Gradle: Implement --update option for setupPaperServer, and add runPaperServer

build.gradle.kts

@@ -135,7 +135,7 @@ subprojects {
   }
 }
 
-tasks.setupPaperServer {
-  minecraftServerPath = "server"
-  paperVersionGroup = "1.18"
+foundation {
+  minecraftServerPath.set("server")
+  paperVersionGroup.set("1.18")
 }

buildSrc/src/main/kotlin/cloud/kubelet/foundation/gradle/FoundationExtension.kt

@@ -0,0 +1,8 @@
+package cloud.kubelet.foundation.gradle
+
+import org.gradle.api.provider.Property
+
+interface FoundationExtension {
+  val paperVersionGroup: Property<String>
+  val minecraftServerPath: Property<String>
+}

buildSrc/src/main/kotlin/cloud/kubelet/foundation/gradle/FoundationGradlePlugin.kt

@@ -2,9 +2,13 @@ package cloud.kubelet.foundation.gradle
 
 import org.gradle.api.Plugin
 import org.gradle.api.Project
+import org.gradle.kotlin.dsl.create
 
 class FoundationGradlePlugin : Plugin<Project> {
   override fun apply(project: Project) {
-    project.tasks.create("setupPaperServer", SetupPaperServer::class.java)
+    project.extensions.create<FoundationExtension>("foundation")
+    val setupPaperServer = project.tasks.create<SetupPaperServer>("setupPaperServer")
+    val runPaperServer = project.tasks.create<RunPaperServer>("runPaperServer")
+    runPaperServer.dependsOn(setupPaperServer)
   }
 }

buildSrc/src/main/kotlin/cloud/kubelet/foundation/gradle/RunPaperServer.kt

@@ -0,0 +1,25 @@
+package cloud.kubelet.foundation.gradle
+
+import org.gradle.api.DefaultTask
+import org.gradle.api.tasks.TaskAction
+import org.gradle.kotlin.dsl.getByType
+
+open class RunPaperServer : DefaultTask() {
+  init {
+    outputs.upToDateWhen { false }
+  }
+
+  @TaskAction
+  fun runPaperServer() {
+    val foundation = project.extensions.getByType<FoundationExtension>()
+
+    val minecraftServerDirectory = project.file(foundation.minecraftServerPath.get())
+    val paperJarFile = minecraftServerDirectory.resolve("paper.jar")
+    project.javaexec {
+      classpath(paperJarFile.absolutePath)
+      workingDir(minecraftServerDirectory)
+      args("nogui")
+      mainClass.set("io.papermc.paperclip.Main")
+    }
+  }
+}

buildSrc/src/main/kotlin/cloud/kubelet/foundation/gradle/SetupPaperServer.kt

@@ -3,34 +3,35 @@ package cloud.kubelet.foundation.gradle
 import org.gradle.api.DefaultTask
 import org.gradle.api.tasks.Input
 import org.gradle.api.tasks.TaskAction
+import org.gradle.api.tasks.options.Option
+import org.gradle.kotlin.dsl.getByType
+import java.io.File
 import java.nio.file.Files
 
 open class SetupPaperServer : DefaultTask() {
-  @get:Input
-  lateinit var paperVersionGroup: String
+  init {
+    outputs.upToDateWhen { false }
+  }
 
   @get:Input
-  lateinit var minecraftServerPath: String
+  @set:Option(option = "update", description = "Update Paper Server")
+  var shouldUpdatePaperServer = false
+
+  private val paperVersionClient = PaperVersionClient()
 
   @TaskAction
   fun downloadPaperTask() {
-    val minecraftServerDirectory = project.file(minecraftServerPath)
-    val client = PaperVersionClient()
-    val builds = client.getVersionBuilds(paperVersionGroup)
-    val build = builds.last()
-    val download = build.downloads["application"]!!
-    val url = client.resolveDownloadUrl(build, download)
+    val foundation = project.extensions.getByType<FoundationExtension>()
+    val minecraftServerDirectory = project.file(foundation.minecraftServerPath.get())
 
     if (!minecraftServerDirectory.exists()) {
       minecraftServerDirectory.mkdirs()
     }
 
-    ant.invokeMethod(
-      "get", mapOf(
-        "src" to url.toString(),
-        "dest" to project.file("${minecraftServerPath}/paper.jar").absolutePath
-      )
-    )
+    val paperJarFile = project.file("${foundation.minecraftServerPath.get()}/paper.jar")
+    if (!paperJarFile.exists() || shouldUpdatePaperServer) {
+      downloadLatestBuild(foundation.paperVersionGroup.get(), paperJarFile)
+    }
 
     val paperPluginsDirectory = minecraftServerDirectory.resolve("plugins")
 
@@ -52,4 +53,20 @@ open class SetupPaperServer : DefaultTask() {
       Files.createSymbolicLink(pluginLinkFile.toPath(), pluginJarFile.toPath())
     }
   }
+
+  private fun downloadLatestBuild(paperVersionGroup: String, paperJarFile: File) {
+    val builds = paperVersionClient.getVersionBuilds(paperVersionGroup)
+    val build = builds.last()
+    val download = build.downloads["application"]!!
+    val url = paperVersionClient.resolveDownloadUrl(build, download)
+
+    ant.invokeMethod(
+      "get", mapOf(
+        "src" to url.toString(),
+        "dest" to paperJarFile.absolutePath
+      )
+    )
+
+    logger.lifecycle("Installed Paper Server ${build.version} build ${build.build}")
+  }
 }