/*
    * 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.JexlBuilder;
  import org.apache.commons.jexl3.JexlContext;
  import org.apache.commons.jexl3.JexlOptions;
  import org.apache.commons.jexl3.parser.ASTArrayAccess;
  import org.apache.commons.jexl3.parser.ASTAssignment;
  import org.apache.commons.jexl3.parser.ASTEQNode;
  import org.apache.commons.jexl3.parser.ASTIdentifier;
  import org.apache.commons.jexl3.parser.ASTNENode;
  import org.apache.commons.jexl3.parser.ASTNullpNode;
  import org.apache.commons.jexl3.parser.ASTReference;
  import org.apache.commons.jexl3.parser.ASTTernaryNode;
  import org.apache.commons.jexl3.parser.JexlNode;
  
  /**
   * An Engine that behaves like JEXL 3.2, bugs included.
   */
  public class Engine32 extends Engine {
      public Engine32(final JexlBuilder conf) {
          super(conf);
      }
  
      public Engine32() {
      }
  
      /**
       * Static delegation of isTernaryProtected.
       * @param ii the interpreter (unused)
       * @param node the node
       * @return true if node is navigation-safe, false otherwise
       */
      static boolean isTernaryProtected(final Interpreter ii, JexlNode node) {
          for (JexlNode walk = node.jjtGetParent(); walk != null; walk = walk.jjtGetParent()) {
              // protect only the condition part of the ternary
              if (walk instanceof ASTTernaryNode
                      || walk instanceof ASTNullpNode
                      || walk instanceof ASTEQNode
                      || walk instanceof ASTNENode) {
                  return node == walk.jjtGetChild(0);
              }
              if (!(walk instanceof ASTReference || walk instanceof ASTArrayAccess)) {
                  break;
              }
              node = walk;
          }
          return false;
      }
  
      /**
       * Static delegation of getVariable.
       * @param ii the interpreter
       * @param frame the frame
       * @param block the scope
       * @param identifier the variable identifier
       * @return the variable value
       */
      static Object getVariable(final Interpreter ii, final Frame frame, final LexicalScope block, final ASTIdentifier identifier) {
          final int symbol = identifier.getSymbol();
          // if we have a symbol, we have a scope thus a frame
          if ((ii.options.isLexicalShade() || identifier.isLexical()) && identifier.isShaded()) {
              return ii.undefinedVariable(identifier, identifier.getName());
          }
          if (symbol >= 0) {
              if (frame.has(symbol)) {
                  final Object value = frame.get(symbol);
                  if (value != Scope.UNDEFINED) {
                      return value;
                  }
              }
          }
          final String name = identifier.getName();
          final Object value = ii.context.get(name);
          if (value == null && !ii.context.has(name)) {
              final boolean ignore = (ii.isSafe()
                      && (symbol >= 0
                      || identifier.jjtGetParent() instanceof ASTAssignment))
                      || (identifier.jjtGetParent() instanceof ASTReference);
              if (!ignore) {
                  return ii.unsolvableVariable(identifier, name, true); // undefined
              }
          }
         return value;
     }
 
     @Override
     protected Interpreter createInterpreter(final JexlContext context, final Frame frame, final JexlOptions opts) {
         return new Interpreter(this, opts, context, frame) {
             @Override
             protected boolean isStrictOperand(final JexlNode node) {
                 return false;
             }
 
             @Override
             protected boolean isTernaryProtected( final JexlNode node) {
                 return Engine32.isTernaryProtected(this, node);
             }
 
             @Override
             protected Object getVariable(final Frame frame, final LexicalScope block, final ASTIdentifier identifier) {
                 return Engine32.getVariable(this, frame, block, identifier);
             }
         };
     }
 
     @Override
     protected Interpreter createTemplateInterpreter(final TemplateInterpreter.Arguments args) {
         return new TemplateInterpreter(args) {
             @Override
             protected boolean isStrictOperand(final JexlNode node) {
                 return false;
             }
 
             @Override
             protected boolean isTernaryProtected( final JexlNode node) {
                 return Engine32.isTernaryProtected(this, node);
             }
 
             @Override
             protected Object getVariable(final Frame frame, final LexicalScope block, final ASTIdentifier identifier) {
                 return Engine32.getVariable(this, frame, block, identifier);
             }
         };
     }
 }