From 64bd8b5eaface432e9030a71cd5adcb751c1837e Mon Sep 17 00:00:00 2001
From: Tadhg Boyle <tadhgsmboyle@gmail.com>
Date: Tue, 30 Nov 2021 11:52:43 -0800
Subject: [PATCH] Add pagination to listgroups command (#3226)

---
 bukkit/src/main/resources/luckperms.commodore |  4 ++-
 .../common/command/spec/CommandSpec.java      |  5 +--
 .../common/commands/group/ListGroups.java     | 35 ++++++++++++++-----
 3 files changed, 32 insertions(+), 12 deletions(-)

diff --git a/bukkit/src/main/resources/luckperms.commodore b/bukkit/src/main/resources/luckperms.commodore
index 1d922effd..5d043c1ca 100644
--- a/bukkit/src/main/resources/luckperms.commodore
+++ b/bukkit/src/main/resources/luckperms.commodore
@@ -69,7 +69,9 @@ luckperms {
       flags brigadier:string greedy_phrase;
     }
   }
-  listgroups;
+  listgroups {
+    page brigadier:integer;
+  }
   createtrack {
     name brigadier:string single_word;
   }
diff --git a/common/src/main/java/me/lucko/luckperms/common/command/spec/CommandSpec.java b/common/src/main/java/me/lucko/luckperms/common/command/spec/CommandSpec.java
index fe5a97409..c162d1b44 100644
--- a/common/src/main/java/me/lucko/luckperms/common/command/spec/CommandSpec.java
+++ b/common/src/main/java/me/lucko/luckperms/common/command/spec/CommandSpec.java
@@ -99,8 +99,9 @@ public enum CommandSpec {
     DELETE_GROUP("/%s deletegroup <group>",
                  arg("name", true)
     ),
-    LIST_GROUPS("/%s listgroups"),
-
+    LIST_GROUPS("/%s listgroups",
+            arg("page", false)
+    ),
     CREATE_TRACK("/%s createtrack <track>",
             arg("name", true)
     ),
diff --git a/common/src/main/java/me/lucko/luckperms/common/commands/group/ListGroups.java b/common/src/main/java/me/lucko/luckperms/common/commands/group/ListGroups.java
index 6f77368eb..5937eae0d 100644
--- a/common/src/main/java/me/lucko/luckperms/common/commands/group/ListGroups.java
+++ b/common/src/main/java/me/lucko/luckperms/common/commands/group/ListGroups.java
@@ -30,17 +30,20 @@ import me.lucko.luckperms.common.command.access.CommandPermission;
 import me.lucko.luckperms.common.command.spec.CommandSpec;
 import me.lucko.luckperms.common.command.utils.ArgumentList;
 import me.lucko.luckperms.common.locale.Message;
+import me.lucko.luckperms.common.model.Group;
 import me.lucko.luckperms.common.model.Track;
 import me.lucko.luckperms.common.plugin.LuckPermsPlugin;
 import me.lucko.luckperms.common.sender.Sender;
+import me.lucko.luckperms.common.util.Iterators;
 import me.lucko.luckperms.common.util.Predicates;
 
+import java.util.Collection;
 import java.util.List;
 import java.util.stream.Collectors;
 
 public class ListGroups extends SingleCommand {
     public ListGroups() {
-        super(CommandSpec.LIST_GROUPS, "ListGroups", CommandPermission.LIST_GROUPS, Predicates.alwaysFalse());
+        super(CommandSpec.LIST_GROUPS, "ListGroups", CommandPermission.LIST_GROUPS, Predicates.notInRange(0, 1));
     }
 
     @Override
@@ -53,15 +56,29 @@ public class ListGroups extends SingleCommand {
             return;
         }
 
-        Message.GROUPS_LIST.send(sender);
-        plugin.getGroupManager().getAll().values().stream()
-                .sorted((o1, o2) -> {
+        int page = args.getIntOrDefault(0, 1);
+        int pageIndex = page - 1;
+
+        List<Group> groups = plugin.getGroupManager().getAll().values().stream().sorted((o1, o2) -> {
                     int i = Integer.compare(o2.getWeight().orElse(0), o1.getWeight().orElse(0));
                     return i != 0 ? i : o1.getName().compareToIgnoreCase(o2.getName());
-                })
-                .forEach(group -> {
-                    List<String> tracks = plugin.getTrackManager().getAll().values().stream().filter(t -> t.containsGroup(group)).map(Track::getName).collect(Collectors.toList());
-                    Message.GROUPS_LIST_ENTRY.send(sender, group, group.getWeight().orElse(0), tracks);
-                });
+                }).collect(Collectors.toList());
+
+        List<List<Group>> pages = Iterators.divideIterable(groups, 8);
+
+        if (pageIndex < 0 || pageIndex >= pages.size()) {
+            page = 1;
+            pageIndex = 0;
+        }
+
+        Message.SEARCH_SHOWING_GROUPS.send(sender, page, pages.size(), groups.size());
+        Message.GROUPS_LIST.send(sender);
+
+        Collection<? extends Track> allTracks = plugin.getTrackManager().getAll().values();
+
+        for (Group group : pages.get(pageIndex)) {
+            List<String> tracks = allTracks.stream().filter(t -> t.containsGroup(group)).map(Track::getName).collect(Collectors.toList());
+            Message.GROUPS_LIST_ENTRY.send(sender, group, group.getWeight().orElse(0), tracks);
+        }
     }
 }