/**
 * MVEL (The MVFLEX Expression Language)
 *
 * Copyright (C) 2007 Christopher Brock, MVFLEX/Valhalla Project and the Codehaus
 *
 * Licensed 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.mvel2.optimizers.impl.refl.nodes;

import org.mvel2.compiler.Accessor;
import org.mvel2.integration.VariableResolverFactory;
import org.mvel2.optimizers.AccessorOptimizer;
import org.mvel2.optimizers.OptimizerFactory;

import static org.mvel2.compiler.AbstractParser.getCurrentThreadParserContext;

/**
 * @author Christopher Brock
 */
public class Union implements Accessor {
  private Accessor accessor;
  private char[] nextExpr;
  private int start;
  private int offset;
  private Accessor nextAccessor;

  public Union(Accessor accessor, char[] nextAccessor, int start, int offset) {
    this.accessor = accessor;
    this.start = start;
    this.offset = offset;
    this.nextExpr = nextAccessor;
  }

  public Object getValue(Object ctx, Object elCtx, VariableResolverFactory variableFactory) {
    if (nextAccessor == null) {
      return get(ctx, elCtx, variableFactory);
    }
    else {
      return nextAccessor.getValue(get(ctx, elCtx, variableFactory), elCtx, variableFactory);
    }
  }

  public Object setValue(Object ctx, Object elCtx, VariableResolverFactory variableFactory, Object value) {
    return nextAccessor.setValue(get(ctx, elCtx, variableFactory), elCtx, variableFactory, value);
  }

  private Object get(Object ctx, Object elCtx, VariableResolverFactory variableFactory) {
    if (nextAccessor == null) {
      Object o = accessor.getValue(ctx, elCtx, variableFactory);
      AccessorOptimizer ao = OptimizerFactory.getDefaultAccessorCompiler();
      Class ingress = accessor.getKnownEgressType();

      nextAccessor = ao.optimizeAccessor(getCurrentThreadParserContext(), nextExpr, start, offset, o, elCtx, variableFactory,
          false, ingress);
      return ao.getResultOptPass();
    }
    else {
      return accessor.getValue(ctx, elCtx, variableFactory);
    }
  }

  public Class getLeftIngressType() {
    return accessor.getKnownEgressType();
  }

  public Class getKnownEgressType() {
    return nextAccessor.getKnownEgressType();
  }
}
