/*
 * SonarQube Java
 * Copyright (C) 2012-2016 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.java.checks;

import com.google.common.collect.ImmutableList;
import org.sonar.check.Rule;
import org.sonar.plugins.java.api.IssuableSubscriptionVisitor;
import org.sonar.plugins.java.api.tree.CatchTree;
import org.sonar.plugins.java.api.tree.StatementTree;
import org.sonar.plugins.java.api.tree.ThrowStatementTree;
import org.sonar.plugins.java.api.tree.Tree;
import org.sonar.plugins.java.api.tree.TryStatementTree;

import java.util.List;

@Rule(key = "S2737")
public class CatchRethrowingCheck extends IssuableSubscriptionVisitor {

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

  @Override
  public void visitNode(Tree tree) {
    if(!hasSemantic()) {
      return;
    }
    TryStatementTree tst = (TryStatementTree) tree;
    if (tst.catches().size() == 1) {
      CatchTree catchTree = tst.catches().get(0);
      if (onlyRethrows(catchTree)) {
        reportIssue(catchTree.block().body().get(0), "Add logic to this catch clause or eliminate it and rethrow the exception automatically.");
      }
    }
  }

  private static boolean onlyRethrows(CatchTree catchTree) {
    List<StatementTree> catchBody = catchTree.block().body();
    if (catchBody.size() == 1) {
      return catchBody.get(0).is(Tree.Kind.THROW_STATEMENT) && catchTree.parameter().symbol().usages().contains(((ThrowStatementTree) catchBody.get(0)).expression());
    }
    return false;
  }
}