/*
 *    This program 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.
 *
 *    This program 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 this program; if not, write to the Free Software
 *    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

/*
 *    StringToNominal.java
 *    Copyright (C) 2002 University of Waikato, Hamilton, New Zealand
 *
 */

package weka.filters.unsupervised.attribute;

import java.util.Enumeration;
import java.util.Vector;

import weka.core.Attribute;
import weka.core.Capabilities;
import weka.core.Capabilities.Capability;
import weka.core.FastVector;
import weka.core.Instance;
import weka.core.Instances;
import weka.core.Option;
import weka.core.OptionHandler;
import weka.core.Range;
import weka.core.RevisionUtils;
import weka.core.UnsupportedAttributeTypeException;
import weka.core.Utils;
import weka.filters.Filter;
import weka.filters.UnsupervisedFilter;

/**
 <!-- globalinfo-start --> 
 * Converts a string attribute (i.e. unspecified
 * number of values) to nominal (i.e. set number of values). You should ensure
 * that all string values that will appear are represented in the first batch of
 * the data.
 * <p/>
 <!-- globalinfo-end -->
 * 
 <!-- options-start --> 
 * Valid options are:
 * <p/>
 * 
 * <pre>
 * -R &lt;col&gt;
 *  Sets the range of attribute indices (default last).
 * </pre>
 * 
 <!-- options-end -->
 * 
 * @author Len Trigg (len@reeltwo.com)
 * @version $Revision: 9273 $
 */
public class StringToNominal extends Filter implements UnsupervisedFilter,
    OptionHandler {

  /** for serialization */
  private static final long serialVersionUID = 4864084427902797605L;

  /** The attribute's range indices setting. */
  private final Range m_AttIndices = new Range("last");

  /**
   * Returns a string describing this filter
   * 
   * @return a description of the filter suitable for displaying in the
   *         explorer/experimenter gui
   */
  public String globalInfo() {

    return "Converts a range of string attributes (unspecified number of values) to nominal "
        + "(set number of values). You should ensure that all string values that "
        + "will appear are represented in the first batch of the data.";
  }

  /**
   * Returns the Capabilities of this filter.
   * 
   * @return the capabilities of this object
   * @see Capabilities
   */
  @Override
  public Capabilities getCapabilities() {
    Capabilities result = super.getCapabilities();
    result.disableAll();

    // attributes
    result.enableAllAttributes();
    result.enable(Capability.MISSING_VALUES);

    // class
    result.enableAllClasses();
    result.enable(Capability.MISSING_CLASS_VALUES);
    result.enable(Capability.NO_CLASS);

    return result;
  }

  /**
   * Sets the format of the input instances.
   * 
   * @param instanceInfo an Instances object containing the input instance
   *          structure (any instances contained in the object are ignored -
   *          only the structure is required).
   * @return true if the outputFormat may be collected immediately.
   * @throws UnsupportedAttributeTypeException if the selected attribute a
   *           string attribute.
   * @throws Exception if the input format can't be set successfully.
   */
  @Override
  public boolean setInputFormat(Instances instanceInfo) throws Exception {

    super.setInputFormat(instanceInfo);
    m_AttIndices.setUpper(instanceInfo.numAttributes() - 1);
    return false;
  }

  /**
   * Input an instance for filtering. The instance is processed and made
   * available for output immediately.
   * 
   * @param instance the input instance.
   * @return true if the filtered instance may now be collected with output().
   * @throws IllegalStateException if no input structure has been defined.
   */
  @Override
  public boolean input(Instance instance) {

    if (getInputFormat() == null) {
      throw new IllegalStateException("No input instance format defined");
    }
    if (m_NewBatch) {
      resetQueue();
      m_NewBatch = false;
    }

    if (isOutputFormatDefined()) {
      Instance newInstance = (Instance) instance.copy();

      // make sure that we get the right indexes set for the converted
      // string attributes when operating on a second batch of instances
      for (int i = 0; i < newInstance.numAttributes(); i++) {
        if (newInstance.attribute(i).isString() && !newInstance.isMissing(i)
            && m_AttIndices.isInRange(i)) {
          Attribute outAtt = getOutputFormat().attribute(
              newInstance.attribute(i).name());
          String inVal = newInstance.stringValue(i);
          int outIndex = outAtt.indexOfValue(inVal);
          if (outIndex < 0) {
            newInstance.setMissing(i);
          } else {
            newInstance.setValue(i, outIndex);
          }
        }
      }
      push(newInstance);
      return true;
    }

    bufferInput(instance);
    return false;
  }

  /**
   * Signifies that this batch of input to the filter is finished. If the filter
   * requires all instances prior to filtering, output() may now be called to
   * retrieve the filtered instances.
   * 
   * @return true if there are instances pending output.
   * @throws IllegalStateException if no input structure has been defined.
   */
  @Override
  public boolean batchFinished() {

    if (getInputFormat() == null) {
      throw new IllegalStateException("No input instance format defined");
    }
    if (!isOutputFormatDefined()) {

      setOutputFormat();

      // Convert pending input instances
      for (int i = 0; i < getInputFormat().numInstances(); i++) {
        Instance temp = (Instance) getInputFormat().instance(i).copy();
        for (int j = 0; j < temp.numAttributes(); j++) {
          if (temp.attribute(j).isString() && !temp.isMissing(j)
              && m_AttIndices.isInRange(j)) {

            // adjust indexes for the removal of the dummy string value
            temp.setValue(j, temp.value(j) - 1);
          }
        }
        push(temp);
      }
    }

    flushInput();
    m_NewBatch = true;
    return (numPendingOutput() != 0);
  }

  /**
   * Returns an enumeration describing the available options.
   * 
   * @return an enumeration of all the available options.
   */
  public Enumeration<Option> listOptions() {

    Vector<Option> newVector = new Vector<Option>(1);

    newVector.addElement(new Option(
        "\tSets the range of attribute indices (default last).", "R", 1,
        "-R <col>"));

    newVector.addElement(new Option("\tInvert the range specified by -R.", "V",
        1, "-V <col>"));

    return newVector.elements();
  }

  /**
   * Parses a given list of options.
   * <p/>
   * 
   * <!-- options-start --> Valid options are:
   * <p/>
   * 
   * <pre>
   * -R &lt;col&gt;
   *  Sets the range of attribute indices (default last).
   * </pre>
   * 
   * <pre>
   * -V &lt;col&gt;
   *  Inverts the selection specified by -R.
   * </pre>
   * 
   * <!-- options-end -->
   * 
   * @param options the list of options as an array of strings
   * @throws Exception if an option is not supported
   */
  public void setOptions(String[] options) throws Exception {

    String attIndices = Utils.getOption('R', options);
    if (attIndices.length() != 0) {
      setAttributeRange(attIndices);
    } else {
      setAttributeRange("last");
    }

    String invertSelection = Utils.getOption('V', options);
    if (invertSelection.length() != 0) {
      m_AttIndices.setInvert(true);
    } else {
      m_AttIndices.setInvert(false);
    }

    if (getInputFormat() != null) {
      setInputFormat(getInputFormat());
    }
  }

  /**
   * Gets the current settings of the filter.
   * 
   * @return an array of strings suitable for passing to setOptions
   */
  public String[] getOptions() {

    String[] options = new String[this.m_AttIndices.getInvert() ? 7 : 6];
    int current = 0;

    options[current++] = "-R";
    options[current++] = "" + (getAttributeRange());

    while (current < options.length) {
      options[current++] = "";
    }

    if (this.m_AttIndices.getInvert()) {
      options[current++] = "-V";
    }

    return options;
  }

  /**
   * @return tip text for this property suitable for displaying in the
   *         explorer/experimenter gui
   */
  public String attributeRangeTipText() {

    return "Sets which attributes to process. This attributes "
        + "must be string attributes (\"first\" and \"last\" are valid values "
        + "as well as ranges and lists)";
  }

  /**
   * Get the range of indices of the attributes used.
   * 
   * @return the index of the attribute
   */
  public String getAttributeRange() {

    return m_AttIndices.getRanges();
  }

  /**
   * Sets range of indices of the attributes used.
   * 
   * @param attIndex the index of the attribute
   */
  public void setAttributeRange(String rangeList) {

    m_AttIndices.setRanges(rangeList);
  }

  /**
   * Set the output format. Takes the current average class values and
   * m_InputFormat and calls setOutputFormat(Instances) appropriately.
   */
  private void setOutputFormat() {

    Instances newData;
    FastVector newAtts, newVals;

    // Compute new attributes

    newAtts = new FastVector(getInputFormat().numAttributes());
    for (int j = 0; j < getInputFormat().numAttributes(); j++) {
      Attribute att = getInputFormat().attribute(j);
      if (!m_AttIndices.isInRange(j) || !att.isString()) {

        // We don't have to copy the attribute because the
        // attribute index remains unchanged.
        newAtts.addElement(att);
      } else {

        // Compute list of attribute values
        newVals = new FastVector(att.numValues());
        for (int i = 1; i < att.numValues(); i++) {
          newVals.addElement(att.value(i));
        }
        Attribute newAtt = new Attribute(att.name(), newVals);
        newAtt.setWeight(att.weight());
        newAtts.addElement(newAtt);
      }
    }

    // Construct new header
    newData = new Instances(getInputFormat().relationName(), newAtts, 0);
    newData.setClassIndex(getInputFormat().classIndex());
    setOutputFormat(newData);
  }

  /**
   * Returns the revision string.
   * 
   * @return the revision
   */
  @Override
  public String getRevision() {
    return RevisionUtils.extract("$Revision: 9273 $");
  }

  /**
   * Main method for testing this class.
   * 
   * @param argv should contain arguments to the filter: use -h for help
   */
  public static void main(String[] argv) {
    runFilter(new StringToNominal(), argv);
  }
}
