/*
 *  ProtocolLib - Bukkit server library that allows access to the Minecraft protocol.
 *  Copyright (C) 2012 Kristian S. Stangeland
 *
 *  This program is free software; you can redistribute it and/or modify it under the terms of the
 *  GNU General Public License as published by the Free Software Foundation; either version 2 of
 *  the License, or (at your option) any later version.
 *
 *  This program 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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along with this program;
 *  if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
 *  02111-1307 USA
 */

package com.comphenix.protocol;

import com.comphenix.protocol.async.AsyncMarker;
import com.comphenix.protocol.events.ListenerPriority;
import com.comphenix.protocol.events.ListeningWhitelist;
import com.comphenix.protocol.events.PacketContainer;
import com.comphenix.protocol.events.PacketListener;
import com.comphenix.protocol.injector.PacketConstructor;
import com.comphenix.protocol.reflect.FieldAccessException;
import com.comphenix.protocol.utility.MinecraftVersion;
import com.google.common.collect.ImmutableSet;
import java.util.Collection;
import java.util.List;
import java.util.Set;
import org.bukkit.Location;
import org.bukkit.World;
import org.bukkit.entity.Entity;
import org.bukkit.entity.Player;
import org.bukkit.plugin.Plugin;

/**
 * Represents an API for accessing the Minecraft protocol.
 *
 * @author Kristian
 */
public interface ProtocolManager extends PacketStream {

    /**
     * Retrieve the protocol version of a given player.
     * <p>
     * This only really makes sense of a server that support clients of multiple Minecraft versions, such as Spigot
     * #1628.
     *
     * @param player - the player.
     * @return The associated protocol version, or {@link Integer#MIN_VALUE} if unknown.
     */
    int getProtocolVersion(Player player);

    /**
     * Send a packet to the given player.
     * <p>
     * Re-sending a previously cancelled packet is discouraged. Use {@link AsyncMarker#incrementProcessingDelay()} to
     * delay a packet until a certain condition has been met.
     *
     * @param receiver - the receiver.
     * @param packet   - packet to send.
     * @param filters  - whether or not to invoke any packet filters below {@link ListenerPriority#MONITOR}.
     */
    @Override
    void sendServerPacket(Player receiver, PacketContainer packet, boolean filters);

    /**
     * Simulate receiving a certain packet from a given player.
     * <p>
     * Receiving a previously cancelled packet is discouraged. Use {@link AsyncMarker#incrementProcessingDelay()} to delay
     * a packet until a certain condition has been met.
     *
     * @param sender  - the sender.
     * @param packet  - the packet that was sent.
     * @param filters - whether or not to invoke any packet filters below {@link ListenerPriority#MONITOR}.
     */
    @Override
    void receiveClientPacket(Player sender, PacketContainer packet, boolean filters);

    /**
     * Broadcast a given packet to every connected player on the server.
     *
     * @param packet - the packet to broadcast.
     * @throws FieldAccessException If we were unable to send the packet due to reflection problems.
     */
    void broadcastServerPacket(PacketContainer packet);

    /**
     * Broadcast a packet to every player that is receiving information about a given entity.
     * <p>
     * This is usually every player in the same world within an observable distance. If the entity is a player, it will
     * only be included if <i>includeTracker</i> is TRUE.
     *
     * @param packet         - the packet to broadcast.
     * @param entity         - the entity whose trackers we will inform.
     * @param includeTracker - whether or not to also transmit the packet to the entity, if it is a tracker.
     * @throws FieldAccessException If we were unable to send the packet due to reflection problems.
     */
    void broadcastServerPacket(PacketContainer packet, Entity entity, boolean includeTracker);

    /**
     * Broadcast a packet to every player within the given maximum observer distance.
     *
     * @param packet              - the packet to broadcast.
     * @param origin              - the origin to consider when calculating the distance to each observer.
     * @param maxObserverDistance - the maximum distance to the origin.
     */
    void broadcastServerPacket(PacketContainer packet, Location origin, int maxObserverDistance);

    void broadcastServerPacket(PacketContainer packet, Collection<? extends Player> targetPlayers);

    /**
     * Retrieves a list of every registered packet listener.
     *
     * @return Every registered packet listener.
     */
    ImmutableSet<PacketListener> getPacketListeners();

    /**
     * Adds a packet listener.
     * <p>
     * Adding an already registered listener has no effect. If you need to change the packets the current listener is
     * observing, you must first remove the packet listener before you can register it again.
     *
     * @param listener - new packet listener.
     */
    void addPacketListener(PacketListener listener);

    /**
     * Removes a given packet listener.
     * <p>
     * Attempting to remove a listener that doesn't exist has no effect.
     *
     * @param listener - the packet listener to remove.
     */
    void removePacketListener(PacketListener listener);

    /**
     * Removes every listener associated with the given plugin.
     *
     * @param plugin - the plugin to unload.
     */
    void removePacketListeners(Plugin plugin);

    /**
     * Constructs a new encapsulated Minecraft packet with the given ID.
     *
     * @param type - packet  type.
     * @return New encapsulated Minecraft packet.
     */
    PacketContainer createPacket(PacketType type);

    /**
     * Constructs a new encapsulated Minecraft packet with the given ID.
     * <p>
     * If set to true, the <i>forceDefaults</i> option will force the system to automatically give non-primitive fields in
     * the packet sensible default values. For instance, certain packets - like Packet60Explosion - require a List or Set
     * to be non-null. If the forceDefaults option is true, the List or Set will be automatically created.
     *
     * @param type          - packet type.
     * @param forceDefaults - TRUE to use sensible defaults in most fields, FALSE otherwise.
     * @return New encapsulated Minecraft packet.
     */
    PacketContainer createPacket(PacketType type, boolean forceDefaults);

    /**
     * Construct a packet using the special builtin Minecraft constructors.
     *
     * @param type      - the packet type.
     * @param arguments - arguments that will be passed to the constructor.
     * @return The packet constructor.
     */
    PacketConstructor createPacketConstructor(PacketType type, Object... arguments);

    /**
     * Completely resend an entity to a list of clients.
     * <p>
     * Note that this method is NOT thread safe. If you call this method from anything but the main thread, it will throw
     * an exception.
     *
     * @param entity    - entity to refresh.
     * @param observers - the clients to update.
     */
    void updateEntity(Entity entity, List<Player> observers);

    /**
     * Retrieve the associated entity.
     *
     * @param container - the world the entity belongs to.
     * @param id        - the unique ID of the entity.
     * @return The associated entity.
     * @throws FieldAccessException Reflection failed.
     */
    Entity getEntityFromID(World container, int id);

    /**
     * Retrieve every client that is receiving information about a given entity.
     *
     * @param entity - the entity that is being tracked.
     * @return Every client/player that is tracking the given entity.
     * @throws FieldAccessException If reflection failed.
     */
    List<Player> getEntityTrackers(Entity entity);

    /**
     * Retrieves a immutable set containing the type of the sent server packets that will be observed by listeners.
     *
     * @return Every filtered server packet.
     */
    Set<PacketType> getSendingFilterTypes();

    /**
     * Retrieves a immutable set containing the type of the received client packets that will be observed by listeners.
     *
     * @return Every filtered client packet.
     */
    Set<PacketType> getReceivingFilterTypes();

    /**
     * Retrieve the current Minecraft version.
     *
     * @return The current version.
     */
    MinecraftVersion getMinecraftVersion();

    /**
     * Determines whether or not this protocol manager has been disabled.
     *
     * @return TRUE if it has, FALSE otherwise.
     */
    boolean isClosed();

    /**
     * Retrieve the current asynchronous packet manager.
     *
     * @return Asynchronous packet manager.
     */
    AsynchronousManager getAsynchronousManager();

    void verifyWhitelist(PacketListener listener, ListeningWhitelist whitelist);
}