Implement LuckPerms permission handler

#1324

src/main/java/fr/xephi/authme/permission/PermissionsManager.java

@@ -3,6 +3,7 @@ package fr.xephi.authme.permission;
 import fr.xephi.authme.ConsoleLogger;
 import fr.xephi.authme.initialization.Reloadable;
 import fr.xephi.authme.permission.handlers.BPermissionsHandler;
+import fr.xephi.authme.permission.handlers.LuckPermsHandler;
 import fr.xephi.authme.permission.handlers.PermissionHandler;
 import fr.xephi.authme.permission.handlers.PermissionHandlerException;
 import fr.xephi.authme.permission.handlers.PermissionsExHandler;
@@ -111,6 +112,8 @@ public class PermissionsManager implements Reloadable {
         }
 
         switch (type) {
+            case LUCK_PERMS:
+                return new LuckPermsHandler();
             case PERMISSIONS_EX:
                 return new PermissionsExHandler();
             case Z_PERMISSIONS:

src/main/java/fr/xephi/authme/permission/PermissionsSystemType.java

@@ -5,6 +5,11 @@ package fr.xephi.authme.permission;
  */
 public enum PermissionsSystemType {
 
+    /**
+     *  LuckPerms.
+     */
+    LUCK_PERMS("LuckPerms", "LuckPerms"),
+
     /**
      * Permissions Ex.
      */

src/main/java/fr/xephi/authme/permission/handlers/LuckPermsHandler.java

@@ -0,0 +1,216 @@
+package fr.xephi.authme.permission.handlers;
+
+import fr.xephi.authme.permission.PermissionNode;
+import fr.xephi.authme.permission.PermissionsSystemType;
+import me.lucko.luckperms.LuckPerms;
+import me.lucko.luckperms.api.DataMutateResult;
+import me.lucko.luckperms.api.Group;
+import me.lucko.luckperms.api.LuckPermsApi;
+import me.lucko.luckperms.api.Node;
+import me.lucko.luckperms.api.User;
+import org.bukkit.Bukkit;
+import org.bukkit.OfflinePlayer;
+import org.bukkit.entity.Player;
+
+import java.util.Collections;
+import java.util.List;
+import java.util.Optional;
+import java.util.UUID;
+import java.util.stream.Collectors;
+
+/**
+ * Handler for LuckPerms.
+ *
+ * @see <a href="https://www.spigotmc.org/resources/luckperms-an-advanced-permissions-system.28140/">LuckPerms SpigotMC page</a>
+ * @see <a href="https://github.com/lucko/LuckPerms">LuckPerms on Github</a>
+ */
+public class LuckPermsHandler implements PermissionHandler {
+
+    private LuckPermsApi luckPermsApi;
+
+    public LuckPermsHandler() throws PermissionHandlerException {
+        try {
+            luckPermsApi = LuckPerms.getApi();
+        } catch (IllegalStateException e) {
+            e.printStackTrace();
+            throw new PermissionHandlerException("Could not get api of LuckPerms");
+        }
+    }
+
+    private User getUser(String playerName) {
+        Player player = Bukkit.getPlayerExact(playerName);
+        if (player != null) {
+            return getUser(player);
+        }
+
+        UUID uuid = luckPermsApi.getStorage().getUUID(playerName).join();
+        if (uuid == null) {
+            return null;
+        }
+
+        return getUser(uuid);
+    }
+
+    private User getUser(OfflinePlayer player) {
+        return getUser(player.getUniqueId());
+    }
+
+    private User getUser(UUID playerUuid) {
+        User user = luckPermsApi.getUser(playerUuid);
+        if (user == null) {
+            // user not loaded, we need to load them from the storage.
+            // this is a blocking call.
+            luckPermsApi.getStorage().loadUser(playerUuid).join();
+
+            // then grab a new instance
+            user = luckPermsApi.getUser(playerUuid);
+        }
+        return user;
+    }
+
+    private void saveUser(User user) {
+        luckPermsApi.getStorage().saveUser(user)
+            .thenAcceptAsync(wasSuccessful -> {
+                if (!wasSuccessful) {
+                    return;
+                }
+                user.refreshPermissions();
+            }, luckPermsApi.getStorage().getAsyncExecutor());
+    }
+
+    private void cleanupUser(User user) {
+        if (Bukkit.getPlayer(user.getUuid()) != null) {
+            luckPermsApi.cleanupUser(user);
+        }
+    }
+
+    @Override
+    public boolean addToGroup(OfflinePlayer player, String group) {
+        Group newGroup = luckPermsApi.getGroup(group);
+        if (newGroup == null) {
+            return false;
+        }
+
+        User user = getUser(player);
+        if (user == null) {
+            return false;
+        }
+
+        DataMutateResult result = user.setPermissionUnchecked(luckPermsApi.getNodeFactory().makeGroupNode(newGroup).build());
+        if (result == DataMutateResult.FAIL) {
+            return false;
+        }
+
+        saveUser(user);
+        cleanupUser(user);
+
+        return true;
+    }
+
+    @Override
+    public boolean hasGroupSupport() {
+        return true;
+    }
+
+    @Override
+    public boolean hasPermissionOffline(String name, PermissionNode node) {
+        User user = getUser(name);
+        if (user == null) {
+            return false;
+        }
+
+        Node permissionNode = luckPermsApi.getNodeFactory().newBuilder(node.getNode()).build();
+        boolean result = user.hasPermission(permissionNode).asBoolean();
+
+        cleanupUser(user);
+        return result;
+    }
+
+    @Override
+    public boolean isInGroup(OfflinePlayer player, String group) {
+        User user = getUser(player);
+        if (user == null) {
+            return false;
+        }
+
+        Group permissionGroup = luckPermsApi.getGroup(group);
+        boolean result = permissionGroup != null && user.isInGroup(permissionGroup);
+
+        cleanupUser(user);
+        return result;
+    }
+
+    @Override
+    public boolean removeFromGroup(OfflinePlayer player, String group) {
+        User user = getUser(player);
+        if (user == null) {
+            return false;
+        }
+
+        Group permissionGroup = luckPermsApi.getGroup(group);
+        if (permissionGroup == null) {
+            return false;
+        }
+
+        Node groupNode = luckPermsApi.getNodeFactory().makeGroupNode(permissionGroup).build();
+        boolean result = user.unsetPermissionUnchecked(groupNode) != DataMutateResult.FAIL;
+
+        cleanupUser(user);
+        return result;
+    }
+
+    @Override
+    public boolean setGroup(OfflinePlayer player, String group) {
+        User user = getUser(player);
+        if (user == null) {
+            return false;
+        }
+        Group permissionGroup = luckPermsApi.getGroup(group);
+        if (permissionGroup == null) {
+            return false;
+        }
+        Node groupNode = luckPermsApi.getNodeFactory().makeGroupNode(permissionGroup).build();
+        DataMutateResult result = user.setPermissionUnchecked(groupNode);
+        if (result == DataMutateResult.FAIL) {
+            return false;
+        }
+        user.clearMatching(node -> node.isGroupNode() && !node.getGroupName().equals(permissionGroup.getName()));
+
+        saveUser(user);
+        cleanupUser(user);
+        return true;
+    }
+
+    @Override
+    public List<String> getGroups(OfflinePlayer player) {
+        User user = getUser(player);
+        if (user == null) {
+            return Collections.emptyList();
+        }
+
+        List<String> result = user.getOwnNodes().stream()
+            .filter(Node::isGroupNode)
+            .map(n -> luckPermsApi.getGroupSafe(n.getGroupName()))
+            .filter(Optional::isPresent)
+            .map(Optional::get)
+            .distinct()
+            .sorted((o1, o2) -> {
+                if (o1.getName().equals(user.getPrimaryGroup()) || o2.getName().equals(user.getPrimaryGroup())) {
+                    return o1.getName().equals(user.getPrimaryGroup()) ? 1 : -1;
+                }
+
+                int i = Integer.compare(o2.getWeight().orElse(0), o1.getWeight().orElse(0));
+                return i != 0 ? i : o1.getName().compareToIgnoreCase(o2.getName());
+            })
+            .map(Group::getName)
+            .collect(Collectors.toList());
+
+        cleanupUser(user);
+        return result;
+    }
+
+    @Override
+    public PermissionsSystemType getPermissionSystem() {
+        return PermissionsSystemType.LUCK_PERMS;
+    }
+}