DefaultPageCreator.kt

package org.jetbrains.dokka.base.translators.documentables

import org.jetbrains.dokka.DokkaConfiguration.DokkaSourceSet
import org.jetbrains.dokka.base.DokkaBaseConfiguration
import org.jetbrains.dokka.base.resolvers.anchors.SymbolAnchorHint
import org.jetbrains.dokka.base.signatures.SignatureProvider
import org.jetbrains.dokka.base.transformers.documentables.CallableExtensions
import org.jetbrains.dokka.base.transformers.documentables.ClashingDriIdentifier
import org.jetbrains.dokka.base.transformers.documentables.InheritorsInfo
import org.jetbrains.dokka.base.transformers.pages.comments.CommentsToContentConverter
import org.jetbrains.dokka.base.transformers.pages.tags.CustomTagContentProvider
import org.jetbrains.dokka.base.translators.documentables.PageContentBuilder.DocumentableContentBuilder
import org.jetbrains.dokka.links.DRI
import org.jetbrains.dokka.model.*
import org.jetbrains.dokka.model.doc.*
import org.jetbrains.dokka.model.properties.PropertyContainer
import org.jetbrains.dokka.model.properties.WithExtraProperties
import org.jetbrains.dokka.pages.*
import org.jetbrains.dokka.utilities.DokkaLogger
import org.jetbrains.kotlin.utils.addToStdlib.safeAs
import kotlin.reflect.KClass
import kotlin.reflect.full.isSubclassOf

internal const val KDOC_TAG_HEADER_LEVEL = 4

private typealias GroupedTags = Map<KClass<out TagWrapper>, List<Pair<DokkaSourceSet?, TagWrapper>>>

private val specialTags: Set<KClass<out TagWrapper>> =
    setOf(Property::class, Description::class, Constructor::class, Param::class, See::class)

open class DefaultPageCreator(
    configuration: DokkaBaseConfiguration?,
    commentsToContentConverter: CommentsToContentConverter,
    signatureProvider: SignatureProvider,
    val logger: DokkaLogger,
    val customTagContentProviders: List<CustomTagContentProvider> = emptyList()
) {
    protected open val contentBuilder = PageContentBuilder(commentsToContentConverter, signatureProvider, logger)

    protected val mergeImplicitExpectActualDeclarations =
        configuration?.mergeImplicitExpectActualDeclarations
            ?: DokkaBaseConfiguration.mergeImplicitExpectActualDeclarationsDefault

    protected val separateInheritedMembers =
        configuration?.separateInheritedMembers ?: DokkaBaseConfiguration.separateInheritedMembersDefault

    open fun pageForModule(m: DModule): ModulePageNode =
        ModulePageNode(m.name.ifEmpty { "<root>" }, contentForModule(m), listOf(m), m.packages.map(::pageForPackage))

    open fun pageForPackage(p: DPackage): PackagePageNode = PackagePageNode(
        p.name, contentForPackage(p), setOf(p.dri), listOf(p),
        if (mergeImplicitExpectActualDeclarations)
            p.classlikes.mergeClashingDocumentable().map(::pageForClasslikes) +
                    p.functions.mergeClashingDocumentable().map(::pageForFunctions) +
                    p.properties.mergeClashingDocumentable().map(::pageForProperties)
        else
            p.classlikes.renameClashingDocumentable().map(::pageForClasslike) +
                    p.functions.renameClashingDocumentable().map(::pageForFunction) +
                    p.properties.mapNotNull(::pageForProperty)
    )

    open fun pageForEnumEntry(e: DEnumEntry): ClasslikePageNode = pageForEnumEntries(listOf(e))

    open fun pageForClasslike(c: DClasslike): ClasslikePageNode = pageForClasslikes(listOf(c))

    open fun pageForEnumEntries(documentables: List<DEnumEntry>): ClasslikePageNode {
        val dri = documentables.dri.also {
            if (it.size != 1) {
                logger.error("Documentable dri should have the same one ${it.first()} inside the one page!")
            }
        }

        val classlikes = documentables.flatMap { it.classlikes }
        val functions = documentables.flatMap { it.filteredFunctions }
        val props = documentables.flatMap { it.filteredProperties }

        val childrenPages = if (mergeImplicitExpectActualDeclarations)
            functions.mergeClashingDocumentable().map(::pageForFunctions) +
                    props.mergeClashingDocumentable().map(::pageForProperties)
        else
            classlikes.renameClashingDocumentable().map(::pageForClasslike) +
                    functions.renameClashingDocumentable().map(::pageForFunction) +
                    props.renameClashingDocumentable().mapNotNull(::pageForProperty)

        return ClasslikePageNode(
            documentables.first().nameAfterClash(), contentForClasslikesAndEntries(documentables), dri, documentables,
            childrenPages
        )
    }

    open fun pageForClasslikes(documentables: List<DClasslike>): ClasslikePageNode {
        val dri = documentables.dri.also {
            if (it.size != 1) {
                logger.error("Documentable dri should have the same one ${it.first()} inside the one page!")
            }
        }

        val constructors = documentables.flatMap { if (it is WithConstructors) it.constructors else emptyList() }

        val classlikes = documentables.flatMap { it.classlikes }
        val functions = documentables.flatMap { it.filteredFunctions }
        val props = documentables.flatMap { it.filteredProperties }
        val entries = documentables.flatMap { if (it is DEnum) it.entries else emptyList() }

        val childrenPages = constructors.map(::pageForFunction) +
                if (mergeImplicitExpectActualDeclarations)
                    classlikes.mergeClashingDocumentable().map(::pageForClasslikes) +
                            functions.mergeClashingDocumentable().map(::pageForFunctions) +
                            props.mergeClashingDocumentable().map(::pageForProperties) +
                            entries.mergeClashingDocumentable().map(::pageForEnumEntries)
                else
                    classlikes.renameClashingDocumentable().map(::pageForClasslike) +
                            functions.renameClashingDocumentable().map(::pageForFunction) +
                            props.renameClashingDocumentable().mapNotNull(::pageForProperty) +
                            entries.renameClashingDocumentable().map(::pageForEnumEntry)


        return ClasslikePageNode(
            documentables.first().nameAfterClash(), contentForClasslikesAndEntries(documentables), dri, documentables,
            childrenPages
        )
    }

    private fun <T> T.toClashedName() where T : Documentable, T : WithExtraProperties<T> =
        (extra[ClashingDriIdentifier]?.value?.joinToString(", ", "[", "]") { it.displayName } ?: "") + name.orEmpty()

    private fun <T : Documentable> List<T>.renameClashingDocumentable(): List<T> =
        groupBy { it.dri }.values.flatMap { elements ->
            if (elements.size == 1) elements else elements.mapNotNull { element ->
                element.renameClashingDocumentable()
            }
        }

    @Suppress("UNCHECKED_CAST")
    private fun <T : Documentable> T.renameClashingDocumentable(): T? = when (this) {
        is DClass -> copy(extra = this.extra + DriClashAwareName(this.toClashedName()))
        is DObject -> copy(extra = this.extra + DriClashAwareName(this.toClashedName()))
        is DAnnotation -> copy(extra = this.extra + DriClashAwareName(this.toClashedName()))
        is DInterface -> copy(extra = this.extra + DriClashAwareName(this.toClashedName()))
        is DEnum -> copy(extra = this.extra + DriClashAwareName(this.toClashedName()))
        is DFunction -> copy(extra = this.extra + DriClashAwareName(this.toClashedName()))
        is DProperty -> copy(extra = this.extra + DriClashAwareName(this.toClashedName()))
        is DTypeAlias -> copy(extra = this.extra + DriClashAwareName(this.toClashedName()))
        else -> null
    } as? T?

    private fun <T : Documentable> List<T>.mergeClashingDocumentable(): List<List<T>> =
        groupBy { it.dri }.values.toList()

    open fun pageForFunction(f: DFunction) =
        MemberPageNode(f.nameAfterClash(), contentForFunction(f), setOf(f.dri), listOf(f))

    open fun pageForFunctions(fs: List<DFunction>): MemberPageNode {
        val dri = fs.dri.also {
            if (it.size != 1) {
                logger.error("Function dri should have the same one ${it.first()} inside the one page!")
            }
        }
        return MemberPageNode(fs.first().nameAfterClash(), contentForMembers(fs), dri, fs)
    }

    open fun pageForProperty(p: DProperty): MemberPageNode? =
        MemberPageNode(p.nameAfterClash(), contentForProperty(p), setOf(p.dri), listOf(p))

    open fun pageForProperties(ps: List<DProperty>): MemberPageNode {
        val dri = ps.dri.also {
            if (it.size != 1) {
                logger.error("Property dri should have the same one ${it.first()} inside the one page!")
            }
        }
        return MemberPageNode(ps.first().nameAfterClash(), contentForMembers(ps), dri, ps)
    }

    private fun <T> T.isInherited(): Boolean where T : Documentable, T : WithExtraProperties<T> =
        sourceSets.all { sourceSet -> extra[InheritedMember]?.isInherited(sourceSet) == true }

    private val WithScope.filteredFunctions: List<DFunction>
        get() = functions.filterNot { it.isInherited() }

    private val WithScope.filteredProperties: List<DProperty>
        get() = properties.filterNot { it.isInherited() }

    private fun <T> Collection<T>.splitInherited(): Pair<List<T>, List<T>> where T : Documentable, T : WithExtraProperties<T> =
        partition { it.isInherited() }

    protected open fun contentForModule(m: DModule) = contentBuilder.contentFor(m) {
        group(kind = ContentKind.Cover) {
            cover(m.name)
            if (contentForDescription(m).isNotEmpty()) {
                sourceSetDependentHint(
                    m.dri,
                    m.sourceSets.toSet(),
                    kind = ContentKind.SourceSetDependentHint,
                    styles = setOf(TextStyle.UnderCoverText)
                ) {
                    +contentForDescription(m)
                }
            }
        }
        +contentForComments(m)

        block(
            "Packages",
            2,
            ContentKind.Packages,
            m.packages,
            m.sourceSets.toSet(),
            needsAnchors = true,
            headers = listOf(
                headers("Name")
            )
        ) {
            val documentations = it.sourceSets.map { platform ->
                it.descriptions[platform]?.also { it.root }
            }
            val haveSameContent =
                documentations.all { it?.root == documentations.firstOrNull()?.root && it?.root != null }

            link(it.name, it.dri)
            if (it.sourceSets.size == 1 || (documentations.isNotEmpty() && haveSameContent)) {
                documentations.first()?.let { firstParagraphComment(kind = ContentKind.Comment, content = it.root) }
            }
        }
    }

    protected open fun contentForPackage(p: DPackage) = contentBuilder.contentFor(p) {
        group(kind = ContentKind.Cover) {
            cover("Package ${p.name}")
            if (contentForDescription(p).isNotEmpty()) {
                sourceSetDependentHint(
                    p.dri,
                    p.sourceSets.toSet(),
                    kind = ContentKind.SourceSetDependentHint,
                    styles = setOf(TextStyle.UnderCoverText)
                ) {
                    +contentForDescription(p)
                }
            }
        }
        group(styles = setOf(ContentStyle.TabbedContent)) {
            +contentForComments(p)
            +contentForScope(p, p.dri, p.sourceSets)
        }
    }

    protected open fun contentForScopes(
        scopes: List<WithScope>,
        sourceSets: Set<DokkaSourceSet>
    ): ContentGroup {
        val types = scopes.flatMap { it.classlikes } + scopes.filterIsInstance<DPackage>().flatMap { it.typealiases }
        val inheritors = scopes.fold(mutableMapOf<DokkaSourceSet, List<DRI>>()) { acc, scope ->
            val inheritorsForScope =
                scope.safeAs<WithExtraProperties<Documentable>>()?.let { it.extra[InheritorsInfo] }?.let { inheritors ->
                    inheritors.value.filter { it.value.isNotEmpty() }
                }.orEmpty()
            inheritorsForScope.forEach { (k, v) ->
                acc.compute(k) { _, value -> value?.plus(v) ?: v }
            }
            acc
        }

        return contentForScope(
            @Suppress("UNCHECKED_CAST")
            (scopes as List<Documentable>).dri,
            sourceSets,
            types,
            scopes.flatMap { it.functions },
            scopes.flatMap { it.properties },
            inheritors
        )
    }

    protected open fun contentForScope(
        s: WithScope,
        dri: DRI,
        sourceSets: Set<DokkaSourceSet>
    ): ContentGroup {
        val types = listOf(
            s.classlikes,
            (s as? DPackage)?.typealiases ?: emptyList()
        ).flatten()
        val inheritors =
            s.safeAs<WithExtraProperties<Documentable>>()?.let { it.extra[InheritorsInfo] }?.let { inheritors ->
                inheritors.value.filter { it.value.isNotEmpty() }
            }.orEmpty()

        return contentForScope(setOf(dri), sourceSets, types, s.functions, s.properties, inheritors)
    }

    protected open fun contentForScope(
        dri: Set<DRI>,
        sourceSets: Set<DokkaSourceSet>,
        types: List<Documentable>,
        functions: List<DFunction>,
        properties: List<DProperty>,
        inheritors: SourceSetDependent<List<DRI>>
    ) = contentBuilder.contentFor(dri, sourceSets) {
        divergentBlock("Types", types, ContentKind.Classlikes, extra = mainExtra + SimpleAttr.header("Types"))
        if (separateInheritedMembers) {
            val (inheritedFunctions, memberFunctions) = functions.splitInherited()
            val (inheritedProperties, memberProperties) = properties.splitInherited()
            propertiesBlock("Properties", memberProperties, sourceSets)
            propertiesBlock("Inherited properties", inheritedProperties, sourceSets)
            functionsBlock("Functions", memberFunctions)
            functionsBlock("Inherited functions", inheritedFunctions)
        } else {
            functionsBlock("Functions", functions)
            propertiesBlock("Properties", properties, sourceSets)
        }
        if (inheritors.values.any()) {
            header(2, "Inheritors") { }
            +ContentTable(
                header = listOf(contentBuilder.contentFor(mainDRI, mainSourcesetData) {
                    text("Name")
                }),
                children = inheritors.entries.flatMap { entry -> entry.value.map { Pair(entry.key, it) } }
                    .groupBy({ it.second }, { it.first }).map { (classlike, platforms) ->
                        val label = classlike.classNames?.substringAfterLast(".") ?: classlike.toString()
                            .also { logger.warn("No class name found for DRI $classlike") }
                        buildGroup(
                            setOf(classlike),
                            platforms.toSet(),
                            ContentKind.Inheritors,
                            extra = mainExtra + SymbolAnchorHint(label, ContentKind.Inheritors)
                        ) {
                            link(label, classlike)
                        }
                    },
                dci = DCI(dri, ContentKind.Inheritors),
                sourceSets = sourceSets.toDisplaySourceSets(),
                style = emptySet(),
                extra = mainExtra + SimpleAttr.header("Inheritors")
            )
        }
    }

    private fun Iterable<DFunction>.sorted() =
        sortedWith(compareBy({ it.name }, { it.parameters.size }, { it.dri.toString() }))

    /**
     * @param documentables a list of [DClasslike] and [DEnumEntry] with the same dri in different sourceSets
     */
    protected open fun contentForClasslikesAndEntries(documentables: List<Documentable>): ContentGroup =
        contentBuilder.contentFor(documentables.dri, documentables.sourceSets) {
            val classlikes = documentables.filterIsInstance<DClasslike>()

            @Suppress("UNCHECKED_CAST")
            val extensions = (classlikes as List<WithExtraProperties<DClasslike>>).flatMap {
                it.extra[CallableExtensions]?.extensions
                    ?.filterIsInstance<Documentable>().orEmpty()
            }

            // Extensions are added to sourceSets since they can be placed outside the sourceSets from classlike
            // Example would be an Interface in common and extension function in jvm
            group(kind = ContentKind.Cover, sourceSets = mainSourcesetData + extensions.sourceSets) {
                cover(documentables.first().name.orEmpty())
                sourceSetDependentHint(documentables.dri, documentables.sourceSets) {
                    documentables.forEach {
                        +buildSignature(it)
                        +contentForDescription(it)
                    }
                }
            }

            group(styles = setOf(ContentStyle.TabbedContent), sourceSets = mainSourcesetData + extensions.sourceSets) {
                +contentForComments(documentables)
                val csWithConstructor = classlikes.filterIsInstance<WithConstructors>()
                if (csWithConstructor.isNotEmpty()) {
                    val constructorsToDocumented = csWithConstructor.flatMap { it.constructors }
                    multiBlock(
                        "Constructors",
                        2,
                        ContentKind.Constructors,
                        constructorsToDocumented.groupBy { it.parameters.map { it.dri } }
                            .map { (_, v) -> v.first().name to v },
                        @Suppress("UNCHECKED_CAST")
                        (csWithConstructor as List<Documentable>).sourceSets,
                        needsAnchors = true,
                        extra = PropertyContainer.empty<ContentNode>() + SimpleAttr.header("Constructors")
                    ) { key, ds ->
                        link(key, ds.first().dri, kind = ContentKind.Main, styles = setOf(ContentStyle.RowTitle))
                        sourceSetDependentHint(
                            ds.dri,
                            ds.sourceSets,
                            kind = ContentKind.SourceSetDependentHint,
                            styles = emptySet(),
                            extra = PropertyContainer.empty<ContentNode>()
                        ) {
                            ds.forEach {
                                +buildSignature(it)
                                contentForBrief(it)
                            }
                        }
                    }
                }
                val csEnum = classlikes.filterIsInstance<DEnum>()
                if (csEnum.isNotEmpty()) {
                    multiBlock(
                        "Entries",
                        2,
                        ContentKind.Classlikes,
                        csEnum.flatMap { it.entries }.groupBy { it.name }.toList(),
                        csEnum.sourceSets,
                        needsSorting = false,
                        needsAnchors = true,
                        extra = mainExtra + SimpleAttr.header("Entries"),
                        styles = emptySet()
                    ) { key, ds ->
                        link(key, ds.first().dri)
                        sourceSetDependentHint(
                            ds.dri,
                            ds.sourceSets,
                            kind = ContentKind.SourceSetDependentHint,
                            extra = PropertyContainer.empty<ContentNode>()
                        ) {
                            ds.forEach {
                                +buildSignature(it)
                                contentForBrief(it)
                            }
                        }
                    }
                }
                +contentForScopes(documentables.filterIsInstance<WithScope>(), documentables.sourceSets)

                divergentBlock(
                    "Extensions",
                    extensions,
                    ContentKind.Extensions,
                    extra = mainExtra + SimpleAttr.header("Extensions")
                )
            }
        }

    @Suppress("UNCHECKED_CAST")
    private inline fun <reified T : TagWrapper> GroupedTags.withTypeUnnamed(): SourceSetDependent<T> =
        (this[T::class] as List<Pair<DokkaSourceSet, T>>?)?.toMap().orEmpty()

    @Suppress("UNCHECKED_CAST")
    private inline fun <reified T : NamedTagWrapper> GroupedTags.withTypeNamed(): Map<String, SourceSetDependent<T>> =
        (this[T::class] as List<Pair<DokkaSourceSet, T>>?)
            ?.groupByTo(linkedMapOf()) { it.second.name }
            ?.mapValues { (_, v) -> v.toMap() }
            .orEmpty()

    private inline fun <reified T : TagWrapper> GroupedTags.isNotEmptyForTag(): Boolean =
        this[T::class]?.isNotEmpty() ?: false

    protected open fun contentForDescription(
        d: Documentable
    ): List<ContentNode> {
        val tags: GroupedTags = d.groupedTags
        val platforms = d.sourceSets.toSet()

        return contentBuilder.contentFor(d, styles = setOf(TextStyle.Block)) {
            val descriptions = d.descriptions
            if (descriptions.any { it.value.root.children.isNotEmpty() }) {
                platforms.forEach { platform ->
                    descriptions[platform]?.also {
                        group(sourceSets = setOf(platform), styles = emptySet()) {
                            comment(it.root)
                        }
                    }
                }
            }

            val customTags = d.customTags
            if (customTags.isNotEmpty()) {
                platforms.forEach { platform ->
                    customTags.forEach { (_, sourceSetTag) ->
                        sourceSetTag[platform]?.let { tag ->
                            customTagContentProviders.filter { it.isApplicable(tag) }.forEach { provider ->
                                group(sourceSets = setOf(platform), styles = setOf(ContentStyle.KDocTag)) {
                                    with(provider) {
                                        contentForDescription(platform, tag)
                                    }
                                }
                            }
                        }
                    }
                }
            }

            val unnamedTags = tags.filterNot { (k, _) -> k.isSubclassOf(NamedTagWrapper::class) || k in specialTags }
                .values.flatten().groupBy { it.first }.mapValues { it.value.map { it.second } }
            if (unnamedTags.isNotEmpty()) {
                platforms.forEach { platform ->
                    unnamedTags[platform]?.let { tags ->
                        if (tags.isNotEmpty()) {
                            tags.groupBy { it::class }.forEach { (_, sameCategoryTags) ->
                                group(sourceSets = setOf(platform), styles = setOf(ContentStyle.KDocTag)) {
                                    header(
                                        level = KDOC_TAG_HEADER_LEVEL,
                                        text = sameCategoryTags.first().toHeaderString(),
                                        styles = setOf()
                                    )
                                    sameCategoryTags.forEach { comment(it.root, styles = setOf()) }
                                }
                            }
                        }
                    }
                }
            }
        }.children
    }

    private fun Set<DokkaSourceSet>.getPossibleFallbackSourcesets(sourceSet: DokkaSourceSet) =
        this.filter { it.sourceSetID in sourceSet.dependentSourceSets }

    private fun <V> Map<DokkaSourceSet, V>.fallback(sourceSets: List<DokkaSourceSet>): V? =
        sourceSets.firstOrNull { it in this.keys }.let { this[it] }

    protected open fun contentForComments(
        d: Documentable,
        isPlatformHintedContent: Boolean = true
    ) = contentForComments(d.dri, d.sourceSets, d.groupedTags, isPlatformHintedContent)

    protected open fun contentForComments(
        d: List<Documentable>,
        isPlatformHintedContent: Boolean = true
    ) = contentForComments(d.first().dri, d.sourceSets, d.groupedTags, isPlatformHintedContent)

    protected open fun contentForComments(
        dri: DRI,
        sourceSets: Set<DokkaSourceSet>,
        tags: GroupedTags,
        isPlatformHintedContent: Boolean = true
    ): List<ContentNode> {

        fun DocumentableContentBuilder.buildContent(
            platforms: Set<DokkaSourceSet>,
            contentBuilder: DocumentableContentBuilder.() -> Unit
        ) = if (isPlatformHintedContent)
            sourceSetDependentHint(
                sourceSets = platforms,
                kind = ContentKind.SourceSetDependentHint,
                block = contentBuilder
            )
        else
            contentBuilder()

        fun DocumentableContentBuilder.contentForParams() {
            if (tags.isNotEmptyForTag<Param>()) {
                val params = tags.withTypeNamed<Param>()
                val availablePlatforms = params.values.flatMap { it.keys }.toSet()

                header(KDOC_TAG_HEADER_LEVEL, "Parameters", kind = ContentKind.Parameters, sourceSets = availablePlatforms)
                group(
                    extra = mainExtra + SimpleAttr.header("Parameters"),
                    styles = setOf(ContentStyle.WithExtraAttributes),
                    sourceSets = availablePlatforms
                ) {
                    buildContent(availablePlatforms) {
                        table(kind = ContentKind.Parameters, sourceSets = availablePlatforms) {
                            availablePlatforms.forEach { platform ->
                                val possibleFallbacks = sourceSets.getPossibleFallbackSourcesets(platform)
                                params.mapNotNull { (_, param) ->
                                    (param[platform] ?: param.fallback(possibleFallbacks))?.let {
                                        row(sourceSets = setOf(platform), kind = ContentKind.Parameters) {
                                            text(
                                                it.name,
                                                kind = ContentKind.Parameters,
                                                styles = mainStyles + ContentStyle.RowTitle
                                            )
                                            if (it.isNotEmpty()) {
                                                comment(it.root)
                                            }
                                        }
                                    }
                                }
                            }
                        }
                    }
                }
            }
        }

        fun DocumentableContentBuilder.contentForSeeAlso() {
            if (tags.isNotEmptyForTag<See>()) {
                val seeAlsoTags = tags.withTypeNamed<See>()
                val availablePlatforms = seeAlsoTags.values.flatMap { it.keys }.toSet()

                header(KDOC_TAG_HEADER_LEVEL, "See also", kind = ContentKind.Comment, sourceSets = availablePlatforms)
                group(
                    extra = mainExtra + SimpleAttr.header("See also"),
                    styles = setOf(ContentStyle.WithExtraAttributes),
                    sourceSets = availablePlatforms
                ) {
                    buildContent(availablePlatforms) {
                        table(kind = ContentKind.Sample) {
                            availablePlatforms.forEach { platform ->
                                val possibleFallbacks = sourceSets.getPossibleFallbackSourcesets(platform)
                                seeAlsoTags.forEach { (_, see) ->
                                    (see[platform] ?: see.fallback(possibleFallbacks))?.let {
                                        row(
                                            sourceSets = setOf(platform),
                                            kind = ContentKind.Comment,
                                            styles = this@group.mainStyles,
                                        ) {
                                            it.address?.let { dri ->
                                                link(
                                                    dri.classNames ?: it.name,
                                                    dri,
                                                    kind = ContentKind.Comment,
                                                    styles = mainStyles + ContentStyle.RowTitle
                                                )
                                            } ?: text(
                                                it.name,
                                                kind = ContentKind.Comment,
                                                styles = mainStyles + ContentStyle.RowTitle
                                            )
                                            if (it.isNotEmpty()) {
                                                comment(it.root)
                                            }
                                        }
                                    }
                                }
                            }
                        }
                    }
                }
            }
        }

        fun DocumentableContentBuilder.contentForThrows() {
            val throws = tags.withTypeNamed<Throws>()
            if (throws.isNotEmpty()) {
                val availablePlatforms = throws.values.flatMap { it.keys }.toSet()

                header(KDOC_TAG_HEADER_LEVEL, "Throws", sourceSets = availablePlatforms)
                buildContent(availablePlatforms) {
                    availablePlatforms.forEach { sourceset ->
                        table(
                            kind = ContentKind.Main,
                            sourceSets = setOf(sourceset),
                            extra = mainExtra + SimpleAttr.header("Throws")
                        ) {
                            throws.entries.forEach { entry ->
                                entry.value[sourceset]?.let { throws ->
                                    row(sourceSets = setOf(sourceset)) {
                                        group(styles = mainStyles + ContentStyle.RowTitle) {
                                            throws.exceptionAddress?.let {
                                                link(text = it.classNames ?: entry.key, address = it)
                                            } ?: text(entry.key)
                                        }
                                        if (throws.isNotEmpty()) {
                                            comment(throws.root)
                                        }
                                    }
                                }
                            }
                        }
                    }
                }
            }
        }

        fun DocumentableContentBuilder.contentForSamples() {
            val samples = tags.withTypeNamed<Sample>()
            if (samples.isNotEmpty()) {
                val availablePlatforms = samples.values.flatMap { it.keys }.toSet()
                header(KDOC_TAG_HEADER_LEVEL, "Samples", kind = ContentKind.Sample, sourceSets = availablePlatforms)
                group(
                    extra = mainExtra + SimpleAttr.header("Samples"),
                    styles = emptySet(),
                    sourceSets = availablePlatforms
                ) {
                    buildContent(availablePlatforms) {
                        availablePlatforms.map { platformData ->
                            val content = samples.filter { it.value.isEmpty() || platformData in it.value }
                            group(
                                sourceSets = setOf(platformData),
                                kind = ContentKind.Sample,
                                styles = setOf(TextStyle.Monospace, ContentStyle.RunnableSample)
                            ) {
                                content.forEach {
                                    text(it.key)
                                }
                            }
                        }
                    }
                }
            }
        }

        return contentBuilder.contentFor(dri, sourceSets) {
            if (tags.isNotEmpty()) {
                contentForSamples()
                contentForSeeAlso()
                contentForParams()
                contentForThrows()
            }
        }.children
    }

    private fun TagWrapper.isNotEmpty() = this.children.isNotEmpty()

    protected open fun DocumentableContentBuilder.contentForBrief(documentable: Documentable) {
        documentable.sourceSets.forEach { sourceSet ->
            documentable.documentation[sourceSet]?.let {
                /*
                    Get description or a tag that holds documentation.
                    This tag can be either property or constructor but constructor tags are handled already in analysis so we
                    only need to keep an eye on property

                    We purposefully ignore all other tags as they should not be visible in brief
                 */
                it.firstMemberOfTypeOrNull<Description>() ?: it.firstMemberOfTypeOrNull<Property>()
                    .takeIf { documentable is DProperty }
            }?.let {
                group(sourceSets = setOf(sourceSet), kind = ContentKind.BriefComment) {
                    if (documentable.hasSeparatePage) createBriefComment(documentable, sourceSet, it)
                    else comment(it.root)
                }
            }
        }
    }

    private fun DocumentableContentBuilder.createBriefComment(
        documentable: Documentable,
        sourceSet: DokkaSourceSet,
        tag: TagWrapper
    ) {
        (documentable as? WithSources)?.documentableLanguage(sourceSet)?.let {
            when (it) {
                DocumentableLanguage.KOTLIN -> firstParagraphComment(tag.root)
                DocumentableLanguage.JAVA -> firstSentenceComment(tag.root)
            }
        } ?: firstParagraphComment(tag.root)
    }

    protected open fun contentForFunction(f: DFunction) = contentForMember(f)

    protected open fun contentForProperty(p: DProperty) = contentForMember(p)

    protected open fun contentForMember(d: Documentable) = contentForMembers(listOf(d))

    protected open fun contentForMembers(doumentables: List<Documentable>) =
        contentBuilder.contentFor(doumentables.dri, doumentables.sourceSets) {
            group(kind = ContentKind.Cover) {
                cover(doumentables.first().name.orEmpty())
            }
            divergentGroup(ContentDivergentGroup.GroupID("member")) {
                doumentables.forEach { d ->
                    instance(setOf(d.dri), d.sourceSets) {
                        divergent {
                            +buildSignature(d)
                        }
                        after {
                            +contentForDescription(d)
                            +contentForComments(d, isPlatformHintedContent = false)
                        }
                    }
                }
            }
        }

    private fun DocumentableContentBuilder.functionsBlock(name: String, list: Collection<DFunction>) = divergentBlock(
        name,
        list.sorted(),
        ContentKind.Functions,
        extra = mainExtra + SimpleAttr.header(name)
    )

    private fun DocumentableContentBuilder.propertiesBlock(
        name: String,
        list: Collection<DProperty>,
        sourceSets: Set<DokkaSourceSet>
    ) {
        multiBlock(
            name,
            2,
            ContentKind.Properties,
            list.groupBy { it.name }.toList(),
            sourceSets,
            needsAnchors = true,
            extra = mainExtra + SimpleAttr.header(name),
            headers = listOf(
                headers("Name", "Summary")
            )
        ) { key, props ->
            link(
                text = key,
                address = props.first().dri,
                kind = ContentKind.Main,
                styles = setOf(ContentStyle.RowTitle)
            )
            sourceSetDependentHint(props.dri, props.sourceSets, kind = ContentKind.SourceSetDependentHint) {
                props.forEach {
                    +buildSignature(it)
                    contentForBrief(it)
                }
            }
        }
    }

    protected open fun DocumentableContentBuilder.divergentBlock(
        name: String,
        collection: Collection<Documentable>,
        kind: ContentKind,
        extra: PropertyContainer<ContentNode> = mainExtra
    ) {
        if (collection.any()) {
            header(2, name, kind = kind)
            table(kind, extra = extra, styles = emptySet()) {
                header {
                    group { text("Name") }
                    group { text("Summary") }
                }
                collection
                    .groupBy { it.name } // This groupBy should probably use LocationProvider
                    // This hacks displaying actual typealias signatures along classlike ones
                    .mapValues { if (it.value.any { it is DClasslike }) it.value.filter { it !is DTypeAlias } else it.value }
                    .toSortedMap(compareBy(nullsLast(String.CASE_INSENSITIVE_ORDER)) { it })
                    .forEach { (elementName, elements) -> // This groupBy should probably use LocationProvider
                        row(
                            dri = elements.map { it.dri }.toSet(),
                            sourceSets = elements.flatMap { it.sourceSets }.toSet(),
                            kind = kind,
                            styles = emptySet(),
                            extra = elementName?.let { name -> extra + SymbolAnchorHint(name, kind) } ?: extra
                        ) {
                            link(
                                text = elementName.orEmpty(),
                                address = elements.first().dri,
                                kind = kind,
                                styles = setOf(ContentStyle.RowTitle),
                                sourceSets = elements.sourceSets.toSet(),
                                extra = extra
                            )
                            divergentGroup(
                                ContentDivergentGroup.GroupID(name),
                                elements.map { it.dri }.toSet(),
                                kind = kind,
                                extra = extra
                            ) {
                                elements.map {
                                    instance(
                                        setOf(it.dri),
                                        it.sourceSets.toSet(),
                                        extra = PropertyContainer.withAll(SymbolAnchorHint(it.name ?: "", kind))
                                    ) {
                                        divergent(extra = PropertyContainer.empty()) {
                                            group {
                                                +buildSignature(it)
                                            }
                                        }
                                        after(extra = PropertyContainer.empty()) {
                                            contentForBrief(it)
                                            contentForCustomTagsBrief(it)
                                        }
                                    }
                                }
                            }
                        }
                    }
            }
        }
    }

    private fun DocumentableContentBuilder.contentForCustomTagsBrief(documentable: Documentable) {
        val customTags = documentable.customTags
        if (customTags.isEmpty()) return

        documentable.sourceSets.forEach { sourceSet ->
            customTags.forEach { (_, sourceSetTag) ->
                sourceSetTag[sourceSet]?.let { tag ->
                    customTagContentProviders.filter { it.isApplicable(tag) }.forEach { provider ->
                        with(provider) {
                            contentForBrief(sourceSet, tag)
                        }
                    }
                }
            }
        }
    }

    protected open fun TagWrapper.toHeaderString() = this.javaClass.toGenericString().split('.').last()

    private val List<Documentable>.sourceSets: Set<DokkaSourceSet>
        get() = flatMap { it.sourceSets }.toSet()

    private val List<Documentable>.dri: Set<DRI>
        get() = map { it.dri }.toSet()

    private val Documentable.groupedTags: GroupedTags
        get() = documentation.flatMap { (pd, doc) ->
            doc.children.map { pd to it }.toList()
        }.groupBy { it.second::class }

    private val List<Documentable>.groupedTags: GroupedTags
        get() = this.flatMap {
            it.documentation.flatMap { (pd, doc) ->
                doc.children.map { pd to it }.toList()
            }
        }.groupBy { it.second::class }

    private val Documentable.descriptions: SourceSetDependent<Description>
        get() = groupedTags.withTypeUnnamed()

    private val Documentable.customTags: Map<String, SourceSetDependent<CustomTagWrapper>>
        get() = groupedTags.withTypeNamed()

    private val Documentable.hasSeparatePage: Boolean
        get() = this !is DTypeAlias

    @Suppress("UNCHECKED_CAST")
    private fun <T : Documentable> T.nameAfterClash(): String =
        ((this as? WithExtraProperties<out Documentable>)?.extra?.get(DriClashAwareName)?.value ?: name).orEmpty()
}