MoneyAddress.parse (#2)

* stub out `DapResolver`
* implement `MoneyAddress` parsing

lib/src/dap.dart

@@ -85,12 +85,3 @@ class Dap {
         (codeUnit >= 123 && codeUnit <= 126);
   }
 }
-
-class DapResolver {
-  /// default constructor with http client and a web5 did resolver
-  /// can construct yourself for mocking purposes etc.
-  /// getRegistryEndpoint() -> resolve registry did, find DAPRegistry service endpoint
-  /// dereferenceHandle() -> makes GET request to registry endpoint to get DAP's DID
-  /// resolveDid() -> resolve DAP's DID, get back did document
-  /// getMoneyAddresses(dap) -> getRegistryEndpoint() -> dereferenceHandle() -> resolveDid() -> parse out money addresses from did document -> return list of money addrrsses
-}

lib/src/dap_resolver.dart

@@ -0,0 +1,19 @@
+import 'package:dap/dap.dart';
+import 'package:http/http.dart' as http;
+import 'package:web5/web5.dart';
+
+class DapResolver {
+  http.Client client;
+  DidResolver didResolver;
+
+  DapResolver(this.didResolver, {http.Client? client})
+      : client = client ?? http.Client();
+
+  Future<void> getMoneyAddresses(Dap dap) async {}
+
+  /// can construct yourself for mocking purposes etc.
+  /// getRegistryEndpoint() -> resolve registry did, find DAPRegistry service endpoint
+  /// dereferenceHandle() -> makes GET request to registry endpoint to get DAP's DID
+  /// resolveDid() -> resolve DAP's DID, get back did document
+  /// getMoneyAddresses(dap) -> getRegistryEndpoint() -> dereferenceHandle() -> resolveDid() -> parse out money addresses from did document -> return list of money addrrsses
+}

lib/src/money_address.dart

@@ -0,0 +1,39 @@
+/// A money address is a Uniform Resource Name (URN) that represents a means
+/// through which an individual can be payed a specific currency.
+/// The URN is structured as follows:
+/// `urn:<currency_code>:<curr_specific_part>`
+/// More info [here](https://github.com/TBD54566975/dap?tab=readme-ov-file#money-address)
+class MoneyAddress {
+  final String currency;
+  final String css;
+
+  String get urn => 'urn:$currency:$css';
+
+  MoneyAddress({required this.currency, required this.css});
+
+  factory MoneyAddress.parse(String input) {
+    if (!input.startsWith('urn:')) {
+      throw FormatException('Expected urn. Got $input');
+    }
+
+    final urnless = input.substring(4);
+    final delimIdx = urnless.indexOf(':');
+    if (delimIdx == -1) {
+      throw FormatException(
+          'Invalid money address. Expected urn:[currency]:[css]. Got $input');
+    }
+
+    final nid = urnless.substring(0, delimIdx);
+    final nss = urnless.substring(delimIdx + 1);
+
+    return MoneyAddress(
+      currency: nid,
+      css: nss,
+    );
+  }
+
+  @override
+  String toString() {
+    return urn;
+  }
+}

test/money_address_test.dart

@@ -0,0 +1,63 @@
+import 'package:test/test.dart';
+import 'package:dap/src/money_address.dart';
+
+class Vector {
+  final String input;
+  final MoneyAddress expected;
+  final bool err;
+
+  Vector({required this.input, required this.expected, required this.err});
+}
+
+void main() {
+  group('MoneyAddress.parse', () {
+    final testCases = [
+      Vector(
+        input: 'urn:usdc:eth:0x2345y7432',
+        expected: MoneyAddress(
+          currency: 'usdc',
+          css: 'eth:0x2345y7432',
+        ),
+        err: false,
+      ),
+      Vector(
+        input: 'urn:btc:addr:m12345677axcv2345',
+        expected: MoneyAddress(
+          currency: 'btc',
+          css: 'addr:m12345677axcv2345',
+        ),
+        err: false,
+      ),
+      Vector(
+        input: 'urn:btc:lnurl:https://someurl.com',
+        expected: MoneyAddress(
+          currency: 'btc',
+          css: 'lnurl:https://someurl.com',
+        ),
+        err: false,
+      ),
+      Vector(
+        input: 'urn:btc:spaddr:sp1234abcd5678',
+        expected: MoneyAddress(
+          currency: 'btc',
+          css: 'spaddr:sp1234abcd5678',
+        ),
+        err: false,
+      ),
+    ];
+
+    for (var testCase in testCases) {
+      test(testCase.input, () {
+        if (testCase.err) {
+          expect(
+              () => MoneyAddress.parse(testCase.input), throwsFormatException);
+        } else {
+          final actual = MoneyAddress.parse(testCase.input);
+          expect(actual.currency, testCase.expected.currency);
+          expect(actual.css, testCase.expected.css);
+          expect(actual.urn, testCase.input);
+        }
+      });
+    }
+  });
+}