Minestom/src/main/java/net/minestom/server/network/player/PlayerConnection.java

package net.minestom.server.network.player;

import net.minestom.server.MinecraftServer;
import net.minestom.server.crypto.PlayerPublicKey;
import net.minestom.server.entity.Entity;
import net.minestom.server.entity.Player;
import net.minestom.server.network.ConnectionState;
import net.minestom.server.network.packet.server.SendablePacket;
import org.jetbrains.annotations.ApiStatus;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

import java.net.SocketAddress;
import java.util.Collection;
import java.util.List;

/**
 * A PlayerConnection is an object needed for all created {@link Player}.
 * It can be extended to create a new kind of player (NPC for instance).
 */
public abstract class PlayerConnection {
    private Player player;
    private volatile ConnectionState clientState;
    private volatile ConnectionState serverState;
    private PlayerPublicKey playerPublicKey;
    volatile boolean online;

    public PlayerConnection() {
        this.online = true;
        this.clientState = ConnectionState.HANDSHAKE;
        this.serverState = ConnectionState.HANDSHAKE;
    }

    /**
     * Returns a printable identifier for this connection, will be the player username
     * or the connection remote address.
     *
     * @return this connection identifier
     */
    public @NotNull String getIdentifier() {
        final Player player = getPlayer();
        return player != null ?
                player.getUsername() :
                getRemoteAddress().toString();
    }

    /**
     * Serializes the packet and send it to the client.
     *
     * @param packet the packet to send
     */
    public abstract void sendPacket(@NotNull SendablePacket packet);

    @ApiStatus.Experimental
    public void sendPackets(@NotNull Collection<SendablePacket> packets) {
        packets.forEach(this::sendPacket);
    }

    @ApiStatus.Experimental
    public void sendPackets(@NotNull SendablePacket... packets) {
        sendPackets(List.of(packets));
    }

    /**
     * Gets the remote address of the client.
     *
     * @return the remote address
     */
    public abstract @NotNull SocketAddress getRemoteAddress();

    /**
     * Gets protocol version of client.
     *
     * @return the protocol version
     */
    public int getProtocolVersion() {
        return MinecraftServer.PROTOCOL_VERSION;
    }

    /**
     * Gets the server address that the client used to connect.
     * <p>
     * WARNING: it is given by the client, it is possible for it to be wrong.
     *
     * @return the server address used
     */
    public @Nullable String getServerAddress() {
        return MinecraftServer.getServer().getAddress();
    }


    /**
     * Gets the server port that the client used to connect.
     * <p>
     * WARNING: it is given by the client, it is possible for it to be wrong.
     *
     * @return the server port used
     */
    public int getServerPort() {
        return MinecraftServer.getServer().getPort();
    }

    /**
     * Forcing the player to disconnect.
     */
    public void disconnect() {
        this.online = false;
        MinecraftServer.getConnectionManager().removePlayer(this);
        final Player player = getPlayer();
        if (player != null && !player.isRemoved()) {
            player.scheduleNextTick(Entity::remove);
        }
    }

    /**
     * Gets the player linked to this connection.
     *
     * @return the player, can be null if not initialized yet
     */
    public @Nullable Player getPlayer() {
        return player;
    }

    /**
     * Changes the player linked to this connection.
     * <p>
     * WARNING: unsafe.
     *
     * @param player the player
     */
    public void setPlayer(Player player) {
        this.player = player;
    }

    /**
     * Gets if the client is still connected to the server.
     *
     * @return true if the player is online, false otherwise
     */
    public boolean isOnline() {
        return online;
    }

    @ApiStatus.Internal
    public void setClientState(@NotNull ConnectionState state) {
        this.clientState = state;
    }

    @ApiStatus.Internal
    public void setServerState(@NotNull ConnectionState state) {
        this.serverState = state;
    }

    /**
     * Gets the client connection state.
     *
     * @return the client connection state
     */
    public @NotNull ConnectionState getClientState() {
        return clientState;
    }

    /**
     * Gets the server connection state.
     *
     * @return the server connection state
     */
    public @NotNull ConnectionState getServerState() {
        return clientState;
    }

    public PlayerPublicKey playerPublicKey() {
        return playerPublicKey;
    }

    public void setPlayerPublicKey(PlayerPublicKey playerPublicKey) {
        this.playerPublicKey = playerPublicKey;
    }

    @Override
    public String toString() {
        return "PlayerConnection{" +
                "clientState=" + clientState +
                ", serverState=" + serverState +
                ", identifier=" + getIdentifier() +
                '}';
    }
}