/*
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html.
 *
 * This file is a derivative of code released under the terms listed below.
 *
 */
/*
*  Copyright (c) 2013,
*      Tobias Blaschke <code@tobiasblaschke.de>
*  All rights reserved.

*  Redistribution and use in source and binary forms, with or without
*  modification, are permitted provided that the following conditions are met:
*
*  1. Redistributions of source code must retain the above copyright notice,
*     this list of conditions and the following disclaimer.
*
*  2. Redistributions in binary form must reproduce the above copyright notice,
*     this list of conditions and the following disclaimer in the documentation
*     and/or other materials provided with the distribution.
*
*  3. The names of the contributors may not be used to endorse or promote
*     products derived from this software without specific prior written
*     permission.
*
*  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
*  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
*  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
*  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
*  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
*  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
*  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
*  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
*  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
*  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
*  POSSIBILITY OF SUCH DAMAGE.
*/
package com.ibm.wala.dalvik.ipa.callgraph.propagation.cfa;

import com.ibm.wala.ipa.callgraph.Context;
import com.ibm.wala.ipa.callgraph.ContextItem;
import com.ibm.wala.ipa.callgraph.ContextKey;

/**
 * Wraps an Intent to be suitable to be a Context-Element.
 *
 * <p>This class takes a parent so we don't loose information by overwriting.
 *
 * @author Tobias Blaschke &lt;code@tobiasblaschke.de&gt;
 * @since 2013-10-14
 */
public class IntentContext implements Context {
  /** Key into the Context that represents the Intent. */
  public static final ContextKey INTENT_KEY = Intent.INTENT_KEY;

  private final Intent intent;
  private final Context parent;

  public IntentContext(Intent intent) {
    this(null, intent);
  }

  public IntentContext(Context parent, Intent intent) {
    this.parent = parent;
    this.intent = intent;
  }

  /**
   * Looks up a ContextKey in the Context.
   *
   * @return an Intent or parent-managed object.
   * @throws IllegalArgumentException if the name is null.
   */
  @Override
  public ContextItem get(ContextKey name) {
    if (name == null) {
      throw new IllegalArgumentException("name is null");
    }
    if (name.equals(INTENT_KEY)) {
      return intent;
    } else if (this.parent != null) {
      return this.parent.get(name);
    } else {
      return null;
    }
  }

  /** Special equality: Object may be equal to an object without associated Intent. */
  @Override
  public boolean equals(Object obj) {
    if (obj == null) {
      return false;
    }
    if (obj instanceof IntentContext) {
      IntentContext other = (IntentContext) obj;
      if (this.intent.equals(other.intent)) {
        if (this.parent != null) {
          return this.parent.equals(other.parent);
        } else {
          return other.parent == null;
        }
      } else {
        return false;
      }
    } else {
      if (this.parent != null) {
        // TODO: do we really want this?
        return this.parent.equals(obj);
      } else {
        return false;
      }
    }
  }

  @Override
  public int hashCode() {
    // TODO: do we want to "clash" with the parent here?
    return 71891 * intent.hashCode();
  }

  @Override
  public String toString() {
    if (this.parent == null) {
      return "Intent: " + this.intent;
    } else {
      return "Intent: " + this.intent + ", parent: " + this.parent;
    }
  }

  public Intent getIntent() {
    return this.intent;
  }
}
