/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You under the Apache License, Version 2.0
    * (the "License"); you may not use this file except in compliance with
    * the License.  You may obtain a copy of the License at
    *
    *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.apache.commons.jexl3.internal;
  
  import org.apache.commons.jexl3.JexlScript;
  import org.apache.commons.jexl3.parser.ASTIdentifier;
  import org.apache.commons.jexl3.parser.ASTIdentifierAccess;
  import org.apache.commons.jexl3.parser.JexlNode;
  
  /**
   * Utility to dump AST, useful in debug sessions.
   */
  public class Dumper {
      private final StringBuilder strb = new StringBuilder();
      private int indent = 0;
  
      private void indent() {
          for (int i = 0; i < indent; ++i) {
              strb.append("  ");
          }
      }
  
      private void dump(final JexlNode node, final Object data) {
          final int num = node.jjtGetNumChildren();
          indent();
          strb.append(node.getClass().getSimpleName());
          if (node instanceof ASTIdentifier) {
              strb.append("@");
              strb.append(node.toString());
          } else if (node instanceof ASTIdentifierAccess) {
              strb.append("@");
              strb.append(node.toString());
          }
          strb.append('(');
          indent += 1;
          for (int c = 0; c < num; ++c) {
              final JexlNode child = node.jjtGetChild(c);
              if (c > 0) {
                  strb.append(',');
              }
              strb.append('\n');
              dump(child, data);
          }
          indent -= 1;
          if (num > 0) {
              strb.append('\n');
              indent();
          }
          strb.append(')');
      }
  
      private Dumper(final JexlScript script) {
          dump(((Script) script).script, null);
      }
  
      @Override
      public String toString() {
          return strb.toString();
      }
  
      public static String toString(final JexlScript script) {
          return new Dumper(script).toString();
      }
  }