/*
 * #!
 * Ontopoly Editor
 * #-
 * Copyright (C) 2001 - 2013 The Ontopia Project
 * #-
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * !#
 */
package ontopoly.models;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.Iterator;
import java.util.List;

import org.apache.wicket.model.LoadableDetachableModel;

import ontopoly.model.FieldInstance;

public class FieldValuesModel extends LoadableDetachableModel<List<FieldValueModel>> implements Comparator<FieldValueModel> {

  private FieldInstanceModel fieldInstanceModel;
  private Comparator<Object> comparator;
  private boolean showExtraField;
  private boolean showExtraFieldUserTriggered;
  private boolean autoExtraField = true;
  
  public FieldValuesModel(FieldInstanceModel fieldInstanceModel) {
    this(fieldInstanceModel, null);
  }
  
  public FieldValuesModel(FieldInstanceModel fieldInstanceModel, Comparator<Object> comparator) {
    if (fieldInstanceModel == null)
      throw new NullPointerException("fieldInstanceModel parameter cannot be null.");
    this.fieldInstanceModel = fieldInstanceModel;
    this.comparator = comparator;
  }
  
  public boolean getAutoExtraField() {
    return autoExtraField;
  }
  
  public void setAutoExtraField(boolean autoExtraField) {
    this.autoExtraField = autoExtraField;
  }
  
  public FieldInstanceModel getFieldInstanceModel() {
    return fieldInstanceModel;    
  }
  
  public boolean getShowExtraField() {
    return showExtraField;
  }

  public boolean getShowExtraFieldUserTriggered() {
    return showExtraFieldUserTriggered;
  }
  
  public void setShowExtraField(boolean showExtraField, boolean userTriggered) {
    this.showExtraField = showExtraField;
    this.showExtraFieldUserTriggered = userTriggered;
  }
  
  /**
   * Returns the number of values in the model. Note that the first
   * one might not represent an actual value. Use getNumberOfValues()
   * to get the real number of actual values in the model.
   * @return the size of the model.
   */
  public int size() {
    List<FieldValueModel> values = getObject();
    return values.size();
  }
  
  /**
   * Get the number of actual existing values. Number is either the same 
   * as size() or one less if the showExtraField is enabled.
   * @return the number of actual values
   */
  public int getNumberOfValues() {
    int size = size();
    if (getShowExtraField())
      size--;
    return size;
  }
  
  public boolean containsExisting() {
    List<FieldValueModel> values = getObject();
    return !values.isEmpty();
  }
  
  protected Collection<? extends Object> getValues(FieldInstance fieldInstance) {
    return fieldInstance.getValues();
  }
  
  @Override
  public List<FieldValueModel> getObject() {
    List<FieldValueModel> values = super.getObject();
    if (values.isEmpty() && autoExtraField)
      setShowExtraField(true, false);
    if (getShowExtraField()) {
      List<FieldValueModel> result = new ArrayList<FieldValueModel>(values);
      FieldValueModel fieldValueModel = FieldValueModel.createModel(fieldInstanceModel, null, false); 
      result.add(0, fieldValueModel);
      return result;
    } else {
      return values;
    }
  }
  
  @Override
  protected List<FieldValueModel> load() {
    FieldInstance fieldInstance = fieldInstanceModel.getFieldInstance();
    Collection<? extends Object> values = getValues(fieldInstance);
    if (values.isEmpty()) {
      return Collections.emptyList();
    } else {
      List<FieldValueModel> result = new ArrayList<FieldValueModel>(values.size());
      Iterator<? extends Object> iter = values.iterator();
      while (iter.hasNext()) {
        Object value = iter.next();
        result.add(FieldValueModel.createModel(fieldInstanceModel,  value, true));
      }
      // sort field value models
      if (comparator != null)
        Collections.sort(result, this);
      return result;
    }
  }

  public int compare(FieldValueModel fvm1, FieldValueModel fvm2) {
    return comparator.compare(fvm1.getFieldValue(), fvm2.getFieldValue());
  }
 
}