Add default WeatherCommand. Partially fixes BUKKIT-2671

By: EvilSeph <evilseph@gmail.com>

paper-api/src/main/java/org/bukkit/command/SimpleCommandMap.java

@@ -54,6 +54,7 @@ public class SimpleCommandMap implements CommandMap {
         fallbackCommands.add(new DefaultGameModeCommand());
         fallbackCommands.add(new SeedCommand());
         fallbackCommands.add(new DifficultyCommand());
+        fallbackCommands.add(new WeatherCommand());
     }
 
     public SimpleCommandMap(final Server server) {

paper-api/src/main/java/org/bukkit/command/defaults/WeatherCommand.java

@@ -0,0 +1,78 @@
+package org.bukkit.command.defaults;
+
+import com.google.common.collect.ImmutableList;
+import org.apache.commons.lang.Validate;
+import org.bukkit.Bukkit;
+import org.bukkit.ChatColor;
+import org.bukkit.World;
+import org.bukkit.command.Command;
+import org.bukkit.command.CommandSender;
+import org.bukkit.util.StringUtil;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Random;
+
+public class WeatherCommand extends VanillaCommand {
+    private static final List<String> WEATHER_TYPES = ImmutableList.of("clear", "rain", "thunder");
+
+    public WeatherCommand() {
+        super("weather");
+        this.description = "Changes the weather";
+        this.usageMessage = "/weather <clear/rain/thunder> [duration in seconds]";
+        this.setPermission("bukkit.command.weather");
+    }
+
+    @Override
+    public boolean execute(CommandSender sender, String currentAlias, String[] args) {
+        if (!testPermission(sender)) return true;
+        if (args.length == 0) {
+            sender.sendMessage(ChatColor.RED + "Usage: " + usageMessage);
+            return false;
+        }
+
+        int duration = (300 + new Random().nextInt(600)) * 20;
+        if (args.length >= 2) {
+            duration = getInteger(sender, args[1], 1, 1000000) * 20;
+        }
+
+        World world = Bukkit.getWorlds().get(0);
+
+        world.setWeatherDuration(duration);
+        world.setThunderDuration(duration);
+
+        if ("clear".equalsIgnoreCase(args[0])) {
+            world.setStorm(false);
+            world.setThundering(false);
+            Command.broadcastCommandMessage(sender, "Changed weather to clear for " + (duration / 20) + " seconds.");
+        } else if ("rain".equalsIgnoreCase(args[0])) {
+            world.setStorm(true);
+            world.setThundering(false);
+            Command.broadcastCommandMessage(sender, "Changed weather to rainy for " + (duration / 20) + " seconds.");
+        } else if ("thunder".equalsIgnoreCase(args[0])) {
+            world.setStorm(true);
+            world.setThundering(true);
+            Command.broadcastCommandMessage(sender, "Changed weather to thundering " + (duration / 20) + " seconds.");
+        }
+
+        return true;
+    }
+
+    @Override
+    public boolean matches(String input) {
+        return input.equalsIgnoreCase("weather");
+    }
+
+    @Override
+    public List<String> tabComplete(CommandSender sender, String alias, String[] args) {
+        Validate.notNull(sender, "Sender cannot be null");
+        Validate.notNull(args, "Arguments cannot be null");
+        Validate.notNull(alias, "Alias cannot be null");
+
+        if (args.length == 1) {
+            return StringUtil.copyPartialMatches(args[0], WEATHER_TYPES, new ArrayList<String>(WEATHER_TYPES.size()));
+        }
+
+        return ImmutableList.of();
+    }
+}