package org.mongodb.morphia.geo;

import com.mongodb.BasicDBObject;
import org.mongodb.morphia.converters.SimpleValueConverter;
import org.mongodb.morphia.converters.TypeConverter;
import org.mongodb.morphia.mapping.MappedField;

A Morphia TypeConverter that knows how to turn things that are labelled with the Geometry interface into the correct concrete class,
based on the GeoJSON type.

Only implements the decode method as the concrete classes can encode themselves without needing a converter. It's when they come out of
the database that there's not enough information for Morphia to automatically create Geometry instances.
/**
 * A Morphia TypeConverter that knows how to turn things that are labelled with the Geometry interface into the correct concrete class,
 * based on the GeoJSON type.
 * <p/>
 * Only implements the decode method as the concrete classes can encode themselves without needing a converter. It's when they come out of
 * the database that there's not enough information for Morphia to automatically create Geometry instances.
 */
public class NamedCoordinateReferenceSystemConverter extends TypeConverter implements SimpleValueConverter {
    
Sets up this converter to work with things that implement the Geometry interface
/**
     * Sets up this converter to work with things that implement the Geometry interface
     */
    public NamedCoordinateReferenceSystemConverter() {
        super(NamedCoordinateReferenceSystem.class);
    }

    @Override
    public Object decode(final Class<?> targetClass, final Object fromDBObject, final MappedField optionalExtraInfo) {
        throw new UnsupportedOperationException("We should never need to decode these");
    }

    @Override
    public Object encode(final Object value, final MappedField optionalExtraInfo) {
        NamedCoordinateReferenceSystem crs = (NamedCoordinateReferenceSystem) value;
        final BasicDBObject dbObject = new BasicDBObject("type", crs.getType().getTypeName());
        dbObject.put("properties", new BasicDBObject("name", crs.getName()));

        return dbObject;
    }

    @Override
    protected boolean isSupported(final Class<?> c, final MappedField optionalExtraInfo) {
        return CoordinateReferenceSystem.class.isAssignableFrom(c);
    }
}