package com.github.theholywaffle.teamspeak3;

/*
 * #%L
 * TeamSpeak 3 Java API
 * %%
 * Copyright (C) 2014 Bert De Geyter
 * %%
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 * #L%
 */

import com.github.theholywaffle.teamspeak3.api.event.*;
import com.github.theholywaffle.teamspeak3.api.exception.TS3UnknownEventException;
import com.github.theholywaffle.teamspeak3.api.wrapper.Wrapper;
import com.github.theholywaffle.teamspeak3.commands.response.DefaultArrayResponse;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.ArrayDeque;
import java.util.Collection;
import java.util.Iterator;
import java.util.Map;
import java.util.Queue;
import java.util.concurrent.CopyOnWriteArrayList;

public class EventManager {

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

        // CopyOnWriteArrayList for thread safety
        private final Collection<ListenerTask> tasks = new CopyOnWriteArrayList<>();
        private final TS3Query ts3;

        EventManager(TS3Query query) {
                ts3 = query;
        }

        public void addListeners(TS3Listener... listeners) {
                for (TS3Listener listener : listeners) {
                        if (listener == null) throw new IllegalArgumentException("A listener was null");
                        ListenerTask task = new ListenerTask(listener);
                        tasks.add(task);
                }
        }

        public void removeListeners(TS3Listener... listeners) {
                // Bad performance (O(n*m)), but this method is rarely if ever used
                Iterator<ListenerTask> taskIterator = tasks.iterator();
                while (taskIterator.hasNext()) {
                        ListenerTask task = taskIterator.next();
                        TS3Listener taskListener = task.getListener();

                        for (TS3Listener listener : listeners) {
                                if (taskListener.equals(listener)) {
                                        taskIterator.remove();
                                        break;
                                }
                        }
                }
        }

        public void fireEvent(String notifyName, String notifyBody) {
                final DefaultArrayResponse response = DefaultArrayResponse.parse(notifyBody);

                for (Wrapper dataWrapper : response.getResponses()) {
                        Map<String, String> eventData = dataWrapper.getMap();
                        TS3Event event = createEvent(notifyName, eventData);

                        fireEvent(event);
                }
        }

        public void fireEvent(TS3Event event) {
                if (event == null) throw new IllegalArgumentException("TS3Event was null");
                for (ListenerTask task : tasks) {
                        task.enqueueEvent(event);
                }
        }

        private static TS3Event createEvent(String notifyName, Map<String, String> eventData) {
                switch (notifyName) {
                        case "notifytextmessage":
                                return new TextMessageEvent(eventData);
                        case "notifycliententerview":
                                return new ClientJoinEvent(eventData);
                        case "notifyclientleftview":
                                return new ClientLeaveEvent(eventData);
                        case "notifyserveredited":
                                return new ServerEditedEvent(eventData);
                        case "notifychanneledited":
                                return new ChannelEditedEvent(eventData);
                        case "notifychanneldescriptionchanged":
                                return new ChannelDescriptionEditedEvent(eventData);
                        case "notifyclientmoved":
                                return new ClientMovedEvent(eventData);
                        case "notifychannelcreated":
                                return new ChannelCreateEvent(eventData);
                        case "notifychanneldeleted":
                                return new ChannelDeletedEvent(eventData);
                        case "notifychannelmoved":
                                return new ChannelMovedEvent(eventData);
                        case "notifychannelpasswordchanged":
                                return new ChannelPasswordChangedEvent(eventData);
                        case "notifytokenused":
                                return new PrivilegeKeyUsedEvent(eventData);
                        default:
                                throw new TS3UnknownEventException(notifyName + " " + eventData);
                }
        }

        /*
         * Do not synchronize on instances of this class from outside the class itself!
         */
        private class ListenerTask implements Runnable {

                private static final int START_QUEUE_SIZE = 16;

                private final TS3Listener listener;
                private final Queue<TS3Event> eventQueue;

                ListenerTask(TS3Listener ts3Listener) {
                        listener = ts3Listener;
                        eventQueue = new ArrayDeque<>(START_QUEUE_SIZE);
                }

                TS3Listener getListener() {
                        return listener;
                }

                synchronized void enqueueEvent(TS3Event event) {
                        if (eventQueue.isEmpty()) {
                                // Add the event to the queue and start a task to process this event and any events
                                // that might be enqueued before the last event is removed from the queue
                                eventQueue.add(event);
                                ts3.submitUserTask("Event listener task", this);
                        } else {
                                // Just add the event to the queue, the running task will pick it up
                                eventQueue.add(event);
                        }
                }

                @Override
                public void run() {
                        TS3Event currentEvent;
                        synchronized (this) {
                                currentEvent = eventQueue.peek();
                                if (currentEvent == null) throw new IllegalStateException("Task started without events");
                        }

                        do {
                                try {
                                        currentEvent.fire(listener);
                                } catch (Throwable throwable) {
                                        log.error("Event listener threw an exception", throwable);
                                }

                                synchronized (this) {
                                        eventQueue.remove();
                                        currentEvent = eventQueue.peek();
                                }
                        } while (currentEvent != null);
                }
        }
}