/*
 * 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.semantic.Symbol;
import org.sonar.plugins.java.api.semantic.Type;
import org.sonar.plugins.java.api.tree.ClassTree;
import org.sonar.plugins.java.api.tree.NewClassTree;
import org.sonar.plugins.java.api.tree.Tree;

import java.util.Collection;
import java.util.List;

@Rule(key = "S2134")
public class ThreadOverridesRunCheck extends IssuableSubscriptionVisitor {

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

  @Override
  public void visitNode(Tree tree) {
    ClassTree classTree = (ClassTree) tree;
    Symbol.TypeSymbol classSymbol = classTree.symbol();
    if (classSymbol != null && isDirectSubtypeOfThread(classSymbol) && !overridesRunMethod(classSymbol)) {
      Tree report = classTree.simpleName();
      Tree parent = classTree.parent();
      if(parent.is(Tree.Kind.NEW_CLASS)) {
        report = ((NewClassTree) parent).identifier();
      }
      reportIssue(report, "Stop extending the Thread class as the \"run\" method is not overridden");
    }
  }

  private static boolean isDirectSubtypeOfThread(Symbol.TypeSymbol classSymbol) {
    Type superClass = classSymbol.superClass();
    return superClass != null && superClass.is("java.lang.Thread");
  }

  private static boolean overridesRunMethod(Symbol.TypeSymbol classSymbol) {
    Collection<Symbol> runSymbols = classSymbol.lookupSymbols("run");
    boolean overridesRunMethod = false;
    for (Symbol run : runSymbols) {
      if (run.isMethodSymbol()) {
        Symbol.MethodSymbol methodSymbol = (Symbol.MethodSymbol) run;
        if (methodSymbol.parameterTypes().isEmpty()) {
          overridesRunMethod = true;
          break;
        }
      }
    }
    return overridesRunMethod;
  }
}