Build: Add dokka generation

build.gradle.kts

@@ -1,8 +1,22 @@
+import org.gradle.kotlin.dsl.support.unzipTo
+import org.jetbrains.dokka.versioning.VersioningConfiguration
+import org.jetbrains.dokka.versioning.VersioningPlugin
+import java.net.HttpURLConnection
+import java.net.URL
+import java.io.ByteArrayOutputStream
+
+buildscript {
+    dependencies {
+        classpath("org.jetbrains.dokka:versioning-plugin:1.8.20")
+    }
+}
+
 plugins {
     kotlin("jvm") version "1.8.21"
     kotlin("plugin.serialization") version "1.8.21"
     id("fabric-loom") version "1.2-SNAPSHOT"
     id("io.github.juuxel.loom-quiltflower") version "1.8.0"
+    id("org.jetbrains.dokka") version "1.8.20"
 }
 
 version = property("mod_version")!!
@@ -40,6 +54,8 @@ dependencies {
     include(modImplementation("gg.essential:elementa-1.18.1-fabric:587")!!)
 
     modRuntimeOnly("me.djtheredstoner:DevAuth-fabric:1.1.2")
+
+    dokkaPlugin("org.jetbrains.dokka:versioning-plugin:1.8.20")
 }
 
 loom {
@@ -50,6 +66,13 @@ base {
     archivesName.set(property("archives_base_name") as String)
 }
 
+java {
+    withSourcesJar()
+
+    sourceCompatibility = JavaVersion.VERSION_17
+    targetCompatibility = JavaVersion.VERSION_17
+}
+
 tasks {
     processResources {
         inputs.property("yarn_mappings", yarnMappings)
@@ -77,9 +100,93 @@ tasks {
     }
 }
 
-java {
-    withSourcesJar()
+tasks.dokkaHtml {
+    val docVersionsDir = projectDir.resolve("build/javadocs")
+    val currentVersion = project.version.toString()
+    val currentDocsDir = docVersionsDir.resolve(currentVersion)
+    outputs.upToDateWhen { docVersionsDir.exists() }
 
-    sourceCompatibility = JavaVersion.VERSION_17
-    targetCompatibility = JavaVersion.VERSION_17
+    outputDirectory.set(file(currentDocsDir))
+
+    pluginConfiguration<VersioningPlugin, VersioningConfiguration> {
+        version = currentVersion
+        olderVersionsDir = docVersionsDir
+        renderVersionsNavigationOnAllPages = true
+    }
+
+    suppressInheritedMembers.set(true)
+
+    val branch = getBranch()
+    dokkaSourceSets {
+        configureEach {
+            jdkVersion.set(17)
+
+            for (pkg in setOf("engine.langs", "engine.loader", "engine.module", "utils", "listeners", "loader", "launch", "commands", "minecraft.wrappers.objects.threading")) {
+                perPackageOption {
+                    matchingRegex.set("${"com.chattriggers.ctjs.$pkg".replace(".", "\\.")}(\$|\\.).*")
+                    suppress.set(true)
+                }
+            }
+
+            sourceLink {
+                localDirectory.set(file("src/main/kotlin"))
+                remoteUrl.set(URL("https://github.com/ChatTriggers/ctjs/blob/$branch/src/main/kotlin"))
+                remoteLineSuffix.set("#L")
+            }
+        }
+    }
+
+    doFirst {
+        val archiveBase = "https://www.chattriggers.com/javadocs-archive/"
+        val versions = String(downloadFile(archiveBase + "versions")).lines().map(String::trim)
+        val tmpFile = File(temporaryDir, "oldVersionsZip.zip")
+
+        versions.filter(String::isNotEmpty).map(String::trim).forEach { version ->
+            val zipBytes = downloadFile("$archiveBase$version.zip")
+            tmpFile.writeBytes(zipBytes)
+            unzipTo(docVersionsDir, tmpFile)
+        }
+
+        tmpFile.delete()
+    }
+
+    doLast {
+        // At this point we have a structure that looks something like this:
+        // javadocs
+        //   \-- 2.2.0-1.8.9
+        //   \-- 3.0.0
+        //         \-- older
+        //
+        // The "older" directory contains all old versions, so we want to
+        // delete the top-level older versions and move everything inside the
+        // latest directory to the top level so the GitHub actions workflow
+        // doesn't need to figure out the correct version name
+
+        docVersionsDir.listFiles()?.forEach {
+            if (it.name != version)
+                it.deleteRecursively()
+        }
+
+        val latestVersionDir = docVersionsDir.listFiles()!!.single()
+        latestVersionDir.listFiles()!!.forEach {
+            it.renameTo(File(it.parentFile.parentFile, it.name))
+        }
+        latestVersionDir.deleteRecursively()
+    }
+}
+
+fun downloadFile(url: String): ByteArray {
+    return (URL(url).openConnection() as HttpURLConnection).apply {
+        requestMethod = "GET"
+        doOutput = true
+    }.inputStream.readAllBytes()
+}
+
+fun getBranch(): String {
+    val stdout = ByteArrayOutputStream()
+    exec {
+        commandLine("git", "rev-parse", "HEAD")
+        standardOutput = stdout
+    }
+    return stdout.toString().trim()
 }