package org.geotools.data.efeature.adapters;

import org.eclipse.emf.query.conditions.Condition;
import org.eclipse.emf.query.conditions.IDataTypeAdapter;

import com.vividsolutions.jts.geom.Geometry;
import com.vividsolutions.jts.io.ParseException;
import com.vividsolutions.jts.io.WKBReader;
import com.vividsolutions.jts.io.WKBWriter;

/**
 * An Adapter class to be used to extract from -adapt- the argument object 
 * to some (primitive) byte array that would later be used in 
 * <code>Condition</code> evaluation.
 * 
 * Clients can subclass it and provide their own implementation
 * 
 * @see {@link Condition}
 */
public abstract class WKBAdapter implements IDataTypeAdapter<byte[]> {
    
    /**
     * Cached {@link WKBWriter} instance for writing
     */
    public final static WKBWriter WRITER = new WKBWriter();

    /**
     * Cached {@link WKBReader} instance for reading
     */
    public final static WKBReader READER = new WKBReader();

    /**
     * The simplest {@link WKBAdapter} implementation that represents 
     * the case when the argument object to adapt is a byte array or
     * a {@link Geometry} instance.
     */
    public static final WKBAdapter DEFAULT = new WKBAdapter() {
        @Override
        public byte[] toWKB(Object object) {
            try {
                //
                // Validate?
                //
                if (object instanceof byte[]) {
                    //
                    // Will fail if not valid geometry
                    //
                    object = READER.read((byte[]) object);
                }
            } catch (ParseException e) { /* Consume */}
            //
            // If geometry, write to WKB
            //
            if (object instanceof Geometry) {
                return WRITER.write((Geometry) object);
            }
            //
            // All attempts to adapt failed
            //
            throw new IllegalArgumentException("Object " + object + " is not a WKB");
        }

    };

    /**
     * Adapts given object to a WKB byte array
     * 
     * @param object - the object to adapt to a WKB byte array 
     * @return a WKB byte array
     */
    public abstract byte[] toWKB(Object object);

    /**
     * Adapts given object to a WKB byte array
     * 
     * @param object - the object to adapt to a WKB byte array 
     * @return a WKB byte array
     */
    @Override
    public byte[] adapt(Object value) {
        return toWKB(value);
    }

}