//Dstl (c) Crown Copyright 2017
package uk.gov.dstl.baleen.annotators.patterns.data;

import com.google.common.base.Objects;

import uk.gov.dstl.baleen.types.semantic.Relation;

/**
 * Wraps a relation, such that it can be used in equals / hashcode for stream.distinct / set
 * operations.
 */
public class RelationWrapper {
	private final Relation relation;

	/**
	 * Instantiates a new relation wrapper.
	 *
	 * @param relation
	 *            the relation
	 */
	public RelationWrapper(final Relation relation) {
		this.relation = relation;
	}

	/**
	 * Gets the relation.
	 *
	 * @return the relation
	 */
	public Relation getRelation() {
		return relation;
	}

	// We specifically equals / hashcode on the specific aspects of Relation

	// TODO: We don't mind about the begin/end value as long as the relation specific info is
	// the same?

	@Override
	public boolean equals(final Object other) {
		if (!(other instanceof RelationWrapper)) {
			return false;
		} else {
			final Relation or = ((RelationWrapper) other).getRelation();
			if (relation.getBegin() != or.getBegin()) {
				return false;
			} else if (relation.getEnd() != or.getEnd()) {
				return false;
			} else if (!stringEquals(relation.getRelationshipType(), or.getRelationshipType())) {
				return false;
			} else if (!stringEquals(relation.getRelationSubType(), or.getRelationSubType())) {
				return false;
			} else if (relation.getSource() != or.getSource()) {
				return false;
			} else if (relation.getTarget() != or.getTarget()) {
				return false;
			}

			return true;
		}
	}
	
	private boolean stringEquals(String a, String b){
		if(a == null && b == null){
			return true;
		}else if ((a == null && b != null) || (a != null && b == null)){
			return false;
		}
		
		return a.equals(b);
	}

	@Override
	public int hashCode() {
		return Objects.hashCode(relation.getBegin(), relation.getEnd(), relation.getRelationshipType(),
				relation.getRelationSubType(), relation.getSource(), relation.getTarget());
	}

}