/*
    * Licensed to The Apereo Foundation under one or more contributor license
    * agreements. See the NOTICE file distributed with this work for additional
    * information regarding copyright ownership.
    *
    *
    * The Apereo Foundation licenses this file to you under the Educational
    * Community 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://opensource.org/licenses/ecl2.txt
   *
   * 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.opencastproject.util.requests;
  
  import static java.util.Objects.requireNonNull;
  
  import java.util.Objects;
  
  /**
   * A sort criterion represents the combination of a field name and a sort {@link Order}
   */
  public final class SortCriterion {
  
    /**
     * Sort order definitions.
     */
    public enum Order {
      None, Ascending, Descending
    }
  
    private final String fieldName;
    private final Order order;
  
    /**
     * Parse a string representation of a sort criterion.
     *
     * @param sortCriterion
     *          the sort criterion string
     * @return the sort criterion
     */
    public static SortCriterion parse(final String sortCriterion) {
      requireNonNull(sortCriterion);
  
      String[] parts = sortCriterion.split(":");
      if (parts.length != 2) {
        throw new IllegalArgumentException("sortOrder must be of form <field name>:ASC/DESC");
      }
  
      if ("ASC".equalsIgnoreCase(parts[1]) || "Ascending".equalsIgnoreCase(parts[1])) {
        return new SortCriterion(parts[0].trim(), Order.Ascending);
      }
      if ("DESC".equalsIgnoreCase(parts[1]) || "Descending".equalsIgnoreCase(parts[1])) {
        return new SortCriterion(parts[0].trim(), Order.Descending);
      }
  
      throw new IllegalArgumentException("Invalid order " + parts[1]);
    }
  
    /**
     * Create a order criterion based on the given field name and order.
     *
     * @param fieldName
     *          the field name
     * @param order
     *          the order
     */
    public SortCriterion(String fieldName, Order order) {
      this.fieldName = fieldName;
      this.order = order;
    }
  
    public String getFieldName() {
      return fieldName;
    }
  
    public Order getOrder() {
      return order;
    }
  
    @Override
    public boolean equals(Object o) {
      if (o == this) {
        return true;
      }
  
      if (!(o instanceof SortCriterion)) {
        return false;
      }
  
     SortCriterion that = (SortCriterion) o;
     return Objects.equals(this.fieldName, that.fieldName) && Objects.equals(this.order, that.order);
   }
 
   @Override
   public int hashCode() {
     return Objects.hash(fieldName, order);
   }
 
   @Override
   public String toString() {
     if (order.equals(Order.Ascending)) {
       return fieldName + ":ASC";
     }
     if (order.equals(Order.Descending)) {
       return fieldName + ":DESC";
     }
     return fieldName + ":NONE";
   }
 
 }