Improve versioning plugin (#2104)

- support for single module projects
- version navigator is on all pages
- dropdown arrow for version navigator

11 files changed, 437 insertions, 146 deletions

diff --git a/plugins/versioning/src/main/kotlin/versioning/DefaultPreviousDocumentationCopyPostAction.kt b/plugins/versioning/src/main/kotlin/versioning/DefaultPreviousDocumentationCopyPostAction.kt
new file mode 100644
index 00000000..6ab81d31
--- /dev/null
+++ b/plugins/versioning/src/main/kotlin/versioning/DefaultPreviousDocumentationCopyPostAction.kt
@@ -0,0 +1,54 @@
+package org.jetbrains.dokka.versioning
+
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.coroutineScope
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.runBlocking
+import org.jetbrains.dokka.renderers.PostAction
+import org.jetbrains.dokka.plugability.DokkaContext
+import org.jetbrains.dokka.plugability.plugin
+import org.jetbrains.dokka.plugability.query
+import org.jetbrains.dokka.plugability.querySingle
+import org.jetbrains.dokka.templates.TemplateProcessingStrategy
+import org.jetbrains.dokka.templates.TemplatingPlugin
+import java.io.File
+
+class DefaultPreviousDocumentationCopyPostAction(private val context: DokkaContext) : PostAction {
+    private val versioningStorage by lazy { context.plugin<VersioningPlugin>().querySingle { versioningStorage } }
+    private val processingStrategies: List<TemplateProcessingStrategy> =
+        context.plugin<TemplatingPlugin>().query { templateProcessingStrategy }
+
+    override fun invoke() {
+        versioningStorage.createVersionFile()
+        versioningStorage.previousVersions.forEach { (_, dirs) -> copyVersion(dirs.src, dirs.dst) }
+    }
+
+    private fun copyVersion(versionRoot: File, targetParent: File) {
+        targetParent.apply { mkdirs() }
+        val ignoreDir = versionRoot.resolve(VersioningConfiguration.OLDER_VERSIONS_DIR)
+        runBlocking(Dispatchers.Default) {
+            coroutineScope {
+                versionRoot.listFiles().orEmpty()
+                    .filter { it.absolutePath != ignoreDir.absolutePath }
+                    .forEach { versionRootContent ->
+                        launch {
+                            processRecursively(versionRootContent, targetParent)
+                        }
+                    }
+            }
+        }
+    }
+
+    private fun processRecursively(versionRootContent: File, targetParent: File) {
+        if (versionRootContent.isDirectory) {
+            val target = targetParent.resolve(versionRootContent.name).also { it.mkdir() }
+            versionRootContent.listFiles()?.forEach {
+                processRecursively(it, target)
+            }
+        } else if (versionRootContent.extension == "html") processingStrategies.first {
+            it.process(versionRootContent, targetParent.resolve(versionRootContent.name), null)
+        } else {
+            versionRootContent.copyTo(targetParent.resolve(versionRootContent.name), overwrite = true)
+        }
+    }
+}
\ No newline at end of file
diff --git a/plugins/versioning/src/main/kotlin/versioning/ReplaceVersionCommandConsumer.kt b/plugins/versioning/src/main/kotlin/versioning/ReplaceVersionCommandConsumer.kt
index 2577b2da..ea524c52 100644
--- a/plugins/versioning/src/main/kotlin/versioning/ReplaceVersionCommandConsumer.kt
+++ b/plugins/versioning/src/main/kotlin/versioning/ReplaceVersionCommandConsumer.kt
@@ -8,6 +8,7 @@ import org.jetbrains.dokka.base.renderers.html.command.consumers.ImmediateResolu
 import org.jetbrains.dokka.base.renderers.html.templateCommandFor
 import org.jetbrains.dokka.base.templating.Command
 import org.jetbrains.dokka.base.templating.ImmediateHtmlCommandConsumer
+import org.jetbrains.dokka.base.templating.ReplaceVersionsCommand
 import org.jetbrains.dokka.plugability.DokkaContext
 import org.jetbrains.dokka.plugability.plugin
 import org.jetbrains.dokka.plugability.querySingle
@@ -16,6 +17,8 @@ class ReplaceVersionCommandConsumer(context: DokkaContext) : ImmediateHtmlComman
 
     private val versionsNavigationCreator =
         context.plugin<VersioningPlugin>().querySingle { versionsNavigationCreator }
+    private val versioningStorage =
+        context.plugin<VersioningPlugin>().querySingle { versioningStorage }
 
     override fun canProcess(command: Command) = command is ReplaceVersionsCommand
 
@@ -27,7 +30,7 @@ class ReplaceVersionCommandConsumer(context: DokkaContext) : ImmediateHtmlComman
         command as ReplaceVersionsCommand
         templateCommandFor(command, tagConsumer).visit {
             unsafe {
-                +versionsNavigationCreator()
+                +versionsNavigationCreator(versioningStorage.currentVersion.dir.resolve(command.location))
             }
         }
     }
@@ -36,10 +39,12 @@ class ReplaceVersionCommandConsumer(context: DokkaContext) : ImmediateHtmlComman
         command: Command,
         block: TemplateBlock,
         tagConsumer: ImmediateResolutionTagConsumer<R>
-    ): R =
-        templateCommandFor(command, tagConsumer).visitAndFinalize(tagConsumer) {
+    ): R {
+        command as ReplaceVersionsCommand
+        return templateCommandFor(command, tagConsumer).visitAndFinalize(tagConsumer) {
             unsafe {
-                +versionsNavigationCreator()
+                +versionsNavigationCreator(versioningStorage.currentVersion.dir.resolve(command.location))
             }
         }
+    }
 }
\ No newline at end of file
diff --git a/plugins/versioning/src/main/kotlin/versioning/ReplaceVersionsCommand.kt b/plugins/versioning/src/main/kotlin/versioning/ReplaceVersionsCommand.kt
index 2d2c8e36..728eac09 100644
--- a/plugins/versioning/src/main/kotlin/versioning/ReplaceVersionsCommand.kt
+++ b/plugins/versioning/src/main/kotlin/versioning/ReplaceVersionsCommand.kt
@@ -2,6 +2,7 @@ package org.jetbrains.dokka.versioning
 
 
 import org.jetbrains.dokka.base.templating.Command
+import org.jetbrains.dokka.base.templating.ReplaceVersionsCommand
 import org.jetbrains.dokka.plugability.DokkaContext
 import org.jetbrains.dokka.plugability.plugin
 import org.jetbrains.dokka.plugability.querySingle
@@ -9,8 +10,6 @@ import org.jetbrains.dokka.templates.CommandHandler
 import org.jsoup.nodes.Element
 import java.io.File
 
-object ReplaceVersionsCommand : Command
-
 class ReplaceVersionCommandHandler(context: DokkaContext) : CommandHandler {
 
     val versionsNavigationCreator by lazy {
diff --git a/plugins/versioning/src/main/kotlin/versioning/VersioningConfiguration.kt b/plugins/versioning/src/main/kotlin/versioning/VersioningConfiguration.kt
index f5c69cf4..56c72257 100644
--- a/plugins/versioning/src/main/kotlin/versioning/VersioningConfiguration.kt
+++ b/plugins/versioning/src/main/kotlin/versioning/VersioningConfiguration.kt
@@ -9,6 +9,7 @@ data class VersioningConfiguration(
     var olderVersions: List<File>? = defaultOlderVersions,
     var versionsOrdering: List<String>? = defaultVersionsOrdering,
     var version: String? = defaultVersion,
+    var renderVersionsNavigationOnAllPages: Boolean? = defaultRenderVersionsNavigationOnAllPages
 ) : ConfigurableBlock {
     internal fun versionFromConfigurationOrModule(dokkaContext: DokkaContext): String =
         version ?: dokkaContext.configuration.moduleVersion ?: "1.0"
@@ -25,5 +26,9 @@ data class VersioningConfiguration(
         val defaultOlderVersions: List<File>? = null
         val defaultVersionsOrdering: List<String>? = null
         val defaultVersion = null
+        val defaultRenderVersionsNavigationOnAllPages = true
+
+        const val OLDER_VERSIONS_DIR = "older"
+        const val VERSIONS_FILE = "version.json"
     }
 }
\ No newline at end of file
diff --git a/plugins/versioning/src/main/kotlin/versioning/VersioningHandler.kt b/plugins/versioning/src/main/kotlin/versioning/VersioningHandler.kt
deleted file mode 100644
index 1cc584b7..00000000
--- a/plugins/versioning/src/main/kotlin/versioning/VersioningHandler.kt
+++ /dev/null
@@ -1,104 +0,0 @@
-package org.jetbrains.dokka.versioning
-
-import com.fasterxml.jackson.annotation.JsonProperty
-import com.fasterxml.jackson.databind.ObjectMapper
-import com.fasterxml.jackson.module.kotlin.readValue
-import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.coroutineScope
-import kotlinx.coroutines.launch
-import kotlinx.coroutines.runBlocking
-import org.jetbrains.dokka.plugability.DokkaContext
-import org.jetbrains.dokka.plugability.configuration
-import org.jetbrains.dokka.plugability.plugin
-import org.jetbrains.dokka.plugability.query
-import org.jetbrains.dokka.templates.TemplateProcessingStrategy
-import org.jetbrains.dokka.templates.TemplatingPlugin
-import java.io.File
-
-interface VersioningHandler : () -> Unit {
-    fun getVersions(): Map<VersionId, File>
-    fun currentVersion(): File?
-}
-
-typealias VersionId = String
-
-class DefaultVersioningHandler(val context: DokkaContext) : VersioningHandler {
-
-    private val mapper = ObjectMapper()
-
-    private lateinit var versions: Map<VersionId, File>
-
-    private val processingStrategies: List<TemplateProcessingStrategy> =
-        context.plugin<TemplatingPlugin>().query { templateProcessingStrategy }
-
-    private val configuration = configuration<VersioningPlugin, VersioningConfiguration>(context)
-
-    override fun getVersions() = versions
-
-    override fun currentVersion() = configuration?.let { versionsConfiguration ->
-        versions[versionsConfiguration.versionFromConfigurationOrModule(context)]
-    }
-
-    override fun invoke() {
-        configuration?.let { versionsConfiguration ->
-            versions =
-                mapOf(versionsConfiguration.versionFromConfigurationOrModule(context) to context.configuration.outputDir)
-            handlePreviousVersions(versionsConfiguration.allOlderVersions(), context.configuration.outputDir)
-            mapper.writeValue(
-                context.configuration.outputDir.resolve(VERSIONS_FILE),
-                Version(versionsConfiguration.versionFromConfigurationOrModule(context))
-            )
-        }
-    }
-
-    private fun handlePreviousVersions(olderVersions: List<File>, output: File): Map<String, File> {
-        return versionsFrom(olderVersions)
-            .also { fetched ->
-                versions = versions + fetched.map { (key, _) ->
-                    key to output.resolve(OLDER_VERSIONS_DIR).resolve(key)
-                }.toMap()
-            }
-            .onEach { (version, path) -> copyVersion(version, path, output) }.toMap()
-    }
-
-    private fun versionsFrom(olderVersions: List<File>) =
-        olderVersions.mapNotNull { versionDir ->
-            versionDir.listFiles { _, name -> name == VERSIONS_FILE }?.firstOrNull()?.let { file ->
-                val versionsContent = mapper.readValue<Version>(file)
-                Pair(versionsContent.version, versionDir)
-            }.also {
-                if (it == null) context.logger.warn("Failed to find versions file named $VERSIONS_FILE in $versionDir")
-            }
-        }
-
-    private fun copyVersion(version: VersionId, versionRoot: File, output: File) {
-        val targetParent = output.resolve(OLDER_VERSIONS_DIR).resolve(version).apply { mkdirs() }
-        val olderDirs = versionRoot.resolve(OLDER_VERSIONS_DIR)
-        runBlocking(Dispatchers.Default) {
-            coroutineScope {
-                versionRoot.listFiles().orEmpty()
-                    .filter { it.absolutePath != olderDirs.absolutePath }
-                    .forEach { versionRootContent ->
-                        launch {
-                            if (versionRootContent.isDirectory) versionRootContent.copyRecursively(
-                                targetParent.resolve(versionRootContent.name),
-                                overwrite = true
-                            )
-                            else processingStrategies.first {
-                                it.process(versionRootContent, targetParent.resolve(versionRootContent.name), null)
-                            }
-                        }
-                    }
-            }
-        }
-    }
-
-    private data class Version(
-        @JsonProperty("version") val version: String,
-    )
-
-    companion object {
-        private const val OLDER_VERSIONS_DIR = "older"
-        private const val VERSIONS_FILE = "version.json"
-    }
-}
diff --git a/plugins/versioning/src/main/kotlin/versioning/VersioningPlugin.kt b/plugins/versioning/src/main/kotlin/versioning/VersioningPlugin.kt
index 9c20a128..e4e8bbae 100644
--- a/plugins/versioning/src/main/kotlin/versioning/VersioningPlugin.kt
+++ b/plugins/versioning/src/main/kotlin/versioning/VersioningPlugin.kt
@@ -1,5 +1,6 @@
 package org.jetbrains.dokka.versioning
 
+import org.jetbrains.dokka.CoreExtensions.postActions
 import org.jetbrains.dokka.base.DokkaBase
 import org.jetbrains.dokka.plugability.DokkaPlugin
 import org.jetbrains.dokka.plugability.configuration
@@ -7,27 +8,36 @@ import org.jetbrains.dokka.templates.TemplatingPlugin
 
 class VersioningPlugin : DokkaPlugin() {
 
-    val versioningHandler by extensionPoint<VersioningHandler>()
+    val versioningStorage by extensionPoint<VersioningStorage>()
     val versionsNavigationCreator by extensionPoint<VersionsNavigationCreator>()
     val versionsOrdering by extensionPoint<VersionsOrdering>()
 
     private val dokkaBase by lazy { plugin<DokkaBase>() }
     private val templatingPlugin by lazy { plugin<TemplatingPlugin>() }
 
-    val defaultVersioningHandler by extending {
-        versioningHandler providing ::DefaultVersioningHandler
+    val defaultVersioningStorage by extending {
+        versioningStorage providing ::DefaultVersioningStorage
     }
     val defaultVersioningNavigationCreator by extending {
         versionsNavigationCreator providing ::HtmlVersionsNavigationCreator
     }
     val replaceVersionCommandHandler by extending {
-        templatingPlugin.directiveBasedCommandHandlers providing ::ReplaceVersionCommandHandler
+        templatingPlugin.directiveBasedCommandHandlers providing ::ReplaceVersionCommandHandler override templatingPlugin.replaceVersionCommandHandler
     }
     val resolveLinkConsumer by extending {
-        dokkaBase.immediateHtmlCommandConsumer providing ::ReplaceVersionCommandConsumer
+        dokkaBase.immediateHtmlCommandConsumer providing ::ReplaceVersionCommandConsumer override dokkaBase.replaceVersionConsumer
     }
     val cssStyleInstaller by extending {
-        dokkaBase.htmlPreprocessors with MultiModuleStylesInstaller order { after(dokkaBase.assetsInstaller) }
+        dokkaBase.htmlPreprocessors providing ::MultiModuleStylesInstaller order {
+            after(dokkaBase.assetsInstaller)
+            before(dokkaBase.customResourceInstaller)
+        }
+    }
+    val notFoundPageInstaller by extending {
+        dokkaBase.htmlPreprocessors providing ::NotFoundPageInstaller order {
+            after(dokkaBase.assetsInstaller)
+            before(dokkaBase.customResourceInstaller)
+        } applyIf { !delayTemplateSubstitution }
     }
     val versionsDefaultOrdering by extending {
         versionsOrdering providing { ctx ->
@@ -36,4 +46,7 @@ class VersioningPlugin : DokkaPlugin() {
             } ?: SemVerVersionOrdering()
         }
     }
+    val previousDocumentationCopyPostAction by extending {
+        postActions providing ::DefaultPreviousDocumentationCopyPostAction applyIf { !delayTemplateSubstitution }
+    }
 }
\ No newline at end of file
diff --git a/plugins/versioning/src/main/kotlin/versioning/VersioningStorage.kt b/plugins/versioning/src/main/kotlin/versioning/VersioningStorage.kt
new file mode 100644
index 00000000..6e1dd7ca
--- /dev/null
+++ b/plugins/versioning/src/main/kotlin/versioning/VersioningStorage.kt
@@ -0,0 +1,65 @@
+package org.jetbrains.dokka.versioning
+
+import com.fasterxml.jackson.annotation.JsonProperty
+import com.fasterxml.jackson.databind.ObjectMapper
+import com.fasterxml.jackson.module.kotlin.readValue
+import org.jetbrains.dokka.plugability.DokkaContext
+import org.jetbrains.dokka.plugability.configuration
+import java.io.File
+
+data class VersionDirs(val src: File, val dst: File)
+data class CurrentVersion(val name: String, val dir: File)
+
+interface VersioningStorage {
+    val previousVersions: Map<VersionId, VersionDirs>
+    val currentVersion: CurrentVersion
+    fun createVersionFile()
+}
+
+typealias VersionId = String
+
+class DefaultVersioningStorage(val context: DokkaContext) : VersioningStorage {
+
+    private val mapper = ObjectMapper()
+    private val configuration = configuration<VersioningPlugin, VersioningConfiguration>(context)
+
+    override val previousVersions: Map<VersionId, VersionDirs> by lazy {
+        configuration?.let { versionsConfiguration ->
+            getPreviousVersions(versionsConfiguration.allOlderVersions(), context.configuration.outputDir)
+        } ?: emptyMap()
+    }
+
+    override val currentVersion: CurrentVersion by lazy {
+        configuration?.let { versionsConfiguration ->
+            CurrentVersion(versionsConfiguration.versionFromConfigurationOrModule(context),
+                context.configuration.outputDir)
+        }?: CurrentVersion(context.configuration.moduleVersion.orEmpty(), context.configuration.outputDir)
+    }
+
+    override fun createVersionFile() {
+        mapper.writeValue(
+            currentVersion.dir.resolve(VersioningConfiguration.VERSIONS_FILE),
+            Version(currentVersion.name)
+        )
+    }
+
+    private fun getPreviousVersions(olderVersions: List<File>, output: File): Map<String, VersionDirs> =
+        versionsFrom(olderVersions).associate { (key, srcDir) ->
+            key to VersionDirs(srcDir, output.resolve(VersioningConfiguration.OLDER_VERSIONS_DIR).resolve(key))
+        }
+
+    private fun versionsFrom(olderVersions: List<File>) =
+        olderVersions.mapNotNull { versionDir ->
+            versionDir.listFiles { _, name -> name == VersioningConfiguration.VERSIONS_FILE }?.firstOrNull()
+                ?.let { file ->
+                    val versionsContent = mapper.readValue<Version>(file)
+                    Pair(versionsContent.version, versionDir)
+                }.also {
+                    if (it == null) context.logger.warn("Failed to find versions file named ${VersioningConfiguration.VERSIONS_FILE} in $versionDir")
+                }
+        }
+
+    private data class Version(
+        @JsonProperty("version") val version: String,
+    )
+}
diff --git a/plugins/versioning/src/main/kotlin/versioning/VersionsNavigationCreator.kt b/plugins/versioning/src/main/kotlin/versioning/VersionsNavigationCreator.kt
index 76653d47..876b3ccf 100644
--- a/plugins/versioning/src/main/kotlin/versioning/VersionsNavigationCreator.kt
+++ b/plugins/versioning/src/main/kotlin/versioning/VersionsNavigationCreator.kt
@@ -1,53 +1,86 @@
 package org.jetbrains.dokka.versioning
 
 import kotlinx.html.a
-import kotlinx.html.button
 import kotlinx.html.div
-import kotlinx.html.i
 import kotlinx.html.stream.appendHTML
+import org.jetbrains.dokka.base.renderers.html.strike
 import org.jetbrains.dokka.plugability.DokkaContext
+import org.jetbrains.dokka.plugability.configuration
 import org.jetbrains.dokka.plugability.plugin
 import org.jetbrains.dokka.plugability.querySingle
+import org.jetbrains.dokka.utilities.urlEncoded
 import java.io.File
-import java.nio.file.Files.isDirectory
-import java.nio.file.Path
 
 interface VersionsNavigationCreator {
-    operator fun invoke(): String
     operator fun invoke(output: File): String
 }
 
-class HtmlVersionsNavigationCreator(val context: DokkaContext) : VersionsNavigationCreator {
+class HtmlVersionsNavigationCreator(private val context: DokkaContext) : VersionsNavigationCreator {
 
-    private val versioningHandler by lazy { context.plugin<VersioningPlugin>().querySingle { versioningHandler } }
+    private val versioningStorage by lazy { context.plugin<VersioningPlugin>().querySingle { versioningStorage } }
 
     private val versionsOrdering by lazy { context.plugin<VersioningPlugin>().querySingle { versionsOrdering } }
 
-    override fun invoke(): String =
-        versioningHandler.currentVersion()?.let { invoke(it) }.orEmpty()
+    private val isOnlyOnRootPage =
+        configuration<VersioningPlugin, VersioningConfiguration>(context)?.renderVersionsNavigationOnAllPages == false
+
+    private val versions: Map<VersionId, File> by lazy {
+        versioningStorage.previousVersions.map { (k, v) -> k to v.dst }.toMap() +
+                (versioningStorage.currentVersion.name to versioningStorage.currentVersion.dir)
+    }
 
     override fun invoke(output: File): String {
+        if (versions.size == 1) {
+            return versioningStorage.currentVersion.name
+        }
         val position = output.takeIf { it.isDirectory } ?: output.parentFile
-        return versioningHandler.getVersions()
+        if (isOnlyOnRootPage) {
+            getActiveVersion(position)?.takeIf {
+                it.value == versioningStorage.currentVersion.dir
+                        && it.value != position
+            }?.also { return@invoke it.key }
+        }
+        return versions
             .let { versions -> versionsOrdering.order(versions.keys.toList()).map { it to versions[it] } }
             .takeIf { it.isNotEmpty() }
-            ?.let { versions ->
+            ?.let { orderedVersions ->
                 StringBuilder().appendHTML().div(classes = "versions-dropdown") {
-                    button(classes = "versions-dropdown-button") {
-                        versions.first { (_, versionLocation) -> versionLocation?.absolutePath == position.absolutePath }
-                            .let { (version, _) ->
-                                text(version)
-                            }
-                        i(classes = "fa fa-caret-down")
+                    val activeVersion = getActiveVersion(position)
+                    val relativePosition: String  = activeVersion?.value?.let { output.toRelativeString(it) } ?: "index.html"
+                    div(classes = "versions-dropdown-button") {
+                        activeVersion?.key?.let { text(it) }
                     }
                     div(classes = "versions-dropdown-data") {
-                        versions.forEach { (version, path) ->
-                            a(href = path?.resolve("index.html")?.toRelativeString(position)) {
-                                text(version)
+                        orderedVersions.forEach { (version, path) ->
+                            if (version == activeVersion?.key) {
+                                a(href = output.name) { text(version) }
+                            } else {
+                                val isExistsFile =
+                                    if (version == versioningStorage.currentVersion.name)
+                                        path?.resolve(relativePosition)?.exists() == true
+                                    else
+                                        versioningStorage.previousVersions[version]?.src?.resolve(relativePosition)
+                                            ?.exists() == true
+
+                                val absolutePath =
+                                    if (isExistsFile)
+                                        path?.resolve(relativePosition)
+                                    else
+                                        versioningStorage.currentVersion.dir.resolve("not-found-version.html")
+
+                                a(href = absolutePath?.toRelativeString(position) +
+                                        if (!isExistsFile) "?v=" + version.urlEncoded() else "") {
+                                        text(version)
+                                }
                             }
                         }
                     }
                 }.toString()
             }.orEmpty()
     }
+
+    private fun getActiveVersion(position: File) =
+        versions.minByOrNull { (_, versionLocation) ->
+            versionLocation.let { position.toRelativeString(it).length }
+        }
 }
\ No newline at end of file
diff --git a/plugins/versioning/src/main/kotlin/versioning/htmlPreprocessors.kt b/plugins/versioning/src/main/kotlin/versioning/htmlPreprocessors.kt
index 5852ba9e..94400898 100644
--- a/plugins/versioning/src/main/kotlin/versioning/htmlPreprocessors.kt
+++ b/plugins/versioning/src/main/kotlin/versioning/htmlPreprocessors.kt
@@ -3,22 +3,36 @@ package org.jetbrains.dokka.versioning
 import org.jetbrains.dokka.pages.RendererSpecificResourcePage
 import org.jetbrains.dokka.pages.RenderingStrategy
 import org.jetbrains.dokka.pages.RootPageNode
+import org.jetbrains.dokka.plugability.DokkaContext
 import org.jetbrains.dokka.transformers.pages.PageTransformer
 
-object MultiModuleStylesInstaller : PageTransformer {
+class MultiModuleStylesInstaller(private val dokkaContext: DokkaContext) : PageTransformer {
     private val stylesPages = listOf(
         "styles/multimodule.css",
     )
 
     override fun invoke(input: RootPageNode): RootPageNode =
-        input.modified(
-            children = input.children + stylesPages.toRenderSpecificResourcePage()
-        ).transformContentPagesTree {
+        input.let { root ->
+            if (dokkaContext.configuration.delayTemplateSubstitution) root
+            else root.modified(children = input.children + stylesPages.toRenderSpecificResourcePage())
+        }.transformContentPagesTree {
             it.modified(
                 embeddedResources = it.embeddedResources + stylesPages
             )
         }
 }
 
+class NotFoundPageInstaller(private val dokkaContext: DokkaContext) : PageTransformer {
+    private val notFoundPage = listOf(
+        "not-found-version.html",
+    )
+
+    override fun invoke(input: RootPageNode): RootPageNode =
+        input.let { root ->
+            if (dokkaContext.configuration.delayTemplateSubstitution) root
+            else root.modified(children = input.children + notFoundPage.toRenderSpecificResourcePage())
+        }
+}
+
 private fun List<String>.toRenderSpecificResourcePage(): List<RendererSpecificResourcePage> =
     map { RendererSpecificResourcePage(it, emptyList(), RenderingStrategy.Copy("/dokka/$it")) }
diff --git a/plugins/versioning/src/main/resources/dokka/not-found-version.html b/plugins/versioning/src/main/resources/dokka/not-found-version.html
new file mode 100644
index 00000000..259a4893
--- /dev/null
+++ b/plugins/versioning/src/main/resources/dokka/not-found-version.html
@@ -0,0 +1,189 @@
+<!DOCTYPE html>
+<html>
+<head>
+    <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
+    <title>Unavailable page</title>
+    <style>
+.article-content h1._big {
+    text-transform: uppercase;
+    color: #161616;
+    font-size: 54px;
+    font-weight: 800;
+    line-height: 45px;
+}
+.sub-title {
+    margin-bottom: 40px;
+    font-size: 20px;
+    font-weight: 400;
+    line-height: 30px;
+}
+.margin-top-vertical-unit-half {
+    margin-top: 25px;
+}
+.wt-row_size_m {
+    --wt-horizontal-layout-gutter: 16px;
+}
+.article-content {
+    color: #343434;
+    font-family: system-ui, -apple-system, BlinkMacSystemFont, Segoe UI, Roboto, Oxygen, Ubuntu, Cantarell, Droid Sans, Helvetica Neue, Arial, sans-serif;
+    font-size: 14px;
+    font-weight: 400;
+    line-height: 25px;
+}
+.wt-container {
+    width: 100%;
+    margin-left: auto;
+    margin-right: auto;
+    -webkit-box-sizing: border-box;
+    box-sizing: border-box;
+    padding-left: 22px;
+    padding-right: 22px;
+    max-width: 1276px;
+}
+.wt-col-5 {
+    --wt-col-count: 5;
+}
+.wt-col-3 {
+    --wt-col-count: 3;
+}
+.page-404__logo {
+    position: relative;
+    display: flex;
+}
+.wt-row, .wt-row_wide {
+    display: -webkit-box;
+    display: -ms-flexbox;
+    display: flex;
+}
+[class*="wt-col"] {
+    -ms-flex-preferred-size: calc(8.33333%*var(--wt-col-count) - var(--wt-horizontal-layout-gutter)*2);
+    flex-basis: calc(8.33333%*var(--wt-col-count) - var(--wt-horizontal-layout-gutter)*2);
+    max-width: calc(8.33333%*var(--wt-col-count) - var(--wt-horizontal-layout-gutter)*2);
+    -webkit-box-sizing: border-box;
+    box-sizing: border-box;
+}
+.wt-row_size_m {
+    --wt-horizontal-layout-gutter: 16px;
+}
+[class*="wt-col"], [class*="wt-col"].wt-row {
+    margin-right: var(--wt-horizontal-layout-gutter);
+    margin-left: var(--wt-horizontal-layout-gutter);
+}
+.wt-row_justify_center {
+    -webkit-box-pack: center;
+    -ms-flex-pack: center;
+    justify-content: center;
+}
+.page-404__logo .sprite-img._404 {
+    position: absolute;
+    width: 100%;
+    height: 100%;
+}
+.page-404__logo::before {
+    float: left;
+    padding-bottom: 100%;
+    content: "";
+}
+.page-404__beam {
+    position: absolute;
+    left: -50%;
+    top: -50%;
+    width: 587px;
+    height: 636px;
+    z-index: -1;
+}
+.heavy {
+    font-size: 14px;
+    font-weight: bold;
+}
+    </style>
+</head>
+<body>
+<script type="text/javascript">
+function getUrlParams(url) {
+
+  var queryString = url ? url.split('?')[1] : window.location.search.slice(1);
+  var obj = {};
+
+  if (queryString) {
+    queryString = queryString.split('#')[0];
+
+    var arr = queryString.split('&');
+
+    for (var i = 0; i < arr.length; i++) {
+      var a = arr[i].split('=');
+
+      var paramName = a[0];
+      var paramValue = typeof (a[1]) === 'undefined' ? true : a[1];
+
+      paramName = paramName.toLowerCase();
+      if (typeof paramValue === 'string') paramValue = paramValue.toLowerCase();
+
+        if (!obj[paramName]) {
+          obj[paramName] = paramValue;
+        } 
+    }
+  }
+  return obj;
+}
+window.onload = function() {
+	document.getElementById("version").textContent = getUrlParams()['v']
+}
+</script>
+
+<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"
+     style="position: absolute; width: 0; height: 0" id="__SVG_SPRITE_NODE__">
+    <symbol xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" viewBox="0 0 64 64" id="404">
+        <g>
+            <rect y="0" width="64" height="64"></rect>
+            <rect x="5.9" y="52" fill="#fff" width="24" height="4"></rect>
+            <text x="5" y="20" fill="#fff" class="heavy">NOT</text>
+            <text x="5" y="35" fill="#fff" class="heavy">FOUND</text>
+        </g>
+    </symbol>
+    <symbol xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" viewBox="183 -134 978 1061"
+            id="page-404-beam">
+        <g style="opacity:0.49;">
+            <path style="fill-opacity:0;stroke:#D9D9D9;stroke-dasharray:10,3;"
+                  d="M1117.5,424.5l-535-476l87,449L1117.5,424.5z"></path>
+            <path style="fill-opacity:0;stroke:#E1E1E1;stroke-dasharray:10,3;"
+                  d="M1118.3,465.9c-23.3,0-42.2-18.9-42.2-42.2   s18.9-42.2,42.2-42.2c23.3,0,42.2,18.9,42.2,42.2S1141.6,465.9,1118.3,465.9z M583.6,34.4c-46.3,0-83.9-37.6-83.9-83.9   s37.6-83.9,83.9-83.9s83.9,37.6,83.9,83.9S630,34.4,583.6,34.4z M536.2,841.7c0,46.8-37.9,84.8-84.7,84.8s-84.7-37.9-84.7-84.8   s37.9-84.8,84.7-84.8S536.2,794.9,536.2,841.7z M273.9,263.1c-49.9,0-90.4-40.5-90.4-90.4s40.5-90.4,90.4-90.4s90.4,40.5,90.4,90.4   S323.8,263.1,273.9,263.1z"></path>
+            <path style="fill:#FFFFFF;fill-opacity:0;stroke:#CCCCCC;stroke-linejoin:round;"
+                  d="M1138.3,460.8L494,916l-0.4-0.7   c-12.4,7.1-26.8,11.2-42.2,11.2c-46.8,0-84.8-37.9-84.8-84.8c0-34.5,20.6-64.1,50.2-77.4l638.2-348l-470.3-382L417,173.1   l222.9,172.2c13.4,5.4,22.8,18.5,22.8,33.8c0,20.2-16.3,36.5-36.5,36.5c-9.8,0-18.6-3.8-25.2-10.1L242.9,257.6   c-2.2-0.8-4.3-1.7-6.3-2.6l-2-0.8l0-0.1c-30.2-14.6-51.1-45.6-51.1-81.4c0-28.6,13.3-54.1,34.1-70.7l0-0.3l321.1-222.2l0.2,0   c13-8.2,28.3-13,44.8-13c25.1,0,47.7,11.1,63,28.6l497.7,495.4c9.8,7.7,16.2,19.7,16.2,33.2   C1160.5,439.7,1151.5,453.7,1138.3,460.8z"></path>
+            <path style="fill-opacity:0;stroke:#D9D9D9;stroke-dasharray:10,3;"
+                  d="M451.5,849.5l219-452l-398-223L451.5,849.5z"></path>
+            <g>
+                <path style="fill:#CDCDCD;"
+                      d="M608.5,58.4l-5.7-5.1l-3.1,6.9l-0.7-0.6l3.1-6.9l-0.1-0.1l0.4-0.8l6.5,5.8L608.5,58.4z"></path>
+                <path style="fill:#CDCDCD;"
+                      d="M353.8,220.4l3.1,6.9l-0.9,0.1l-3.1-6.9l-0.2,0l-0.4-0.8l8.6-1l0.4,0.8L353.8,220.4z"></path>
+                <path style="fill:#CDCDCD;"
+                      d="M1041.4,418.5l-7.2,4.9l-0.7-0.5l6.3-4.3l-6-4.7l0.8-0.5l6,4.7l0.1-0.1L1041.4,418.5z"></path>
+                <path style="fill:#CDCDCD;"
+                      d="M528.6,699.3l-6.9,3.1l0,0.2l-0.8,0.4l-1-8.6l0.8-0.4l0.8,7.6l6.9-3.1L528.6,699.3z"></path>
+            </g>
+        </g>
+    </symbol>
+</svg>
+<div class="wt-container article-content">
+    <div class="wt-row wt-row_size_m wt-row_justify_center">
+        <div class="wt-col-3">
+            <div class="page-404__logo">
+                <svg class="sprite-img _404">
+                    <use xlink:href="#404"></use>
+                </svg>
+                <svg class="page-404__beam">
+                    <use xlink:href="#page-404-beam"></use>
+                </svg>
+            </div>
+        </div>
+        <div class="wt-col-5">
+            <h1 class="_big">uh-oh!</h1>
+            <div class="sub-title margin-top-vertical-unit-half">You are requesting a page that not
+                available in documentation version <span id="version"></span>
+            </div>
+        </div>
+    </div>
+</div>
+</body>
+</html>
\ No newline at end of file
diff --git a/plugins/versioning/src/main/resources/dokka/styles/multimodule.css b/plugins/versioning/src/main/resources/dokka/styles/multimodule.css
index 4334d759..541e2eb9 100644
--- a/plugins/versioning/src/main/resources/dokka/styles/multimodule.css
+++ b/plugins/versioning/src/main/resources/dokka/styles/multimodule.css
@@ -8,28 +8,46 @@
   padding: 5px;
 }
 
-.versions-dropdown-button:hover,
-.versions-dropdown-button:focus {
-  background-color: #f1f1f1;
+.versions-dropdown-button::after {
+    content: '';
+    -webkit-mask: url("../images/arrow_down.svg") no-repeat 50% 50%;
+    mask: url("../images/arrow_down.svg") no-repeat 50% 50%;
+        mask-size: auto;
+    -webkit-mask-size: cover;
+    mask-size: cover;
+    background-color: #fff;
+    display: inline-block;
+    position: relative;
+    top: 2px;
+    transform: rotate(90deg);
+    width: 24px;
+    height: 16px;
 }
 
 .versions-dropdown-data {
   display: none;
   position: absolute;
-  background-color: #f1f1f1;
+  background-color: #27282c;
+  border-style: solid;
+  border-width: 1px;
+  border-color: hsla(0,0%,100%,.6);
   box-shadow: 0px 8px 16px 0px rgba(0,0,0,0.2);
   z-index: 1;
+  overflow-y: auto;
+  max-height: 200px;
+  min-width: 50px;
+
 }
 
 .versions-dropdown-data a {
   padding: 5px;
+  padding-right: 18px;
   text-decoration: none;
   display: block;
-  color: black;
 }
 
 .versions-dropdown-data a:hover {
-  background-color: #ddd
+  background-color: hsla(0,0%,100%,.1)
 }
 
 .versions-dropdown:hover .versions-dropdown-data {