// Reference: 0Harmony

using System;
using System.Collections.Generic;
using HarmonyLib;
using Network;
using Network.Visibility;
using Oxide.Core.Plugins;

namespace Oxide.Plugins
{
    [Info("CircularNetworkDistance", "Vice/Cobalt Studios (Whispers88) Edit", "1.0.4")]
    public class CircularNetworkDistance : RustPlugin
    {
        #region Harmony

        void Init()
        {
            ConVar.Net.visibilityRadiusFarOverride = 6;
            ConVar.Net.visibilityRadiusNearOverride = 4;
        }

        #endregion

        [HarmonyPatch(typeof(NetworkVisibilityGrid), "GetVisibleFrom"), AutoPatch]
        public static class GetVisibleFromPatch
        {
            [HarmonyPrefix]
            public static bool Prefix(NetworkVisibilityGrid __instance, Group group, List<Group> groups, int radius)
            {
                return GetVisibleFromCircle(__instance, group, groups, radius);
            }
        }

        // hardcoded values because this is probably fastest
        private static readonly List<int> EightCircle = new List<int>() { 2, 4, 6, 6, 7, 7, 8, 8, 8, 8, 8, 7, 7, 6, 6, 4, 2 };
        private static readonly List<int> SevenCircle = new List<int>() { 2, 4, 5, 6, 6, 7, 7, 7, 7, 7, 6, 6, 5, 4, 2 };
        private static readonly List<int> SixCircle = new List<int>() { 2, 4, 5, 5, 6, 6, 6, 6, 6, 5, 5, 4, 2 };
        private static readonly List<int> FiveCircle = new List<int>() { 2, 3, 4, 5, 5, 5, 5, 5, 4, 3, 2 };
        private static readonly List<int> FourCircle = new List<int>() { 2, 3, 4, 4, 4, 4, 4, 3, 2 };
        private static readonly List<int> ThreeCircle = new List<int>() { 1, 2, 3, 3, 3, 2, 1 };
        private static readonly List<int> TwoCircle = new List<int>() { 1, 2, 2, 2, 1 };

        static List<int>? GetCircleSizeLookup(int radius)
        {
            switch (radius)
            {
                case 8: return EightCircle;
                case 7: return SevenCircle;
                case 6: return SixCircle;
                case 5: return FiveCircle;
                case 4: return FourCircle;
                case 3: return ThreeCircle;
                case 2: return TwoCircle;

                default: return null;
            }
        }

        static bool GetVisibleFromCircle(NetworkVisibilityGrid grid, Group group, List<Group> groups, int radius)
        {
            List<int>? lookup = GetCircleSizeLookup(radius);
            if (lookup == null)
                return true;

            // Global netgroup
            groups.Add(Net.sv.visibility.Get(0U));
            if (group.restricted)
            {
                groups.Add(group);
                return false;
            }
            int id = (int)group.ID;
            if (id < grid.startID)
                return false;

            ValueTuple<int, int, int> valueTuple = DeconstructGroupId(grid, id);
            int item1 = valueTuple.Item1;
            int item2 = valueTuple.Item2;
            int item3 = valueTuple.Item3;

            for (int deltaY = -radius; deltaY <= radius; deltaY++)
            {
                int bounds = lookup[deltaY + radius];
                for (int deltaX = -bounds; deltaX <= bounds; deltaX++)
                {
                    AddLayers(grid, groups, item1 + deltaX, item2 + deltaY, item3);
                }
            }
            return false;
        }

        private static ValueTuple<int, int, int> DeconstructGroupId(NetworkVisibilityGrid grid, int groupId)
        {
            int num;
            int num1;
            groupId -= grid.startID;
            int num2 = Math.DivRem(groupId, grid.cellCount * grid.cellCount, out num);
            return new ValueTuple<int, int, int>(Math.DivRem(num, grid.cellCount, out num1), num1, num2);
        }

        static void AddLayers(NetworkVisibilityGrid grid, List<Group> groups, int groupX, int groupY, int groupLayer)
        {
            Add(grid, groups, groupX, groupY, groupLayer);
            if (groupLayer == 0)
            {
                Add(grid, groups, groupX, groupY, 1);
            }
            else if (groupLayer == 1)
            {
                Add(grid, groups, groupX, groupY, 2);
                Add(grid, groups, groupX, groupY, 0);
            }
            else if (groupLayer == 2)
            {
                Add(grid, groups, groupX, groupY, 1);
            }
        }

        static void Add(NetworkVisibilityGrid grid, List<Group> groups, int groupX, int groupY, int groupLayer) => groups.Add(Net.sv.visibility.Get(CoordToID(grid, groupX, groupY, groupLayer)));

        static uint CoordToID(NetworkVisibilityGrid grid, int x, int y, int layer) => (uint)(layer * (grid.cellCount * grid.cellCount) + x * grid.cellCount + y + grid.startID);

    }
}