package com.terradue.jcatalogue.client.internal.converters;
   
   /*
    *    Copyright 2011-2012 Terradue srl
    *
    *    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.
   */
  
  import static java.lang.String.format;
  import static org.apache.commons.beanutils.ConvertUtils.lookup;
  
  import org.apache.commons.beanutils.ConversionException;
  import org.apache.commons.beanutils.Converter;
  
  import com.terradue.jcatalogue.client.geo.Line;
  import com.terradue.jcatalogue.client.geo.Point;
  import com.terradue.jcatalogue.client.geo.Polygon;
  
  public final class GeoConverter
      implements Converter
  {
  
      private static final String SEPARATOR = " ";
  
      private static final int EVEN_VERIFIER = 2;
  
      private final Converter doubleConverter = lookup( Double.class );
  
      public Object convert( @SuppressWarnings( "rawtypes" ) Class type, Object value )
      {
          if ( value == null )
          {
              throw new ConversionException( "Null values not supported in this version." );
          }
  
          if ( value instanceof String )
          {
              String stringValue = (String) value;
  
              if ( stringValue.isEmpty() )
              {
                  throw new ConversionException( "empty value cannot be converted to a valid GeoLocation" );
              }
  
              String[] values = ( stringValue ).split( SEPARATOR );
  
              if ( ( values.length % EVEN_VERIFIER ) != 0 )
              {
                  throw new ConversionException( format( "Cannot convert %s to a Geo representation, coordinates must be even in number (%s)",
                                                         value, values.length ) );
              }
  
              // extract points
              Point[] points = new Point[values.length / EVEN_VERIFIER];
  
              for ( int i = 0; i < values.length; i += EVEN_VERIFIER )
              {
                  Double latitude = (Double) doubleConverter.convert( Double.class, values[i] );
                  Double longitude = (Double) doubleConverter.convert( Double.class, values[i+1] );
  
                  points[i / EVEN_VERIFIER] = new Point( latitude, longitude );
              }
  
              if ( Line.class == type )
              {
                  return new Line( points );
              }
              else if ( Point.class == type )
              {
                  return points[0];
              }
              else if ( Polygon.class == type )
              {
                  if ( !points[0].equals( points[points.length - 1] ) )
                  {
                      throw new ConversionException( "Input points don't descrive a valid Polygon, first and last Points are not equals" );
                  }
                  return new Polygon( points );
              }
          }
          throw new ConversionException( format( "type %s and value %s not supported", type, value ) );
      }
  
  }