feat: amount string group separator based on locale and parse those formatted strings back to amounts based on localized decimal pattern

lib/utilities/amount/amount_formatter.dart

@@ -63,4 +63,13 @@ class AmountFormatter {
       tokenContract: ethContract,
     );
   }
+
+  Amount? amountFrom(
+    String string, {
+    required String locale,
+    required Coin coin,
+    EthContract? ethContract,
+  }) {
+    return unit.tryParse(string, locale: locale, coin: coin);
+  }
 }

lib/utilities/amount/amount_unit.dart

@@ -164,6 +164,51 @@ extension AmountUnitExt on AmountUnit {
     }
   }
 
+  Amount? tryParse(
+    String value, {
+    required String locale,
+    required Coin coin,
+    EthContract? tokenContract,
+  }) {
+    final precisionLost = value.startsWith("~");
+
+    final parts = (precisionLost ? value.substring(1) : value).split(" ");
+
+    if (parts.first.isEmpty) {
+      return null;
+    }
+
+    String str = parts.first;
+    if (str.startsWith(RegExp(r'[+-]'))) {
+      str = str.substring(1);
+    }
+
+    if (str.isEmpty) {
+      return null;
+    }
+
+    // get number symbols for decimal place and group separator
+    final numberSymbols = numberFormatSymbols[locale] as NumberSymbols? ??
+        numberFormatSymbols[locale.substring(0, 2)] as NumberSymbols?;
+
+    final groupSeparator = numberSymbols?.GROUP_SEP ?? ",";
+    final decimalSeparator = numberSymbols?.DECIMAL_SEP ?? ".";
+
+    str = str.replaceAll(groupSeparator, "");
+
+    final decimalString = str.replaceFirst(decimalSeparator, ".");
+    final Decimal? decimal = Decimal.tryParse(decimalString);
+
+    if (decimal == null) {
+      return null;
+    }
+
+    final decimalPlaces = tokenContract?.decimals ?? coin.decimals;
+    final realShift = math.min(shift, decimalPlaces);
+
+    return decimal.shift(0 - realShift).toAmount(fractionDigits: decimalPlaces);
+  }
+
   String displayAmount({
     required Amount amount,
     required String locale,
@@ -191,6 +236,17 @@ extension AmountUnitExt on AmountUnit {
     // start building the return value with just the whole value
     String returnValue = wholeNumber.toString();
 
+    // get number symbols for decimal place and group separator
+    final numberSymbols = numberFormatSymbols[locale] as NumberSymbols? ??
+        numberFormatSymbols[locale.substring(0, 2)] as NumberSymbols?;
+
+    // insert group separator
+    final regex = RegExp(r'\B(?=(\d{3})+(?!\d))');
+    returnValue = returnValue.replaceAllMapped(
+      regex,
+      (m) => "${m.group(0)}${numberSymbols?.GROUP_SEP ?? ","}",
+    );
+
     // if true and withUnitName is true, we will show "~" prepended on amount
     bool didLosePrecision = false;
 
@@ -239,11 +295,7 @@ extension AmountUnitExt on AmountUnit {
       }
 
       // get decimal separator based on locale
-      final String separator =
+      final String separator = numberSymbols?.DECIMAL_SEP ?? ".";
-          (numberFormatSymbols[locale] as NumberSymbols?)?.DECIMAL_SEP ??
-              (numberFormatSymbols[locale.substring(0, 2)] as NumberSymbols?)
-                  ?.DECIMAL_SEP ??
-              ".";
 
       // append separator and fractional amount
       returnValue += "$separator$remainder";

test/utilities/amount/amount_unit_test.dart

@@ -28,7 +28,7 @@ void main() {
         coin: Coin.bitcoin,
         maxDecimalPlaces: 8,
       ),
-      "10123.45678 mBTC",
+      "10,123.45678 mBTC",
     );
 
     expect(
@@ -38,7 +38,7 @@ void main() {
         coin: Coin.bitcoin,
         maxDecimalPlaces: 8,
       ),
-      "10123456.78 µBTC",
+      "10,123,456.78 µBTC",
     );
 
     expect(
@@ -48,7 +48,7 @@ void main() {
         coin: Coin.bitcoin,
         maxDecimalPlaces: 8,
       ),
-      "1012345678 sats",
+      "1,012,345,678 sats",
     );
     final dec = Decimal.parse("10.123456789123456789");
 
@@ -98,7 +98,7 @@ void main() {
         coin: Coin.ethereum,
         maxDecimalPlaces: 9,
       ),
-      "~10123.456789123 mETH",
+      "~10,123.456789123 mETH",
     );
 
     expect(
@@ -108,7 +108,7 @@ void main() {
         coin: Coin.ethereum,
         maxDecimalPlaces: 8,
       ),
-      "~10123456.78912345 µETH",
+      "~10,123,456.78912345 µETH",
     );
 
     expect(
@@ -118,7 +118,7 @@ void main() {
         coin: Coin.ethereum,
         maxDecimalPlaces: 1,
       ),
-      "~10123456789.1 gwei",
+      "~10,123,456,789.1 gwei",
     );
 
     expect(
@@ -128,7 +128,7 @@ void main() {
         coin: Coin.ethereum,
         maxDecimalPlaces: 18,
       ),
-      "10123456789123.456789 mwei",
+      "10,123,456,789,123.456789 mwei",
     );
 
     expect(
@@ -138,7 +138,7 @@ void main() {
         coin: Coin.ethereum,
         maxDecimalPlaces: 4,
       ),
-      "10123456789123456.789 kwei",
+      "10,123,456,789,123,456.789 kwei",
     );
 
     expect(
@@ -148,7 +148,78 @@ void main() {
         coin: Coin.ethereum,
         maxDecimalPlaces: 1,
       ),
-      "10123456789123456789 wei",
+      "10,123,456,789,123,456,789 wei",
+    );
+  });
+
+  test("parse eth string to amount", () {
+    final Amount amount = Amount.fromDecimal(
+      Decimal.parse("10.123456789123456789"),
+      fractionDigits: Coin.ethereum.decimals,
+    );
+
+    expect(
+      AmountUnit.nano.tryParse(
+        "~10,123,456,789.1 gwei",
+        locale: "en_US",
+        coin: Coin.ethereum,
+      ),
+      Amount.fromDecimal(
+        Decimal.parse("10.1234567891"),
+        fractionDigits: Coin.ethereum.decimals,
+      ),
+    );
+
+    expect(
+      AmountUnit.atto.tryParse(
+        "10,123,456,789,123,456,789 wei",
+        locale: "en_US",
+        coin: Coin.ethereum,
+      ),
+      amount,
+    );
+  });
+
+  test("parse btc string to amount", () {
+    final Amount amount = Amount(
+      rawValue: BigInt.from(1012345678),
+      fractionDigits: 8,
+    );
+
+    expect(
+      AmountUnit.normal.tryParse(
+        "10.12345678 BTC",
+        locale: "en_US",
+        coin: Coin.bitcoin,
+      ),
+      amount,
+    );
+
+    expect(
+      AmountUnit.milli.tryParse(
+        "10,123.45678 mBTC",
+        locale: "en_US",
+        coin: Coin.bitcoin,
+      ),
+      amount,
+    );
+
+    expect(
+      AmountUnit.micro.tryParse(
+        "10,123,456.7822 µBTC",
+        locale: "en_US",
+        coin: Coin.bitcoin,
+      ),
+      amount,
+    );
+
+    expect(
+      AmountUnit.nano.tryParse(
+        "1,012,345,678 sats",
+        locale: "en_US",
+        coin: Coin.bitcoin,
+      ),
+      amount,
     );
   });
 }