returnValue ${overrideUnit ?? unitForCoin(coin)}";
   }
 }
diff --git a/test/utilities/amount/amount_unit_test.dart b/test/utilities/amount/amount_unit_test.dart
index 2dcd5125c..7af988def 100644
--- a/test/utilities/amount/amount_unit_test.dart
+++ b/test/utilities/amount/amount_unit_test.dart
@@ -68,7 +68,17 @@ void main() {
         coin: Coin.ethereum,
         maxDecimalPlaces: 8,
       ),
-      "10.12345678 ETH",
+      "~10.12345678 ETH",
+    );
+
+    expect(
+      AmountUnit.normal.displayAmount(
+        amount: amount,
+        locale: "en_US",
+        coin: Coin.ethereum,
+        maxDecimalPlaces: 4,
+      ),
+      "~10.1234 ETH",
     );
 
     expect(
@@ -88,7 +98,7 @@ void main() {
         coin: Coin.ethereum,
         maxDecimalPlaces: 9,
       ),
-      "10123.456789123 mETH",
+      "~10123.456789123 mETH",
     );
 
     expect(
@@ -98,7 +108,7 @@ void main() {
         coin: Coin.ethereum,
         maxDecimalPlaces: 8,
       ),
-      "10123456.78912345 µETH",
+      "~10123456.78912345 µETH",
     );
 
     expect(
@@ -108,7 +118,7 @@ void main() {
         coin: Coin.ethereum,
         maxDecimalPlaces: 1,
       ),
-      "10123456789.1 gwei",
+      "~10123456789.1 gwei",
     );
 
     expect(