/*
 * This file is part of ELKI:
 * Environment for Developing KDD-Applications Supported by Index-Structures
 *
 * Copyright (C) 2022
 * ELKI Development Team
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */
package elki.gui.configurator;

import java.awt.Dimension;
import java.awt.GridBagConstraints;

import javax.swing.JComponent;
import javax.swing.JLabel;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
import javax.swing.event.EventListenerList;

import elki.gui.icons.StockIcon;
import elki.logging.LoggingUtil;
import elki.utilities.optionhandling.parameterization.ListParameterization;
import elki.utilities.optionhandling.parameterization.TrackParameters;
import elki.utilities.optionhandling.parameters.Flag;
import elki.utilities.optionhandling.parameters.Parameter;

/**
 * Abstract class to produce a configurator for a particular parameter.
 * 
 * @author Erich Schubert
 * @since 0.4.0
 * 
 * @has - - - StockIcon
 * 
 * @param <T> parameter type
 */
public abstract class AbstractParameterConfigurator<T extends Parameter<?>> implements ParameterConfigurator {
  /**
   * The parameter to configure
   */
  final T param;

  /**
   * The parent container
   */
  final JComponent parent;

  /**
   * The event listeners for this parameter.
   */
  protected EventListenerList listenerList = new EventListenerList();

  /**
   * Constructor.
   * 
   * @param param Parameter
   * @param parent Parent
   */
  public AbstractParameterConfigurator(T param, JComponent parent) {
    super();
    this.param = param;
    this.parent = parent;
  }

  /**
   * Complete the current grid row, adding the icon at the end
   */
  protected void finishGridRow() {
    GridBagConstraints constraints = new GridBagConstraints();
    constraints.gridwidth = GridBagConstraints.REMAINDER;
    constraints.weightx = 0;
    final JLabel icon;
    if(param.isOptional()) {
      if(param.isDefined() && param.tookDefaultValue() && !(param instanceof Flag)) {
        // TODO: better icon for default value?
        icon = new JLabel(StockIcon.getStockIcon(StockIcon.DIALOG_INFORMATION));
        icon.setToolTipText("Default value: "+param.getDefaultValueAsString());
      }
      else {
        icon = new JLabel();
        icon.setMinimumSize(new Dimension(16, 16));
      }
    }
    else {
      if(!param.isDefined()) {
        icon = new JLabel(StockIcon.getStockIcon(StockIcon.DIALOG_ERROR));
        icon.setToolTipText("Missing value.");
      }
      else {
        icon = new JLabel();
        icon.setMinimumSize(new Dimension(16, 16));
      }
    }
    parent.add(icon, constraints);
  }

  @Override
  public void addParameter(Object owner, Parameter<?> param, TrackParameters track) {
    LoggingUtil.warning(this.getClass() + " does not support sub-parameters!");
  }

  @Override
  public void addChangeListener(ChangeListener listener) {
    listenerList.add(ChangeListener.class, listener);
  }

  @Override
  public void removeChangeListener(ChangeListener listener) {
    listenerList.remove(ChangeListener.class, listener);
  }

  /**
   * Notify listeners of a changed value.
   */
  protected void fireValueChanged() {
    // FIXME: compare with previous value?
    ChangeEvent evt = new ChangeEvent(this);
    for(ChangeListener listener : listenerList.getListeners(ChangeListener.class)) {
      listener.stateChanged(evt);
    }
  }

  @Override
  public void appendParameters(ListParameterization params) {
    Object val = getUserInput();
    if(val instanceof String && ((String) val).length() == 0) {
      val = null;
    }
    if(val != null) {
      params.addParameter(param.getOptionID(), val);
    }
  }

  /**
   * Get the value given by the user.
   * 
   * @return value for parameter
   */
  public abstract Object getUserInput();
}