Rework and expose ProtocolVersion to the API

api/src/main/java/com/velocitypowered/api/network/ProtocolVersion.java

@@ -0,0 +1,138 @@
+package com.velocitypowered.api.network;
+
+import com.google.common.collect.ImmutableMap;
+import com.velocitypowered.api.proxy.server.ServerInfo;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Represents each Minecraft protocol version
+ */
+public enum ProtocolVersion {
+    UNKNOWN(-1, "Unknown"),
+    LEGACY(-1, "Legacy"),
+    MINECRAFT_1_8(47, "1.8"),
+    MINECRAFT_1_9(107, "1.9"),
+    MINECRAFT_1_9_1(108, "1.9.1"),
+    MINECRAFT_1_9_2(109, "1.9.2"),
+    MINECRAFT_1_9_4(110, "1.9.4"),
+    MINECRAFT_1_10(210, "1.10"),
+    MINECRAFT_1_11(315, "1.11"),
+    MINECRAFT_1_11_1(316, "1.11.1"),
+    MINECRAFT_1_12(335, "1.12"),
+    MINECRAFT_1_12_1(338, "1.12.1"),
+    MINECRAFT_1_12_2(340, "1.12.2"),
+    MINECRAFT_1_13(393, "1.13"),
+    MINECRAFT_1_13_1(401, "1.13.1"),
+    MINECRAFT_1_13_2(404, "1.13.2");
+
+    private final int protocol;
+    private final String name;
+
+    /**
+     * Represents the lowest supported version
+     */
+    public static final ProtocolVersion MINIMUM_VERSION = MINECRAFT_1_8;
+    /**
+     * Represents the highest supported version
+     */
+    public static final ProtocolVersion MAXIMUM_VERSION = MINECRAFT_1_13_2;
+
+    /**
+     * The user-friendly representation of the lowest and highest supported versions
+     */
+    public static final String SUPPORTED_VERSION_STRING = String.format("%s-%s", MINIMUM_VERSION, MAXIMUM_VERSION);
+
+    /**
+     * A map linking the protocol version number to its {@link ProtocolVersion} representation
+     */
+    public static final ImmutableMap<Integer, ProtocolVersion> ID_TO_PROTOCOL_CONSTANT;
+
+    static {
+        Map<Integer, ProtocolVersion> versions = new HashMap<>();
+        for (ProtocolVersion version : values()) {
+            versions.put(version.protocol, version);
+        }
+
+        ID_TO_PROTOCOL_CONSTANT = ImmutableMap.copyOf(versions);
+    }
+
+    ProtocolVersion(int protocol, String name) {
+        this.protocol = protocol;
+        this.name = name;
+    }
+
+    /**
+     * Returns the protocol as an int
+     *
+     * @return the protocol version
+     */
+    public int getProtocol() {
+        return protocol;
+    }
+
+    /**
+     * Returns the user-friendly name for this protocol
+     *
+     * @return the protocol name
+     */
+    public String getName() {
+        return name;
+    }
+
+    /**
+     * Gets the {@link ProtocolVersion} for the given protocol
+     *
+     * @param protocol the protocol as an int
+     * @return the protocol version
+     */
+    public static ProtocolVersion getProtocolVersion(int protocol) {
+        return ID_TO_PROTOCOL_CONSTANT.getOrDefault(protocol, UNKNOWN);
+    }
+
+    /**
+     * Returns whether the protocol is supported
+     *
+     * @param protocol the protocol as an int
+     * @return if the protocol supported
+     */
+    public static boolean isSupported(int protocol) {
+        ProtocolVersion version = ID_TO_PROTOCOL_CONSTANT.get(protocol);
+
+        return version != null && !version.isUnknown();
+    }
+
+    /**
+     * Returns whether the {@link ProtocolVersion} is supported
+     *
+     * @param version the protocol version
+     * @return if the protocol supported
+     */
+    public static boolean isSupported(ProtocolVersion version) {
+        return version != null && !version.isUnknown();
+    }
+
+    /**
+     * Returns whether this {@link ProtocolVersion} is unknown to the proxy
+     *
+     * @return if the protocol is unknown
+     */
+    public boolean isUnknown() {
+        return this == UNKNOWN;
+    }
+
+    /**
+     * Returns whether this {@link ProtocolVersion} is a legacy protocol
+     *
+     * @return if the protocol is legacy
+     */
+    public boolean isLegacy() {
+        return this == LEGACY;
+    }
+
+    @Override
+    public String toString() {
+        return name;
+    }
+}

api/src/main/java/com/velocitypowered/api/proxy/InboundConnection.java

@@ -1,5 +1,7 @@
 package com.velocitypowered.api.proxy;
 
+import com.velocitypowered.api.network.ProtocolVersion;
+
 import java.net.InetSocketAddress;
 import java.util.Optional;
 
@@ -34,5 +36,5 @@ public interface InboundConnection {
    *
    * @return the protocol version the connection uses
    */
-  int getProtocolVersion();
+  ProtocolVersion getProtocolVersion();
 }

api/src/main/java/com/velocitypowered/api/proxy/server/ServerPing.java

@@ -10,6 +10,8 @@ import java.util.Arrays;
 import java.util.List;
 import java.util.Optional;
 import java.util.UUID;
+
+import com.velocitypowered.api.network.ProtocolVersion;
 import net.kyori.text.Component;
 import org.checkerframework.checker.nullness.qual.Nullable;