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 * JBoss, Home of Professional Open Source.
 * Copyright 2020, Red Hat, Inc., and individual contributors
 * as indicated by the @author tags. See the copyright.txt file in the
 * distribution for a full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.wildfly.extension.metrics;

import static org.jboss.as.controller.descriptions.ModelDescriptionConstants.FAILURE_DESCRIPTION;
import static org.jboss.as.controller.descriptions.ModelDescriptionConstants.NAME;
import static org.jboss.as.controller.descriptions.ModelDescriptionConstants.OP;
import static org.jboss.as.controller.descriptions.ModelDescriptionConstants.OP_ADDR;
import static org.jboss.as.controller.descriptions.ModelDescriptionConstants.READ_ATTRIBUTE_OPERATION;
import static org.jboss.as.controller.descriptions.ModelDescriptionConstants.RESULT;
import static org.wildfly.extension.metrics._private.MetricsLogger.LOGGER;

import java.util.OptionalDouble;

import org.jboss.as.controller.LocalModelControllerClient;
import org.jboss.as.controller.PathAddress;
import org.jboss.as.controller.descriptions.ModelDescriptionConstants;
import org.jboss.dmr.ModelNode;

public class WildFlyMetric implements Metric {

    private static final ModelNode UNDEFINED = new ModelNode();

    private LocalModelControllerClient modelControllerClient;
    private final PathAddress address;
    private final String attributeName;

    static {
        UNDEFINED.protect();
    }

    public WildFlyMetric(LocalModelControllerClient modelControllerClient, PathAddress address, String attributeName) {
        this.modelControllerClient = modelControllerClient;
        this.address = address;
        this.attributeName = attributeName;
    }

    @Override
    public OptionalDouble getValue() {
        ModelNode result = readAttributeValue(address, attributeName);
        if (result.isDefined()) {
            try {
                return OptionalDouble.of(result.asDouble());
            } catch (Exception e) {
                LOGGER.unableToConvertAttribute(attributeName, address, e);
            }
        }
        return OptionalDouble.empty();
    }

    private ModelNode readAttributeValue(PathAddress address, String attributeName) {
        final ModelNode readAttributeOp = new ModelNode();
        readAttributeOp.get(OP).set(READ_ATTRIBUTE_OPERATION);
        readAttributeOp.get(OP_ADDR).set(address.toModelNode());
        readAttributeOp.get(ModelDescriptionConstants.INCLUDE_UNDEFINED_METRIC_VALUES).set(false);
        readAttributeOp.get(NAME).set(attributeName);
        ModelNode response = modelControllerClient.execute(readAttributeOp);
        String error = getFailureDescription(response);
        // TODO: Revisit this handling
        if (error != null) {
            // [WFLY-11933] if the value can not be read if the management resource is not accessible due to RBAC,
            // it is logged it at a lower level.
            if (error.contains("WFLYCTL0216")) {
                LOGGER.debugf("Unable to read attribute %s: %s.", attributeName, error);
            } else{
                LOGGER.unableToReadAttribute(attributeName, address, error);
            }
            return UNDEFINED;
        }
        return  response.get(RESULT);
    }

    private String getFailureDescription(ModelNode result) {
        if (result.hasDefined(FAILURE_DESCRIPTION)) {
            return result.get(FAILURE_DESCRIPTION).toString();
        }
        return null;
    }
}
