/*
 * Copyright 2017 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.polatis.netconf;

import com.google.common.collect.Range;
import org.apache.commons.configuration.HierarchicalConfiguration;
import org.onosproject.net.Direction;
import org.onosproject.net.OchSignal;
import org.onosproject.net.PortNumber;
import org.onosproject.net.behaviour.PowerConfig;
import org.onosproject.net.driver.AbstractHandlerBehaviour;
import org.slf4j.Logger;

import java.util.ArrayList;
import java.util.List;
import java.util.NoSuchElementException;
import java.util.Optional;

import static org.onosproject.drivers.polatis.netconf.PolatisOpticalUtility.POWER_MULTIPLIER;
import static org.onosproject.drivers.polatis.netconf.PolatisOpticalUtility.VOA_MULTIPLIER;
import static org.onosproject.drivers.polatis.netconf.PolatisOpticalUtility.POWER_RANGE;
import static org.onosproject.drivers.polatis.netconf.PolatisNetconfUtility.netconfGet;
import static org.onosproject.drivers.polatis.netconf.PolatisNetconfUtility.netconfEditConfig;
import static org.onosproject.drivers.polatis.netconf.PolatisNetconfUtility.configAt;
import static org.onosproject.drivers.polatis.netconf.PolatisNetconfUtility.configsAt;
import static org.onosproject.drivers.polatis.netconf.PolatisNetconfUtility.xml;
import static org.onosproject.drivers.polatis.netconf.PolatisNetconfUtility.xmlOpen;
import static org.onosproject.drivers.polatis.netconf.PolatisNetconfUtility.xmlClose;
import static org.onosproject.drivers.polatis.netconf.PolatisNetconfUtility.KEY_PORT;
import static org.onosproject.drivers.polatis.netconf.PolatisNetconfUtility.KEY_PORTID;
import static org.onosproject.drivers.polatis.netconf.PolatisNetconfUtility.KEY_OPM;
import static org.onosproject.drivers.polatis.netconf.PolatisNetconfUtility.KEY_OPM_XMLNS;
import static org.onosproject.drivers.polatis.netconf.PolatisNetconfUtility.KEY_DATA_OPM;
import static org.onosproject.drivers.polatis.netconf.PolatisNetconfUtility.KEY_DATA_OPM_PORT;
import static org.onosproject.drivers.polatis.netconf.PolatisNetconfUtility.KEY_VOA;
import static org.onosproject.drivers.polatis.netconf.PolatisNetconfUtility.KEY_VOA_XMLNS;
import static org.onosproject.drivers.polatis.netconf.PolatisNetconfUtility.KEY_DATA_VOA_PORT;
import static org.onosproject.drivers.polatis.netconf.PolatisNetconfUtility.CFG_MODE_MERGE;

import static org.slf4j.LoggerFactory.getLogger;

/**
 * Get current or target port/channel power from a Polatis optical netconf device.
 * Set target port power or channel attenuation to an optical netconf device.
 */
public class PolatisPowerConfig<T> extends AbstractHandlerBehaviour
        implements PowerConfig<T> {

    private static final String KEY_POWER = "power";
    private static final String KEY_ATTEN_LEVEL = "atten-level";
    private static final String KEY_ATTEN_MODE = "atten-mode";
    private static final String VALUE_ATTEN_MODE = "VOA_MODE_ABSOLUTE";

    private static final Logger log = getLogger(PolatisPowerConfig.class);

    @Override
    public Optional<Double> getTargetPower(PortNumber port, T component) {
        Long power = acquireCurrentPower(port, component);
        if (power == null) {
            return Optional.empty();
        }
        return Optional.of(power.doubleValue());
    }

    @Override
    public void setTargetPower(PortNumber port, T component, double power) {
        if (component instanceof OchSignal) {
            log.warn("Channel power is not applicable.");
            return;
        }
        setPortTargetPower(port, (long) power);
    }

    @Override
    public Optional<Double> currentPower(PortNumber port, T component) {
        Long power = acquireCurrentPower(port, component);
        if (power == null) {
            return Optional.empty();
        }
        return Optional.of(power.doubleValue());
    }

    @Override
    public Optional<Range<Double>> getTargetPowerRange(PortNumber port, T component) {
        Range<Long> power = getTxPowerRange(port, component);
        if (power == null) {
            return Optional.empty();
        }
        return Optional.of(Range.closed((double) power.lowerEndpoint(), (double) power.upperEndpoint()));
    }

    @Override
    public Optional<Range<Double>> getInputPowerRange(PortNumber port, T component) {
        Range<Long> power = getRxPowerRange(port, component);
        if (power == null) {
            return Optional.empty();
        }
        return Optional.of(Range.closed((double) power.lowerEndpoint(), (double) power.upperEndpoint()));
    }

    @Override
    public List<PortNumber> getPorts(T component) {
        if (component instanceof OchSignal) {
            log.warn("Channel component is not applicable.");
            return new ArrayList<PortNumber>();
        }
        log.debug("Get port config ports...");
        return acquirePorts();
    }

    private List<PortNumber> acquirePorts() {
        String filter = getPortPowerFilter(null);
        String reply = netconfGet(handler(), filter);
        List<HierarchicalConfiguration> subtrees = configsAt(reply, KEY_DATA_OPM);
        List<PortNumber> ports = new ArrayList<PortNumber>();
        for (HierarchicalConfiguration portConfig : subtrees) {
            ports.add(PortNumber.portNumber(portConfig.getLong(KEY_PORTID)));
        }
        return ports;
    }

    /**
     * Get the filter string for the OPM power NETCONF request.
     *
     * @param port the port, null to return all the opm ports
     * @return filter string
     */
    private String getPortPowerFilter(PortNumber port) {
        StringBuilder filter = new StringBuilder(xmlOpen(KEY_OPM_XMLNS))
                .append(xmlOpen(KEY_PORT))
                .append(xmlOpen(KEY_PORTID));
        if (port != null) {
            filter.append(port.toLong());
        }
        return filter.append(xmlClose(KEY_PORTID))
                .append(xmlClose(KEY_PORT))
                .append(xmlClose(KEY_OPM))
                .toString();
    }

    private Long acquireTargetPower(PortNumber port, T component) {
        if (component instanceof OchSignal) {
            log.warn("Channel power is not applicable.");
            return null;
        }
        log.debug("Get port{} target power...", port);
        return acquirePortAttenuation(port);
    }

    /**
     * Get the filter string for the attenuation NETCONF request.
     *
     * @param port the port, null to return all the attenuation ports
     * @return filter string
     */
    private String getPortAttenuationFilter(PortNumber port) {
        StringBuilder filter = new StringBuilder(xmlOpen(KEY_VOA_XMLNS))
                .append(xmlOpen(KEY_PORT))
                .append(xmlOpen(KEY_PORTID));
        if (port != null) {
            filter.append(port.toLong());
        }
        return filter.append(xmlClose(KEY_PORTID))
                .append(xmlOpen(KEY_ATTEN_LEVEL))
                .append(xmlClose(KEY_ATTEN_LEVEL))
                .append(xmlClose(KEY_PORT))
                .append(xmlClose(KEY_VOA))
                .toString();
    }

    private Long acquirePortAttenuation(PortNumber port) {
        String filter = getPortAttenuationFilter(port);
        String reply = netconfGet(handler(), filter);
        HierarchicalConfiguration info = configAt(reply, KEY_DATA_VOA_PORT);
        if (info == null) {
            return null;
        }
        long attenuation = 0;
        try {
            attenuation = (long) (info.getDouble(KEY_ATTEN_LEVEL) * VOA_MULTIPLIER);
        } catch (NoSuchElementException e) {
            log.debug("Could not find atten-level for port {}", port);
        }

        return attenuation;
    }

    private Long acquireCurrentPower(PortNumber port, T component) {
        if (component instanceof OchSignal) {
            log.warn("Channel power is not applicable.");
            return null;
        }
        log.debug("Get port{} current power...", port);
        return acquirePortPower(port);
    }

    private Long acquirePortPower(PortNumber port) {
        String filter = getPortPowerFilter(port);
        String reply = netconfGet(handler(), filter);
        HierarchicalConfiguration info = configAt(reply, KEY_DATA_OPM_PORT);
        if (info == null) {
            return null;
        }
        return (long) (info.getDouble(KEY_POWER) * POWER_MULTIPLIER);
    }

    private boolean setPortTargetPower(PortNumber port, long power) {
        log.debug("Set port{} target power...", port);
        String cfg = new StringBuilder(xmlOpen(KEY_VOA_XMLNS))
                .append(xmlOpen(KEY_PORT))
                .append(xml(KEY_PORTID, Long.toString(port.toLong())))
                .append(xml(KEY_ATTEN_MODE, VALUE_ATTEN_MODE))
                .append(xml(KEY_ATTEN_LEVEL, Double.toString((double) power / VOA_MULTIPLIER)))
                .append(xmlClose(KEY_PORT))
                .append(xmlClose(KEY_VOA))
                .toString();
        return netconfEditConfig(handler(), CFG_MODE_MERGE, cfg);
    }

    private Range<Long> getPowerRange() {
        return POWER_RANGE;
    }

    private Range<Long> getTxPowerRange(PortNumber port, T component) {
        if (component instanceof Direction) {
            log.debug("Get target port{} power range...", port);
            return getPowerRange();
        } else {
            log.warn("Channel power is not applicable.");
            return null;
        }
    }

    private Range<Long> getRxPowerRange(PortNumber port, T component) {
        log.debug("Get input port{} power range...", port);
        return getPowerRange();
    }
}