/*
 * Copyright 2017-present Open Networking Laboratory
 *
 * 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.ofagent.impl;

import io.netty.channel.Channel;
import org.onosproject.net.Device;
import org.onosproject.net.Port;
import org.onosproject.net.flow.FlowRule;
import org.onosproject.net.packet.InboundPacket;
import org.onosproject.ofagent.api.OFSwitch;
import org.onosproject.ofagent.api.OFSwitchCapabilities;
import org.projectfloodlight.openflow.protocol.OFControllerRole;
import org.projectfloodlight.openflow.protocol.OFMessage;

import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;

import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
import static org.projectfloodlight.openflow.protocol.OFControllerRole.*;

/**
 * Implementation of OF switch.
 */
public final class DefaultOFSwitch implements OFSwitch {

    private static final String ERR_CH_DUPLICATE = "Channel already exists: ";
    private static final String ERR_CH_NOT_FOUND = "Channel not found: ";

    private final Device device;
    private final OFSwitchCapabilities capabilities;

    private final ConcurrentHashMap<Channel, OFControllerRole> controllerRoleMap
            = new ConcurrentHashMap<>();

    private DefaultOFSwitch(Device device, OFSwitchCapabilities capabilities) {
        this.device = device;
        this.capabilities = capabilities;
    }

    // TODO add builder

    @Override
    public Device device() {
        return null;
    }

    @Override
    public OFSwitchCapabilities capabilities() {
        return null;
    }

    @Override
    public boolean isConnected() {
        return false;
    }

    @Override
    public void started() {
        // TODO do some initial setups
    }

    @Override
    public void stopped() {
        // TODO implement
    }

    @Override
    public void addControllerChannel(Channel channel) {
        controllerRoleMap.compute(channel, (ch, existing) -> {
            final String error = ERR_CH_DUPLICATE + channel.remoteAddress();
            checkArgument(existing == null, error);
            return ROLE_EQUAL;
        });
    }

    @Override
    public void deleteControllerChannel(Channel channel) {
        if (controllerRoleMap.remove(channel) == null) {
            final String error = ERR_CH_NOT_FOUND + channel.remoteAddress();
            throw new IllegalStateException(error);
        }
    }

    @Override
    public void setRole(Channel channel, OFControllerRole role) {
        controllerRoleMap.compute(channel, (ch, existing) -> {
            final String error = ERR_CH_NOT_FOUND + channel.remoteAddress();
            checkNotNull(existing, error);
            return role;
        });
    }

    @Override
    public OFControllerRole role(Channel channel) {
        OFControllerRole role = controllerRoleMap.get(channel);
        if (role == null) {
            final String error = ERR_CH_NOT_FOUND + channel.remoteAddress();
            throw new IllegalStateException(error);
        }
        return role;
    }

    @Override
    public Set<Channel> controllerChannels() {
        return null;
    }

    @Override
    public void processPortAdded(Port port) {
        // TODO generate FEATURES_REPLY message and send it to the controller
    }

    @Override
    public void processPortDown(Port port) {
        // TODO generate PORT_STATUS message and send it to the controller
    }

    @Override
    public void processPortUp(Port port) {
        // TODO generate PORT_STATUS message and send it to the controller
    }

    @Override
    public void processFlowRemoved(FlowRule flowRule) {
        // TODO generate FLOW_REMOVED message and send it to the controller
    }

    @Override
    public void processPacketIn(InboundPacket packet) {
        // TODO generate PACKET_IN message and send it to the controller
    }

    @Override
    public void processControllerCommand(Channel channel, OFMessage msg) {
        // TODO process controller command
    }

    @Override
    public void processStatsRequest(Channel channel, OFMessage msg) {
        // TODO process request and send reply
    }

    @Override
    public void processRoleRequest(Channel channel, OFMessage msg) {
        // TODO process role request and send reply
    }

    @Override
    public void processFeaturesRequest(Channel channel, OFMessage msg) {
        // TODO process features request and send reply
    }

    @Override
    public void processLldp(Channel channel, OFMessage msg) {
        // TODO process lldp
    }
}