Add /npc gamemode command

src/main/java/net/citizensnpcs/command/command/NPCCommands.java

@@ -46,6 +46,7 @@ import net.citizensnpcs.util.StringHelper;
 import net.citizensnpcs.util.Util;
 
 import org.bukkit.Bukkit;
+import org.bukkit.GameMode;
 import org.bukkit.Location;
 import org.bukkit.World;
 import org.bukkit.command.CommandSender;
@@ -373,6 +374,40 @@ public class NPCCommands {
         Messaging.sendTr(sender, Messages.NPC_DESPAWNED, npc.getName());
     }
 
+    @Command(
+            aliases = { "npc" },
+            usage = "gamemode [gamemode]",
+            desc = "Changes the gamemode",
+            modifiers = { "gravity" },
+            min = 1,
+            max = 2,
+            permission = "npc.gravity")
+    @Requirements(selected = true, ownership = true, types = { EntityType.PLAYER })
+    public void gamemode(CommandContext args, CommandSender sender, NPC npc) {
+        Player player = (Player) npc.getBukkitEntity();
+        if (args.argsLength() == 1) {
+            Messaging.sendTr(sender, Messages.GAMEMODE_DESCRIBE, npc.getName(), player.getGameMode().name()
+                    .toLowerCase());
+            return;
+        }
+        GameMode mode = null;
+        try {
+            int value = args.getInteger(1);
+            mode = GameMode.getByValue(value);
+        } catch (NumberFormatException ex) {
+            try {
+                mode = GameMode.valueOf(args.getString(1));
+            } catch (IllegalArgumentException e) {
+            }
+        }
+        if (mode == null) {
+            Messaging.sendErrorTr(sender, Messages.GAMEMODE_INVALID, args.getString(1));
+            return;
+        }
+        player.setGameMode(mode);
+        Messaging.sendTr(sender, Messages.GAMEMODE_SET, mode.name().toLowerCase());
+    }
+
     @Command(
             aliases = { "npc" },
             usage = "gravity",

src/main/java/net/citizensnpcs/util/Messages.java

@@ -175,4 +175,7 @@ public class Messages {
     public static final String WAYPOINT_PROVIDER_SET = "citizens.waypoints.set-provider";
     public static final String WRITING_DEFAULT_SETTING = "citizens.settings.writing-default";
     public static final String PATHFINDING_RANGE_SET = "citizens.commands.npc.pathfindingrange.set";
+    public static final String GAMEMODE_DESCRIBE = "citizens.commands.npc.gamemode.describe";
+    public static final String GAMEMODE_INVALID = "citizens.commands.npc.gamemode.invalid";
+    public static final String GAMEMODE_SET = "citizens.commands.npc.gamemode.set";
 }

src/main/resources/messages_en.properties

@@ -10,6 +10,9 @@ citizens.commands.npc.age.cannot-be-aged=The mob type {0} cannot be aged.
 citizens.commands.npc.age.help=Can only be used on entities that can become babies. Use the [[-l]] flag to lock age over time (note: relogs may be required to see this).
 citizens.commands.npc.age.invalid-age=Invalid age. Valid ages are adult, baby, number between -24000 and 0
 citizens.commands.npc.age.locked=Age locked.
+citizens.commands.npc.gamemode.describe={0}'s gamemode is [[{1}]].
+citizens.commands.npc.gamemode.invalid={0} is not a valid gamemode.
+citizens.commands.npc.gamemode.set=Gamemode set to [[{0}]].
 citizens.commands.npc.age.set-adult=[[{0}]] is now an adult.
 citizens.commands.npc.age.set-baby=[[{0}]] is now a baby.
 citizens.commands.npc.age.set-normal=[[{0}]] is now age [[{1}]].