////////////////////////////////////////////////////////////////////////////////
   // 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.sizes;
  
  import java.util.ArrayDeque;
  import java.util.Deque;
  
  import com.puppycrawl.tools.checkstyle.FileStatefulCheck;
  import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
  import com.puppycrawl.tools.checkstyle.api.DetailAST;
  import com.puppycrawl.tools.checkstyle.api.TokenTypes;
  
  /**
   * Restricts the number of executable statements to a specified limit
   * (default = 30).
   */
  @FileStatefulCheck
  public final class ExecutableStatementCountCheck
      extends AbstractCheck {
  
      /**
       * A key is pointing to the warning message text in "messages.properties"
       * file.
       */
      public static final String MSG_KEY = "executableStatementCount";
  
      /** Default threshold. */
      private static final int DEFAULT_MAX = 30;
  
      /** Stack of method contexts. */
      private final Deque<Context> contextStack = new ArrayDeque<>();
  
      /** Threshold to report error for. */
      private int max;
  
      /** Current method context. */
      private Context context;
  
      /** Constructs a {@code ExecutableStatementCountCheck}. */
      public ExecutableStatementCountCheck() {
          max = DEFAULT_MAX;
      }
  
      @Override
      public int[] getDefaultTokens() {
          return new int[] {
              TokenTypes.CTOR_DEF,
              TokenTypes.METHOD_DEF,
              TokenTypes.INSTANCE_INIT,
              TokenTypes.STATIC_INIT,
              TokenTypes.SLIST,
          };
      }
  
      @Override
      public int[] getRequiredTokens() {
          return new int[] {TokenTypes.SLIST};
      }
  
      @Override
      public int[] getAcceptableTokens() {
          return new int[] {
              TokenTypes.CTOR_DEF,
              TokenTypes.METHOD_DEF,
              TokenTypes.INSTANCE_INIT,
              TokenTypes.STATIC_INIT,
              TokenTypes.SLIST,
          };
      }
  
      /**
       * Sets the maximum threshold.
       * @param max the maximum threshold.
       */
      public void setMax(int max) {
          this.max = max;
      }
  
      @Override
      public void beginTree(DetailAST rootAST) {
          context = new Context(null);
          contextStack.clear();
     }
 
     @Override
     public void visitToken(DetailAST ast) {
         switch (ast.getType()) {
             case TokenTypes.CTOR_DEF:
             case TokenTypes.METHOD_DEF:
             case TokenTypes.INSTANCE_INIT:
             case TokenTypes.STATIC_INIT:
                 visitMemberDef(ast);
                 break;
             case TokenTypes.SLIST:
                 visitSlist(ast);
                 break;
             default:
                 throw new IllegalStateException(ast.toString());
         }
     }
 
     @Override
     public void leaveToken(DetailAST ast) {
         switch (ast.getType()) {
             case TokenTypes.CTOR_DEF:
             case TokenTypes.METHOD_DEF:
             case TokenTypes.INSTANCE_INIT:
             case TokenTypes.STATIC_INIT:
                 leaveMemberDef(ast);
                 break;
             case TokenTypes.SLIST:
                 // Do nothing
                 break;
             default:
                 throw new IllegalStateException(ast.toString());
         }
     }
 
     /**
      * Process the start of the member definition.
      * @param ast the token representing the member definition.
      */
     private void visitMemberDef(DetailAST ast) {
         contextStack.push(context);
         context = new Context(ast);
     }
 
     /**
      * Process the end of a member definition.
      *
      * @param ast the token representing the member definition.
      */
     private void leaveMemberDef(DetailAST ast) {
         final int count = context.getCount();
         if (count > max) {
             log(ast, MSG_KEY, count, max);
         }
         context = contextStack.pop();
     }
 
     /**
      * Process the end of a statement list.
      *
      * @param ast the token representing the statement list.
      */
     private void visitSlist(DetailAST ast) {
         if (context.getAST() != null) {
             // find member AST for the statement list
             final DetailAST contextAST = context.getAST();
             DetailAST parent = ast.getParent();
             int type = parent.getType();
             while (type != TokenTypes.CTOR_DEF
                 && type != TokenTypes.METHOD_DEF
                 && type != TokenTypes.INSTANCE_INIT
                 && type != TokenTypes.STATIC_INIT) {
                 parent = parent.getParent();
                 type = parent.getType();
             }
             if (parent == contextAST) {
                 context.addCount(ast.getChildCount() / 2);
             }
         }
     }
 
     /**
      * Class to encapsulate counting information about one member.
      */
     private static class Context {
 
         /** Member AST node. */
         private final DetailAST ast;
 
         /** Counter for context elements. */
         private int count;
 
         /**
          * Creates new member context.
          * @param ast member AST node.
          */
         /* package */ Context(DetailAST ast) {
             this.ast = ast;
             count = 0;
         }
 
         /**
          * Increase count.
          * @param addition the count increment.
          */
         public void addCount(int addition) {
             count += addition;
         }
 
         /**
          * Gets the member AST node.
          * @return the member AST node.
          */
         public DetailAST getAST() {
             return ast;
         }
 
         /**
          * Gets the count.
          * @return the count.
          */
         public int getCount() {
             return count;
         }
 
     }
 
 }