package org.javers.core.diff.changetype;

import java.util.Optional;

import org.javers.core.commit.CommitMetadata;
import org.javers.core.metamodel.object.GlobalId;

import java.util.Objects;

import static org.javers.common.string.ToStringBuilder.addField;

/**
 * Changed reference to Entity or ValueObject (in *ToOne relation)
 *
 * @author bartosz walacik
 */
public final class ReferenceChange extends PropertyChange {
    private final GlobalId left;
    private final GlobalId right;
    private transient final Optional<Object> leftObject;
    private transient final Optional<Object> rightObject;

    public ReferenceChange(GlobalId affectedCdoId, String propertyName, GlobalId leftReference,
                           GlobalId rightReference, Object leftObject, Object rightObject) {
        this(affectedCdoId, propertyName, leftReference, rightReference, leftObject, rightObject, Optional.empty());
    }

    public ReferenceChange(GlobalId affectedCdoId, String propertyName, GlobalId leftReference,
                           GlobalId rightReference, Object leftObject, Object rightObject, Optional<CommitMetadata> commitMetadata ) {
        super(affectedCdoId, propertyName, commitMetadata);
        this.left = leftReference;
        this.right = rightReference;
        this.leftObject = Optional.ofNullable(leftObject);
        this.rightObject = Optional.ofNullable(rightObject);
    }

    /**
     * GlobalId of left (or previous) domain object reference
     */
    public GlobalId getLeft() {
        return left;
    }

    /**
     * GlobalId of right (or current) domain object reference
     */
    public GlobalId getRight() {
        return right;
    }

    /**
     * Domain object reference at left side of a diff.
     *<br/><br/>
     *
     * <b>Optional</b> - available only for freshly generated diff.
     * Not available for Changes read from JaversRepository
     */
    public Optional<Object> getLeftObject() {
    	return leftObject;
    }

    /**
     * Domain object reference at right side of a diff.
     *<br/><br/>
     *
     * <b>Optional</b> - available only for freshly generated diff.
     * Not available for Changes read from JaversRepository
     */
    public Optional<Object> getRightObject() {
    	return rightObject;
    }

    @Override
    protected String fieldsToString() {
        return super.fieldsToString() + addField("oldRef", left) + addField("newRef", right);
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        if (obj instanceof ReferenceChange) {
            ReferenceChange that = (ReferenceChange) obj;
            return super.equals(that)
                    && Objects.equals(this.getLeft(), that.getLeft())
                    && Objects.equals(this.getRight(), that.getRight());
        }
        return false;
    }

    @Override
    public int hashCode() {
        return Objects.hash(super.hashCode(), getLeft(), getRight());
    }
}