feat(commands): add contextual tab completion

src/main/java/games/dmg/spigottyrant/SpigotTyrantPlugin.java

@@ -136,6 +136,14 @@ public final class SpigotTyrantPlugin extends JavaPlugin {
                 settings.pendingSelectionTimeout(),
                 random
             ));
+        Objects.requireNonNull(getCommand("tyrant"), "Missing tyrant command metadata")
+            .setTabCompleter(new TyrantTabCompleter(stateManager, onlinePlayers));
+        Objects.requireNonNull(getCommand("vigilante"), "Missing vigilante metadata")
+            .setTabCompleter(new VigilanteTabCompleter(
+                stateManager, followers, onlinePlayers
+            ));
+        Objects.requireNonNull(getCommand("tyrantadmin"), "Missing tyrantadmin metadata")
+            .setTabCompleter(new TyrantAdminTabCompleter(onlinePlayers));
         getServer().getPluginManager().registerEvents(
             new PlayerJoinListener(stateManager, clock, tyrantPresentation),
             this

src/main/java/games/dmg/spigottyrant/TabSuggestions.java

@@ -0,0 +1,19 @@
+package games.dmg.spigottyrant;
+
+import java.util.Collection;
+import java.util.List;
+import java.util.Locale;
+
+public final class TabSuggestions {
+    private TabSuggestions() {
+    }
+
+    public static List<String> matching(String prefix, Collection<String> candidates) {
+        String normalized = prefix == null ? "" : prefix.toLowerCase(Locale.ROOT);
+        return candidates.stream()
+            .filter(candidate -> candidate.toLowerCase(Locale.ROOT).startsWith(normalized))
+            .distinct()
+            .sorted(String.CASE_INSENSITIVE_ORDER)
+            .toList();
+    }
+}

src/main/java/games/dmg/spigottyrant/TyrantAdminTabCompleter.java

@@ -0,0 +1,60 @@
+package games.dmg.spigottyrant;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.UUID;
+import org.bukkit.command.Command;
+import org.bukkit.command.CommandSender;
+import org.bukkit.command.TabCompleter;
+import org.bukkit.entity.Player;
+
+public final class TyrantAdminTabCompleter implements TabCompleter {
+    private static final String PERMISSION = "spigottyrant.admin";
+    private static final List<String> SUBCOMMANDS = List.of(
+        "status", "start", "pause", "resume", "reset"
+    );
+    private final OnlinePlayerDirectory onlinePlayers;
+
+    public TyrantAdminTabCompleter(OnlinePlayerDirectory onlinePlayers) {
+        this.onlinePlayers = onlinePlayers;
+    }
+
+    @Override
+    public List<String> onTabComplete(
+        CommandSender sender,
+        Command command,
+        String alias,
+        String[] arguments
+    ) {
+        if (!sender.hasPermission(PERMISSION) || arguments.length == 0) {
+            return List.of();
+        }
+        if (arguments.length == 1) {
+            return TabSuggestions.matching(arguments[0], SUBCOMMANDS);
+        }
+        String subcommand = arguments[0].toLowerCase(java.util.Locale.ROOT);
+        if (arguments.length == 2) {
+            return switch (subcommand) {
+                case "start" -> TabSuggestions.matching(arguments[1], onlineNames(null));
+                case "reset" -> TabSuggestions.matching(arguments[1], List.of("confirm"));
+                default -> List.of();
+            };
+        }
+        if (arguments.length == 3 && subcommand.equals("start")) {
+            return TabSuggestions.matching(arguments[2], onlineNames(arguments[1]));
+        }
+        return List.of();
+    }
+
+    private List<String> onlineNames(String excludedName) {
+        List<String> names = new ArrayList<>();
+        for (UUID playerId : onlinePlayers.onlinePlayerIds()) {
+            Player player = onlinePlayers.findById(playerId);
+            if (player != null && (excludedName == null
+                    || !player.getName().equalsIgnoreCase(excludedName))) {
+                names.add(player.getName());
+            }
+        }
+        return List.copyOf(names);
+    }
+}

src/main/java/games/dmg/spigottyrant/TyrantTabCompleter.java

@@ -0,0 +1,84 @@
+package games.dmg.spigottyrant;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.UUID;
+import org.bukkit.command.Command;
+import org.bukkit.command.CommandSender;
+import org.bukkit.command.TabCompleter;
+import org.bukkit.entity.Player;
+
+public final class TyrantTabCompleter implements TabCompleter {
+    private static final List<String> SUBCOMMANDS = List.of(
+        "menu", "status", "choices", "buy", "assign", "item", "intelligence",
+        "optout", "optin", "relinquish"
+    );
+    private static final List<String> UNLOCKS = java.util.Arrays.stream(TyrantUnlock.values())
+        .map(value -> value.name().toLowerCase(java.util.Locale.ROOT))
+        .toList();
+    private static final List<String> CLASSES = List.of("assassin", "fixer", "tamer");
+    private final TyrantStateManager stateManager;
+    private final OnlinePlayerDirectory onlinePlayers;
+
+    public TyrantTabCompleter(
+        TyrantStateManager stateManager,
+        OnlinePlayerDirectory onlinePlayers
+    ) {
+        this.stateManager = stateManager;
+        this.onlinePlayers = onlinePlayers;
+    }
+
+    @Override
+    public List<String> onTabComplete(
+        CommandSender sender,
+        Command command,
+        String alias,
+        String[] arguments
+    ) {
+        if (!(sender instanceof Player player) || arguments.length == 0) {
+            return List.of();
+        }
+        if (arguments.length == 1) {
+            return TabSuggestions.matching(arguments[0], SUBCOMMANDS);
+        }
+        String subcommand = arguments[0].toLowerCase(java.util.Locale.ROOT);
+        if (arguments.length == 2) {
+            return switch (subcommand) {
+                case "buy" -> TabSuggestions.matching(arguments[1], UNLOCKS);
+                case "assign" -> TabSuggestions.matching(arguments[1], CLASSES);
+                case "relinquish" -> TabSuggestions.matching(
+                    arguments[1], List.of("confirm")
+                );
+                default -> List.of();
+            };
+        }
+        if (arguments.length == 3 && subcommand.equals("assign")) {
+            return TabSuggestions.matching(arguments[2], eligibleAssignees(player));
+        }
+        return List.of();
+    }
+
+    private List<String> eligibleAssignees(Player tyrant) {
+        Map<UUID, PlayerState> states = stateManager.players();
+        GameState game = stateManager.game();
+        Set<UUID> online = onlinePlayers.onlinePlayerIds();
+        List<String> names = new ArrayList<>();
+        for (UUID playerId : online) {
+            if (playerId.equals(tyrant.getUniqueId())
+                    || game != null && game.tyrantId().filter(playerId::equals).isPresent()) {
+                continue;
+            }
+            PlayerState state = states.get(playerId);
+            if (state != null && state.optedOutUntil().isPresent()) {
+                continue;
+            }
+            Player candidate = onlinePlayers.findById(playerId);
+            if (candidate != null) {
+                names.add(candidate.getName());
+            }
+        }
+        return List.copyOf(names);
+    }
+}

src/main/java/games/dmg/spigottyrant/VigilanteTabCompleter.java

@@ -0,0 +1,96 @@
+package games.dmg.spigottyrant;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.UUID;
+import org.bukkit.command.Command;
+import org.bukkit.command.CommandSender;
+import org.bukkit.command.TabCompleter;
+import org.bukkit.entity.Player;
+
+public final class VigilanteTabCompleter implements TabCompleter {
+    private static final List<String> SUBCOMMANDS = List.of(
+        "menu", "item", "invite", "accept", "dismiss", "leave"
+    );
+    private final TyrantStateManager stateManager;
+    private final FollowerService followers;
+    private final OnlinePlayerDirectory onlinePlayers;
+
+    public VigilanteTabCompleter(
+        TyrantStateManager stateManager,
+        FollowerService followers,
+        OnlinePlayerDirectory onlinePlayers
+    ) {
+        this.stateManager = stateManager;
+        this.followers = followers;
+        this.onlinePlayers = onlinePlayers;
+    }
+
+    @Override
+    public List<String> onTabComplete(
+        CommandSender sender,
+        Command command,
+        String alias,
+        String[] arguments
+    ) {
+        if (!(sender instanceof Player player) || arguments.length == 0) {
+            return List.of();
+        }
+        if (arguments.length == 1) {
+            return TabSuggestions.matching(arguments[0], SUBCOMMANDS);
+        }
+        if (arguments.length != 2) {
+            return List.of();
+        }
+        return switch (arguments[0].toLowerCase(java.util.Locale.ROOT)) {
+            case "invite" -> TabSuggestions.matching(
+                arguments[1], eligibleInvitees(player)
+            );
+            case "dismiss" -> TabSuggestions.matching(
+                arguments[1], currentFollowers(player)
+            );
+            default -> List.of();
+        };
+    }
+
+    private List<String> eligibleInvitees(Player vigilante) {
+        GameState game = stateManager.game();
+        Map<UUID, PlayerState> states = stateManager.players();
+        Set<UUID> pending = followers.invitedPlayerIds(vigilante.getUniqueId());
+        List<String> names = new ArrayList<>();
+        for (UUID playerId : onlinePlayers.onlinePlayerIds()) {
+            PlayerState state = states.get(playerId);
+            boolean assignedRole = game.tyrantId().filter(playerId::equals).isPresent()
+                || game.vigilanteId().filter(playerId::equals).isPresent();
+            boolean ineligibleState = state != null
+                && (state.optedOutUntil().isPresent() || state.followerOf().isPresent());
+            if (assignedRole || ineligibleState || pending.contains(playerId)) {
+                continue;
+            }
+            Player candidate = onlinePlayers.findById(playerId);
+            if (candidate != null) {
+                names.add(candidate.getName());
+            }
+        }
+        return List.copyOf(names);
+    }
+
+    private List<String> currentFollowers(Player vigilante) {
+        Map<UUID, PlayerState> states = stateManager.players();
+        List<String> names = new ArrayList<>();
+        for (UUID playerId : onlinePlayers.onlinePlayerIds()) {
+            PlayerState state = states.get(playerId);
+            if (state == null
+                    || state.followerOf().filter(vigilante.getUniqueId()::equals).isEmpty()) {
+                continue;
+            }
+            Player candidate = onlinePlayers.findById(playerId);
+            if (candidate != null) {
+                names.add(candidate.getName());
+            }
+        }
+        return List.copyOf(names);
+    }
+}