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/* Bindings.java --

   Copyright (C) 2004 Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath 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, or (at your option)

any later version.

GNU Classpath 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.  See the GNU

General Public License for more details.

You should have received a copy of the GNU General Public License

along with GNU Classpath; see the file COPYING.  If not, write to the

Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

02110-1301 USA.

Linking this library statically or dynamically with other modules is

making a combined work based on this library.  Thus, the terms and

conditions of the GNU General Public License cover the whole

combination.

As a special exception, the copyright holders of this library give you

permission to link this library with independent modules to produce an

executable, regardless of the license terms of these independent

modules, and to copy and distribute the resulting executable under

terms of your choice, provided that you also meet, for each linked

independent module, the terms and conditions of the license of that

module.  An independent module is a module which is not derived from

or based on this library.  If you modify this library, you may extend

this exception to your version of the library, but you are not

obligated to do so.  If you do not wish to do so, delete this

exception statement from your version. */

package gnu.xml.transform;

import java.util.Collection;

import java.util.Collections;

import java.util.HashMap;

import java.util.HashSet;

import java.util.Iterator;

import java.util.LinkedList;

import java.util.Map;

import javax.xml.namespace.QName;

import javax.xml.xpath.XPathVariableResolver;

import org.w3c.dom.Node;

/**

 * The set of variable bindings in effect for a stylesheet.

 *

 * @author <a href='mailto:dog@gnu.org'>Chris Burdess</a>

 */

public class Bindings

  implements XPathVariableResolver, Cloneable

{

  static final int VARIABLE = 0;

  static final int PARAM = 1;

  static final int WITH_PARAM = 2;

  final Stylesheet stylesheet;

  /**

   * Global variables.

   */

  final LinkedList variables;

  /**

   * Parameter value stack.

   */

  final LinkedList parameters;

  /**

   * Argument (with-param) value stack.

   */

  final LinkedList withParameters;

  Bindings(Stylesheet stylesheet)

  {

    this.stylesheet = stylesheet;

    variables = new LinkedList();

    parameters = new LinkedList();

    withParameters = new LinkedList();

    for (int i = 0; i < 3; i++)

      {

        push(i);

      }

  }

  public Object clone()

  {

    try

      {

        return (Bindings) super.clone();

      }

    catch (CloneNotSupportedException e)

      {

        throw new Error(e.getMessage());

      }

  }

  void push(int type)

  {

    switch (type)

      {

      case VARIABLE:

        variables.addFirst(new HashMap());

        break;

      case PARAM:

        parameters.addFirst(new HashMap());

        break;

      case WITH_PARAM:

        withParameters.addFirst(new HashMap());

        break;

      }

  }

  void pop(int type)

  {

    switch (type)

      {

      case VARIABLE:

        variables.removeFirst();

        break;

      case PARAM:

        parameters.removeFirst();

        break;

      case WITH_PARAM:

        withParameters.removeFirst();

        break;

      }

  }

  public boolean containsKey(QName name, int type)

  {

    Iterator i = null;

    switch (type)

      {

      case VARIABLE:

        i = variables.iterator();

        break;

      case PARAM:

        i = parameters.iterator();

        break;

      case WITH_PARAM:

        Map ctx = (Map) withParameters.getFirst();

        return ctx.containsKey(name);

      }

    if (i != null)

      {

        while (i.hasNext())

          {

            Map ctx = (Map) i.next();

            if (ctx.containsKey(name))

              {

                return true;

              }

          }

      }

    return false;

  }

  public Object get(QName name, Node context, int pos, int len)

  {

    //System.err.println("bindings.get: "+name);

    //System.err.println("\t"+toString());

    Object ret = null;

    //if (parameters.size() > 1 && containsKey(name, PARAM))

      // check that template defines parameter

      {

        Map cwp = (Map) withParameters.getFirst();

        ret = cwp.get(name);

        //System.err.println("\twith-param: ret="+ret);

      }

    if (ret == null)

      {

        for (Iterator i = variables.iterator(); i.hasNext() && ret == null; )

          {

            Map vctx = (Map) i.next();

            ret = vctx.get(name);

          }

        //System.err.println("\tvariable: ret="+ret);

      }

    if (ret == null)

      {

        for (Iterator i = parameters.iterator(); i.hasNext() && ret == null; )

          {

            Map pctx = (Map) i.next();

            ret = pctx.get(name);

          }

        //System.err.println("\tparam: ret="+ret);

      }

    /*if (ret instanceof Expr && context != null)

      {

        Expr expr = (Expr) ret;

        ret = expr.evaluate(context, 1, 1);

      }*/

    if (ret instanceof Node)

      {

        ret = Collections.singleton(ret);

      }

    if (ret == null)

      {

        ret = "";

      }

    //System.err.println("\tret="+ret);

    return ret;

  }

  void set(QName name, Object value, int type)

  {

    switch (type)

      {

      case VARIABLE:

        Map vctx = (Map) variables.getFirst();

        vctx.put(name, value);

        break;

      case PARAM:

        Map pctx = (Map) parameters.getFirst();

        pctx.put(name, value);

        break;

      case WITH_PARAM:

        Map wctx = (Map) withParameters.getFirst();

        wctx.put(name, value);

        break;

      }

    //System.err.println("Set "+name+"="+value);

  }

  public Object resolveVariable(QName qName)

  {

    return get(qName, null, 1, 1);

  }

  public String toString()

  {

    StringBuffer buf = new StringBuffer();

    boolean next = false;

    Collection seen = new HashSet();

    Map wctx = (Map) withParameters.getFirst();

    buf.append('(');

    for (Iterator i = wctx.entrySet().iterator(); i.hasNext(); )

      {

        if (next)

          {

            buf.append(',');

          }

        else

          {

            next = true;

          }

        Map.Entry entry = (Map.Entry) i.next();

        Object key = entry.getKey();

        if (!seen.contains(key))

          {

            buf.append(key);

            buf.append('=');

            buf.append(entry.getValue());

            seen.add(key);

          }

      }

    buf.append(')');

    next = false;

    seen.clear();

    buf.append('{');

    for (Iterator i = variables.iterator(); i.hasNext(); )

      {

        Map ctx = (Map) i.next();

        for (Iterator j = ctx.entrySet().iterator(); j.hasNext(); )

          {

            if (next)

              {

                buf.append(',');

              }

            else

              {

                next = true;

              }

            Map.Entry entry = (Map.Entry) j.next();

            Object key = entry.getKey();

            if (!seen.contains(key))

              {

                buf.append(key);

                buf.append('=');

                buf.append(entry.getValue());

                seen.add(key);

              }

          }

      }

    buf.append('}');

    next = false;

    seen.clear();

    buf.append('[');

    for (Iterator i = parameters.iterator(); i.hasNext(); )

      {

        Map ctx = (Map) i.next();

        for (Iterator j = ctx.entrySet().iterator(); j.hasNext(); )

          {

            if (next)

              {

                buf.append(',');

              }

            else

              {

                next = true;

              }

            Map.Entry entry = (Map.Entry) j.next();

            Object key = entry.getKey();

            if (!seen.contains(key))

              {

                buf.append(key);

                buf.append('=');

                buf.append(entry.getValue());

                seen.add(key);

              }

          }

      }

    buf.append(']');

    return buf.toString();

  }

}