ClaimLink/ClaimLink/ClaimLinkBufferProtection.cs

using Vintagestory.API.Common;
using Vintagestory.API.MathTools;
using Vintagestory.API.Server;

namespace ClaimLink;

internal static class ClaimLinkBufferProtection
{
    internal static void Register(ICoreServerAPI api)
    {
        api.Event.CanPlaceOrBreakBlock += OnCanPlaceOrBreakBlock;
        api.Event.CanUseBlock += OnCanUseBlock;
    }

    private static bool OnCanUseBlock(IServerPlayer byPlayer, BlockSelection blockSel) =>
        IsAllowed(byPlayer, blockSel.Position, EnumBlockAccessFlags.Use);

    private static bool OnCanPlaceOrBreakBlock(
        IServerPlayer byPlayer,
        BlockSelection blockSel,
        out string claimant
    )
    {
        bool allowed = IsAllowed(byPlayer, blockSel.Position, EnumBlockAccessFlags.BuildOrBreak);
        claimant = allowed ? null! : "custommessage-claimlink-buffer-zone";
        return allowed;
    }

    private static bool IsAllowed(
        IServerPlayer byPlayer,
        BlockPos pos,
        EnumBlockAccessFlags accessFlag
    )
    {
        bool allowed = true;

        foreach (int groupId in ClaimLinkBufferIndex.CandidateGroupIds(pos))
        {
            if (IsMember(byPlayer, groupId))
                continue;

            foreach (Cuboidi buffer in ClaimLinkBufferIndex.CachedBuffer(groupId))
                if (buffer.Contains(pos))
                    allowed = false;
        }

        return allowed || HasClaimAccess(byPlayer, pos, accessFlag);
    }

    private static bool IsMember(IServerPlayer player, int groupId)
    {
        foreach (PlayerGroupMembership membership in player.Groups)
            if (membership.GroupUid == groupId)
                return true;
        return false;
    }

    private static bool HasClaimAccess(
        IServerPlayer player,
        BlockPos pos,
        EnumBlockAccessFlags accessFlag
    )
    {
        LandClaim[]? claims = ClaimLinkModSystem.LandClaimAPI.Get(pos);
        if (claims == null)
            return false;

        foreach (LandClaim claim in claims)
        {
            if (claim.TestPlayerAccess(player, accessFlag) != EnumPlayerAccessResult.Denied)
                return true;
            if (accessFlag == EnumBlockAccessFlags.Use && claim.AllowUseEveryone)
                return true;
        }

        return false;
    }
}