/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you 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 org.apache.myfaces.tobago.internal.layout;
  
  import org.apache.myfaces.tobago.layout.Measure;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.util.ArrayList;
  import java.util.List;
  
  public class IntervalList extends ArrayList<Interval> {
  
    private static final Logger LOG = LoggerFactory.getLogger(IntervalList.class);
  
    private Measure minimum;
    private Measure current;
  
    public void evaluate() {
      List<Measure> minimumList = collectMinimum();
      List<Measure> maximumList = collectMaximum();
      minimum = Measure.max(minimumList);
      Measure maximum = Measure.min(maximumList);
      if (minimum.greaterThan(maximum)) {
        if (LOG.isDebugEnabled()) {
          LOG.debug("Layout: Found a minimum constraint " + minimum
              + " which is greater than a maximum constraint " + maximum + "!");
        }
        current = minimum;
      } else {
        List<Measure> preferred = findPreferredInInterval(minimum, maximum);
        if (!preferred.isEmpty()) {
          current = Measure.max(preferred);
        } else {
          current = minimum;
        }
      }
    }
  
    private List<Measure> collectMinimum() {
      List<Measure> result = new ArrayList<Measure>();
      for (Interval interval : this) {
        if (interval.getMinimum() != null) {
          result.add(interval.getMinimum());
        }
        if (interval.getCurrent() != null) {
          result.add(interval.getCurrent());
        }
      }
      return result;
    }
  
    private List<Measure> collectMaximum() {
      List<Measure> result = new ArrayList<Measure>();
      for (Interval interval : this) {
        if (interval.getMaximum() != null) {
          result.add(interval.getMaximum());
        }
      }
      return result;
    }
  
    private List<Measure> findPreferredInInterval(Measure min, Measure max) {
      List<Measure> result = new ArrayList<Measure>();
      for (Interval interval : this) {
        Measure value = interval.getCurrent();
        if (value == null) {
          value = interval.getPreferred();
        }
        if (value != null && value.greaterOrEqualThan(min) && value.lessOrEqualThan(max)) {
          result.add(value);
        }
      }
      return result;
    }
  
    public Measure getMinimum() {
      return minimum;
    }
  
    public Measure getCurrent() {
      return current;
   }
 }