Kotlin Facet: Configure facet automatically on Gradle project import

idea/idea-maven/src/org/jetbrains/kotlin/idea/maven/KotlinMavenImporter.kt

@@ -35,6 +35,7 @@ import org.jetbrains.jps.model.java.JavaSourceRootType
 import org.jetbrains.jps.model.module.JpsModuleSourceRootType
 import org.jetbrains.kotlin.config.LanguageVersion
 import org.jetbrains.kotlin.config.TargetPlatformKind
+import org.jetbrains.kotlin.idea.facet.configureFacet
 import org.jetbrains.kotlin.idea.facet.getOrCreateFacet
 import org.jetbrains.kotlin.idea.facet.initializeIfNeeded
 import org.jetbrains.kotlin.idea.facet.mavenLibraryId
@@ -90,22 +91,9 @@ class KotlinMavenImporter : MavenImporter(KotlinPluginGroupId, KotlinPluginArtif
     }
 
     private fun configureFacet(mavenProject: MavenProject, modifiableModelsProvider: IdeModifiableModelsProvider, module: Module) {
-        val compilerVersion = mavenProject.findPlugin(KotlinMavenConfigurator.GROUP_ID, KotlinMavenConfigurator.MAVEN_PLUGIN_ID)?.version ?: return
-        val artifacts = mavenProject.dependencyArtifactIndex.data[KotlinPluginGroupId]?.values?.flatMap { it.filter { it.isResolved } }
-        val expectedLibraryIds = TargetPlatformKind.ALL_PLATFORMS.map { it.mavenLibraryId }
-        val stdlibArtifact = artifacts?.firstOrNull { it.artifactId in expectedLibraryIds }
-
-        val facet = module.getOrCreateFacet(modifiableModelsProvider)
-        with(facet.configuration.settings.versionInfo) {
-            targetPlatformKind = null
-            apiLevel = null
-            facet.configuration.settings.initializeIfNeeded(module, modifiableModelsProvider.getModifiableRootModel(module))
-            languageLevel = LanguageVersion.fromFullVersionString(compilerVersion)
-            // Both apiLevel and languageLevel should be initialized in the lines above
-            if (apiLevel!! > languageLevel!!) {
-                apiLevel = languageLevel
-            }
-        }
+        val compilerVersion = mavenProject.findPlugin(KotlinMavenConfigurator.GROUP_ID, KotlinMavenConfigurator.MAVEN_PLUGIN_ID)?.version
+                              ?: return
+        module.getOrCreateFacet(modifiableModelsProvider).configureFacet(compilerVersion, modifiableModelsProvider)
     }
 
     // TODO in theory it should work like this but it doesn't as it couldn't unmark source roots that are not roots anymore.

idea/src/META-INF/gradle.xml

@@ -9,6 +9,8 @@
         <pluginDescriptions implementation="org.jetbrains.kotlin.idea.configuration.KotlinGradlePluginDescription"/>
     </extensions>
     <extensions defaultExtensionNs="com.intellij">
+        <externalProjectDataService implementation="org.jetbrains.kotlin.idea.configuration.KotlinGradleProjectDataService"/>
+
         <localInspection
             implementationClass="org.jetbrains.kotlin.idea.inspections.gradle.DifferentKotlinGradleVersionInspection"
             displayName="Kotlin Gradle and IDE plugins versions are different"

idea/src/org/jetbrains/kotlin/idea/configuration/KotlinGradleProjectDataService.kt

@@ -0,0 +1,53 @@
+/*
+ * Copyright 2010-2016 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jetbrains.kotlin.idea.configuration
+
+import com.intellij.openapi.externalSystem.model.DataNode
+import com.intellij.openapi.externalSystem.model.ProjectKeys
+import com.intellij.openapi.externalSystem.model.project.ProjectData
+import com.intellij.openapi.externalSystem.service.project.IdeModifiableModelsProvider
+import com.intellij.openapi.externalSystem.service.project.manage.AbstractProjectDataService
+import com.intellij.openapi.externalSystem.util.ExternalSystemApiUtil
+import com.intellij.openapi.project.Project
+import org.jetbrains.kotlin.idea.facet.configureFacet
+import org.jetbrains.kotlin.idea.facet.getOrCreateFacet
+import org.jetbrains.kotlin.idea.inspections.gradle.findAll
+import org.jetbrains.kotlin.idea.inspections.gradle.findKotlinPluginVersion
+import org.jetbrains.plugins.gradle.model.data.BuildScriptClasspathData
+import org.jetbrains.plugins.gradle.model.data.GradleSourceSetData
+
+class KotlinGradleProjectDataService : AbstractProjectDataService<GradleSourceSetData, Void>() {
+    override fun getTargetDataKey() = GradleSourceSetData.KEY
+
+    override fun postProcess(
+            toImport: Collection<DataNode<GradleSourceSetData>>,
+            projectData: ProjectData?,
+            project: Project,
+            modelsProvider: IdeModifiableModelsProvider
+    ) {
+        for (sourceSetNode in toImport) {
+            val sourceSetData = sourceSetNode.data
+            val ideModule = modelsProvider.findIdeModule(sourceSetData) ?: continue
+
+            val moduleNode = ExternalSystemApiUtil.findParent(sourceSetNode, ProjectKeys.MODULE)
+            val compilerVersion = moduleNode?.findAll(BuildScriptClasspathData.KEY)?.firstOrNull()?.data?.let(::findKotlinPluginVersion)
+                                  ?: continue
+
+            ideModule.getOrCreateFacet(modelsProvider).configureFacet(compilerVersion, modelsProvider)
+        }
+    }
+}

idea/src/org/jetbrains/kotlin/idea/facet/facetUtils.kt

@@ -146,3 +146,19 @@ fun Module.getOrCreateFacet(modelsProvider: IdeModifiableModelsProvider): Kotlin
     facetModel.addFacet(facet)
     return facet
 }
+
+fun KotlinFacet.configureFacet(compilerVersion: String, modelsProvider: IdeModifiableModelsProvider) {
+    val module = module
+    with(configuration.settings) {
+        versionInfo.targetPlatformKind = null
+        versionInfo.apiLevel = null
+        initializeIfNeeded(module, modelsProvider.getModifiableRootModel(module))
+        with(versionInfo) {
+            languageLevel = LanguageVersion.fromFullVersionString(compilerVersion) ?: LanguageVersion.LATEST
+            // Both apiLevel and languageLevel should be initialized in the lines above
+            if (apiLevel!! > languageLevel!!) {
+                apiLevel = languageLevel
+            }
+        }
+    }
+}

idea/src/org/jetbrains/kotlin/idea/inspections/gradle/DifferentStdlibGradleVersionInspection.kt

@@ -16,6 +16,7 @@
 
 package org.jetbrains.kotlin.idea.inspections.gradle
 
+import com.intellij.openapi.externalSystem.model.DataNode
 import com.intellij.openapi.externalSystem.model.ProjectKeys
 import com.intellij.openapi.roots.ProjectRootManager
 import com.intellij.psi.PsiFile
@@ -50,7 +51,7 @@ class DifferentStdlibGradleVersionInspection : GradleBaseInspection() {
             if (dependenciesCall.parent !is PsiFile) return
 
             val stdlibStatement = findLibraryStatement(closure, "org.jetbrains.kotlin", libraryId) ?: return
-            val stdlibVersion = getResolvedKotlinStdlibVersion(closure.containingFile, "org.jetbrains.kotlin:$libraryId:") ?: return
+            val stdlibVersion = getResolvedKotlinStdlibVersion(closure.containingFile, libraryId) ?: return
 
             onFound(stdlibVersion, stdlibStatement)
         }
@@ -99,21 +100,27 @@ class DifferentStdlibGradleVersionInspection : GradleBaseInspection() {
             return null
         }
 
-        private fun getResolvedKotlinStdlibVersion(file: PsiFile, libraryNameMarker: String): String? {
+        private fun getResolvedKotlinStdlibVersion(file: PsiFile, libraryId: String): String? {
             val projectStructureNode = findGradleProjectStructure(file) ?: return null
             val module = ProjectRootManager.getInstance(file.project).fileIndex.getModuleForFile(file.virtualFile) ?: return null
 
             for (moduleData in projectStructureNode.findAll(ProjectKeys.MODULE).filter { it.data.internalName == module.name }) {
-                for (sourceSetData in moduleData.node.findAll(GradleSourceSetData.KEY).filter { it.data.internalName.endsWith("main") }) {
-                    for (libraryDependencyData in sourceSetData.node.findAll(ProjectKeys.LIBRARY_DEPENDENCY)) {
-                        if (libraryDependencyData.data.externalName.startsWith(libraryNameMarker)) {
-                            return libraryDependencyData.data.externalName.substringAfter(libraryNameMarker)
-                        }
-                    }
-                }
+                moduleData.node.getResolvedKotlinStdlibVersionByModuleData(libraryId)?.let { return it }
             }
 
             return null
         }
     }
+}
+
+internal fun DataNode<*>.getResolvedKotlinStdlibVersionByModuleData(libraryId: String): String? {
+    val libraryNameMarker = "org.jetbrains.kotlin:$libraryId:"
+    for (sourceSetData in findAll(GradleSourceSetData.KEY).filter { it.data.internalName.endsWith("main") }) {
+        for (libraryDependencyData in sourceSetData.node.findAll(ProjectKeys.LIBRARY_DEPENDENCY)) {
+            if (libraryDependencyData.data.externalName.startsWith(libraryNameMarker)) {
+                return libraryDependencyData.data.externalName.substringAfter(libraryNameMarker)
+            }
+        }
+    }
+    return null
 }

idea/src/org/jetbrains/kotlin/idea/inspections/gradle/KotlinGradleInspectionVisitor.kt

@@ -72,7 +72,7 @@ fun getResolvedKotlinGradleVersion(module: Module): String? {
     return null
 }
 
-private fun findKotlinPluginVersion(classpathData: BuildScriptClasspathData): String? {
+internal fun findKotlinPluginVersion(classpathData: BuildScriptClasspathData): String? {
     for (classPathEntry in classpathData.classpathEntries) {
         for (path in classPathEntry.classesFile) {
             val uniformedPath = path.replace('\\', '/')