Add completion contributor for Bukkit event handlers

src/main/kotlin/platform/bukkit/completion/BukkitEventHandlerCompletionContributor.kt

@@ -0,0 +1,36 @@
+/*
+ * Minecraft Development for IntelliJ
+ *
+ * https://mcdev.io/
+ *
+ * Copyright (C) 2025 minecraft-dev
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published
+ * by the Free Software Foundation, version 3.0 only.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.demonwav.mcdev.platform.bukkit.completion
+
+import com.intellij.codeInsight.completion.CompletionContributor
+import com.intellij.codeInsight.completion.CompletionType
+import com.intellij.patterns.PlatformPatterns
+import com.intellij.psi.PsiClass
+
+class BukkitEventHandlerCompletionContributor : CompletionContributor() {
+    init {
+        extend(
+            CompletionType.BASIC,
+            PlatformPatterns.psiElement().inside(PsiClass::class.java),
+            BukkitEventHandlerCompletionProvider()
+        )
+    }
+}

src/main/kotlin/platform/bukkit/completion/BukkitEventHandlerCompletionProvider.kt

@@ -0,0 +1,99 @@
+/*
+ * Minecraft Development for IntelliJ
+ *
+ * https://mcdev.io/
+ *
+ * Copyright (C) 2025 minecraft-dev
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published
+ * by the Free Software Foundation, version 3.0 only.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.demonwav.mcdev.platform.bukkit.completion
+
+import com.demonwav.mcdev.platform.bukkit.util.BukkitConstants
+import com.demonwav.mcdev.util.findContainingClass
+import com.demonwav.mcdev.util.findContainingMethod
+import com.intellij.codeInsight.completion.CompletionParameters
+import com.intellij.codeInsight.completion.CompletionProvider
+import com.intellij.codeInsight.completion.CompletionResultSet
+import com.intellij.codeInsight.completion.PrioritizedLookupElement
+import com.intellij.codeInsight.lookup.LookupElementBuilder
+import com.intellij.icons.AllIcons
+import com.intellij.psi.PsiModifier
+import com.intellij.psi.impl.JavaPsiFacadeEx
+import com.intellij.psi.search.GlobalSearchScope
+import com.intellij.psi.search.searches.ClassInheritorsSearch
+import com.intellij.util.ProcessingContext
+
+class BukkitEventHandlerCompletionProvider : CompletionProvider<CompletionParameters>() {
+
+    override fun addCompletions(
+        completionParameters: CompletionParameters,
+        processingContext: ProcessingContext,
+        completionResultSet: CompletionResultSet
+    ) {
+        val prefix = completionResultSet.prefixMatcher.prefix
+        if (!prefix.startsWith("on") || prefix.length == 2) {
+            return
+        }
+
+        val position = completionParameters.position
+        val containingClass = position.findContainingClass() ?: return
+        val project = position.project
+        val facade = JavaPsiFacadeEx.getInstance(project)
+
+        val eventListenerClass = facade.findClass(BukkitConstants.LISTENER_CLASS, GlobalSearchScope.allScope(project)) ?: return
+        if (!containingClass.isInheritor(eventListenerClass, true)) {
+            return
+        }
+
+        if (position.findContainingMethod() != null) {
+            return
+        }
+
+        val scope = GlobalSearchScope.allScope(project)
+        val eventBaseClass = facade.findClass(BukkitConstants.EVENT_CLASS, scope) ?: return
+        val eventNameFilter = prefix.substring(2).lowercase()
+
+        ClassInheritorsSearch.search(eventBaseClass, scope, true)
+            .forEach { psiClass ->
+                if (psiClass.isInterface || psiClass.hasModifierProperty(PsiModifier.ABSTRACT)) {
+                    return@forEach
+                }
+
+                val eventSimpleName = psiClass.name ?: return@forEach
+                if (eventNameFilter.isNotEmpty() && !eventSimpleName.lowercase().startsWith(eventNameFilter)) {
+                    return@forEach
+                }
+
+                val lookupString = "on$eventSimpleName"
+                val qualifiedName = psiClass.qualifiedName
+
+                val element = LookupElementBuilder
+                    .create(lookupString)
+                    .withPresentableText("$lookupString()")
+                    .withTailText(" - $qualifiedName", true)
+                    .withTypeText("@EventHandler")
+                    .withIcon(AllIcons.Nodes.Method)
+                    .withBaseLookupString(lookupString)
+                    .withBoldness(true)
+                    .withInsertHandler(BukkitEventHandlerInsertHandler(psiClass))
+
+                completionResultSet.addElement(
+                    PrioritizedLookupElement.withPriority(element, 100.0)
+                )
+            }
+
+        completionResultSet.stopHere()
+    }
+}

src/main/kotlin/platform/bukkit/completion/BukkitEventHandlerInsertHandler.kt

@@ -0,0 +1,58 @@
+/*
+ * Minecraft Development for IntelliJ
+ *
+ * https://mcdev.io/
+ *
+ * Copyright (C) 2025 minecraft-dev
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published
+ * by the Free Software Foundation, version 3.0 only.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.demonwav.mcdev.platform.bukkit.completion
+
+import com.demonwav.mcdev.util.psiType
+import com.intellij.codeInsight.completion.InsertHandler
+import com.intellij.codeInsight.completion.InsertionContext
+import com.intellij.codeInsight.intention.impl.TypeExpression
+import com.intellij.codeInsight.lookup.LookupElement
+import com.intellij.codeInsight.template.TemplateManager
+import com.intellij.codeInsight.template.impl.TemplateSettings
+import com.intellij.codeInsight.template.impl.Variable
+import com.intellij.psi.PsiClass
+import com.jetbrains.rd.util.string.printToString
+
+class BukkitEventHandlerInsertHandler(
+    private val psiClass: PsiClass
+) : InsertHandler<LookupElement> {
+
+    override fun handleInsert(insertionContext: InsertionContext, lookupElement: LookupElement) {
+        insertionContext.document.deleteString(
+            insertionContext.startOffset,
+            insertionContext.tailOffset
+        )
+
+        val sourceTemplate = TemplateSettings.getInstance().getTemplate("event_handler", "Bukkit") ?: return
+        val template = sourceTemplate.copy()
+
+        val classTypeExpr = TypeExpression(insertionContext.project, listOf(psiClass.psiType))
+
+        val index = template.variables.indexOfFirst { it.name == "EVENT_CLASS" }
+        if (index != -1) {
+            template.removeVariable(index)
+        }
+
+        template.addVariable(Variable("EVENT_CLASS", classTypeExpr, classTypeExpr, false, false));
+
+        TemplateManager.getInstance(insertionContext.project).startTemplate(insertionContext.editor, template)
+    }
+}

src/main/kotlin/platform/bukkit/macro/BukkitEventNameMacro.kt

@@ -0,0 +1,42 @@
+/*
+ * Minecraft Development for IntelliJ
+ *
+ * https://mcdev.io/
+ *
+ * Copyright (C) 2025 minecraft-dev
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published
+ * by the Free Software Foundation, version 3.0 only.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.demonwav.mcdev.platform.bukkit.macro
+
+import com.intellij.codeInsight.template.Expression
+import com.intellij.codeInsight.template.ExpressionContext
+import com.intellij.codeInsight.template.Result
+import com.intellij.codeInsight.template.TextResult
+import com.intellij.codeInsight.template.macro.MacroBase
+
+class BukkitEventNameMacro : MacroBase("bukkitEventName", "Usage: bukkitEventName(ClassType)") {
+    override fun calculateResult(
+        params: Array<out Expression?>,
+        context: ExpressionContext?,
+        quick: Boolean
+    ): Result? {
+        val text = params[0]
+            ?.calculateResult(context)
+            ?.toString() ?: return null
+
+        val result = text.split("\\.").last().removeSuffix("Event")
+        return TextResult(result)
+    }
+}

src/main/resources/META-INF/plugin.xml

@@ -532,6 +532,17 @@
         <library.presentationProvider
                 implementation="com.demonwav.mcdev.platform.bukkit.framework.ModernPaperPresentationProvider"/>
 
+        <!-- Bukkit Completion Contributor -->
+
+        <completion.contributor
+                language="JAVA"
+                implementationClass="com.demonwav.mcdev.platform.bukkit.completion.BukkitEventHandlerCompletionContributor"
+                order="first"/>
+
+        <defaultLiveTemplates file="/liveTemplates/Bukkit.xml"/>
+
+        <liveTemplateMacro implementation="com.demonwav.mcdev.platform.bukkit.macro.BukkitEventNameMacro"/>
+
         <!--endregion-->
 
         <!--region SPONGE-->

src/main/resources/liveTemplates/Bukkit.xml

@@ -0,0 +1,32 @@
+<!--
+    Minecraft Development for IntelliJ
+
+    https://mcdev.io/
+
+    Copyright (C) 2025 minecraft-dev
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published
+    by the Free Software Foundation, version 3.0 only.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+-->
+
+<templateSet group="Bukkit">
+    <template
+            name="event_handler"
+            value="@org.bukkit.event.EventHandler&#10;public void on$NAME$($EVENT_CLASS$ $PARAM_NAME$) {&#10;$END$&#10;}"
+            toReformat="true"
+            toShortenFQNames="true"
+            key="live.template.bukkit.event_handler.description"
+            resource-bundle="messages.MinecraftDevelopment">
+        <variable name="NAME" expression="bukkitEventName(EVENT_CLASS)" alwaysStopAt="true"/>
+        <variable name="PARAM_NAME" expression="&quot;event&quot;" alwaysStopAt="true"/>
+    </template>
+</templateSet>

src/main/resources/messages/MinecraftDevelopment.properties

@@ -370,3 +370,5 @@ template.provider.builtin.label=Built In
 template.provider.remote.label=Remote
 template.provider.local.label=Local
 template.provider.zip.label=Archive
+
+live.template.bukkit.event_handler.description=Create an event handler