feat(commands): show player stealth progress

src/main/java/games/dmg/spigotstealth/SpigotStealthPlugin.java

@@ -2,6 +2,7 @@ package games.dmg.spigotstealth;
 
 import java.nio.file.Path;
 import java.time.Clock;
+import java.util.Objects;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.CompletionException;
 import org.bukkit.plugin.java.JavaPlugin;
@@ -58,6 +59,8 @@ public final class SpigotStealthPlugin extends JavaPlugin {
                 manager, settings.unlockThreshold(), System::nanoTime, notifier);
         getServer().getPluginManager().registerEvents(
                 new InvisibilityEffectListener(progression, Clock.systemUTC()), this);
+        Objects.requireNonNull(getCommand("stealth"), "stealth command")
+                .setExecutor(new StealthCommand(manager, progression, settings));
         getServer().getScheduler().runTaskTimer(this, ignored -> {
             for (java.util.UUID playerId : progression.activePlayerIds()) {
                 logSaveFailure(progression.checkpoint(playerId));

src/main/java/games/dmg/spigotstealth/StealthCommand.java

@@ -0,0 +1,51 @@
+package games.dmg.spigotstealth;
+
+import java.util.Locale;
+import java.util.Objects;
+import org.bukkit.command.Command;
+import org.bukkit.command.CommandExecutor;
+import org.bukkit.command.CommandSender;
+import org.bukkit.entity.Player;
+
+/** Player-facing progress command. */
+public final class StealthCommand implements CommandExecutor {
+    private final StealthStateManager stateManager;
+    private final QualifyingInvisibilityService progression;
+    private final StealthSettings settings;
+
+    public StealthCommand(
+            StealthStateManager stateManager,
+            QualifyingInvisibilityService progression,
+            StealthSettings settings) {
+        this.stateManager = Objects.requireNonNull(stateManager, "stateManager");
+        this.progression = Objects.requireNonNull(progression, "progression");
+        this.settings = Objects.requireNonNull(settings, "settings");
+    }
+
+    @Override
+    public boolean onCommand(CommandSender sender, Command command, String label, String[] arguments) {
+        if (!(sender instanceof Player player)) {
+            sender.sendMessage("Only players can check personal stealth progress.");
+            return true;
+        }
+        if (arguments.length != 1 || !"progress".equals(arguments[0].toLowerCase(Locale.ROOT))) {
+            sender.sendMessage("Usage: /" + label + " progress");
+            return true;
+        }
+        PlayerStealthState state = stateManager.snapshot().player(player.getUniqueId());
+        long accumulated = progression.currentAccumulatedMillis(player.getUniqueId());
+        if (state.unlocked()) {
+            player.sendMessage("Stealth is unlocked.");
+            player.sendMessage("Drink an invisibility potion and log out while invisible to conceal your next login.");
+            return true;
+        }
+        long target = settings.unlockThreshold().toMillis();
+        long remaining = Math.max(0L, target - accumulated);
+        String message = settings.progressMessage()
+                .replace("{progress}", StealthProgressFormatter.duration(accumulated))
+                .replace("{target}", StealthProgressFormatter.duration(target))
+                .replace("{remaining}", StealthProgressFormatter.duration(remaining));
+        player.sendMessage(message);
+        return true;
+    }
+}

src/main/java/games/dmg/spigotstealth/StealthProgressFormatter.java

@@ -0,0 +1,32 @@
+package games.dmg.spigotstealth;
+
+/** Human-readable duration and progress presentation. */
+public final class StealthProgressFormatter {
+    private StealthProgressFormatter() { }
+
+    public static String duration(long milliseconds) {
+        long totalSeconds = Math.max(0L, milliseconds) / 1000L;
+        long hours = totalSeconds / 3600L;
+        long minutes = (totalSeconds % 3600L) / 60L;
+        long seconds = totalSeconds % 60L;
+        StringBuilder formatted = new StringBuilder();
+        if (hours > 0L) {
+            formatted.append(hours).append('h');
+        }
+        if (minutes > 0L) {
+            appendSpace(formatted);
+            formatted.append(minutes).append('m');
+        }
+        if (seconds > 0L || formatted.length() == 0) {
+            appendSpace(formatted);
+            formatted.append(seconds).append('s');
+        }
+        return formatted.toString();
+    }
+
+    private static void appendSpace(StringBuilder value) {
+        if (value.length() > 0) {
+            value.append(' ');
+        }
+    }
+}