/*
 * Copyright 2018-present Open Networking Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.onosproject.drivers.ciena.c5162.netconf;

import static com.google.common.base.Preconditions.checkNotNull;
import static org.slf4j.LoggerFactory.getLogger;

import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.CompletableFuture;

import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;

import org.onosproject.drivers.netconf.TemplateManager;
import org.onosproject.net.PortNumber;
import org.onosproject.net.behaviour.PortAdmin;
import org.onosproject.net.driver.AbstractHandlerBehaviour;
import org.onosproject.netconf.NetconfController;
import org.onosproject.netconf.NetconfException;
import org.onosproject.netconf.NetconfSession;
import org.slf4j.Logger;
import org.w3c.dom.Node;

/**
 * Handles port administration for Ciena 5162 devices using the NETCONF
 * protocol.
 */
public class Ciena5162PortAdmin extends AbstractHandlerBehaviour implements PortAdmin {

    private static final Logger log = getLogger(Ciena5162PortAdmin.class);
    private static final TemplateManager TEMPLATE_MANAGER = new TemplateManager();

    static {
        TEMPLATE_MANAGER.load(Ciena5162PortAdmin.class, "/templates/requests/%s.j2", "logicalPort", "port-admin-state");
    }

    /**
     * Sets the administrative state of the given port to the given value.
     *
     * @param number
     *            port number
     * @param value
     *            state, true for enabled, false for disabled
     * @return true if successfully set
     */
    private CompletableFuture<Boolean> setAdminState(PortNumber number, Boolean value) {
        NetconfController controller = checkNotNull(handler().get(NetconfController.class));
        NetconfSession session = controller.getDevicesMap().get(handler().data().deviceId()).getSession();

        try {
            Map<String, Object> templateContext = new HashMap<String, Object>();
            templateContext.put("port-number", number.toLong());
            templateContext.put("admin-state", value.toString());
            Node req = (Node) TEMPLATE_MANAGER.doRequest(session, "port-admin-state", templateContext, "/",
                    XPathConstants.NODE);
            XPath xp = XPathFactory.newInstance().newXPath();

            // If OK element exists then it worked.
            Node ok = (Node) xp.evaluate("/rpc-reply/ok", req, XPathConstants.NODE);
            return CompletableFuture.completedFuture(ok != null);
        } catch (XPathExpressionException | NetconfException e) {
            log.error("Unable to set port admin state for port {} to {}", number, handler().data().deviceId(), value,
                    e);
        }
        return CompletableFuture.completedFuture(false);

    }

    @Override
    public CompletableFuture<Boolean> enable(PortNumber number) {
        return setAdminState(number, true);
    }

    @Override
    public CompletableFuture<Boolean> disable(PortNumber number) {
        return setAdminState(number, false);
    }

    @Override
    public CompletableFuture<Boolean> isEnabled(PortNumber number) {
        NetconfController controller = checkNotNull(handler().get(NetconfController.class));
        NetconfSession session = controller.getDevicesMap().get(handler().data().deviceId()).getSession();

        try {
            Map<String, Object> templateContext = new HashMap<String, Object>();
            templateContext.put("port-number", number.toString());
            Node port = TEMPLATE_MANAGER.doRequest(session, "logicalPort", templateContext);
            XPath xp = XPathFactory.newInstance().newXPath();
            return CompletableFuture.completedFuture(Boolean.valueOf(xp.evaluate("admin-status/text()", port)));
        } catch (XPathExpressionException | NetconfException e) {
            log.error("Unable to query port state for port {} from device {}", number, handler().data().deviceId(), e);
        }
        return CompletableFuture.completedFuture(false);
    }

}