/*
 * Copyright (c) 2019 the Eclipse Milo Authors
 *
 * This program and the accompanying materials are made
 * available under the terms of the Eclipse Public License 2.0
 * which is available at https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 */

package org.eclipse.milo.opcua.sdk.server.events.operators;

import org.eclipse.milo.opcua.sdk.server.events.FilterContext;
import org.eclipse.milo.opcua.sdk.server.events.OperatorContext;
import org.eclipse.milo.opcua.sdk.server.events.ValidationException;
import org.eclipse.milo.opcua.sdk.server.model.nodes.objects.BaseEventTypeNode;
import org.eclipse.milo.opcua.stack.core.StatusCodes;
import org.eclipse.milo.opcua.stack.core.UaException;
import org.eclipse.milo.opcua.stack.core.types.builtin.NodeId;
import org.eclipse.milo.opcua.stack.core.types.structured.FilterOperand;
import org.jetbrains.annotations.Nullable;

import static org.eclipse.milo.opcua.sdk.server.events.EventContentFilter.subtypeOf;

public class OfType implements Operator<Boolean> {

    OfType() {}

    @Override
    public void validate(FilterContext context, FilterOperand[] operands) throws ValidationException {
        if (operands.length < 1) {
            throw new ValidationException(StatusCodes.Bad_FilterOperandCountMismatch);
        }
    }

    @Nullable
    @Override
    public Boolean apply(
        OperatorContext context,
        BaseEventTypeNode eventNode,
        FilterOperand[] operands
    ) throws UaException {

        validate(context, operands);

        Object value = context.resolve(operands[0], eventNode);

        if (value instanceof NodeId) {
            NodeId eventTypeDefinitionId =
                eventNode.getTypeDefinitionNode().getNodeId();

            NodeId targetTypeDefinitionId = (NodeId) value;

            return eventTypeDefinitionId.equals(targetTypeDefinitionId) ||
                subtypeOf(eventTypeDefinitionId, targetTypeDefinitionId, context.getServer());
        } else {
            return false;
        }
    }

}
