/*
 * Copyright 2013 Google Inc. All Rights Reserved.
 *
 * 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.google.errorprone.bugpatterns.inject.guice;

import static com.google.errorprone.BugPattern.Category.GUICE;
import static com.google.errorprone.BugPattern.MaturityLevel.EXPERIMENTAL;
import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
import static com.google.errorprone.matchers.Matchers.hasAnnotation;

import com.google.errorprone.BugPattern;
import com.google.errorprone.VisitorState;
import com.google.errorprone.bugpatterns.BugChecker;
import com.google.errorprone.bugpatterns.BugChecker.MethodTreeMatcher;
import com.google.errorprone.fixes.SuggestedFix;
import com.google.errorprone.matchers.Description;
import com.google.errorprone.matchers.Matcher;
import com.google.errorprone.matchers.Matchers;
import com.google.errorprone.util.ASTHelpers;

import com.sun.source.tree.MethodTree;
import com.sun.tools.javac.code.Attribute.Compound;
import com.sun.tools.javac.code.Symbol.MethodSymbol;

import javax.lang.model.element.TypeElement;

/**
 * This checker matches methods that
 *   1) are not themselves annotated with @Inject
 *     (neither javax.inject.Inject nor com.google.inject.Inject)
 *   2) descend from a method that is annotated with @com.google.inject.Inject
 *
 * @author sgoldfeder@google.com (Steven Goldfeder)
 */
@BugPattern(
  name = "OverridesGuiceInjectableMethod",
  summary =
      "This method is not annotated with @Inject, but it overrides a "
          + "method that is annotated with @com.google.inject.Inject. Guice will inject this "
          + "method, and it is recommended to annotate it explicitly.",
  explanation =
      "Unlike with `@javax.inject.Inject`, if a method overrides a method annotated with "
          + "`@com.google.inject.Inject`, Guice will inject it even if it itself is not annotated. "
          + "This differs from the behavior of methods that override `@javax.inject.Inject` "
          + "methods since according to the JSR-330 spec, a method that overrides a method "
          + "annotated with `@javax.inject.Inject` will not be injected unless it iself is "
          + "annotated with `@Inject`. Because of this difference, it is recommended that you "
          + "annotate this method explicitly.",
  category = GUICE,
  severity = WARNING,
  maturity = EXPERIMENTAL
)
public class OverridesGuiceInjectableMethod extends BugChecker implements MethodTreeMatcher {

  private static final String OVERRIDE_ANNOTATION = "java.lang.Override";
  private static final String GUICE_INJECT_ANNOTATION = "com.google.inject.Inject";
  private static final String JAVAX_INJECT_ANNOTATION = "javax.inject.Inject";

  private static final Matcher<MethodTree> INJECTABLE_METHOD_MATCHER =
      Matchers.<MethodTree>anyOf(
          hasAnnotation(GUICE_INJECT_ANNOTATION), hasAnnotation(JAVAX_INJECT_ANNOTATION));

  private static final Matcher<MethodTree> OVERRIDE_METHOD_MATCHER =
      Matchers.<MethodTree>hasAnnotation(OVERRIDE_ANNOTATION);

  @Override
  public Description matchMethod(MethodTree methodTree, VisitorState state) {
    // if method is itself annotated with @Inject or it has no ancestor methods, return No_MATCH;
    if (!INJECTABLE_METHOD_MATCHER.matches(methodTree, state)
        && OVERRIDE_METHOD_MATCHER.matches(methodTree, state)) {
      MethodSymbol method = ASTHelpers.getSymbol(methodTree);
      for (MethodSymbol superMethod : ASTHelpers.findSuperMethods(method, state.getTypes())) {
        if (isAnnotatedWith(superMethod, GUICE_INJECT_ANNOTATION)) {
          return buildDescription(methodTree)
              .addFix(
                  SuggestedFix.builder()
                      .addImport(JAVAX_INJECT_ANNOTATION)
                      .prefixWith(methodTree, "@Inject\n")
                      .build())
              .setMessage(
                  String.format(
                      "This method is not annotated with @Inject, but overrides the method in %s "
                          + "that is annotated with @com.google.inject.Inject. Guice will inject "
                          + "this method, and it is recommended to annotate it explicitly.",
                      ASTHelpers.enclosingClass(superMethod).getQualifiedName()))
              .build();
        }
      }
    }
    return Description.NO_MATCH;
  }

  private static boolean isAnnotatedWith(MethodSymbol method, String annotation) {
    for (Compound c : method.getAnnotationMirrors()) {
      if (((TypeElement) c.getAnnotationType().asElement())
          .getQualifiedName()
          .contentEquals(annotation)) {
        return true;
      }
    }
    return false;
  }
}

@@ -1470,125 +1470,27 @@
 ode.
-Attribute.Compound;%0Aimport com.sun.tools.javac.code.Symbol.MethodSymbol;%0A%0Aimport javax.lang.model.element.TypeElement
+Symbol.MethodSymbol
 ;%0A%0A/
@@ -3633,17 +3633,17 @@
 return N
-o
+O
 _MATCH;%0A
@@ -3938,25 +3938,37 @@
     if (
-i
+ASTHelpers.ha
 sAnnotat
 edWith(s
@@ -3959,22 +3959,19 @@
 sAnnotat
-edWith
+ion
 (superMe
@@ -3999,16 +3999,23 @@
 NOTATION
+, state
 )) %7B%0A   
@@ -4791,333 +4791,7 @@
 %0A  %7D
-%0A%0A  private static boolean isAnnotatedWith(MethodSymbol method, String annotation) %7B%0A    for (Compound c : method.getAnnotationMirrors()) %7B%0A      if (((TypeElement) c.getAnnotationType().asElement())%0A          .getQualifiedName()%0A          .contentEquals(annotation)) %7B%0A        return true;%0A      %7D%0A    %7D%0A    return false;%0A  %7D
 %0A%7D%0A

Use standard hasAnnotation method in OverridesJavaxInjectableMethod