[lc] extract common code to KtLightClassForFacadeBase

^KT-53543

analysis/light-classes-base/src/org/jetbrains/kotlin/asJava/classes/KtLightClassForFacadeBase.kt

@@ -12,12 +12,15 @@ import com.intellij.psi.impl.light.LightEmptyImplementsList
 import com.intellij.psi.impl.light.LightModifierList
 import org.jetbrains.annotations.NonNls
 import org.jetbrains.kotlin.asJava.elements.FakeFileForLightClass
+import org.jetbrains.kotlin.asJava.elements.KtLightField
+import org.jetbrains.kotlin.asJava.elements.KtLightMethod
 import org.jetbrains.kotlin.fileClasses.JvmFileClassUtil
 import org.jetbrains.kotlin.fileClasses.javaFileFacadeFqName
 import org.jetbrains.kotlin.idea.KotlinLanguage
 import org.jetbrains.kotlin.load.java.structure.LightClassOriginKind
 import org.jetbrains.kotlin.load.kotlin.PackagePartClassUtils
 import org.jetbrains.kotlin.name.FqName
+import org.jetbrains.kotlin.name.JvmNames
 import org.jetbrains.kotlin.name.JvmNames.JVM_NAME_SHORT
 import org.jetbrains.kotlin.psi.KtClassOrObject
 import org.jetbrains.kotlin.psi.KtFile
@@ -28,15 +31,25 @@ import javax.swing.Icon
 
 abstract class KtLightClassForFacadeBase constructor(
     override val facadeClassFqName: FqName,
-    override val files: Collection<KtFile>
+    final override val files: Collection<KtFile>
 ) : KtLightClassBase(files.first().manager), KtLightClassForFacade {
-    private val firstFileInFacade by lazyPub { files.iterator().next() }
+    private val firstFileInFacade by lazyPub { files.first() }
 
-    private val modifierList: PsiModifierList =
-        LightModifierList(manager, KotlinLanguage.INSTANCE, PsiModifier.PUBLIC, PsiModifier.FINAL)
+    val isMultiFileClass: Boolean by lazyPub {
+        files.size > 1 || JvmFileClassUtil.findAnnotationEntryOnFileNoResolve(firstFileInFacade, JvmNames.JVM_MULTIFILE_CLASS_SHORT) != null
+    }
 
-    private val implementsList: LightEmptyImplementsList =
+    private val _modifierList: PsiModifierList by lazyPub {
+        if (isMultiFileClass)
+            LightModifierList(manager, KotlinLanguage.INSTANCE, PsiModifier.PUBLIC, PsiModifier.FINAL)
+        else
+            createModifierListForSimpleFacade()
+    }
+
+
+    private val _implementsList: LightEmptyImplementsList by lazyPub {
         LightEmptyImplementsList(manager)
+    }
 
     private val packageClsFile by lazyPub {
         FakeFileForLightClass(
@@ -46,6 +59,19 @@ abstract class KtLightClassForFacadeBase constructor(
         )
     }
 
+    private val _ownMethods: List<KtLightMethod> by lazyPub {
+        createOwnMethods()
+    }
+
+    private val _ownFields: List<KtLightField> by lazyPub {
+        createOwnFields()
+    }
+
+    abstract fun createOwnMethods(): List<KtLightMethod>
+    abstract fun createOwnFields(): List<KtLightField>
+
+    abstract fun createModifierListForSimpleFacade(): PsiModifierList
+
     override fun getParent(): PsiElement = containingFile
 
     override val kotlinOrigin: KtClassOrObject? get() = null
@@ -53,7 +79,7 @@ abstract class KtLightClassForFacadeBase constructor(
     val fqName: FqName
         get() = facadeClassFqName
 
-    override fun getModifierList() = modifierList
+    override fun getModifierList() = _modifierList
 
     override fun hasModifierProperty(@NonNls name: String) = modifierList.hasModifierProperty(name)
 
@@ -79,7 +105,7 @@ abstract class KtLightClassForFacadeBase constructor(
 
     override fun getDocComment(): Nothing? = null
 
-    override fun getImplementsList() = implementsList
+    override fun getImplementsList() = _implementsList
 
     override fun getImplementsListTypes(): Array<out PsiClassType> = PsiClassType.EMPTY_ARRAY
 
@@ -204,5 +230,9 @@ abstract class KtLightClassForFacadeBase constructor(
 
     override fun isWritable() = files.all { it.isWritable }
 
+    override fun getOwnFields() = _ownFields
+
+    override fun getOwnMethods() = _ownMethods
+
     override fun getVisibleSignatures(): MutableCollection<HierarchicalMethodSignature> = PsiSuperMethodImplUtil.getVisibleSignatures(this)
 }