Add Kotlin JVM bindings

.github/workflows/ci.yml

@@ -497,6 +497,25 @@ jobs:
       - name: Run Dart tests
         run: nix develop -L .#bindings --command just test-dart
 
+  kotlin-binding-tests:
+    name: "Kotlin binding tests"
+    runs-on: self-hosted
+    timeout-minutes: 30
+    needs: pre-commit-checks
+    steps:
+      - name: checkout
+        uses: actions/checkout@v4
+      - uses: cachix/cachix-action@v16
+        with:
+          name: cashudevkit
+          authToken: ${{ secrets.CACHIX_AUTH_TOKEN }}
+          useDaemon: false
+        continue-on-error: true
+      - name: Build native library and generate bindings
+        run: nix develop -L .#bindings --command just binding-kotlin
+      - name: Run Kotlin tests
+        run: nix develop -L .#bindings --command just test-kotlin
+
   swift-binding-tests:
     name: "Swift binding tests"
     runs-on: macos-latest

.gitignore

@@ -34,3 +34,17 @@ __pycache__
 libcdk_ffi*
 cdk_ffi.py
 
+# Kotlin bindings
+.gradle/
+!gradle/wrapper/gradle-wrapper.jar
+local.properties
+*.iml
+*.ipr
+*.iws
+bin/
+gen/
+out/
+bindings/kotlin/cdk-jvm/src/main/kotlin/uniffi/
+bindings/kotlin/cdk-jvm/src/main/resources/*.so
+bindings/kotlin/cdk-jvm/src/main/resources/*.dylib
+

Cargo.toml

@@ -3,6 +3,7 @@ members = [
     "crates/*",
     "bindings/dart/rust",
     "bindings/swift/rust",
+    "bindings/kotlin/rust",
 ]
 exclude = [
     "fuzz",

bindings/kotlin/build.gradle.kts

@@ -0,0 +1,3 @@
+plugins {
+    kotlin("jvm") version "1.9.24" apply false
+}

bindings/kotlin/cdk-jvm/build.gradle.kts

@@ -0,0 +1,57 @@
+plugins {
+    kotlin("jvm")
+    `java-library`
+    `maven-publish`
+}
+
+java {
+    sourceCompatibility = JavaVersion.VERSION_17
+    targetCompatibility = JavaVersion.VERSION_17
+    withSourcesJar()
+    withJavadocJar()
+}
+
+kotlin {
+    jvmToolchain(17)
+}
+
+dependencies {
+    implementation("net.java.dev.jna:jna:5.14.0")
+    implementation("org.jetbrains.kotlin:kotlin-stdlib:1.9.24")
+    implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:1.8.1")
+
+    testImplementation("org.junit.jupiter:junit-jupiter:5.10.2")
+    testImplementation("org.jetbrains.kotlinx:kotlinx-coroutines-test:1.8.1")
+}
+
+sourceSets {
+    main {
+        kotlin.srcDirs("src/main/kotlin")
+        resources.srcDirs("src/main/resources")
+    }
+}
+
+tasks.test {
+    useJUnitPlatform()
+    testLogging {
+        events("passed", "skipped", "failed")
+        showStandardStreams = true
+    }
+    systemProperty("junit.jupiter.execution.timeout.default", "60s")
+    jvmArgs("-Djava.library.path=${project.projectDir}/src/main/resources")
+}
+
+tasks.processResources {
+    duplicatesStrategy = DuplicatesStrategy.INCLUDE
+}
+
+publishing {
+    publications {
+        create<MavenPublication>("maven") {
+            groupId = project.property("GROUP") as String
+            artifactId = "cdk-jvm"
+            version = project.property("VERSION_NAME") as String
+            from(components["java"])
+        }
+    }
+}

bindings/kotlin/cdk-jvm/src/test/kotlin/org/cashudevkit/WalletTest.kt

@@ -0,0 +1,66 @@
+package org.cashudevkit
+
+import kotlinx.coroutines.runBlocking
+import org.junit.jupiter.api.AfterEach
+import org.junit.jupiter.api.Assertions.*
+import org.junit.jupiter.api.BeforeEach
+import org.junit.jupiter.api.Test
+import java.io.File
+
+class WalletTest {
+
+    private lateinit var wallet: Wallet
+    private lateinit var dbFile: File
+
+    @BeforeEach
+    fun setUp() {
+        dbFile = File.createTempFile("cdk_test_", ".sqlite")
+        val mnemonic = generateMnemonic()
+        wallet = Wallet(
+            mintUrl = "https://testnut.cashudevkit.org",
+            unit = CurrencyUnit.Sat,
+            mnemonic = mnemonic,
+            store = WalletStore.Sqlite(path = dbFile.absolutePath),
+            config = WalletConfig(targetProofCount = null),
+        )
+    }
+
+    @AfterEach
+    fun tearDown() {
+        wallet.close()
+        dbFile.delete()
+    }
+
+    @Test
+    fun `initial balance is zero`() = runBlocking {
+        val balance = wallet.totalBalance()
+        assertEquals(0UL, balance.value)
+    }
+
+    @Test
+    fun `mint flow`() = runBlocking {
+        val quote = wallet.mintQuote(
+            paymentMethod = PaymentMethod.Bolt11,
+            amount = Amount(value = 100UL),
+            description = null,
+            extra = null,
+        )
+
+        assertTrue(quote.id.isNotEmpty())
+        assertTrue(quote.request.isNotEmpty())
+
+        // testnut pays quotes automatically, wait for payment to settle
+        kotlinx.coroutines.delay(3000)
+
+        val proofs = wallet.mint(
+            quoteId = quote.id,
+            amountSplitTarget = SplitTarget.None,
+            spendingConditions = null,
+        )
+
+        assertTrue(proofs.isNotEmpty())
+
+        val balance = wallet.totalBalance()
+        assertEquals(100UL, balance.value)
+    }
+}

bindings/kotlin/gradle.properties

@@ -0,0 +1,7 @@
+org.gradle.jvmargs=-Xmx2048m -Dfile.encoding=UTF-8
+org.gradle.parallel=true
+org.gradle.caching=true
+kotlin.code.style=official
+
+GROUP=org.cashudevkit
+VERSION_NAME=0.16.0-rc.2

bindings/kotlin/gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,7 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.12.1-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists