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/*
 * SonarQube Java
 * Copyright (C) 2012 SonarSource
 * [email protected]
 *
 * 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; either
 * version 3 of the License, or (at your option) any later version.
 *
 * 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
 * Lesser 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, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02
 */
package org.sonar.java.checks;

import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import org.sonar.api.server.rule.RulesDefinition;
import org.sonar.check.Priority;
import org.sonar.check.Rule;
import org.sonar.java.checks.helpers.ExpressionsHelper;
import org.sonar.java.tag.Tag;
import org.sonar.plugins.java.api.tree.BinaryExpressionTree;
import org.sonar.plugins.java.api.tree.ExpressionTree;
import org.sonar.plugins.java.api.tree.Tree;
import org.sonar.plugins.java.api.tree.UnaryExpressionTree;
import org.sonar.squidbridge.annotations.SqaleConstantRemediation;
import org.sonar.squidbridge.annotations.SqaleSubCharacteristic;

import java.util.List;
import java.util.Map;

@Rule(
  key = "S1940",
  name = "Boolean checks should not be inverted",
  priority = Priority.MAJOR,
  tags = {Tag.PITFALL})
@SqaleSubCharacteristic(RulesDefinition.SubCharacteristics.UNDERSTANDABILITY)
@SqaleConstantRemediation("2min")
public class BooleanInversionCheck extends SubscriptionBaseVisitor {

  private static final Map OPERATORS = ImmutableMap.builder()
    .put("==", "!=")
    .put("!=", "==")
    .put("<", ">=")
    .put(">", "<=")
    .put("<=", ">")
    .put(">=", "<")
    .build();

  @Override
  public List nodesToVisit() {
    return ImmutableList.of(Tree.Kind.LOGICAL_COMPLEMENT);
  }

  @Override
  public void visitNode(Tree tree) {
    ExpressionTree expression = ExpressionsHelper.skipParentheses(((UnaryExpressionTree) tree).expression());
    if (expression.is(
        Tree.Kind.EQUAL_TO, Tree.Kind.NOT_EQUAL_TO,
        Tree.Kind.LESS_THAN, Tree.Kind.GREATER_THAN,
        Tree.Kind.LESS_THAN_OR_EQUAL_TO, Tree.Kind.GREATER_THAN_OR_EQUAL_TO)) {
      context.addIssue(tree, this, "Use the opposite operator (\"" + OPERATORS.get(((BinaryExpressionTree) expression).operatorToken().text()) + "\") instead.");
    }
  }

}