/*
 * SonarQube JavaScript Plugin
 * Copyright (C) 2011-2016 SonarSource SA
 * mailto:contact AT sonarsource DOT com
 *
 * 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  02110-1301, USA.
 */
package org.sonar.javascript.checks;

import org.sonar.api.server.rule.RulesDefinition;
import org.sonar.check.Priority;
import org.sonar.check.Rule;
import org.sonar.javascript.tree.SyntacticEquivalence;
import org.sonar.plugins.javascript.api.tree.Tree;
import org.sonar.plugins.javascript.api.tree.expression.AssignmentExpressionTree;
import org.sonar.plugins.javascript.api.tree.expression.UnaryExpressionTree;
import org.sonar.plugins.javascript.api.visitors.DoubleDispatchVisitorCheck;
import org.sonar.squidbridge.annotations.ActivatedByDefault;
import org.sonar.squidbridge.annotations.SqaleConstantRemediation;
import org.sonar.squidbridge.annotations.SqaleSubCharacteristic;

@Rule(
  key = "S2123",
  name = "Values should not be uselessly incremented",
  priority = Priority.CRITICAL,
  tags = {Tags.BUG})
@ActivatedByDefault
@SqaleSubCharacteristic(RulesDefinition.SubCharacteristics.LOGIC_RELIABILITY)
@SqaleConstantRemediation("5min")
public class UselessIncrementCheck extends DoubleDispatchVisitorCheck {

  private static final String MESSAGE = "Remove this %s or correct the code not to waste it.";

  @Override
  public void visitAssignmentExpression(AssignmentExpressionTree assignment) {
    if (assignment.expression().is(Tree.Kind.POSTFIX_INCREMENT, Tree.Kind.POSTFIX_DECREMENT)) {
      UnaryExpressionTree postfix = (UnaryExpressionTree) assignment.expression();
      if (SyntacticEquivalence.areEquivalent(assignment.variable(), postfix.expression())) {
        String type = postfix.is(Tree.Kind.POSTFIX_INCREMENT) ? "increment" : "decrement";
        String message = String.format(MESSAGE, type);
        addLineIssue(postfix, message);
      }
    }
    super.visitAssignmentExpression(assignment);
  }

}
