IDEA-118569 Add quick doc for live template lookup items

java/java-tests/testSrc/com/intellij/codeInsight/completion/JavaAutoPopupTest.groovy

@@ -24,6 +24,7 @@ import com.intellij.codeInsight.lookup.LookupManager
 import com.intellij.codeInsight.lookup.PsiTypeLookupItem
 import com.intellij.codeInsight.lookup.impl.LookupImpl
 import com.intellij.codeInsight.template.*
+import com.intellij.codeInsight.template.impl.LiveTemplateDocumentationProvider
 import com.intellij.codeInsight.template.impl.TemplateImpl
 import com.intellij.codeInsight.template.impl.TemplateManagerImpl
 import com.intellij.codeInsight.template.impl.TemplateSettings
@@ -1518,6 +1519,25 @@ class X extends Foo {
     assert myFixture.lookupElementStrings == ['public int getField']
   }
 
+  public void "test live template quick doc"() {
+    myFixture.configureByText "a.java", """
+class Cls {
+  void foo() {
+    <caret>
+  }
+  void mySout() {}
+}
+""" 
+    type('sout')
+    assert lookup
+    assert 'sout' in myFixture.lookupElementStrings
+
+    def docProvider = new LiveTemplateDocumentationProvider()
+    def docElement = docProvider.getDocumentationElementForLookupItem(myFixture.psiManager, lookup.currentItem, null)
+    assert docElement.presentation.presentableText == 'sout'
+    assert docProvider.generateDoc(docElement, docElement).contains('System.out')
+  }
+
   public void "test finishing class reference property value completion with dot opens autopopup"() {
     myFixture.configureByText "a.properties", "myprop=ja<caret>"
     type 'v'
@@ -1552,5 +1572,4 @@ class Foo {
     def tabKeyPresentation = KeyEvent.getKeyText(TemplateSettings.TAB_CHAR as int)
     assert p.typeText == "  [$tabKeyPresentation] "
   }
-
 }

platform/lang-impl/src/com/intellij/codeInsight/template/impl/LiveTemplateDocumentationProvider.java

@@ -0,0 +1,108 @@
+/*
+ * Copyright 2000-2013 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.intellij.codeInsight.template.impl;
+
+import com.intellij.lang.documentation.AbstractDocumentationProvider;
+import com.intellij.navigation.ItemPresentation;
+import com.intellij.openapi.util.text.StringUtil;
+import com.intellij.psi.PsiElement;
+import com.intellij.psi.PsiManager;
+import com.intellij.psi.impl.FakePsiElement;
+import com.intellij.psi.impl.source.DummyHolder;
+import com.intellij.psi.impl.source.DummyHolderFactory;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import javax.swing.*;
+
+public class LiveTemplateDocumentationProvider extends AbstractDocumentationProvider {
+  @Override
+  public PsiElement getDocumentationElementForLookupItem(PsiManager psiManager, Object object, PsiElement element) {
+    if (object instanceof LiveTemplateLookupElement) {
+      TemplateImpl template = ((LiveTemplateLookupElement)object).getTemplate();
+      final TemplateImpl templateFromSettings = TemplateSettings.getInstance().getTemplate(template.getKey(), template.getGroupName());
+      if (templateFromSettings != null) {
+        return new LiveTemplateElement(templateFromSettings, psiManager);
+      }
+    }
+    return null;
+  }
+
+  @Override
+  public String generateDoc(PsiElement element, @Nullable PsiElement originalElement) {
+    if (!(element instanceof LiveTemplateElement)) {
+      return null;
+    }
+
+    TemplateImpl template = ((LiveTemplateElement)element).getTemplate();
+    String description = template.getDescription();
+    if (StringUtil.isEmpty(description)) {
+      description = template.getTemplateText();
+    }
+    return "<h2>" + template.getKey() + "</h2>" +
+           "<pre>" + StringUtil.escapeXml(description) + "</pre>";
+  }
+
+  private static class LiveTemplateElement extends FakePsiElement {
+    @NotNull private final TemplateImpl myTemplate;
+    @NotNull private final PsiManager myPsiManager;
+    @NotNull private DummyHolder myDummyHolder;
+
+    public LiveTemplateElement(@NotNull TemplateImpl template, @NotNull PsiManager psiManager) {
+      myTemplate = template;
+      myPsiManager = psiManager;
+      myDummyHolder = DummyHolderFactory.createHolder(myPsiManager, null);
+    }
+
+    @NotNull
+    public TemplateImpl getTemplate() {
+      return myTemplate;
+    }
+
+    @Override
+    public PsiElement getParent() {
+      return myDummyHolder;
+    }
+
+    @Override
+    public ItemPresentation getPresentation() {
+      return new ItemPresentation() {
+        @Nullable
+        @Override
+        public String getPresentableText() {
+          return myTemplate.getKey();
+        }
+
+        @Nullable
+        @Override
+        public String getLocationString() {
+          return null;
+        }
+
+        @Nullable
+        @Override
+        public Icon getIcon(boolean unused) {
+          return null;
+        }
+      };
+    }
+
+    @Override
+    public PsiManager getManager() {
+      return myPsiManager;
+    }
+  }
+}

platform/platform-resources/src/META-INF/LangExtensions.xml

@@ -374,6 +374,7 @@
     <applicationConfigurable instance="com.intellij.codeInsight.template.impl.LiveTemplatesConfigurable" id="editing.templates"
                              key="templates.settings.page.title" bundle="messages.CodeInsightBundle"/>
     <lookup.actionProvider implementation="com.intellij.codeInsight.template.impl.LiveTemplateLookupActionProvider"/>
+    <documentationProvider implementation="com.intellij.codeInsight.template.impl.LiveTemplateDocumentationProvider"/>
 
     <!-- File Templates-->
     <applicationConfigurable instance="com.intellij.ide.fileTemplates.impl.AllFileTemplatesConfigurable" id="fileTemplates"