////////////////////////////////////////////////////////////////////////////////
   // checkstyle: Checks Java source code for adherence to a set of rules.
   // Copyright (C) 2001-2019 the original author or authors.
   //
   // This library 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 2.1 of the License, or (at your option) any later version.
   //
  // This library 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 library; if not, write to the Free Software
  // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  ////////////////////////////////////////////////////////////////////////////////
  
  package com.puppycrawl.tools.checkstyle.checks;
  
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.Set;
  import java.util.stream.Collectors;
  
  import com.puppycrawl.tools.checkstyle.StatelessCheck;
  import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
  import com.puppycrawl.tools.checkstyle.api.DetailAST;
  import com.puppycrawl.tools.checkstyle.api.TokenTypes;
  import com.puppycrawl.tools.checkstyle.utils.CheckUtil;
  import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
  
  /**
   * Check that method/constructor/catch/foreach parameters are final.
   * The user can set the token set to METHOD_DEF, CONSTRUCTOR_DEF,
   * LITERAL_CATCH, FOR_EACH_CLAUSE or any combination of these token
   * types, to control the scope of this check.
   * Default scope is both METHOD_DEF and CONSTRUCTOR_DEF.
   * <p>
   * Check has an option <b>ignorePrimitiveTypes</b> which allows ignoring lack of
   * final modifier at
   * <a href="https://docs.oracle.com/javase/tutorial/java/nutsandbolts/datatypes.html">
   *  primitive data type</a> parameter. Default value <b>false</b>.
   * </p>
   * E.g.:
   * <p>
   * {@code
   * private void foo(int x) { ... } //parameter is of primitive type
   * }
   * </p>
   *
   */
  @StatelessCheck
  public class FinalParametersCheck extends AbstractCheck {
  
      /**
       * A key is pointing to the warning message text in "messages.properties"
       * file.
       */
      public static final String MSG_KEY = "final.parameter";
  
      /**
       * Contains
       * <a href="https://docs.oracle.com/javase/tutorial/java/nutsandbolts/datatypes.html">
       * primitive datatypes</a>.
       */
      private final Set<Integer> primitiveDataTypes = Collections.unmodifiableSet(
          Arrays.stream(new Integer[] {
              TokenTypes.LITERAL_BYTE,
              TokenTypes.LITERAL_SHORT,
              TokenTypes.LITERAL_INT,
              TokenTypes.LITERAL_LONG,
              TokenTypes.LITERAL_FLOAT,
              TokenTypes.LITERAL_DOUBLE,
              TokenTypes.LITERAL_BOOLEAN,
              TokenTypes.LITERAL_CHAR, })
          .collect(Collectors.toSet()));
  
      /**
       * Option to ignore primitive types as params.
       */
      private boolean ignorePrimitiveTypes;
  
      /**
       * Sets ignoring primitive types as params.
       * @param ignorePrimitiveTypes true or false.
       */
      public void setIgnorePrimitiveTypes(boolean ignorePrimitiveTypes) {
          this.ignorePrimitiveTypes = ignorePrimitiveTypes;
      }
  
      @Override
      public int[] getDefaultTokens() {
          return new int[] {
              TokenTypes.METHOD_DEF,
              TokenTypes.CTOR_DEF,
          };
      }
 
     @Override
     public int[] getAcceptableTokens() {
         return new int[] {
             TokenTypes.METHOD_DEF,
             TokenTypes.CTOR_DEF,
             TokenTypes.LITERAL_CATCH,
             TokenTypes.FOR_EACH_CLAUSE,
         };
     }
 
     @Override
     public int[] getRequiredTokens() {
         return CommonUtil.EMPTY_INT_ARRAY;
     }
 
     @Override
     public void visitToken(DetailAST ast) {
         // don't flag interfaces
         final DetailAST container = ast.getParent().getParent();
         if (container.getType() != TokenTypes.INTERFACE_DEF) {
             if (ast.getType() == TokenTypes.LITERAL_CATCH) {
                 visitCatch(ast);
             }
             else if (ast.getType() == TokenTypes.FOR_EACH_CLAUSE) {
                 visitForEachClause(ast);
             }
             else {
                 visitMethod(ast);
             }
         }
     }
 
     /**
      * Checks parameters of the method or ctor.
      * @param method method or ctor to check.
      */
     private void visitMethod(final DetailAST method) {
         final DetailAST modifiers =
             method.findFirstToken(TokenTypes.MODIFIERS);
 
         // ignore abstract and native methods
         if (modifiers.findFirstToken(TokenTypes.ABSTRACT) == null
                 && modifiers.findFirstToken(TokenTypes.LITERAL_NATIVE) == null) {
             final DetailAST parameters =
                 method.findFirstToken(TokenTypes.PARAMETERS);
             DetailAST child = parameters.getFirstChild();
             while (child != null) {
                 // children are PARAMETER_DEF and COMMA
                 if (child.getType() == TokenTypes.PARAMETER_DEF) {
                     checkParam(child);
                 }
                 child = child.getNextSibling();
             }
         }
     }
 
     /**
      * Checks parameter of the catch block.
      * @param catchClause catch block to check.
      */
     private void visitCatch(final DetailAST catchClause) {
         checkParam(catchClause.findFirstToken(TokenTypes.PARAMETER_DEF));
     }
 
     /**
      * Checks parameter of the for each clause.
      * @param forEachClause for each clause to check.
      */
     private void visitForEachClause(final DetailAST forEachClause) {
         checkParam(forEachClause.findFirstToken(TokenTypes.VARIABLE_DEF));
     }
 
     /**
      * Checks if the given parameter is final.
      * @param param parameter to check.
      */
     private void checkParam(final DetailAST param) {
         if (param.findFirstToken(TokenTypes.MODIFIERS).findFirstToken(TokenTypes.FINAL) == null
                 && !isIgnoredParam(param)
                 && !CheckUtil.isReceiverParameter(param)) {
             final DetailAST paramName = param.findFirstToken(TokenTypes.IDENT);
             final DetailAST firstNode = CheckUtil.getFirstNode(param);
             log(firstNode,
                 MSG_KEY, paramName.getText());
         }
     }
 
     /**
      * Checks for skip current param due to <b>ignorePrimitiveTypes</b> option.
      * @param paramDef {@link TokenTypes#PARAMETER_DEF PARAMETER_DEF}
      * @return true if param has to be skipped.
      */
     private boolean isIgnoredParam(DetailAST paramDef) {
         boolean result = false;
         if (ignorePrimitiveTypes) {
             final DetailAST parameterType = paramDef
                 .findFirstToken(TokenTypes.TYPE).getFirstChild();
             if (primitiveDataTypes.contains(parameterType.getType())) {
                 result = true;
             }
         }
         return result;
     }
 
 }