correctly handle ₿ prefix in BIP353

See ACINQ/phoenix#588.

build.gradle.kts

@@ -132,6 +132,11 @@ kotlin {
                 implementation("app.cash.sqldelight:coroutines-extensions:${Versions.sqlDelight}")
             }
         }
+        commonTest {
+            dependencies {
+                implementation(kotlin("test"))
+            }
+        }
         jvmMain {
             dependencies {
                 implementation("app.cash.sqldelight:sqlite-driver:${Versions.sqlDelight}")

src/commonMain/kotlin/fr/acinq/lightning/bin/Api.kt

@@ -162,7 +162,10 @@ class Api(
                     call.respond(nodeParams.defaultOffer(peer.walletParams.trampolineNode.id).first.encode())
                 }
                 get("getlnaddress") {
-                    call.respond(if (peer.channels.isNotEmpty()) peer.requestAddress("en") else "must have one channel")
+                    when (val address = if (peer.channels.isNotEmpty()) peer.requestAddress("en") else null) {
+                        null -> call.respond("must have one channel")
+                        else -> call.respond("₿$address")
+                    }
                 }
                 get("payments/incoming") {
                     val listAll = call.parameters["all"]?.toBoolean() ?: false // by default, only list incoming payments that have been received

src/commonMain/kotlin/fr/acinq/lightning/bin/payments/Parser.kt

@@ -15,7 +15,7 @@ object Parser {
             return null
         }
 
-        val username = components[0].lowercase()
+        val username = components[0].lowercase().dropWhile { it == '₿' }
         val domain = components[1]
         return username to domain
     }

src/commonTest/kotlin/fr/acinq/lightning/bin/payments/ParserTestsCommon.kt

@@ -0,0 +1,20 @@
+package fr.acinq.lightning.bin.payments
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class ParserTestsCommon {
+
+    @Test
+    fun `test address parsing`() {
+        data class TestCase(val address: String, val user: String, val domain: String)
+
+        val testcases = listOf(
+            TestCase("[email protected]", "foo", "bar.com"),
+            TestCase("₿[email protected]", "foo", "bar.com"),
+            TestCase("₿₿[email protected]", "foo", "bar.com"),
+        )
+
+        testcases.forEach { testCase -> assertEquals(testCase.user to testCase.domain, Parser.parseEmailLikeAddress(testCase.address)) }
+    }
+}