feat: filter buffer data sent to visualizer clients by view distance

Modified command messages.

ClaimLink/ClaimLink.cs

@@ -0,0 +1,27 @@
+using System.Collections.Generic;
+using ProtoBuf;
+
+namespace ClaimLink;
+
+[ProtoContract]
+public class ClaimLinkSaveData
+{
+    [ProtoMember(1)]
+    public List<int> Links = new();
+
+    [ProtoMember(2)]
+    public List<ClaimLinkEntrySaveData> Entries = new();
+}
+
+[ProtoContract]
+public class ClaimLinkEntrySaveData
+{
+    [ProtoMember(1)]
+    public string OwnerPlayerUid = "";
+
+    [ProtoMember(2)]
+    public int GroupId;
+
+    [ProtoMember(3)]
+    public List<int> ClaimIndicies = new();
+}

ClaimLink/ClaimLink.csproj

@@ -12,6 +12,14 @@
       <HintPath>$(VINTAGE_STORY)/VintagestoryAPI.dll</HintPath>
       <Private>false</Private>
     </Reference>
+    <Reference Include="CommandHook">
+       <HintPath>$(COMMANDHOOK)/CommandHook.dll</HintPath>
+       <Private>false</Private>
+    </Reference>
+    <Reference Include="protobuf-net">
+       <HintPath>$(VINTAGE_STORY)/Lib/protobuf-net.dll</HintPath>
+       <Private>false</Private>
+    </Reference>
   </ItemGroup>
 
 <ItemGroup>

ClaimLink/ClaimLinkBuffer.cs

@@ -0,0 +1,140 @@
+using System.Collections.Generic;
+using Vintagestory.API.Common;
+using Vintagestory.API.MathTools;
+
+namespace ClaimLink;
+
+internal static class ClaimLinkBuffer
+{
+    internal static List<Cuboidi> GetBuffer(int groupId)
+    {
+        List<Cuboidi> cuboids = new();
+
+        foreach (string uid in ClaimLinkModSystem.Registry.MemberUidsForGroup(groupId))
+        {
+            foreach (
+                int claimIndex in ClaimLinkModSystem.Registry.ClaimsForPlayerInGroup(uid, groupId)
+            )
+            {
+                if (
+                    !ClaimLinkModSystem.TryResolveOwnedClaim(uid, claimIndex, out LandClaim? claim)
+                    || claim == null
+                )
+                    continue;
+
+                foreach (Cuboidi area in claim.Areas)
+                    cuboids.Add(GrowOne(area));
+            }
+        }
+
+        return cuboids;
+    }
+
+    internal static bool TryFindOverlappingClaimLink(
+        List<Cuboidi> areas,
+        ISet<int>? excludeGroupIds,
+        out int violatingGroupId
+    )
+    {
+        foreach (int groupId in ClaimLinkModSystem.Registry.All)
+        {
+            if (excludeGroupIds != null && excludeGroupIds.Contains(groupId))
+                continue;
+
+            foreach (Cuboidi bufferCuboid in GetBuffer(groupId))
+                foreach (Cuboidi area in areas)
+                    if (area.Intersects(bufferCuboid))
+                    {
+                        violatingGroupId = groupId;
+                        return true;
+                    }
+        }
+
+        violatingGroupId = -1;
+        return false;
+    }
+
+    internal static bool TryFindOverlappingClaim(
+        List<Cuboidi> areas,
+        string excludeOwnerUid,
+        ISet<int>? excludeGroupIds,
+        out LandClaim? violatingClaim
+    )
+    {
+        HashSet<LandClaim> excludedClaims = new();
+        if (excludeGroupIds != null)
+            foreach (int groupId in excludeGroupIds)
+                foreach (string uid in ClaimLinkModSystem.Registry.MemberUidsForGroup(groupId))
+                    foreach (
+                        int claimIndex in ClaimLinkModSystem.Registry.ClaimsForPlayerInGroup(
+                            uid,
+                            groupId
+                        )
+                    )
+                        if (
+                            ClaimLinkModSystem.TryResolveOwnedClaim(
+                                uid,
+                                claimIndex,
+                                out LandClaim? excludedClaim
+                            )
+                            && excludedClaim != null
+                        )
+                            excludedClaims.Add(excludedClaim);
+
+        foreach (LandClaim claim in ClaimLinkModSystem.LandClaimAPI.All)
+        {
+            if (claim.OwnedByPlayerUid == excludeOwnerUid)
+                continue;
+
+            if (excludedClaims.Contains(claim))
+                continue;
+
+            foreach (Cuboidi claimArea in claim.Areas)
+                foreach (Cuboidi area in areas)
+                    if (area.Intersects(claimArea))
+                    {
+                        violatingClaim = claim;
+                        return true;
+                    }
+        }
+
+        violatingClaim = null;
+        return false;
+    }
+
+    internal static ISet<int> MemberClaimLinkIds(string uid)
+    {
+        HashSet<int> groupIds = new();
+        var memberships = ClaimLinkModSystem.PlayerData.GetPlayerDataByUid(uid)?.PlayerGroupMemberships;
+        if (memberships == null)
+            return groupIds;
+
+        foreach (int groupId in memberships.Keys)
+            if (ClaimLinkModSystem.Registry.Exists(groupId))
+                groupIds.Add(groupId);
+
+        return groupIds;
+    }
+
+    internal static List<Cuboidi> GrowAreas(List<Cuboidi> areas)
+    {
+        List<Cuboidi> grown = new();
+        foreach (Cuboidi area in areas)
+            grown.Add(GrowOne(area));
+        return grown;
+    }
+
+    private static Cuboidi GrowOne(Cuboidi area)
+    {
+        Cuboidi normalized = new Cuboidi(
+            area.MinX,
+            area.MinY,
+            area.MinZ,
+            area.MaxX,
+            area.MaxY,
+            area.MaxZ
+        );
+        int bufferSize = ClaimLinkModSystem.Config.BufferSize;
+        return normalized.GrowBy(bufferSize, bufferSize, bufferSize);
+    }
+}

ClaimLink/ClaimLinkChatCommand.cs

@@ -0,0 +1,933 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using Vintagestory.API.Common;
+using Vintagestory.API.Config;
+using Vintagestory.API.MathTools;
+using Vintagestory.API.Server;
+
+namespace ClaimLink;
+
+public static class ClaimLinkChatCommand
+{
+    private readonly struct CommandSpec
+    {
+        public readonly string[] Names;
+        public readonly string Description;
+        public readonly ICommandArgumentParser[] Args;
+        public readonly bool IsPlayerOnly;
+        public readonly OnCommandDelegate Handler;
+
+        public CommandSpec(
+            string[] names,
+            string description,
+            ICommandArgumentParser[] args,
+            bool isPlayerOnly,
+            OnCommandDelegate handler
+        )
+        {
+            Names = names;
+            Description = description;
+            Args = args;
+            IsPlayerOnly = isPlayerOnly;
+            Handler = handler;
+        }
+    }
+
+    private static void BuildSubCommand(IChatCommand parent, CommandSpec spec)
+    {
+        var sub =
+            spec.Names.Length > 1
+                ? parent.BeginSubCommands(spec.Names)
+                : parent.BeginSubCommand(spec.Names[0]);
+
+        sub.WithDescription(spec.Description);
+
+        if (spec.Args.Length > 0)
+            sub.WithArgs(spec.Args);
+
+        if (spec.IsPlayerOnly)
+            sub.RequiresPlayer();
+        else
+            sub.RequiresPrivilege(Privilege.controlserver);
+
+        sub.HandleWith(spec.Handler).EndSubCommand();
+    }
+
+    public static void Register(ICoreServerAPI api)
+    {
+        var p = api.ChatCommands.Parsers;
+
+        var root = api
+            .ChatCommands.Create("claimlink")
+            .WithAlias("clink", "claiml", "cl")
+            .WithDescription("Link vanilla land claims together via group.")
+            .RequiresPrivilege(Privilege.chat);
+
+        CommandSpec[] playerCommands =
+        {
+            new(
+                new[] { "new", "n" },
+                "Promote a group you own to a claim link.",
+                new ICommandArgumentParser[] { p.OptionalWord("groupname") },
+                true,
+                New
+            ),
+            new(
+                new[] { "link", "l" },
+                "Link a claim you own to a claim link.",
+                new ICommandArgumentParser[]
+                {
+                    p.IntRange("claim", 0, 999),
+                    p.OptionalWord("groupname"),
+                },
+                true,
+                Link
+            ),
+            new(
+                new[] { "confirm", "c" },
+                "Confirm pending action.",
+                Array.Empty<ICommandArgumentParser>(),
+                true,
+                Confirm
+            ),
+            new(
+                new[] { "cancel" },
+                "Cancel pending action.",
+                Array.Empty<ICommandArgumentParser>(),
+                true,
+                Cancel
+            ),
+            new(
+                new[] { "unlink", "ul" },
+                "Remove a claim you own from its claim link.",
+                new ICommandArgumentParser[] { p.IntRange("claim", 0, 999) },
+                true,
+                Unlink
+            ),
+            new(
+                new[] { "kick" },
+                "Force-unlink all of a player's claims from the claim link.",
+                new ICommandArgumentParser[] { p.Word("groupname"), p.OptionalWord("playername") },
+                true,
+                Kick
+            ),
+            new(
+                new[] { "delete" },
+                "Delete a claim link.",
+                new ICommandArgumentParser[] { p.OptionalWord("groupname") },
+                true,
+                Delete
+            ),
+            new(
+                new[] { "transferownership", "transfer", "to" },
+                "Transfer ownership of the claim link to another player.",
+                new ICommandArgumentParser[] { p.Word("groupname"), p.OptionalWord("playername") },
+                true,
+                TransferOwnership
+            ),
+            new(
+                new[] { "info", "i" },
+                "Show a claim link's members and linked claims.",
+                new ICommandArgumentParser[] { p.OptionalWord("groupname") },
+                true,
+                Info
+            ),
+            new(
+                new[] { "list", "ls" },
+                "List all claim links.",
+                Array.Empty<ICommandArgumentParser>(),
+                true,
+                List
+            ),
+        };
+
+        foreach (var spec in playerCommands)
+            BuildSubCommand(root, spec);
+
+        var admin = root.BeginSubCommands("admin", "a")
+            .WithDescription("Admin commands for claim link.")
+            .RequiresPrivilege(Privilege.controlserver);
+
+        CommandSpec[] adminCommands =
+        {
+            new(
+                new[] { "delete", "del" },
+                "Delete a claim link.",
+                new ICommandArgumentParser[] { p.OptionalWord("groupname") },
+                false,
+                AdminDelete
+            ),
+            new(
+                new[] { "unlink" },
+                "Unlink a claim.",
+                new ICommandArgumentParser[] { p.Word("playername"), p.IntRange("claim", 0, 999) },
+                false,
+                AdminUnlink
+            ),
+            new(
+                new[] { "kick" },
+                "Force-unlink all of a player's claims.",
+                new ICommandArgumentParser[] { p.Word("groupname"), p.OptionalWord("playername") },
+                false,
+                AdminKick
+            ),
+            new(
+                new[] { "transferownership", "transfer", "to" },
+                "Transfer ownership of any claim link to another player.",
+                new ICommandArgumentParser[]
+                {
+                    p.PlayerUids("playername"),
+                    p.OptionalWord("groupname"),
+                },
+                false,
+                AdminTransferOwnership
+            ),
+        };
+
+        foreach (var spec in adminCommands)
+            BuildSubCommand(admin, spec);
+
+        admin.EndSubCommand();
+    }
+
+    internal static readonly Dictionary<
+        string,
+        (int GroupId, Func<TextCommandResult> Action)
+    > PendingActions = new();
+
+    internal static readonly Dictionary<string, string> LastCancelReason = new();
+
+    private static TextCommandResult Stage(
+        string playerUid,
+        int groupId,
+        string prompt,
+        Func<TextCommandResult> action
+    )
+    {
+        PendingActions[playerUid] = (groupId, action);
+        LastCancelReason.Remove(playerUid);
+        return TextCommandResult.Success(
+            $"{prompt} Use /claimlink confirm to proceed, or /claimlink cancel to cancel."
+        );
+    }
+
+    internal static void RemovePendingActionsForGroup(int groupId, string reason)
+    {
+        List<string>? toRemove = null;
+        foreach (var (uid, entry) in PendingActions)
+            if (entry.GroupId == groupId)
+                (toRemove ??= new()).Add(uid);
+
+        if (toRemove == null)
+            return;
+
+        foreach (string uid in toRemove)
+        {
+            PendingActions.Remove(uid);
+            LastCancelReason[uid] = reason;
+        }
+    }
+
+    internal static void CancelPendingAction(string uid, int groupId, string reason)
+    {
+        if (!PendingActions.TryGetValue(uid, out var pending) || pending.GroupId != groupId)
+            return;
+
+        PendingActions.Remove(uid);
+        LastCancelReason[uid] = reason;
+    }
+
+    private static TextCommandResult? TryResolveGroup(string groupName, out PlayerGroup group)
+    {
+        group = ClaimLinkModSystem.Groups.GetPlayerGroupByName(groupName)!;
+        return group == null
+            ? TextCommandResult.Error($"No group named '{groupName}' exists.")
+            : null;
+    }
+
+    private static TextCommandResult? TryResolveGroupArg(
+        TextCommandCallingArgs args,
+        int argIndex,
+        out PlayerGroup group
+    )
+    {
+        if (!args.Parsers[argIndex].IsMissing)
+            return TryResolveGroup((string)args[argIndex], out group);
+
+        int chatGroupId = args.Caller.FromChatGroupId;
+        if (!ClaimLinkModSystem.Groups.PlayerGroupsById.TryGetValue(chatGroupId, out group!))
+            return TextCommandResult.Error(
+                "No group specified and you are not sending this from a group chat channel."
+            );
+
+        return null;
+    }
+
+    private static TextCommandResult? TryResolveClaimLink(PlayerGroup group)
+    {
+        return !ClaimLinkModSystem.Registry.Exists(group.Uid)
+            ? TextCommandResult.Error($"'{group.Name}' is not a claim link.")
+            : null;
+    }
+
+    private static TextCommandResult? RequireMember(IPlayer player, PlayerGroup group)
+    {
+        return player.GetGroup(group.Uid) == null
+            ? TextCommandResult.Error($"'{player.PlayerName}' is not a member of '{group.Name}'.")
+            : null;
+    }
+
+    private static TextCommandResult? RequireOwner(IPlayer player, PlayerGroup group)
+    {
+        return group.OwnerUID != player.PlayerUID
+            ? TextCommandResult.Error($"You do not own '{group.Name}'.")
+            : null;
+    }
+
+    private static TextCommandResult? RequireOpOrOwner(IPlayer player, PlayerGroup group)
+    {
+        if (group.OwnerUID == player.PlayerUID)
+            return null;
+
+        PlayerGroupMembership? membership = player.GetGroup(group.Uid);
+        return membership == null || membership.Level < EnumPlayerGroupMemberShip.Op
+            ? TextCommandResult.Error($"You must be an operator of '{group.Name}' to do that.")
+            : null;
+    }
+
+    public static TextCommandResult New(TextCommandCallingArgs args)
+    {
+        string playerUid = args.Caller.Player.PlayerUID;
+
+        TextCommandResult? err = TryResolveGroupArg(args, 0, out PlayerGroup group);
+        if (err != null)
+            return err;
+
+        err = RequireOwner(args.Caller.Player, group);
+        if (err != null)
+            return err;
+
+        if (ClaimLinkModSystem.Registry.Exists(group.Uid))
+            return TextCommandResult.Error($"'{group.Name}' is already a claim link.");
+
+        int groupId = group.Uid;
+        string groupName = group.Name;
+        return Stage(
+            playerUid,
+            groupId,
+            $"'{groupName}' will become a claim link.",
+            () =>
+            {
+                if (!ClaimLinkModSystem.Groups.PlayerGroupsById.ContainsKey(groupId))
+                    return TextCommandResult.Error($"'{groupName}' no longer exists.");
+
+                ClaimLinkModSystem.Registry.Add(groupId);
+                return TextCommandResult.Success($"'{groupName}' is now a claim link.");
+            }
+        );
+    }
+
+    public static TextCommandResult Confirm(TextCommandCallingArgs args)
+    {
+        string playerUid = args.Caller.Player.PlayerUID;
+
+        if (!PendingActions.TryGetValue(playerUid, out var pending))
+        {
+            if (LastCancelReason.Remove(playerUid, out string? reason))
+                return TextCommandResult.Error($"You do not have a pending action ({reason}).");
+            return TextCommandResult.Error("You do not have a pending action.");
+        }
+
+        PendingActions.Remove(playerUid);
+        LastCancelReason.Remove(playerUid);
+        return pending.Action();
+    }
+
+    public static TextCommandResult Cancel(TextCommandCallingArgs args)
+    {
+        string playerUid = args.Caller.Player.PlayerUID;
+
+        if (!PendingActions.Remove(playerUid))
+            return TextCommandResult.Error("You do not have a pending action.");
+
+        return TextCommandResult.Success("Pending action cancelled.");
+    }
+
+    public static TextCommandResult Link(TextCommandCallingArgs args)
+    {
+        int claimIndex = (int)args[0];
+
+        TextCommandResult? err = TryResolveGroupArg(args, 1, out PlayerGroup group);
+        if (err != null)
+            return err;
+
+        err = TryResolveClaimLink(group);
+        if (err != null)
+            return err;
+
+        IPlayer player = args.Caller.Player;
+        err = RequireMember(player, group);
+        if (err != null)
+            return err;
+
+        string playerUid = player.PlayerUID;
+        int groupId = group.Uid;
+        string groupName = group.Name;
+
+        if (
+            !ClaimLinkModSystem.TryResolveOwnedClaim(playerUid, claimIndex, out LandClaim? claim)
+            || claim == null
+        )
+            return TextCommandResult.Error($"You don't have a claim at index {claimIndex}.");
+
+        if (ClaimLinkModSystem.Registry.IsClaimLinked(playerUid, claimIndex))
+            return TextCommandResult.Error("That claim is already part of a claim link.");
+
+        List<Cuboidi> grownAreas = ClaimLinkBuffer.GrowAreas(claim.Areas);
+        ISet<int> excludeGroupIds = new HashSet<int> { groupId };
+
+        if (
+            ClaimLinkBuffer.TryFindOverlappingClaimLink(
+                grownAreas,
+                excludeGroupIds,
+                out int violatingGroupId
+            )
+        )
+        {
+            string violatingName = ClaimLinkModSystem.Groups.PlayerGroupsById.TryGetValue(
+                violatingGroupId,
+                out PlayerGroup? violatingGroup
+            )
+                ? violatingGroup!.Name
+                : "another claim link";
+            return TextCommandResult.Error(
+                $"Cannot link that claim, it overlaps the protected buffer of '{violatingName}'."
+            );
+        }
+
+        if (
+            ClaimLinkBuffer.TryFindOverlappingClaim(
+                grownAreas,
+                playerUid,
+                excludeGroupIds,
+                out LandClaim? violatingClaim
+            )
+        )
+        {
+            return TextCommandResult.Error(
+                $"Cannot link that claim, its buffer would overlap the claim owned by {violatingClaim!.LastKnownOwnerName}."
+            );
+        }
+
+        string claimDesc = DescribeClaim(playerUid, claimIndex);
+        return Stage(
+            playerUid,
+            groupId,
+            $"'{claimDesc}' will be linked into '{groupName}'.",
+            () =>
+            {
+                bool stillMember =
+                    ClaimLinkModSystem
+                        .PlayerData.GetPlayerDataByUid(playerUid)
+                        ?.PlayerGroupMemberships.ContainsKey(groupId) == true;
+                if (!stillMember)
+                    return TextCommandResult.Error($"You are no longer a member of '{groupName}'.");
+
+                bool success = ClaimLinkModSystem.Registry.AddEntry(playerUid, groupId, claimIndex);
+                return success
+                    ? TextCommandResult.Success($"Linked '{claimDesc}' to '{groupName}'.")
+                    : TextCommandResult.Error(
+                        $"Unable to link claim {claimIndex} to '{groupName}', it is currently being modified."
+                    );
+            }
+        );
+    }
+
+    public static TextCommandResult Unlink(TextCommandCallingArgs args)
+    {
+        int claimIndex = (int)args[0];
+        string playerUid = args.Caller.Player.PlayerUID;
+
+        int? groupId = ClaimLinkModSystem.Registry.FindGroupContaining(playerUid, claimIndex);
+        if (groupId == null)
+            return TextCommandResult.Error(
+                $"Claim {claimIndex} is not linked into any claim link by you."
+            );
+
+        string groupName = ClaimLinkModSystem.Groups.PlayerGroupsById[(int)groupId].Name;
+        string claimDesc = DescribeClaim(playerUid, claimIndex);
+
+        return Stage(
+            playerUid,
+            (int)groupId,
+            $"'{claimDesc}' will be unlinked from '{groupName}'.",
+            () =>
+            {
+                ClaimLinkModSystem.Registry.RemoveEntry(playerUid, (int)groupId, claimIndex);
+                return TextCommandResult.Success($"Unlinked '{claimDesc}' from '{groupName}'.");
+            }
+        );
+    }
+
+    public static TextCommandResult Kick(TextCommandCallingArgs args)
+    {
+        string word1 = (string)args[0];
+        string? word2 = args.Parsers[1].IsMissing ? null : (string)args[1];
+
+        string targetName;
+        PlayerGroup group;
+        if (word2 != null)
+        {
+            TextCommandResult? err = TryResolveGroup(word1, out group);
+            if (err != null)
+                return err;
+            targetName = word2;
+        }
+        else
+        {
+            int chatGroupId = args.Caller.FromChatGroupId;
+            if (!ClaimLinkModSystem.Groups.PlayerGroupsById.TryGetValue(chatGroupId, out group!))
+                return TextCommandResult.Error(
+                    "No group specified and you are not sending this from a group chat channel."
+                );
+            targetName = word1;
+        }
+
+        TextCommandResult? linkErr = TryResolveClaimLink(group);
+        if (linkErr != null)
+            return linkErr;
+
+        linkErr = RequireOpOrOwner(args.Caller.Player, group);
+        if (linkErr != null)
+            return linkErr;
+
+        string? targetUid = ClaimLinkModSystem
+            .PlayerData.GetPlayerDataByLastKnownName(targetName)
+            ?.PlayerUID;
+        if (targetUid == null)
+            return TextCommandResult.Error($"No such player '{targetName}'.");
+
+        string playerUid = args.Caller.Player.PlayerUID;
+        string groupName = group.Name;
+
+        if (!ClaimLinkModSystem.Registry.HasAnyEntry(targetUid, group.Uid))
+            return TextCommandResult.Error($"{targetName} has no claims linked in '{groupName}'.");
+
+        return Stage(
+            playerUid,
+            group.Uid,
+            $"All of {targetName}'s claims will be unlinked from '{groupName}'.",
+            () =>
+            {
+                ClaimLinkModSystem.Registry.RemoveAllForPlayerInGroup(targetUid, group.Uid);
+                CommandListener.PendingLoads.Remove(targetUid);
+                PendingActions.Remove(targetUid);
+
+                return TextCommandResult.Success(
+                    $"Unlinked all claims of {targetName} from '{groupName}'."
+                );
+            }
+        );
+    }
+
+    public static TextCommandResult Delete(TextCommandCallingArgs args)
+    {
+        string playerUid = args.Caller.Player.PlayerUID;
+
+        TextCommandResult? err = TryResolveGroupArg(args, 0, out PlayerGroup group);
+        if (err != null)
+            return err;
+
+        err = TryResolveClaimLink(group);
+        if (err != null)
+            return err;
+
+        err = RequireOwner(args.Caller.Player, group);
+        if (err != null)
+            return err;
+
+        int groupId = group.Uid;
+        string groupName = group.Name;
+        return Stage(
+            playerUid,
+            groupId,
+            $"'{groupName}' will be deleted as a claim link.",
+            () =>
+            {
+                RemovePendingActionsForGroup(groupId, "claim link was deleted");
+                ClaimLinkModSystem.Registry.Remove(groupId);
+                return TextCommandResult.Success($"'{groupName}' is no longer a claim link.");
+            }
+        );
+    }
+
+    public static TextCommandResult TransferOwnership(TextCommandCallingArgs args)
+    {
+        string word1 = (string)args[0];
+        string? word2 = args.Parsers[1].IsMissing ? null : (string)args[1];
+
+        string targetName;
+        PlayerGroup group;
+        if (word2 != null)
+        {
+            TextCommandResult? groupErr = TryResolveGroup(word1, out group);
+            if (groupErr != null)
+                return groupErr;
+            targetName = word2;
+        }
+        else
+        {
+            int chatGroupId = args.Caller.FromChatGroupId;
+            if (!ClaimLinkModSystem.Groups.PlayerGroupsById.TryGetValue(chatGroupId, out group!))
+                return TextCommandResult.Error(
+                    "No group specified and you are not sending this from a group chat channel."
+                );
+            targetName = word1;
+        }
+
+        IPlayer player = args.Caller.Player;
+        string playerUid = player.PlayerUID;
+
+        TextCommandResult? err = TryResolveOnlinePlayerByName(targetName, out IPlayer target);
+        if (err != null)
+            return err;
+
+        err = TryResolveClaimLink(group);
+        if (err != null)
+            return err;
+
+        err = RequireOwner(player, group);
+        if (err != null)
+            return err;
+
+        err = RequireMember(target, group);
+        if (err != null)
+            return err;
+
+        err = RequireNotAlreadyOwner(group, target);
+        if (err != null)
+            return err;
+
+        string groupName = group.Name;
+        return Stage(
+            playerUid,
+            group.Uid,
+            $"Ownership of '{groupName}' will be transferred to {target.PlayerName}.",
+            () => ExecuteTransferOwnership(group, target)
+        );
+    }
+
+    private static TextCommandResult? TryResolveOnlinePlayerByName(string name, out IPlayer target)
+    {
+        target = null!;
+
+        foreach (IPlayer online in ClaimLinkModSystem.World.AllOnlinePlayers)
+        {
+            if (string.Equals(online.PlayerName, name, StringComparison.OrdinalIgnoreCase))
+            {
+                target = online;
+                return null;
+            }
+        }
+
+        return TextCommandResult.Error($"No such player '{name}' online.");
+    }
+
+    private static TextCommandResult? TryResolveTargetPlayer(
+        PlayerUidName[] matches,
+        out IPlayer target
+    )
+    {
+        target = null!;
+
+        if (matches.Length != 1)
+            return TextCommandResult.Error("Name a single player.");
+
+        IPlayer? resolved = ClaimLinkModSystem.World.PlayerByUid(matches[0].Uid);
+        if (resolved == null)
+            return TextCommandResult.Error($"No such player '{matches[0].Name}'.");
+
+        target = resolved;
+        return null;
+    }
+
+    private static TextCommandResult? RequireNotAlreadyOwner(PlayerGroup group, IPlayer target)
+    {
+        return target.PlayerUID == group.OwnerUID
+            ? TextCommandResult.Error($"{target.PlayerName} already owns '{group.Name}'.")
+            : null;
+    }
+
+    private static TextCommandResult ExecuteTransferOwnership(PlayerGroup group, IPlayer target)
+    {
+        string oldOwnerUid = group.OwnerUID;
+        IPlayer? oldOwner = ClaimLinkModSystem.World.PlayerByUid(oldOwnerUid);
+        PlayerGroupMembership? oldOwnerMembership = oldOwner?.GetGroup(group.Uid);
+        PlayerGroupMembership targetMembership = target.GetGroup(group.Uid)!;
+
+        group.OwnerUID = target.PlayerUID;
+        targetMembership.Level = EnumPlayerGroupMemberShip.Owner;
+
+        if (oldOwnerMembership != null)
+            oldOwnerMembership.Level = EnumPlayerGroupMemberShip.Op;
+
+        PendingActions.Remove(oldOwnerUid);
+
+        string notice = $"'{group.Name}' is now owned by {target.PlayerName}.";
+
+        HashSet<string> notifyUids = ClaimLinkModSystem
+            .Registry.MemberUidsForGroup(group.Uid)
+            .ToHashSet();
+        notifyUids.Add(oldOwnerUid);
+        notifyUids.Add(target.PlayerUID);
+
+        foreach (string uid in notifyUids)
+            NotifyIfOnline(ClaimLinkModSystem.World.PlayerByUid(uid), notice);
+
+        return TextCommandResult.Success(notice);
+    }
+
+    private static void NotifyIfOnline(IPlayer? player, string message)
+    {
+        if (player is IServerPlayer sp && sp.ConnectionState == EnumClientState.Playing)
+            sp.SendMessage(GlobalConstants.GeneralChatGroup, message, EnumChatType.Notification);
+    }
+
+    public static TextCommandResult Info(TextCommandCallingArgs args)
+    {
+        TextCommandResult? err = TryResolveGroupArg(args, 0, out PlayerGroup group);
+        if (err != null)
+            return err;
+
+        err = TryResolveClaimLink(group);
+        if (err != null)
+            return err;
+
+        IPlayer player = args.Caller.Player;
+        bool showDetails =
+            player.HasPrivilege(Privilege.controlserver) || player.GetGroup(group.Uid) != null;
+
+        return TextCommandResult.Success(FormatInfo(group.Name, group.Uid, showDetails));
+    }
+
+    public static TextCommandResult List(TextCommandCallingArgs args)
+    {
+        List<int> groupIds = new(ClaimLinkModSystem.Registry.All);
+        groupIds.Sort((a, b) => GroupMemberCount(b).CompareTo(GroupMemberCount(a)));
+
+        if (groupIds.Count == 0)
+            return TextCommandResult.Success("There are no claim links.");
+
+        StringBuilder sb = new();
+        int shown = 0;
+
+        foreach (int groupId in groupIds)
+        {
+            if (
+                !ClaimLinkModSystem.Groups.PlayerGroupsById.TryGetValue(
+                    groupId,
+                    out PlayerGroup? group
+                )
+            )
+            {
+                RemovePendingActionsForGroup(groupId, "group no longer exists");
+                ClaimLinkModSystem.Registry.Remove(groupId);
+                continue;
+            }
+
+            int memberCount = GroupMemberCount(groupId);
+            sb.AppendLine($"  {group.Name}: {memberCount} member{(memberCount == 1 ? "" : "s")}");
+            shown++;
+        }
+
+        if (shown == 0)
+            return TextCommandResult.Success("There are no claim links.");
+
+        return TextCommandResult.Success($"Claim links ({shown}):\n{sb}");
+    }
+
+    private static IEnumerable<string> GroupMemberUids(int groupId)
+    {
+        foreach (var playerData in ClaimLinkModSystem.PlayerData.PlayerDataByUid.Values)
+            if (playerData.PlayerGroupMemberships.ContainsKey(groupId))
+                yield return playerData.PlayerUID;
+    }
+
+    private static int GroupMemberCount(int groupId)
+    {
+        int count = 0;
+        foreach (string _ in GroupMemberUids(groupId))
+            count++;
+        return count;
+    }
+
+    private static string DescribeClaim(string ownerPlayerUid, int claimIndex)
+    {
+        if (
+            !ClaimLinkModSystem.TryResolveOwnedClaim(
+                ownerPlayerUid,
+                claimIndex,
+                out LandClaim? claim
+            )
+            || claim == null
+        )
+            return $"claim {claimIndex}";
+
+        return string.IsNullOrEmpty(claim.Description) ? $"claim {claimIndex}" : claim.Description;
+    }
+
+    private static string FormatInfo(string groupName, int groupId, bool showDetails)
+    {
+        int memberCount = GroupMemberCount(groupId);
+
+        StringBuilder sb = new();
+        sb.AppendLine(
+            $"Claim link '{groupName}' ({memberCount} member{(memberCount == 1 ? "" : "s")}):"
+        );
+
+        foreach (string uid in GroupMemberUids(groupId))
+        {
+            string name = ClaimLinkModSystem.World.PlayerByUid(uid)?.PlayerName ?? uid;
+
+            if (!showDetails)
+            {
+                sb.AppendLine($"  {name}");
+                continue;
+            }
+
+            IEnumerable<string> claims = ClaimLinkModSystem
+                .Registry.ClaimsForPlayerInGroup(uid, groupId)
+                .Select(i => DescribeClaim(uid, i));
+            sb.AppendLine($"  {name}: [{string.Join(", ", claims)}]");
+        }
+
+        return sb.ToString();
+    }
+
+    public static TextCommandResult AdminDelete(TextCommandCallingArgs args)
+    {
+        TextCommandResult? err = TryResolveGroupArg(args, 0, out PlayerGroup group);
+        if (err != null)
+            return err;
+
+        err = TryResolveClaimLink(group);
+        if (err != null)
+            return err;
+
+        int groupId = group.Uid;
+        string groupName = group.Name;
+
+        RemovePendingActionsForGroup(groupId, "claim link was deleted");
+        ClaimLinkModSystem.Registry.Remove(groupId);
+        return TextCommandResult.Success($"'{groupName}' is no longer a claim link.");
+    }
+
+    public static TextCommandResult AdminUnlink(TextCommandCallingArgs args)
+    {
+        string playerName = (string)args[0];
+        int claimIndex = (int)args[1];
+
+        string? targetUid = ClaimLinkModSystem
+            .PlayerData.GetPlayerDataByLastKnownName(playerName)
+            ?.PlayerUID;
+        if (targetUid == null)
+            return TextCommandResult.Error($"No such player '{playerName}'.");
+
+        int? groupId = ClaimLinkModSystem.Registry.FindGroupContaining(targetUid, claimIndex);
+        if (groupId == null)
+            return TextCommandResult.Error(
+                $"Claim {claimIndex} is not linked into any claim link by {playerName}."
+            );
+
+        string groupName = ClaimLinkModSystem.Groups.PlayerGroupsById[(int)groupId].Name;
+        string claimDesc = DescribeClaim(targetUid, claimIndex);
+
+        ClaimLinkModSystem.Registry.RemoveEntry(targetUid, (int)groupId, claimIndex);
+        return TextCommandResult.Success(
+            $"Unlinked '{claimDesc}' from '{groupName}' (owned by {playerName})."
+        );
+    }
+
+    public static TextCommandResult AdminKick(TextCommandCallingArgs args)
+    {
+        string word1 = (string)args[0];
+        string? word2 = args.Parsers[1].IsMissing ? null : (string)args[1];
+
+        string targetName;
+        PlayerGroup group;
+        if (word2 != null)
+        {
+            TextCommandResult? err = TryResolveGroup(word1, out group);
+            if (err != null)
+                return err;
+            targetName = word2;
+        }
+        else
+        {
+            int chatGroupId = args.Caller.FromChatGroupId;
+            if (!ClaimLinkModSystem.Groups.PlayerGroupsById.TryGetValue(chatGroupId, out group!))
+                return TextCommandResult.Error(
+                    "No group specified and you are not sending this from a group chat channel."
+                );
+            targetName = word1;
+        }
+
+        TextCommandResult? linkErr = TryResolveClaimLink(group);
+        if (linkErr != null)
+            return linkErr;
+
+        string? targetUid = ClaimLinkModSystem
+            .PlayerData.GetPlayerDataByLastKnownName(targetName)
+            ?.PlayerUID;
+        if (targetUid == null)
+            return TextCommandResult.Error($"No such player '{targetName}'.");
+
+        string groupName = group.Name;
+
+        if (!ClaimLinkModSystem.Registry.HasAnyEntry(targetUid, group.Uid))
+            return TextCommandResult.Error($"{targetName} has no claims linked in '{groupName}'.");
+
+        ClaimLinkModSystem.Registry.RemoveAllForPlayerInGroup(targetUid, group.Uid);
+        CommandListener.PendingLoads.Remove(targetUid);
+        PendingActions.Remove(targetUid);
+
+        return TextCommandResult.Success(
+            $"Unlinked all claims of {targetName} from '{groupName}'."
+        );
+    }
+
+    public static TextCommandResult AdminTransferOwnership(TextCommandCallingArgs args)
+    {
+        TextCommandResult? err = TryResolveTargetPlayer(
+            (PlayerUidName[])args[0],
+            out IPlayer target
+        );
+        if (err != null)
+            return err;
+
+        err = TryResolveGroupArg(args, 1, out PlayerGroup group);
+        if (err != null)
+            return err;
+
+        err = TryResolveClaimLink(group);
+        if (err != null)
+            return err;
+
+        err = RequireMember(target, group);
+        if (err != null)
+            return err;
+
+        err = RequireNotAlreadyOwner(group, target);
+        if (err != null)
+            return err;
+
+        return ExecuteTransferOwnership(group, target);
+    }
+
+    internal static void OnPlayerDisconnect(IServerPlayer player)
+    {
+        PendingActions.Remove(player.PlayerUID);
+    }
+}

ClaimLink/ClaimLinkConfig.cs

@@ -0,0 +1,6 @@
+namespace ClaimLink;
+
+internal class ClaimLinkConfig
+{
+    public int BufferSize = 16;
+}

ClaimLink/ClaimLinkModSystem.cs

@@ -1,7 +1,105 @@
-using Vintagestory.API.Common;
+using System.Collections.Generic;
+using CommandHook;
+using Vintagestory.API.Common;
+using Vintagestory.API.Server;
 
 namespace ClaimLink;
 
 public class ClaimLinkModSystem : ModSystem
 {
+    internal static ILandClaimAPI LandClaimAPI = null!;
+    internal static ILogger Logger = null!;
+    internal static ClaimLinkRegistry Registry = null!;
+    internal static IGroupManager Groups = null!;
+    internal static IWorldAccessor World = null!;
+    internal static IPlayerDataManager PlayerData = null!;
+    internal static ClaimLinkConfig Config = null!;
+    internal CommandListener? CmdListener;
+    internal GroupCommandListener? GroupCmdListener;
+
+    public override bool ShouldLoad(EnumAppSide forSide) => forSide == EnumAppSide.Server;
+
+    public override void StartServerSide(ICoreServerAPI api)
+    {
+        LandClaimAPI = api.World.Claims;
+        World = api.World;
+        Groups = api.Groups;
+        Logger = api.Logger;
+        PlayerData = api.PlayerData;
+        Config = api.LoadModConfig<ClaimLinkConfig>("claimlink.json") ?? new ClaimLinkConfig();
+        api.StoreModConfig(Config, "claimlink.json");
+        Registry = new ClaimLinkRegistry(api.WorldManager.SaveGame);
+
+        CmdListener = new CommandListener();
+        CommandHookModSystem.Register(CmdListener);
+        GroupCmdListener = new GroupCommandListener();
+        CommandHookModSystem.Register(GroupCmdListener);
+        ClaimLinkChatCommand.Register(api);
+        ClaimLinkVisualizerNetwork.Start(api);
+
+        api.Event.PlayerDisconnect += CommandListener.OnPlayerDisconnect;
+        api.Event.PlayerDisconnect += GroupCommandListener.OnPlayerDisconnect;
+        api.Event.PlayerDisconnect += ClaimLinkChatCommand.OnPlayerDisconnect;
+    }
+
+    public override void Dispose()
+    {
+        if (CmdListener != null)
+            CommandHookModSystem.Unregister(CmdListener);
+        if (GroupCmdListener != null)
+            CommandHookModSystem.Unregister(GroupCmdListener);
+    }
+
+    private static IEnumerable<(int claimIndex, LandClaim claim)> EnumerateOwnedClaims(
+        string ownerPlayerUid
+    )
+    {
+        int index = 0;
+        foreach (LandClaim c in LandClaimAPI.All)
+        {
+            if (c.OwnedByPlayerUid != ownerPlayerUid)
+                continue;
+
+            yield return (index, c);
+            index++;
+        }
+    }
+
+    public static bool TryResolveOwnedClaim(
+        string ownerPlayerUid,
+        int claimIndex,
+        out LandClaim? claim
+    )
+    {
+        foreach ((int index, LandClaim c) in EnumerateOwnedClaims(ownerPlayerUid))
+        {
+            if (index == claimIndex)
+            {
+                claim = c;
+                return true;
+            }
+        }
+
+        claim = null;
+        return false;
+    }
+
+    internal static bool TryResolveClaimIndex(
+        string ownerPlayerUid,
+        LandClaim target,
+        out int claimIndex
+    )
+    {
+        foreach ((int index, LandClaim c) in EnumerateOwnedClaims(ownerPlayerUid))
+        {
+            if (ReferenceEquals(c, target))
+            {
+                claimIndex = index;
+                return true;
+            }
+        }
+
+        claimIndex = -1;
+        return false;
+    }
 }

ClaimLink/ClaimLinkRegistry.cs

@@ -0,0 +1,201 @@
+using System.Collections.Generic;
+using Vintagestory.API.Server;
+
+namespace ClaimLink;
+
+public class ClaimLinkRegistry
+{
+    private const string SaveKey = "claimlink:claimlinkdata";
+
+    private readonly ISaveGame saveGame;
+
+    private readonly List<int> claimLinks = new();
+    private readonly Dictionary<string, Dictionary<int, List<int>>> entries = new();
+
+    public ClaimLinkRegistry(ISaveGame saveGame)
+    {
+        this.saveGame = saveGame;
+
+        ClaimLinkSaveData? data = saveGame.GetData<ClaimLinkSaveData?>(SaveKey, null);
+        if (data == null)
+            return;
+
+        claimLinks.AddRange(data.Links);
+
+        foreach (var entry in data.Entries)
+        {
+            if (!entries.ContainsKey(entry.OwnerPlayerUid))
+                entries[entry.OwnerPlayerUid] = new Dictionary<int, List<int>>();
+
+            entries[entry.OwnerPlayerUid][entry.GroupId] = new(entry.ClaimIndicies);
+        }
+    }
+
+    public IReadOnlyList<int> All => claimLinks;
+
+    public bool Exists(int groupId) => claimLinks.Contains(groupId);
+
+    public void Add(int groupId)
+    {
+        claimLinks.Add(groupId);
+        Save();
+    }
+
+    public void Remove(int groupId)
+    {
+        claimLinks.Remove(groupId);
+        foreach (var groups in entries.Values)
+            groups.Remove(groupId);
+        Prune();
+        Save();
+    }
+
+    public bool IsClaimLinked(string uid, int claimIndex) =>
+        FindGroupContaining(uid, claimIndex) != null;
+
+    public int? FindGroupContaining(string uid, int claimIndex)
+    {
+        if (!entries.TryGetValue(uid, out var groups))
+            return null;
+        foreach (var (groupId, claims) in groups)
+            if (claims.Contains(claimIndex))
+                return groupId;
+        return null;
+    }
+
+    public bool AddEntry(string uid, int groupId, int claimIndex)
+    {
+        if (CommandListener.PendingLoads.ContainsKey(uid))
+            return false;
+        if (!Exists(groupId))
+            return false;
+        if (!entries.TryGetValue(uid, out var groups))
+            entries[uid] = groups = new();
+        if (!groups.TryGetValue(groupId, out var claims))
+            groups[groupId] = claims = new();
+        claims.Add(claimIndex);
+        Save();
+        return true;
+    }
+
+    public void RemoveEntry(string uid, int groupId, int claimIndex)
+    {
+        if (entries.TryGetValue(uid, out var groups) && groups.TryGetValue(groupId, out var claims))
+            claims.Remove(claimIndex);
+        Prune();
+        Save();
+    }
+
+    public void ClaimRemoved(string uid, int removedIndex)
+    {
+        if (!entries.TryGetValue(uid, out var groups))
+            return;
+
+        foreach (var claims in groups.Values)
+        {
+            claims.Remove(removedIndex);
+            for (int i = 0; i < claims.Count; i++)
+                if (claims[i] > removedIndex)
+                    claims[i]--;
+        }
+
+        Prune();
+        Save();
+    }
+
+    public void ClaimSaved(string uid, int claimIndex)
+    {
+        if (!entries.TryGetValue(uid, out var groups))
+            return;
+
+        int count = 0;
+        foreach (Vintagestory.API.Common.LandClaim c in ClaimLinkModSystem.LandClaimAPI.All)
+            if (c.OwnedByPlayerUid == uid)
+                count++;
+        int newIndex = count - 1;
+
+        foreach (var claims in groups.Values)
+        {
+            int i = claims.IndexOf(claimIndex);
+
+            for (int j = 0; j < claims.Count; j++)
+                if (j != i && claims[j] > claimIndex)
+                    claims[j]--;
+
+            if (i >= 0)
+                claims[i] = newIndex;
+        }
+
+        Save();
+    }
+
+    public bool HasAnyEntry(string uid, int groupId) =>
+        entries.TryGetValue(uid, out var groups)
+        && groups.TryGetValue(groupId, out var claims)
+        && claims.Count > 0;
+
+    public void RemoveAllForPlayerInGroup(string uid, int groupId)
+    {
+        if (entries.TryGetValue(uid, out var groups))
+            groups.Remove(groupId);
+        Prune();
+        Save();
+    }
+
+    public void ClearAllForPlayer(string uid)
+    {
+        entries.Remove(uid);
+        Save();
+    }
+
+    public IEnumerable<string> MemberUidsForGroup(int groupId)
+    {
+        foreach (var (uid, groups) in entries)
+            if (groups.ContainsKey(groupId))
+                yield return uid;
+    }
+
+    public int MemberCountForGroup(int groupId)
+    {
+        int count = 0;
+        foreach (var uid in MemberUidsForGroup(groupId))
+            count++;
+        return count;
+    }
+
+    public IReadOnlyList<int> ClaimsForPlayerInGroup(string uid, int groupId) =>
+        entries.TryGetValue(uid, out var groups) && groups.TryGetValue(groupId, out var claims)
+            ? claims
+            : System.Array.Empty<int>();
+
+    private void Prune()
+    {
+        List<string>? empty = null;
+        foreach (var (uid, groups) in entries)
+            if (groups.Count == 0)
+                (empty ??= new()).Add(uid);
+        if (empty != null)
+            foreach (var uid in empty)
+                entries.Remove(uid);
+    }
+
+    public void Save()
+    {
+        var entryList = new List<ClaimLinkEntrySaveData>();
+        foreach (var (uid, groups) in entries)
+            foreach (var (groupId, claims) in groups)
+                entryList.Add(
+                    new ClaimLinkEntrySaveData
+                    {
+                        OwnerPlayerUid = uid,
+                        GroupId = groupId,
+                        ClaimIndicies = new(claims),
+                    }
+                );
+
+        saveGame.StoreData(
+            SaveKey,
+            new ClaimLinkSaveData { Links = claimLinks, Entries = entryList }
+        );
+    }
+}

ClaimLink/ClaimLinkVisualizerNetwork.cs

@@ -0,0 +1,107 @@
+using System.Collections.Generic;
+using ProtoBuf;
+using Vintagestory.API.MathTools;
+using Vintagestory.API.Server;
+
+namespace ClaimLink;
+
+[ProtoContract]
+public class ClaimLinkBufferRequest { }
+
+[ProtoContract]
+public class ClaimLinkBufferCuboidDto
+{
+    [ProtoMember(1)]
+    public int MinX;
+
+    [ProtoMember(2)]
+    public int MinY;
+
+    [ProtoMember(3)]
+    public int MinZ;
+
+    [ProtoMember(4)]
+    public int MaxX;
+
+    [ProtoMember(5)]
+    public int MaxY;
+
+    [ProtoMember(6)]
+    public int MaxZ;
+}
+
+[ProtoContract]
+public class ClaimLinkBufferEntryDto
+{
+    [ProtoMember(1)]
+    public int GroupId;
+
+    [ProtoMember(2)]
+    public List<ClaimLinkBufferCuboidDto> Cuboids = new();
+}
+
+[ProtoContract]
+public class ClaimLinkBufferResponse
+{
+    [ProtoMember(1)]
+    public List<ClaimLinkBufferEntryDto> Entries = new();
+}
+
+internal static class ClaimLinkVisualizerNetwork
+{
+    internal const string ChannelName = "claimlinkvisualizer";
+
+    internal static void Start(ICoreServerAPI api)
+    {
+        api.Network
+            .RegisterChannel(ChannelName)
+            .RegisterMessageType<ClaimLinkBufferRequest>()
+            .RegisterMessageType<ClaimLinkBufferResponse>()
+            .SetMessageHandler<ClaimLinkBufferRequest>((fromPlayer, _) =>
+                SendBuffers(api, fromPlayer)
+            );
+    }
+
+    private static void SendBuffers(ICoreServerAPI api, IServerPlayer toPlayer)
+    {
+        ClaimLinkBufferResponse response = new();
+
+        BlockPos playerPos = toPlayer.Entity.Pos.AsBlockPos;
+        int radius = toPlayer.WorldData.LastApprovedViewDistance;
+
+        foreach (int groupId in ClaimLinkModSystem.Registry.All)
+        {
+            ClaimLinkBufferEntryDto entry = new() { GroupId = groupId };
+            foreach (Cuboidi cuboid in ClaimLinkBuffer.GetBuffer(groupId))
+            {
+                if (!IsNearby(cuboid, playerPos, radius))
+                    continue;
+
+                entry.Cuboids.Add(
+                    new ClaimLinkBufferCuboidDto
+                    {
+                        MinX = cuboid.MinX,
+                        MinY = cuboid.MinY,
+                        MinZ = cuboid.MinZ,
+                        MaxX = cuboid.MaxX,
+                        MaxY = cuboid.MaxY,
+                        MaxZ = cuboid.MaxZ,
+                    }
+                );
+            }
+
+            if (entry.Cuboids.Count > 0)
+                response.Entries.Add(entry);
+        }
+
+        api.Network.GetChannel(ChannelName).SendPacket(response, toPlayer);
+    }
+
+    private static bool IsNearby(Cuboidi cuboid, BlockPos playerPos, int radius) =>
+        cuboid.MinX <= playerPos.X + radius
+        && cuboid.MaxX >= playerPos.X - radius
+        && cuboid.MinY <= playerPos.Y + radius
+        && cuboid.MaxY >= playerPos.Y - radius
+        && cuboid.MinZ <= playerPos.Z + radius
+        && cuboid.MaxZ >= playerPos.Z - radius;
+}

ClaimLink/CommandListener.cs

@@ -0,0 +1,416 @@
+using System.Collections.Generic;
+using CommandHook;
+using Vintagestory.API.Common;
+using Vintagestory.API.Config;
+using Vintagestory.API.MathTools;
+using Vintagestory.API.Server;
+
+namespace ClaimLink;
+
+public class CommandListener : ICommandHookListener
+{
+    public string ModId => "claimlink";
+
+    public IReadOnlyList<string> Commands => new[] { "land" };
+
+    public CommandRegistration Registration => new(Before, After);
+
+    internal static Dictionary<string, int> PendingLoads = new Dictionary<string, int>();
+    internal static Dictionary<string, List<Cuboidi>?> PendingSaveChecks =
+        new Dictionary<string, List<Cuboidi>?>();
+
+    private delegate void SubHandler(Caller caller, CmdArgs args);
+
+    private static readonly Dictionary<string, SubHandler> topLevel = new()
+    {
+        ["claim"] = Claim,
+        ["free"] = Free,
+        ["adminfree"] = AdminFree,
+        ["adminfreehere"] = AdminFreeHere,
+    };
+
+    private static readonly Dictionary<string, SubHandler> claimSub = new()
+    {
+        ["load"] = ClaimLoad,
+        ["new"] = ClaimNew,
+        ["save"] = ClaimSave,
+        ["cancel"] = ClaimCancel,
+    };
+
+    private static void Dispatch(TextCommandCallingArgs args)
+    {
+        CmdArgs rawArgs = args.RawArgs.Clone();
+
+        while (rawArgs.Length > 0)
+        {
+            string word = rawArgs.PeekWord();
+
+            if (topLevel.TryGetValue(word, out SubHandler? handler))
+            {
+                rawArgs.PopWord();
+                handler(args.Caller, rawArgs);
+            }
+            else
+            {
+                rawArgs.PopWord();
+            }
+        }
+    }
+
+    private TextCommandResult? Before(TextCommandCallingArgs args)
+    {
+        Dispatch(args);
+        return null;
+    }
+
+    private void After(TextCommandCallingArgs args, TextCommandResult result)
+    {
+        if (args.Caller.Player == null)
+            return;
+
+        string uid = args.Caller.Player.PlayerUID;
+        if (!PendingSaveChecks.Remove(uid, out List<Cuboidi>? snapshot))
+            return;
+
+        if (result.Status != EnumCommandStatus.Success)
+            return;
+
+        List<LandClaim> allClaims = ClaimLinkModSystem.LandClaimAPI.All;
+        if (allClaims.Count == 0)
+            return;
+
+        LandClaim savedClaim = allClaims[allClaims.Count - 1];
+        if (savedClaim.OwnedByPlayerUid != uid)
+            return;
+
+        int? linkedGroupId = null;
+        if (ClaimLinkModSystem.TryResolveClaimIndex(uid, savedClaim, out int savedIndex))
+            linkedGroupId = ClaimLinkModSystem.Registry.FindGroupContaining(uid, savedIndex);
+
+        bool isLinked = linkedGroupId != null;
+        List<Cuboidi> checkAreas = isLinked
+            ? ClaimLinkBuffer.GrowAreas(savedClaim.Areas)
+            : savedClaim.Areas;
+
+        ISet<int> excludeGroupIds = isLinked
+            ? new HashSet<int> { linkedGroupId!.Value }
+            : ClaimLinkBuffer.MemberClaimLinkIds(uid);
+
+        LandClaim? violatingClaim = null;
+        bool violatesClaimLink = ClaimLinkBuffer.TryFindOverlappingClaimLink(
+            checkAreas,
+            excludeGroupIds,
+            out int violatingGroupId
+        );
+        bool violatesClaim =
+            isLinked
+            && !violatesClaimLink
+            && ClaimLinkBuffer.TryFindOverlappingClaim(
+                checkAreas,
+                uid,
+                excludeGroupIds,
+                out violatingClaim
+            );
+
+        if (!violatesClaimLink && !violatesClaim)
+            return;
+
+        ClaimLinkModSystem.LandClaimAPI.Remove(savedClaim);
+
+        string reason = violatesClaimLink
+            ? (
+                ClaimLinkModSystem.Groups.PlayerGroupsById.TryGetValue(
+                    violatingGroupId,
+                    out PlayerGroup? violatingGroup
+                )
+                    ? $"it overlaps the protected buffer of '{violatingGroup!.Name}'"
+                    : "it overlaps the protected buffer of another claim link"
+            )
+            : $"its buffer would overlap the claim owned by {violatingClaim!.LastKnownOwnerName}";
+
+        if (snapshot != null)
+        {
+            savedClaim.Areas.Clear();
+            savedClaim.Areas.AddRange(snapshot);
+            ClaimLinkModSystem.LandClaimAPI.Add(savedClaim);
+            NotifyPlayer(args.Caller.Player, $"Your claim growth was reverted: {reason}.");
+        }
+        else
+        {
+            NotifyPlayer(args.Caller.Player, $"Your claim was rejected: {reason}.");
+        }
+    }
+
+    private static void NotifyPlayer(IPlayer player, string message)
+    {
+        if (player is IServerPlayer sp)
+            sp.SendMessage(GlobalConstants.GeneralChatGroup, message, EnumChatType.Notification);
+    }
+
+    private static void Claim(Caller caller, CmdArgs args)
+    {
+        string? word = args.PeekWord();
+        if (word == null)
+            return;
+
+        if (claimSub.TryGetValue(word, out SubHandler? handler))
+        {
+            args.PopWord();
+            handler(caller, args);
+        }
+    }
+
+    private static void ClaimSave(Caller caller, CmdArgs args)
+    {
+        if (caller.Player == null)
+            return;
+
+        string uid = caller.Player.PlayerUID;
+        PendingSaveChecks[uid] = null;
+
+        if (!PendingLoads.TryGetValue(uid, out int pendingIndex))
+            return;
+
+        if (
+            ClaimLinkModSystem.TryResolveOwnedClaim(uid, pendingIndex, out LandClaim? existingClaim)
+            && existingClaim != null
+        )
+        {
+            List<Cuboidi> snapshot = new();
+            foreach (Cuboidi area in existingClaim.Areas)
+                snapshot.Add(area.Clone());
+            PendingSaveChecks[uid] = snapshot;
+        }
+
+        ClaimLinkModSystem.Registry.ClaimSaved(uid, pendingIndex);
+        PendingLoads.Remove(uid);
+        ClaimLinkChatCommand.PendingActions.Remove(uid);
+    }
+
+    private static void ClaimLoad(Caller caller, CmdArgs args)
+    {
+        int? claimIndex = args.PopInt();
+        if (caller.Player == null || claimIndex == null)
+            return;
+
+        if (
+            ClaimLinkModSystem.TryResolveOwnedClaim(caller.Player.PlayerUID, (int)claimIndex, out _)
+        )
+            PendingLoads[caller.Player.PlayerUID] = (int)claimIndex;
+    }
+
+    private static void ClaimNew(Caller caller, CmdArgs args)
+    {
+        if (caller.Player == null)
+            return;
+
+        PendingLoads.Remove(caller.Player.PlayerUID);
+    }
+
+    private static void ClaimCancel(Caller caller, CmdArgs args)
+    {
+        if (caller.Player == null)
+            return;
+
+        PendingLoads.Remove(caller.Player.PlayerUID);
+    }
+
+    private static void Free(Caller caller, CmdArgs args)
+    {
+        if (caller.Player == null)
+            return;
+
+        string uid = caller.Player.PlayerUID;
+        int? claimIndex = args.PopInt();
+        if (claimIndex == null)
+            return;
+
+        if (args.PopWord() != "confirm")
+            return;
+
+        ClaimLinkModSystem.Registry.ClaimRemoved(uid, (int)claimIndex);
+        ClaimLinkChatCommand.PendingActions.Remove(uid);
+    }
+
+    private static void AdminFree(Caller caller, CmdArgs args)
+    {
+        if (caller.Player == null)
+            return;
+
+        string? name = args.PopWord();
+        if (name == null)
+            return;
+
+        string? uid = ClaimLinkModSystem.PlayerData.GetPlayerDataByLastKnownName(name)?.PlayerUID;
+        if (uid == null)
+            return;
+
+        ClaimLinkModSystem.Registry.ClearAllForPlayer(uid);
+        ClaimLinkChatCommand.PendingActions.Remove(uid);
+    }
+
+    private static void AdminFreeHere(Caller caller, CmdArgs args)
+    {
+        if (caller.Player == null)
+            return;
+
+        LandClaim[] claims = ClaimLinkModSystem.LandClaimAPI.Get(
+            caller.Player.Entity.Pos.AsBlockPos
+        );
+
+        foreach (LandClaim c in claims)
+            if (ClaimLinkModSystem.TryResolveClaimIndex(c.OwnedByPlayerUid, c, out int claimIndex))
+            {
+                ClaimLinkModSystem.Registry.ClaimRemoved(c.OwnedByPlayerUid, claimIndex);
+                ClaimLinkChatCommand.PendingActions.Remove(c.OwnedByPlayerUid);
+            }
+    }
+
+    internal static void OnPlayerDisconnect(IServerPlayer player)
+    {
+        PendingLoads.Remove(player.PlayerUID);
+        PendingSaveChecks.Remove(player.PlayerUID);
+    }
+}
+
+public class GroupCommandListener : ICommandHookListener
+{
+    public string ModId => "claimlink.group";
+
+    public IReadOnlyList<string> Commands => new[] { "group" };
+
+    public CommandRegistration Registration => new(Before, After);
+
+    internal static Dictionary<string, int> PendingDisbands = new Dictionary<string, int>();
+    internal static Dictionary<string, (string AffectedUid, int GroupId)> PendingMembershipChecks =
+        new Dictionary<string, (string, int)>();
+
+    private TextCommandResult? Before(TextCommandCallingArgs args)
+    {
+        if (args.Caller.Player == null)
+            return null;
+
+        string callerUid = args.Caller.Player.PlayerUID;
+        CmdArgs rawArgs = args.RawArgs.Clone();
+        string? word = rawArgs.PopWord();
+
+        switch (word)
+        {
+            case "confirmdisband":
+                ConfirmDisband(args, callerUid, rawArgs);
+                break;
+            case "leave":
+                Leave(args, callerUid, rawArgs);
+                break;
+            case "kick":
+                Kick(args, callerUid, rawArgs);
+                break;
+        }
+
+        return null;
+    }
+
+    private static void ConfirmDisband(
+        TextCommandCallingArgs args,
+        string callerUid,
+        CmdArgs rawArgs
+    )
+    {
+        string? name = rawArgs.PopWord();
+        int? groupId =
+            name != null
+                ? ClaimLinkModSystem.Groups.GetPlayerGroupByName(name)?.Uid
+                : args.Caller.FromChatGroupId;
+
+        if (groupId != null)
+            PendingDisbands[callerUid] = (int)groupId;
+    }
+
+    private static void Leave(TextCommandCallingArgs args, string callerUid, CmdArgs rawArgs)
+    {
+        string? name = rawArgs.PopWord();
+        int? groupId =
+            name != null
+                ? ClaimLinkModSystem.Groups.GetPlayerGroupByName(name)?.Uid
+                : args.Caller.FromChatGroupId;
+
+        if (groupId != null)
+            PendingMembershipChecks[callerUid] = (callerUid, (int)groupId);
+    }
+
+    private static void Kick(TextCommandCallingArgs args, string callerUid, CmdArgs rawArgs)
+    {
+        string? word1 = rawArgs.PopWord();
+        string? word2 = rawArgs.PopWord();
+
+        string? targetName;
+        int? groupId;
+        if (word2 != null)
+        {
+            groupId =
+                word1 != null ? ClaimLinkModSystem.Groups.GetPlayerGroupByName(word1)?.Uid : null;
+            targetName = word2;
+        }
+        else
+        {
+            targetName = word1;
+            groupId = args.Caller.FromChatGroupId;
+        }
+
+        if (targetName == null || groupId == null)
+            return;
+
+        string? targetUid = ClaimLinkModSystem
+            .PlayerData.GetPlayerDataByLastKnownName(targetName)
+            ?.PlayerUID;
+        if (targetUid != null)
+            PendingMembershipChecks[callerUid] = (targetUid, (int)groupId);
+    }
+
+    private void After(TextCommandCallingArgs args, TextCommandResult result)
+    {
+        if (args.Caller.Player == null)
+            return;
+
+        string callerUid = args.Caller.Player.PlayerUID;
+
+        if (PendingDisbands.TryGetValue(callerUid, out int disbandedGroupId))
+        {
+            PendingDisbands.Remove(callerUid);
+
+            if (!ClaimLinkModSystem.Groups.PlayerGroupsById.ContainsKey(disbandedGroupId))
+            {
+                ClaimLinkChatCommand.RemovePendingActionsForGroup(
+                    disbandedGroupId,
+                    "group no longer exists"
+                );
+
+                if (ClaimLinkModSystem.Registry.Exists(disbandedGroupId))
+                    ClaimLinkModSystem.Registry.Remove(disbandedGroupId);
+            }
+        }
+
+        if (PendingMembershipChecks.TryGetValue(callerUid, out var check))
+        {
+            PendingMembershipChecks.Remove(callerUid);
+
+            bool stillMember =
+                ClaimLinkModSystem
+                    .PlayerData.GetPlayerDataByUid(check.AffectedUid)
+                    ?.PlayerGroupMemberships.ContainsKey(check.GroupId) == true;
+
+            if (!stillMember)
+                ClaimLinkChatCommand.CancelPendingAction(
+                    check.AffectedUid,
+                    check.GroupId,
+                    "you are no longer a member of the group"
+                );
+        }
+    }
+
+    internal static void OnPlayerDisconnect(IServerPlayer player)
+    {
+        PendingDisbands.Remove(player.PlayerUID);
+        PendingMembershipChecks.Remove(player.PlayerUID);
+    }
+}

ClaimLink/modinfo.json

@@ -3,12 +3,14 @@
     "type": "Code",
     "modid": "claimlink",
     "name": "ClaimLink",
+    "side": "Server",
     "authors": [
-        "Unknown"
+        "anth64"
     ],
-    "description": "To be added",
+    "description": "Link claims together with groups.",
-    "version": "1.0.0",
+    "version": "0.3.0",
     "dependencies": {
-        "game": "1.21.0"
+        "game": "1.22.5",
+        "commandhook": "2.1.0"
     }
 }