path: root/plugins/kotlin/completion/src/org/jetbrains/kotlin/idea/completion/smart/TypeInstantiationItems.kt

// Copyright 2000-2021 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.

package org.jetbrains.kotlin.idea.completion.smart

import com.intellij.codeInsight.completion.InsertHandler
import com.intellij.codeInsight.completion.InsertionContext
import com.intellij.codeInsight.lookup.LookupElement
import com.intellij.codeInsight.lookup.LookupElementDecorator
import com.intellij.codeInsight.lookup.LookupElementPresentation
import com.intellij.psi.PsiClass
import com.intellij.psi.search.GlobalSearchScope
import com.intellij.psi.search.searches.ClassInheritorsSearch
import org.jetbrains.kotlin.asJava.toLightClass
import org.jetbrains.kotlin.builtins.KotlinBuiltIns
import org.jetbrains.kotlin.builtins.isFunctionType
import org.jetbrains.kotlin.builtins.jvm.JavaToKotlinClassMap
import org.jetbrains.kotlin.descriptors.*
import org.jetbrains.kotlin.descriptors.annotations.Annotations
import org.jetbrains.kotlin.idea.caches.resolve.util.resolveToDescriptor
import org.jetbrains.kotlin.idea.codeInsight.DescriptorToSourceUtilsIde
import org.jetbrains.kotlin.idea.codeInsight.collectSyntheticStaticMembersAndConstructors
import org.jetbrains.kotlin.idea.completion.*
import org.jetbrains.kotlin.idea.completion.handlers.KotlinFunctionCompositeDeclarativeInsertHandler
import org.jetbrains.kotlin.idea.completion.handlers.KotlinFunctionInsertHandler
import org.jetbrains.kotlin.idea.core.ExpectedInfo
import org.jetbrains.kotlin.idea.core.KotlinIndicesHelper
import org.jetbrains.kotlin.idea.core.Tail
import org.jetbrains.kotlin.idea.core.multipleFuzzyTypes
import org.jetbrains.kotlin.idea.core.overrideImplement.ImplementMembersHandler
import org.jetbrains.kotlin.idea.formatter.kotlinCustomSettings
import org.jetbrains.kotlin.idea.resolve.ResolutionFacade
import org.jetbrains.kotlin.idea.util.*
import org.jetbrains.kotlin.incremental.components.NoLookupLocation
import org.jetbrains.kotlin.psi.KtClassOrObject
import org.jetbrains.kotlin.psi.KtDeclaration
import org.jetbrains.kotlin.resolve.BindingContext
import org.jetbrains.kotlin.resolve.DescriptorUtils
import org.jetbrains.kotlin.resolve.descriptorUtil.resolveTopLevelClass
import org.jetbrains.kotlin.resolve.sam.SamConstructorDescriptor
import org.jetbrains.kotlin.resolve.scopes.DescriptorKindFilter
import org.jetbrains.kotlin.types.*
import org.jetbrains.kotlin.util.constructors
import org.jetbrains.kotlin.util.kind
import org.jetbrains.kotlin.utils.addIfNotNull
import java.util.*

class TypeInstantiationItems(
    val resolutionFacade: ResolutionFacade,
    val bindingContext: BindingContext,
    val visibilityFilter: (DeclarationDescriptor) -> Boolean,
    val toFromOriginalFileMapper: ToFromOriginalFileMapper,
    val inheritorSearchScope: GlobalSearchScope,
    val lookupElementFactory: LookupElementFactory,
    val forOrdinaryCompletion: Boolean,
    val indicesHelper: KotlinIndicesHelper
) {
    fun addTo(
        items: MutableCollection<LookupElement>,
        inheritanceSearchers: MutableCollection<InheritanceItemsSearcher>,
        expectedInfos: Collection<ExpectedInfo>
    ) {
        val expectedInfosGrouped = LinkedHashMap<FuzzyType, MutableList<ExpectedInfo>>()
        for (expectedInfo in expectedInfos) {
            for (fuzzyType in expectedInfo.multipleFuzzyTypes) {
                expectedInfosGrouped.getOrPut(fuzzyType.makeNotNullable()) { ArrayList() }.add(expectedInfo)
            }
        }

        for ((type, infos) in expectedInfosGrouped) {
            val tail = mergeTails(infos.map { it.tail })
            addTo(items, inheritanceSearchers, type, tail)
        }
    }

    private fun addTo(
        items: MutableCollection<LookupElement>,
        inheritanceSearchers: MutableCollection<InheritanceItemsSearcher>,
        fuzzyType: FuzzyType,
        tail: Tail?
    ) {
        if (fuzzyType.type.isFunctionType) return // do not show "object: ..." for function types

        val classifier = fuzzyType.type.constructor.declarationDescriptor as? ClassifierDescriptorWithTypeParameters ?: return
        val classDescriptor = when (classifier) {
            is ClassDescriptor -> classifier
            is TypeAliasDescriptor -> classifier.classDescriptor
            else -> null
        }

        addSamConstructorItem(items, classifier, classDescriptor, tail)
        items.addIfNotNull(createTypeInstantiationItem(fuzzyType, classDescriptor, tail))

        indicesHelper.resolveTypeAliasesUsingIndex(fuzzyType.type, classifier.name.asString()).forEach {
            addSamConstructorItem(items, it, classDescriptor, tail)
            val typeAliasFuzzyType = it.defaultType.toFuzzyType(fuzzyType.freeParameters)
            items.addIfNotNull(createTypeInstantiationItem(typeAliasFuzzyType, classDescriptor, tail))
        }

        if (classDescriptor != null && !forOrdinaryCompletion && !KotlinBuiltIns.isAny(classDescriptor)) { // do not search inheritors of Any
            val typeArgs = fuzzyType.type.arguments
            inheritanceSearchers.addInheritorSearcher(classDescriptor, classDescriptor, typeArgs, fuzzyType.freeParameters, tail)

            val javaClassId = JavaToKotlinClassMap.mapKotlinToJava(DescriptorUtils.getFqName(classifier))
            if (javaClassId != null) {
                val javaAnalog =
                    resolutionFacade.moduleDescriptor.resolveTopLevelClass(javaClassId.asSingleFqName(), NoLookupLocation.FROM_IDE)
                if (javaAnalog != null) {
                    inheritanceSearchers.addInheritorSearcher(javaAnalog, classDescriptor, typeArgs, fuzzyType.freeParameters, tail)
                }
            }
        }
    }

    private fun MutableCollection<InheritanceItemsSearcher>.addInheritorSearcher(
        descriptor: ClassDescriptor,
        kotlinClassDescriptor: ClassDescriptor,
        typeArgs: List<TypeProjection>,
        freeParameters: Collection<TypeParameterDescriptor>,
        tail: Tail?
    ) {
        val _declaration = DescriptorToSourceUtilsIde.getAnyDeclaration(resolutionFacade.project, descriptor) ?: return
        val declaration = if (_declaration is KtDeclaration)
            toFromOriginalFileMapper.toOriginalFile(_declaration) ?: return
        else
            _declaration

        val psiClass: PsiClass = when (declaration) {
            is PsiClass -> declaration
            is KtClassOrObject -> declaration.toLightClass() ?: return
            else -> return
        }
        add(InheritanceSearcher(psiClass, kotlinClassDescriptor, typeArgs, freeParameters, tail))
    }

    private fun createTypeInstantiationItem(fuzzyType: FuzzyType, classDescriptor: ClassDescriptor?, tail: Tail?): LookupElement? {
        val classifier = fuzzyType.type.constructor.declarationDescriptor as? ClassifierDescriptorWithTypeParameters ?: return null

        var lookupElement = lookupElementFactory.createLookupElement(classifier, useReceiverTypes = false)

        if (DescriptorUtils.isNonCompanionObject(classifier)) {
            return lookupElement.addTail(tail)
        }

        // not all inner classes can be instantiated and we handle them via constructors returned by ReferenceVariantsHelper
        if (classifier.isInner) return null

        val isAbstract = classDescriptor?.modality == Modality.ABSTRACT
        if (forOrdinaryCompletion && isAbstract) return null

        val allConstructors = classifier.constructors
        val visibleConstructors = allConstructors.filter {
            if (isAbstract)
                visibilityFilter(it) || it.visibility == DescriptorVisibilities.PROTECTED
            else
                visibilityFilter(it)
        }
        if (allConstructors.isNotEmpty() && visibleConstructors.isEmpty()) return null

        var lookupString = lookupElement.lookupString
        var allLookupStrings = setOf(lookupString)
        var itemText = lookupString
        var signatureText: String? = null
        val typeText = IdeDescriptorRenderers.SOURCE_CODE.renderClassifierName(classifier)

        val insertHandler: InsertHandler<LookupElement>
        if (isAbstract) {
            val typeArgs = fuzzyType.type.arguments
            // drop "in" and "out" from type arguments - they cannot be used in constructor call
            val typeArgsToUse = typeArgs.map { TypeProjectionImpl(Variance.INVARIANT, it.type) }

            val allTypeArgsKnown =
                fuzzyType.freeParameters.isEmpty() || typeArgs.none { it.type.areTypeParametersUsedInside(fuzzyType.freeParameters) }
            itemText += if (allTypeArgsKnown) {
                IdeDescriptorRenderers.SOURCE_CODE_SHORT_NAMES_NO_ANNOTATIONS.renderTypeArguments(typeArgsToUse)
            } else {
                "<...>"
            }

            val constructorParenthesis = if (classifier.kind != ClassKind.INTERFACE) "()" else ""
            itemText += constructorParenthesis
            itemText = "object : $itemText{...}"
            lookupString = "object"
            allLookupStrings = setOf(lookupString, lookupElement.lookupString)
            insertHandler = InsertHandler<LookupElement> { context, _ ->
                val startOffset = context.startOffset

                val settings = context.file.kotlinCustomSettings
                val spaceBefore = if (settings.SPACE_BEFORE_EXTEND_COLON) " " else ""
                val spaceAfter = if (settings.SPACE_AFTER_EXTEND_COLON) " " else ""
                val text1 = "object$spaceBefore:$spaceAfter$typeText"
                val text2 = "$constructorParenthesis {}"
                val text = if (allTypeArgsKnown)
                    text1 + IdeDescriptorRenderers.SOURCE_CODE.renderTypeArguments(typeArgsToUse) + text2
                else
                    "$text1<>$text2"

                context.document.replaceString(startOffset, context.tailOffset, text)

                if (allTypeArgsKnown) {
                    context.editor.caretModel.moveToOffset(startOffset + text.length - 1)

                    shortenReferences(context, startOffset, startOffset + text.length)

                    ImplementMembersHandler().invoke(context.project, context.editor, context.file, true)
                } else {
                    context.editor.caretModel.moveToOffset(startOffset + text1.length + 1) // put caret into "<>"

                    shortenReferences(context, startOffset, startOffset + text.length)
                }
            }
            lookupElement = lookupElement.suppressAutoInsertion()
            lookupElement = lookupElement.assignSmartCompletionPriority(SmartCompletionItemPriority.ANONYMOUS_OBJECT)
        } else {
            //TODO: when constructor has one parameter of lambda type with more than one parameter, generate special additional item
            signatureText = when (visibleConstructors.size) {
                0 -> "()"

                1 -> {
                    val constructor = visibleConstructors.single()
                    val substitutor = TypeSubstitutor.create(fuzzyType.presentationType())
                    val substitutedConstructor = constructor.substitute(substitutor)
                        ?: constructor // render original signature if failed to substitute
                    BasicLookupElementFactory.SHORT_NAMES_RENDERER.renderFunctionParameters(substitutedConstructor)
                }

                else -> "(...)"
            }

            val baseInsertHandler = when (visibleConstructors.size) {
                0 -> KotlinFunctionInsertHandler.Normal(
                    CallType.DEFAULT,
                    inputTypeArguments = false,
                    inputValueArguments = false,
                    argumentsOnly = true
                )

                1 -> lookupElementFactory.insertHandlerProvider.insertHandler(visibleConstructors.single(), argumentsOnly = true)

                else -> KotlinFunctionInsertHandler.Normal(
                    CallType.DEFAULT,
                    inputTypeArguments = false,
                    inputValueArguments = true,
                    argumentsOnly = true
                )
            }

            insertHandler = InsertHandler { context, item ->
                context.document.replaceString(context.startOffset, context.tailOffset, typeText)
                context.tailOffset = context.startOffset + typeText.length

                baseInsertHandler.handleInsert(context, item)

                shortenReferences(context, context.startOffset, context.tailOffset)
            }

            run {
                val (inputValueArgs, isLambda) = when (baseInsertHandler) {
                    is KotlinFunctionInsertHandler.Normal -> baseInsertHandler.inputValueArguments to (baseInsertHandler.lambdaInfo != null)
                    is KotlinFunctionCompositeDeclarativeInsertHandler -> baseInsertHandler.inputValueArguments to baseInsertHandler.isLambda
                    else -> false to false
                }
                if (inputValueArgs) {
                    lookupElement = lookupElement.keepOldArgumentListOnTab()
                }
                if (isLambda) {
                    lookupElement.putUserData(KotlinCompletionCharFilter.ACCEPT_OPENING_BRACE, Unit)
                }
            }
            lookupElement = lookupElement.assignSmartCompletionPriority(SmartCompletionItemPriority.INSTANTIATION)
        }

        class InstantiationLookupElement : LookupElementDecorator<LookupElement>(lookupElement) {
            override fun getLookupString() = lookupString

            override fun getAllLookupStrings() = allLookupStrings

            override fun renderElement(presentation: LookupElementPresentation) {
                delegate.renderElement(presentation)
                presentation.itemText = itemText

                presentation.clearTail()
                signatureText?.let {
                    presentation.appendTailText(it, false)
                }
                presentation.appendTailText(" (" + DescriptorUtils.getFqName(classifier.containingDeclaration) + ")", true)
            }

            override fun handleInsert(context: InsertionContext) {
                insertHandler.handleInsert(context, delegate)
            }

            override fun equals(other: Any?): Boolean {
                if (other === this) return true
                if (other !is InstantiationLookupElement) return false
                if (getLookupString() != other.lookupString) return false
                val presentation1 = LookupElementPresentation()
                val presentation2 = LookupElementPresentation()
                renderElement(presentation1)
                other.renderElement(presentation2)
                return presentation1.itemText == presentation2.itemText && presentation1.tailText == presentation2.tailText
            }

            override fun hashCode() = lookupString.hashCode()
        }

        return InstantiationLookupElement().addTail(tail)
    }

    private fun KotlinType.areTypeParametersUsedInside(freeParameters: Collection<TypeParameterDescriptor>): Boolean {
        return FuzzyType(this, freeParameters).freeParameters.isNotEmpty()
    }

    private fun addSamConstructorItem(
        collection: MutableCollection<LookupElement>,
        classifier: ClassifierDescriptorWithTypeParameters,
        classDescriptor: ClassDescriptor?,
        tail: Tail?
    ) {
        if (classDescriptor?.kind == ClassKind.INTERFACE) {
            val samConstructor = run {
                val scope = when (val container = classifier.containingDeclaration) {
                    is PackageFragmentDescriptor -> container.getMemberScope()
                    is ClassDescriptor -> container.unsubstitutedMemberScope
                    else -> return
                }
                scope.collectSyntheticStaticMembersAndConstructors(
                        resolutionFacade,
                        DescriptorKindFilter.FUNCTIONS
                    ) { classifier.name == it }
                    .filterIsInstance<SamConstructorDescriptor>()
                    .singleOrNull() ?: return
            }
            lookupElementFactory
                .createStandardLookupElementsForDescriptor(samConstructor, useReceiverTypes = false)
                .mapTo(collection) { it.assignSmartCompletionPriority(SmartCompletionItemPriority.INSTANTIATION).addTail(tail) }
        }
    }

    private inner class InheritanceSearcher(
        private val psiClass: PsiClass,
        classDescriptor: ClassDescriptor,
        typeArgs: List<TypeProjection>,
        private val freeParameters: Collection<TypeParameterDescriptor>,
        private val tail: Tail?
    ) : InheritanceItemsSearcher {

        private val baseHasTypeArgs = classDescriptor.declaredTypeParameters.isNotEmpty()
        private val expectedType = KotlinTypeFactory.simpleNotNullType(Annotations.EMPTY, classDescriptor, typeArgs)
        private val expectedFuzzyType = expectedType.toFuzzyType(freeParameters)

        override fun search(nameFilter: (String) -> Boolean, consumer: (LookupElement) -> Unit) {
            val parameters = ClassInheritorsSearch.SearchParameters(psiClass, inheritorSearchScope, true, true, false, nameFilter)
            for (inheritor in ClassInheritorsSearch.search(parameters)) {
                val descriptor = inheritor.resolveToDescriptor(
                    resolutionFacade
                ) { toFromOriginalFileMapper.toSyntheticFile(it) } ?: continue
                if (!visibilityFilter(descriptor)) continue

                var inheritorFuzzyType = descriptor.defaultType.toFuzzyType(descriptor.typeConstructor.parameters)
                val hasTypeArgs = descriptor.declaredTypeParameters.isNotEmpty()
                if (hasTypeArgs || baseHasTypeArgs) {
                    val substitutor = inheritorFuzzyType.checkIsSubtypeOf(expectedFuzzyType) ?: continue
                    if (!substitutor.isEmpty) {
                        val inheritorTypeSubstituted = substitutor.substitute(inheritorFuzzyType.type, Variance.INVARIANT)!!
                        inheritorFuzzyType = inheritorTypeSubstituted.toFuzzyType(freeParameters + inheritorFuzzyType.freeParameters)
                    }
                }

                val lookupElement = createTypeInstantiationItem(inheritorFuzzyType, descriptor, tail) ?: continue
                consumer(lookupElement.assignSmartCompletionPriority(SmartCompletionItemPriority.INHERITOR_INSTANTIATION))
            }
        }
    }
}