build: replace empty javadoc stub with real Dokka HTML (#14)

The plugin is written in Kotlin, so the stock Java-only javadoc task produced nothing and withJavadocJar() shipped an EMPTY -javadoc.jar to Maven Central. Apply Dokka 2.2.0 and add its rendered HTML to the javadoc jar so consumers get a real API reference. Verified locally: the jar now contains 96 files / 27 HTML pages incl. index.html.

Author: jamesarich

gradle/libs.versions.toml

@@ -1,10 +1,12 @@
 [versions]
 detekt = "1.23.8"
+dokka = "2.2.0"
 nmcp = "1.6.1"
 
 [plugins]
 gradle-plugin-publish = { id = "com.gradle.plugin-publish", version = "2.1.1" }
 detekt = { id = "io.gitlab.arturbosch.detekt", version.ref = "detekt" }
+dokka = { id = "org.jetbrains.dokka", version.ref = "dokka" }
 nmcp = { id = "com.gradleup.nmcp", version.ref = "nmcp" }
 
 [libraries]

plugin/build.gradle.kts

@@ -21,6 +21,7 @@ plugins {
     `kotlin-dsl`
     alias(libs.plugins.gradle.plugin.publish)
     alias(libs.plugins.detekt)
+    alias(libs.plugins.dokka)
     alias(libs.plugins.nmcp)
     signing
 }
@@ -36,6 +37,27 @@ java {
     withJavadocJar()
 }
 
+// Populate the Maven Central -javadoc.jar with real Dokka HTML. This plugin is
+// written in Kotlin, so the stock (Java-only) `javadoc` task produces nothing
+// and withJavadocJar() would otherwise ship an empty jar. Dokka renders the
+// public API; its HTML output is added to the javadoc jar.
+dokka {
+    moduleName.set("Gradle Flatpak Sources")
+    dokkaSourceSets.configureEach {
+        sourceLink {
+            localDirectory.set(file("src/main/kotlin"))
+            remoteUrl("https://github.com/meshtastic/gradle-flatpak-sources/blob/main/plugin/src/main/kotlin")
+            remoteLineSuffix.set("#L")
+        }
+    }
+}
+
+tasks.named<Jar>("javadocJar") {
+    dependsOn("dokkaGeneratePublicationHtml")
+    from(tasks.named("dokkaGeneratePublicationHtml"))
+    duplicatesStrategy = DuplicatesStrategy.EXCLUDE
+}
+
 detekt {
     buildUponDefaultConfig = true
     allRules = false