/*
 * Copyright (c) 1998-2011 Caucho Technology -- all rights reserved
 *
 * This file is part of Resin(R) Open Source
 *
 * Each copy or derived work must preserve the copyright notice and this
 * notice unmodified.
 *
 * Resin Open Source is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * Resin Open Source 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, or any warranty
 * of NON-INFRINGEMENT.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Resin Open Source; if not, write to the
 *
 *   Free Software Foundation, Inc.
 *   59 Temple Place, Suite 330
 *   Boston, MA 02111-1307  USA
 *
 * @author Scott Ferguson
 */

package javax.script;

import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.Reader;
import java.io.Writer;
import java.util.ArrayList;
import java.util.List;

/**
 * Basic implementation of a script context.
 */
public class SimpleScriptContext implements ScriptContext {
  protected Bindings engineScope = new SimpleBindings();
  protected Bindings globalScope = new SimpleBindings();
  
  protected Reader reader = new InputStreamReader(System.in);
  protected Writer writer = new OutputStreamWriter(System.out);
  protected Writer errorWriter = new OutputStreamWriter(System.err);

  /**
   * Sets the bindings with the given scope.
   */
  public void setBindings(Bindings bindings, int scope)
  {
    switch (scope) {
    case ENGINE_SCOPE:
      this.engineScope = bindings;
      break;
    case GLOBAL_SCOPE:
      this.globalScope = bindings;
      break;
    default:
      throw new IllegalArgumentException("scope '" + scope + " must either be ENGINE_SCOPE or GLOBAL_SCOPE.");
    }
  }

  /**
   * Gets the bindings with the given scope.
   */
  public Bindings getBindings(int scope)
  {
    switch (scope) {
    case ENGINE_SCOPE:
      return this.engineScope;
    case GLOBAL_SCOPE:
      return this.globalScope;
    default:
      throw new IllegalArgumentException("scope '" + scope + " must either be ENGINE_SCOPE or GLOBAL_SCOPE.");
    }
  }

  /**
   * Returns the attribute value.
   */
  public Object getAttribute(String name)
  {
    Object v = null;

    if (this.engineScope != null)
      v = this.engineScope.get(name);

    if (v != null)
      return v;

    if (this.globalScope != null)
      v = this.globalScope.get(name);

    return v;
  }

  /**
   * Returns the attribute value.
   */
  public int getAttributesScope(String name)
  {
    Object v = this.engineScope.get(name);

    if (v != null)
      return ENGINE_SCOPE;

    v = this.globalScope.get(name);

    if (v != null)
      return GLOBAL_SCOPE;

    return -1;
  }

  /**
   * Returns the attribute value for the given scope.
   */
  public Object getAttribute(String name, int scope)
  {
    return getBindings(scope).get(name);
  }

  /**
   * Removes the attribute value for the given scope.
   */
  public Object removeAttribute(String name, int scope)
  {
    return getBindings(scope).remove(name);
  }

  /**
   * Sets the attribute value for the given scope.
   */
  public void setAttribute(String name, Object value, int scope)
  {
    getBindings(scope).put(name, value);
  }

  /**
   * Returns the reader.
   */
  public Reader getReader()
  {
    return this.reader;
  }

  /**
   * Sets the reader.
   */
  public void setReader(Reader reader)
  {
    this.reader = reader;
  }

  /**
   * Returns the writer.
   */
  public Writer getWriter()
  {
    return this.writer;
  }

  /**
   * Sets the writer.
   */
  public void setWriter(Writer writer)
  {
    this.writer = writer;
  }

  /**
   * Returns the error writer.
   */
  public Writer getErrorWriter()
  {
    return this.errorWriter;
  }

  /**
   * Sets the error writer.
   */
  public void setErrorWriter(Writer writer)
  {
    this.errorWriter = writer;
  }

  public List<Integer> getScopes()
  {
    ArrayList<Integer> scopes = new ArrayList<Integer>();

    scopes.add(ENGINE_SCOPE);
    scopes.add(GLOBAL_SCOPE);

    return scopes;
  }
}