KotlinToJavaConverter.kt

package org.jetbrains.dokka.kotlinAsJava.converters

import org.jetbrains.dokka.kotlinAsJava.hasJvmOverloads
import org.jetbrains.dokka.kotlinAsJava.hasJvmSynthetic
import org.jetbrains.dokka.kotlinAsJava.jvmField
import org.jetbrains.dokka.kotlinAsJava.transformers.JvmNameProvider
import org.jetbrains.dokka.kotlinAsJava.transformers.withCallableName
import org.jetbrains.dokka.links.Callable
import org.jetbrains.dokka.links.DRI
import org.jetbrains.dokka.links.PointingToDeclaration
import org.jetbrains.dokka.links.withClass
import org.jetbrains.dokka.model.*
import org.jetbrains.dokka.model.properties.PropertyContainer
import org.jetbrains.kotlin.builtins.jvm.JavaToKotlinClassMap
import org.jetbrains.kotlin.name.ClassId
import org.jetbrains.kotlin.name.FqName
import org.jetbrains.kotlin.resolve.jvm.JvmPrimitiveType

val jvmNameProvider = JvmNameProvider()

private val DProperty.isConst: Boolean
    get() = extra[AdditionalModifiers]
        ?.content
        ?.any { (_, modifiers) ->
            ExtraModifiers.KotlinOnlyModifiers.Const in modifiers
        } == true

private val DProperty.isJvmField: Boolean
    get() = jvmField() != null

internal fun DPackage.asJava(): DPackage {
    val syntheticClasses =
        (properties.map { jvmNameProvider.nameForSyntheticClass(it) to it }
                + functions.map { jvmNameProvider.nameForSyntheticClass(it) to it })
            .groupBy({ it.first }) { it.second }
            .map { (syntheticClassName, nodes) ->
                DClass(
                    dri = dri.withClass(syntheticClassName.name),
                    name = syntheticClassName.name,
                    properties = nodes
                        .filterIsInstance<DProperty>()
                        .filterNot { it.hasJvmSynthetic() }
                        .map { it.asJava(true) },
                    constructors = emptyList(),
                    functions = (
                            nodes
                                .filterIsInstance<DProperty>()
                                .filterNot { it.isConst || it.isJvmField || it.hasJvmSynthetic() }
                                .flatMap { it.javaAccessors(relocateToClass = syntheticClassName.name) } +
                                    nodes
                                        .filterIsInstance<DFunction>()
                                        .flatMap { it.asJava(syntheticClassName.name, true) })
                        .filterNot { it.hasJvmSynthetic() },
                    classlikes = emptyList(),
                    sources = emptyMap(),
                    expectPresentInSet = null,
                    visibility = sourceSets.associateWith {
                        JavaVisibility.Public
                    },
                    companion = null,
                    generics = emptyList(),
                    supertypes = emptyMap(),
                    documentation = emptyMap(),
                    modifier = sourceSets.associateWith { JavaModifier.Final },
                    sourceSets = sourceSets,
                    isExpectActual = false,
                    extra = PropertyContainer.empty()
                )
            }

    return copy(
        functions = emptyList(),
        properties = emptyList(),
        classlikes = classlikes.map { it.asJava() } + syntheticClasses,
        typealiases = emptyList()
    )
}

internal fun DProperty.asJava(isTopLevel: Boolean = false, relocateToClass: String? = null) =
    copy(
        dri = if (relocateToClass.isNullOrBlank()) {
            dri
        } else {
            dri.withClass(relocateToClass)
        },
        modifier = javaModifierFromSetter(),
        visibility = visibility.mapValues {
            if (isTopLevel && isConst) {
                JavaVisibility.Public
            } else if (jvmField() != null || (getter == null && setter == null)) {
                it.value.asJava()
            } else {
                it.value.propertyVisibilityAsJava()
            }
        },
        type = type.asJava(), // TODO: check
        setter = null,
        getter = null, // Removing getters and setters as they will be available as functions
        extra = if (isTopLevel) extra +
                extra.mergeAdditionalModifiers(
                    sourceSets.associateWith {
                        setOf(ExtraModifiers.JavaOnlyModifiers.Static)
                    }
                )
        else extra
    )

internal fun Visibility.asJava() =
    when (this) {
        is JavaVisibility -> this
        is KotlinVisibility.Public, KotlinVisibility.Internal -> JavaVisibility.Public
        is KotlinVisibility.Private -> JavaVisibility.Private
        is KotlinVisibility.Protected -> JavaVisibility.Protected
    }

internal fun DProperty.javaModifierFromSetter() =
    modifier.mapValues {
        when {
            it.value is JavaModifier -> it.value
            setter == null -> JavaModifier.Final
            else -> JavaModifier.Empty
        }
    }

internal fun DProperty.javaAccessors(isTopLevel: Boolean = false, relocateToClass: String? = null): List<DFunction> =
    listOfNotNull(
        getter?.let { getter ->
            val name = "get" + name.capitalize()
            getter.copy(
                dri = if (relocateToClass.isNullOrBlank()) {
                    getter.dri
                } else {
                    getter.dri.withClass(relocateToClass)
                }.withCallableName(name),
                name = name,
                modifier = javaModifierFromSetter(),
                visibility = visibility.mapValues { JavaVisibility.Public },
                type = getter.type.asJava(),
                extra = if (isTopLevel) getter.extra +
                        getter.extra.mergeAdditionalModifiers(
                            sourceSets.associateWith {
                                setOf(ExtraModifiers.JavaOnlyModifiers.Static)
                            }
                        )
                else getter.extra
            )
        },
        setter?.let { setter ->
            val name = "set" + name.capitalize()
            val baseDRI = (if (relocateToClass.isNullOrBlank()) {
                setter.dri
            } else {
                setter.dri.withClass(relocateToClass)
            }).withCallableName(name)
            setter.copy(
                dri = baseDRI,
                name = name,
                parameters = setter.parameters.map {
                    it.copy(
                        dri = baseDRI.copy(
                            target = it.dri.target,
                            extra = it.dri.extra
                        ), type = it.type.asJava()
                    )
                },
                modifier = javaModifierFromSetter(),
                visibility = visibility.mapValues { JavaVisibility.Public },
                type = Void,
                extra = if (isTopLevel) setter.extra + setter.extra.mergeAdditionalModifiers(
                    sourceSets.associateWith {
                        setOf(ExtraModifiers.JavaOnlyModifiers.Static)
                    }
                )
                else setter.extra
            )
        }
    )

private fun DFunction.asJava(
    containingClassName: String,
    newName: String,
    parameters: List<DParameter>,
    isTopLevel: Boolean = false
): DFunction {
    return copy(
        dri = dri.copy(classNames = containingClassName, callable = dri.callable?.copy(name = newName)),
        name = newName,
        type = type.asJava(),
        modifier = if (modifier.all { (_, v) -> v is KotlinModifier.Final } && isConstructor)
            sourceSets.associateWith { JavaModifier.Empty }
        else sourceSets.associateWith { modifier.values.first() },
        parameters = listOfNotNull(receiver?.asJava()) + parameters.map { it.asJava() },
        visibility = visibility.map { (sourceSet, visibility) -> Pair(sourceSet, visibility.asJava()) }.toMap(),
        receiver = null,
        extra = if (isTopLevel) {
            extra + extra.mergeAdditionalModifiers(
                sourceSets.associateWith {
                    setOf(ExtraModifiers.JavaOnlyModifiers.Static)
                }
            )
        } else {
            extra
        }
    )
}

private fun DFunction.withJvmOverloads(
    containingClassName: String,
    newName: String,
    isTopLevel: Boolean = false
): List<DFunction>? {
    val (paramsWithDefaults, paramsWithoutDefaults) = parameters
        .withIndex()
        .partition { (_, p) -> p.extra[DefaultValue] != null }
    return paramsWithDefaults
        .runningFold(paramsWithoutDefaults) { acc, param -> (acc + param) }
        .map { params ->
            asJava(
                containingClassName,
                newName,
                params
                    .sortedBy(IndexedValue<DParameter>::index)
                    .map { it.value },
                isTopLevel
            )
        }
        .reversed()
        .takeIf { it.isNotEmpty() }
}

internal fun DFunction.asJava(containingClassName: String, isTopLevel: Boolean = false): List<DFunction> {
    val newName = when {
        isConstructor -> containingClassName
        else -> name
    }
    val baseFunction = asJava(containingClassName, newName, parameters, isTopLevel)
    return if (hasJvmOverloads()) {
        withJvmOverloads(containingClassName, newName, isTopLevel) ?: listOf(baseFunction)
    } else {
        listOf(baseFunction)
    }
}

internal fun DClasslike.asJava(): DClasslike = when (this) {
    is DClass -> asJava()
    is DEnum -> asJava()
    is DAnnotation -> asJava()
    is DObject -> asJava()
    is DInterface -> asJava()
    else -> throw IllegalArgumentException("$this shouldn't be here")
}

internal fun DClass.asJava(): DClass = copy(
    constructors = constructors
        .filterNot { it.hasJvmSynthetic() }
        .flatMap {
            it.asJava(
                dri.classNames ?: name
            )
        }, // name may not always be valid here, however classNames should always be not null
    functions = functionsInJava(),
    properties = properties
        .filterNot { it.hasJvmSynthetic() }
        .map { it.asJava() },
    classlikes = classlikes.map { it.asJava() },
    generics = generics.map { it.asJava() },
    supertypes = supertypes.mapValues { it.value.map { it.asJava() } },
    modifier = if (modifier.all { (_, v) -> v is KotlinModifier.Empty }) sourceSets.associateWith { JavaModifier.Final }
    else sourceSets.associateWith { modifier.values.first() }
)

internal fun DClass.functionsInJava(): List<DFunction> =
    properties
        .filter { it.jvmField() == null && !it.hasJvmSynthetic() }
        .flatMap { property -> listOfNotNull(property.getter, property.setter) }
        .plus(functions)
        .filterNot { it.hasJvmSynthetic() }
        .flatMap { it.asJava(it.dri.classNames ?: it.name) }

private fun DTypeParameter.asJava(): DTypeParameter = copy(
    variantTypeParameter = variantTypeParameter.withDri(dri.possiblyAsJava()),
    bounds = bounds.map { it.asJava() }
)

private fun Projection.asJava(): Projection = when (this) {
    is Star -> Star
    is Covariance<*> -> copy(inner.asJava())
    is Contravariance<*> -> copy(inner.asJava())
    is Invariance<*> -> copy(inner.asJava())
    is Bound -> asJava()
}

private fun Bound.asJava(): Bound = when (this) {
    is TypeParameter -> copy(dri.possiblyAsJava())
    is GenericTypeConstructor -> copy(
        dri = dri.possiblyAsJava(),
        projections = projections.map { it.asJava() }
    )
    is FunctionalTypeConstructor -> copy(
        dri = dri.possiblyAsJava(),
        projections = projections.map { it.asJava() }
    )
    is TypeAliased -> copy(
        typeAlias = typeAlias.asJava(),
        inner = inner.asJava()
    )
    is Nullable -> copy(inner.asJava())
    is PrimitiveJavaType -> this
    is Void -> this
    is JavaObject -> this
    is Dynamic -> this
    is UnresolvedBound -> this
}

internal fun DEnum.asJava(): DEnum = copy(
    constructors = constructors.flatMap { it.asJava(dri.classNames ?: name) },
    functions = functions
        .plus(
            properties
                .filterNot { it.hasJvmSynthetic() }
                .flatMap { listOf(it.getter, it.setter) }
        )
        .filterNotNull()
        .filterNot { it.hasJvmSynthetic() }
        .flatMap { it.asJava(dri.classNames ?: name) },
    properties = properties
        .filterNot { it.hasJvmSynthetic() }
        .map { it.asJava() },
    classlikes = classlikes.map { it.asJava() },
    supertypes = supertypes.mapValues { it.value.map { it.asJava() } }
//    , entries = entries.map { it.asJava() }
)

internal fun DObject.asJava(): DObject = copy(
    functions = functions
        .plus(
            properties
                .filterNot { it.hasJvmSynthetic() }
                .flatMap { listOf(it.getter, it.setter) }
        )
        .filterNotNull()
        .filterNot { it.hasJvmSynthetic() }
        .flatMap { it.asJava(dri.classNames ?: name.orEmpty()) },
    properties = properties
        .filterNot { it.hasJvmSynthetic() }
        .map { it.asJava() } +
            DProperty(
                name = "INSTANCE",
                modifier = sourceSets.associateWith { JavaModifier.Final },
                dri = dri.copy(callable = Callable("INSTANCE", null, emptyList())),
                documentation = emptyMap(),
                sources = emptyMap(),
                visibility = sourceSets.associateWith {
                    JavaVisibility.Public
                },
                type = GenericTypeConstructor(dri, emptyList()),
                setter = null,
                getter = null,
                sourceSets = sourceSets,
                receiver = null,
                generics = emptyList(),
                expectPresentInSet = expectPresentInSet,
                isExpectActual = false,
                extra = PropertyContainer.withAll(sourceSets.map {
                    mapOf(it to setOf(ExtraModifiers.JavaOnlyModifiers.Static)).toAdditionalModifiers()
                })
            ),
    classlikes = classlikes.map { it.asJava() },
    supertypes = supertypes.mapValues { it.value.map { it.asJava() } }
)

internal fun DInterface.asJava(): DInterface = copy(
    functions = functions
        .plus(
            properties
                .filterNot { it.hasJvmSynthetic() }
                .flatMap { listOf(it.getter, it.setter) }
        )
        .filterNotNull()
        .filterNot { it.hasJvmSynthetic() }
        .flatMap { it.asJava(dri.classNames ?: name) },
    properties = emptyList(),
    classlikes = classlikes.map { it.asJava() }, // TODO: public static final class DefaultImpls with impls for methods
    generics = generics.map { it.asJava() },
    supertypes = supertypes.mapValues { it.value.map { it.asJava() } }
)

internal fun DAnnotation.asJava(): DAnnotation = copy(
    properties = properties.map { it.asJava() },
    constructors = emptyList(),
    classlikes = classlikes.map { it.asJava() }
) // TODO investigate if annotation class can have methods and properties not from constructor

internal fun DParameter.asJava(): DParameter = copy(
    type = type.asJava(),
    name = if (name.isNullOrBlank()) "\$self" else name
)

internal fun Visibility.propertyVisibilityAsJava(): Visibility =
    if (this is JavaVisibility) this
    else JavaVisibility.Private

internal fun String.getAsPrimitive(): JvmPrimitiveType? = org.jetbrains.kotlin.builtins.PrimitiveType.values()
    .find { it.typeFqName.asString() == this }
    ?.let { JvmPrimitiveType.get(it) }

private fun DRI.partialFqName() = packageName?.let { "$it." } + classNames
private fun DRI.possiblyAsJava() = this.partialFqName().mapToJava()?.toDRI(this) ?: this
private fun TypeConstructor.possiblyAsJava(): TypeConstructor = when (this) {
    is GenericTypeConstructor -> copy(dri = this.dri.possiblyAsJava())
    is FunctionalTypeConstructor -> copy(dri = this.dri.possiblyAsJava())
}

private fun String.mapToJava(): ClassId? =
    JavaToKotlinClassMap.mapKotlinToJava(FqName(this).toUnsafe())

internal fun ClassId.toDRI(dri: DRI?): DRI = DRI(
    packageName = packageFqName.asString(),
    classNames = classNames(),
    callable = dri?.callable,//?.asJava(), TODO: check this
    extra = null,
    target = PointingToDeclaration
)

internal fun TypeConstructorWithKind.asJava(): TypeConstructorWithKind =
    TypeConstructorWithKind(
        typeConstructor = typeConstructor.possiblyAsJava(),
        kind = kind.asJava()
    )

internal fun ClassKind.asJava(): ClassKind {
    return when (this) {
        is JavaClassKindTypes -> this
        KotlinClassKindTypes.CLASS -> JavaClassKindTypes.CLASS
        KotlinClassKindTypes.INTERFACE -> JavaClassKindTypes.INTERFACE
        KotlinClassKindTypes.ENUM_CLASS -> JavaClassKindTypes.ENUM_CLASS
        KotlinClassKindTypes.ENUM_ENTRY -> JavaClassKindTypes.ENUM_ENTRY
        KotlinClassKindTypes.ANNOTATION_CLASS -> JavaClassKindTypes.ANNOTATION_CLASS
        KotlinClassKindTypes.OBJECT -> JavaClassKindTypes.CLASS
        else -> throw IllegalStateException("Non exchaustive match while trying to convert $this to Java")
    }
}

private fun PropertyContainer<out Documentable>.mergeAdditionalModifiers(second: SourceSetDependent<Set<ExtraModifiers>>) =
    this[AdditionalModifiers]?.squash(AdditionalModifiers(second)) ?: AdditionalModifiers(second)

private fun AdditionalModifiers.squash(second: AdditionalModifiers) =
    AdditionalModifiers(content + second.content)

internal fun ClassId.classNames(): String =
    shortClassName.identifier + (outerClassId?.classNames()?.let { ".$it" } ?: "")