/*
 * Copyright 2017 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;

import static com.google.errorprone.BugPattern.Category.JDK;
import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
import static com.google.errorprone.matchers.Description.NO_MATCH;
import static com.google.errorprone.util.ASTHelpers.getType;
import static com.google.errorprone.util.ASTHelpers.isSameType;

import com.google.errorprone.BugPattern;
import com.google.errorprone.VisitorState;
import com.google.errorprone.bugpatterns.BugChecker.BinaryTreeMatcher;
import com.google.errorprone.fixes.SuggestedFix;
import com.google.errorprone.matchers.Description;
import com.sun.source.tree.BinaryTree;
import com.sun.source.tree.Tree;
import com.sun.tools.javac.tree.JCTree;

/** @author cushon@google.com (Liam Miller-Cushon) */
@BugPattern(
  name = "ShortCircuitBoolean",
  category = JDK,
  summary = "Prefer the short-circuiting boolean operators && and || to & and |.",
  severity = WARNING
)
public class ShortCircuitBoolean extends BugChecker implements BinaryTreeMatcher {
  @Override
  public Description matchBinary(BinaryTree tree, VisitorState state) {
    switch (tree.getKind()) {
      case AND:
      case OR:
        break;
      default:
        return NO_MATCH;
    }
    if (!isSameType(getType(tree), state.getSymtab().booleanType, state)) {
      return NO_MATCH;
    }
    return describeMatch(
        tree,
        SuggestedFix.replace(
            state.getEndPosition(tree.getLeftOperand()),
            ((JCTree) tree.getRightOperand()).getStartPosition(),
            tree.getKind() == Tree.Kind.AND ? " && " : " || "));
  }
}