Scaffold :shared KMP module and :desktop Compose app for bunker signing

Adds a Kotlin Multiplatform :shared module (androidTarget + jvm("desktop"))
depending on the multiplatform com.vitorpamplona.quartz:quartz coordinate
(which resolves quartz-android for Android and quartz-jvm for desktop via
Gradle variant-aware resolution), plus a new :desktop module scaffolded
with Compose Multiplatform Desktop and packaging config for
deb/msi/dmg installers. The :app module is untouched and still builds.

build.gradle.kts

@@ -7,6 +7,11 @@ plugins {
     alias(libs.plugins.serialization) apply false
     alias(libs.plugins.kotlin.ksp) version libs.versions.ksp.get() apply false
     alias(libs.plugins.gradle.ktlint) version libs.versions.ktlint.get() apply false
+    alias(libs.plugins.kotlinMultiplatform) apply false
+    alias(libs.plugins.jetbrainsCompose) apply false
+    alias(libs.plugins.jetbrainsComposeCompiler) apply false
+    alias(libs.plugins.androidKotlinMultiplatformLibrary) apply false
+    alias(libs.plugins.kotlinJvm) apply false
 }
 
 tasks.register<Copy>("installGitHook") {

desktop/build.gradle.kts

@@ -0,0 +1,40 @@
+import org.jetbrains.compose.desktop.application.dsl.TargetFormat
+
+plugins {
+    alias(libs.plugins.kotlinJvm)
+    alias(libs.plugins.jetbrainsCompose)
+    alias(libs.plugins.jetbrainsComposeCompiler)
+    alias(libs.plugins.gradle.ktlint) version libs.versions.ktlint.get()
+}
+
+kotlin {
+    jvmToolchain(21)
+}
+
+dependencies {
+    implementation(project(":shared"))
+
+    implementation(compose.desktop.currentOs)
+    implementation(compose.material3)
+    implementation(compose.materialIconsExtended)
+
+    implementation(libs.quartz.multiplatform)
+    implementation(libs.kotlinx.coroutines.core)
+    implementation(libs.core) // zxing core, for bunker connection QR codes
+    implementation(libs.java.keyring)
+    implementation(libs.androidx.sqlite.bundled)
+
+    testImplementation(kotlin("test"))
+}
+
+compose.desktop {
+    application {
+        mainClass = "com.greenart7c3.nostrsigner.desktop.MainKt"
+
+        nativeDistributions {
+            targetFormats(TargetFormat.Dmg, TargetFormat.Msi, TargetFormat.Deb)
+            packageName = "Amber Bunker"
+            packageVersion = "1.0.0"
+        }
+    }
+}

desktop/src/main/kotlin/com/greenart7c3/nostrsigner/desktop/Main.kt

@@ -0,0 +1,23 @@
+package com.greenart7c3.nostrsigner.desktop
+
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.window.Window
+import androidx.compose.ui.window.application
+
+fun main() = application {
+    Window(onCloseRequest = ::exitApplication, title = "Amber Bunker") {
+        App()
+    }
+}
+
+@Composable
+fun App() {
+    MaterialTheme {
+        Surface {
+            Text("Amber Bunker Desktop")
+        }
+    }
+}

gradle/libs.versions.toml

@@ -33,6 +33,9 @@ coroutinesTest = "1.11.0"
 kmpTor = "2.6.0"
 kmpTorResource = "409.5.0"
 secp256k1Jni = "0.23.0"
+composeMultiplatform = "1.11.1"
+androidxSqliteBundled = "2.6.2"
+javaKeyring = "1.0.4"
 
 [libraries]
 datastore-preferences = { module = "androidx.datastore:datastore-preferences", version.ref = "datastorePreferences" }
@@ -53,6 +56,7 @@ material-icons-extended = { module = "androidx.compose.material:material-icons-e
 material3 = { module = "androidx.compose.material3:material3", version.ref = "material3" }
 navigation-compose = { module = "androidx.navigation:navigation-compose", version.ref = "nav_version" }
 quartz = { module = "com.vitorpamplona.quartz:quartz-android", version.ref = "quartz" }
+quartz-multiplatform = { module = "com.vitorpamplona.quartz:quartz", version.ref = "quartz" }
 kotlinx-collections-immutable = { module = "org.jetbrains.kotlinx:kotlinx-collections-immutable", version.ref = "collections" }
 room-compiler = { module = "androidx.room:room-compiler", version.ref = "roomKtx" }
 room-ktx = { module = "androidx.room:room-ktx", version.ref = "roomKtx" }
@@ -79,15 +83,22 @@ paging-common = { group = "androidx.paging", name = "paging-common", version.ref
 paging-compose = { group = "androidx.paging", name = "paging-compose", version.ref = "pagingCommon" }
 paging-runtime = { group = "androidx.paging", name = "paging-runtime", version.ref = "pagingCommon" }
 mockk = { module = "io.mockk:mockk", version.ref = "mockk" }
+kotlinx-coroutines-core = { module = "org.jetbrains.kotlinx:kotlinx-coroutines-core", version.ref = "coroutinesTest" }
 kotlinx-coroutines-test = { module = "org.jetbrains.kotlinx:kotlinx-coroutines-test", version.ref = "coroutinesTest" }
 kmptor-runtime = { module = "io.matthewnelson.kmp-tor:runtime", version.ref = "kmpTor" }
 kmptor-resource-exec = { module = "io.matthewnelson.kmp-tor:resource-exec-tor", version.ref = "kmpTorResource" }
 secp256k1-jni-jvm = { module = "fr.acinq.secp256k1:secp256k1-kmp-jni-jvm", version.ref = "secp256k1Jni" }
+androidx-sqlite-bundled = { module = "androidx.sqlite:sqlite-bundled", version.ref = "androidxSqliteBundled" }
+java-keyring = { module = "com.github.javakeyring:java-keyring", version.ref = "javaKeyring" }
 
 [plugins]
 androidLibrary = { id = "com.android.library", version.ref = "agp" }
+androidKotlinMultiplatformLibrary = { id = "com.android.kotlin.multiplatform.library", version.ref = "agp" }
 androidApplication = { id = "com.android.application", version.ref = "agp" }
 gradle_ktlint = { id = "org.jlleitschuh.gradle.ktlint", version = "ktlint" }
 serialization = { id = "org.jetbrains.kotlin.plugin.serialization", version.ref = "kotlin" }
 kotlin_ksp = { id = "com.google.devtools.ksp", version = "ksp" }
 jetbrainsComposeCompiler = { id = "org.jetbrains.kotlin.plugin.compose", version.ref = "kotlin" }
+kotlinMultiplatform = { id = "org.jetbrains.kotlin.multiplatform", version.ref = "kotlin" }
+kotlinJvm = { id = "org.jetbrains.kotlin.jvm", version.ref = "kotlin" }
+jetbrainsCompose = { id = "org.jetbrains.compose", version.ref = "composeMultiplatform" }

settings.gradle.kts

@@ -17,3 +17,5 @@ dependencyResolutionManagement {
 }
 rootProject.name = "Nostr Signer"
 include(":app")
+include(":shared")
+include(":desktop")

shared/build.gradle.kts

@@ -0,0 +1,37 @@
+import org.jetbrains.kotlin.gradle.dsl.JvmTarget
+
+plugins {
+    alias(libs.plugins.kotlinMultiplatform)
+    alias(libs.plugins.androidKotlinMultiplatformLibrary)
+    alias(libs.plugins.gradle.ktlint) version libs.versions.ktlint.get()
+}
+
+kotlin {
+    android {
+        namespace = "com.greenart7c3.nostrsigner.shared"
+        compileSdk = 37
+        minSdk = 26
+
+        compilerOptions {
+            jvmTarget.set(JvmTarget.JVM_21)
+        }
+
+        withHostTest {}
+    }
+    jvm("desktop") {
+        compilerOptions {
+            jvmTarget.set(JvmTarget.JVM_21)
+        }
+    }
+
+    sourceSets {
+        commonMain.dependencies {
+            implementation(libs.quartz.multiplatform)
+            implementation(libs.kotlinx.coroutines.core)
+        }
+        commonTest.dependencies {
+            implementation(kotlin("test"))
+            implementation(libs.kotlinx.coroutines.test)
+        }
+    }
+}

shared/src/commonMain/kotlin/com/greenart7c3/nostrsigner/shared/BunkerSigner.kt

@@ -0,0 +1,19 @@
+package com.greenart7c3.nostrsigner.shared
+
+import com.vitorpamplona.quartz.nip01Core.crypto.KeyPair
+import com.vitorpamplona.quartz.nip01Core.signers.NostrSignerInternal
+
+/** Thin, platform-agnostic wrapper around a Quartz [NostrSignerInternal] used by the bunker signing engine. */
+class BunkerSigner(keyPair: KeyPair) {
+    private val signer = NostrSignerInternal(keyPair)
+
+    val pubKey: String get() = signer.pubKey
+
+    suspend fun nip44Encrypt(plainText: String, toPublicKey: String): String = signer.nip44Encrypt(plainText, toPublicKey)
+
+    suspend fun nip44Decrypt(cipherText: String, fromPublicKey: String): String = signer.nip44Decrypt(cipherText, fromPublicKey)
+
+    suspend fun nip04Encrypt(plainText: String, toPublicKey: String): String = signer.nip04Encrypt(plainText, toPublicKey)
+
+    suspend fun nip04Decrypt(cipherText: String, fromPublicKey: String): String = signer.nip04Decrypt(cipherText, fromPublicKey)
+}