New J2K: suggest user to configure Kotlin in a project before nj2k conversion

nj2k/nj2k-services/build.gradle.kts

@@ -31,6 +31,7 @@ dependencies {
     compile(project(":idea:fir-view"))
     compile(project(":idea:idea-core"))
     compile(project(":idea:ide-common"))
+    compile(project(":idea:idea-jvm"))
     compile(project(":idea:idea-jps-common"))
     compile(project(":idea:kotlin-gradle-tooling"))
     compile(project(":plugins:uast-kotlin"))

nj2k/nj2k-services/src/org/jetbrains/kotlin/nj2k/NewJ2kConveterExtension.kt

@@ -1,8 +1,15 @@
 package org.jetbrains.kotlin.nj2k
 
+import com.intellij.openapi.module.Module
 import com.intellij.openapi.project.Project
+import com.intellij.openapi.ui.Messages
+import org.jetbrains.kotlin.idea.configuration.getAbleToRunConfigurators
+import org.jetbrains.kotlin.idea.configuration.hasAnyKotlinRuntimeInScope
+import org.jetbrains.kotlin.idea.configuration.isModuleConfigured
+import org.jetbrains.kotlin.idea.configuration.toModuleGroup
 import org.jetbrains.kotlin.j2k.*
 import org.jetbrains.kotlin.nj2k.postProcessing.NewJ2kPostProcessor
+import org.jetbrains.kotlin.platform.jvm.isJvm
 
 class NewJ2kConverterExtension : J2kConverterExtension() {
     override val isNewJ2k = true
@@ -16,4 +23,43 @@ class NewJ2kConverterExtension : J2kConverterExtension() {
 
     override fun createPostProcessor(formatCode: Boolean): PostProcessor =
         NewJ2kPostProcessor()
+
+    override fun doCheckBeforeConversion(project: Project, module: Module): Boolean =
+        checkKotlinIsConfigured(project, module)
+
+    private fun checkKotlinIsConfigured(project: Project, module: Module): Boolean {
+        val kotlinIsConfigured =
+            hasAnyKotlinRuntimeInScope(module) || isModuleConfigured(module.toModuleGroup())
+        if (kotlinIsConfigured) return true
+
+        val title = "Kotlin is not configured in the project"
+        if (Messages.showOkCancelDialog(
+                project,
+                "You will have to configure Kotlin in project before performing a conversion.",
+                title,
+                "OK, configure Kotlin in the project",
+                "No, cancel conversion",
+                Messages.getWarningIcon()
+            ) == Messages.OK
+        ) {
+            val configurators = getAbleToRunConfigurators(module).filter { it.targetPlatform.isJvm() }
+            when {
+                configurators.isEmpty() -> Messages.showErrorDialog("There aren't configurators available", title)
+                configurators.size == 1 -> configurators.single().configure(project, emptyList())
+                else -> {
+                    val resultIndex = Messages.showChooseDialog(//TODO a better dialog?
+                        project,
+                        "Choose Configurator",
+                        title,
+                        null,
+                        configurators.map { it.presentableText }.toTypedArray(),
+                        configurators.first().presentableText
+                    )
+                    configurators.getOrNull(resultIndex)?.configure(project, emptyList())
+                }
+            }
+        }
+
+        return false
+    }
 }