Make it so you don't rematch with people you just dived in with

ProjectLighthouse/Controllers/MatchController.cs

@@ -1,6 +1,5 @@
 #nullable enable
 using System;
-using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using System.Text.Json;
@@ -66,60 +65,28 @@ namespace LBPUnion.ProjectLighthouse.Controllers
 
             #region Process match data
 
-            if (matchData is UpdateMyPlayerData)
+            if (matchData is UpdateMyPlayerData) MatchHelper.SetUserLocation(user.UserId, token.UserLocation);
-            {
-                if (MatchHelper.UserLocations.TryGetValue(user.UserId, out string? _)) MatchHelper.UserLocations.Remove(user.UserId);
-                MatchHelper.UserLocations.Add(user.UserId, token.UserLocation);
-            }
 
-            if (matchData is FindBestRoom findBestRoom)
+            if (matchData is FindBestRoom && MatchHelper.UserLocations.Count > 1)
-            {
-                if (MatchHelper.UserLocations.Count > 1)
             {
                 foreach ((int id, string? location) in MatchHelper.UserLocations)
                 {
                     if (id == user.UserId) continue;
                     if (location == null) continue;
+                    if (MatchHelper.DidUserRecentlyDiveInWith(user.UserId, id)) continue;
 
                     User? otherUser = await this.database.Users.FirstOrDefaultAsync(u => u.UserId == id);
                     if (otherUser == null) continue;
 
-                        FindBestRoomResponse response = new()
+                    FindBestRoomResponse response = MatchHelper.FindBestRoomResponse(user.Username, otherUser.Username, token.UserLocation, location);
-                        {
-                            Players = new List<Player>
-                            {
-                                new()
-                                {
-                                    MatchingRes = 0,
-                                    PlayerId = otherUser.Username,
-                                },
-                                new()
-                                {
-                                    MatchingRes = 1,
-                                    PlayerId = user.Username,
-                                },
-                            },
-                            Locations = new List<string>
-                            {
-                                location,
-                                token.UserLocation,
-                            },
-                            Slots = new List<List<int>>
-                            {
-                                new()
-                                {
-                                    5,
-                                    0,
-                                },
-                            },
-                        };
 
                     string serialized = JsonSerializer.Serialize(response, typeof(FindBestRoomResponse));
 
+                    MatchHelper.AddUserRecentlyDivedIn(user.UserId, id);
+
                     return new ObjectResult($"[{{\"StatusCode\":200}},{serialized}]");
                 }
             }
-            }
 
             #endregion
 

ProjectLighthouse/Helpers/MatchHelper.cs

@@ -1,6 +1,7 @@
 #nullable enable
 using System;
 using System.Collections.Generic;
+using System.Diagnostics;
 using System.Linq;
 using System.Text.Json;
 using System.Text.RegularExpressions;
@@ -10,7 +11,64 @@ namespace LBPUnion.ProjectLighthouse.Helpers
 {
     public static class MatchHelper
     {
-        public static Dictionary<int, string?> UserLocations = new();
+        public static readonly Dictionary<int, string?> UserLocations = new();
+        public static readonly Dictionary<int, List<int>?> UserRecentlyDivedIn = new();
+
+        public static void SetUserLocation(int userId, string location)
+        {
+            if (UserLocations.TryGetValue(userId, out string? _)) UserLocations.Remove(userId);
+            UserLocations.Add(userId, location);
+        }
+
+        public static void AddUserRecentlyDivedIn(int userId, int otherUserId)
+        {
+            if (!UserRecentlyDivedIn.TryGetValue(userId, out List<int>? recentlyDivedIn))
+            {
+                UserRecentlyDivedIn.Add(userId, recentlyDivedIn = new List<int>());
+            }
+
+            Debug.Assert(recentlyDivedIn != null, nameof(recentlyDivedIn) + " is null, somehow.");
+
+            recentlyDivedIn.Add(otherUserId);
+        }
+
+        public static bool DidUserRecentlyDiveInWith(int userId, int otherUserId)
+        {
+            if (!UserRecentlyDivedIn.TryGetValue(userId, out List<int>? recentlyDivedIn) || recentlyDivedIn == null) return false;
+
+            return recentlyDivedIn.Contains(otherUserId);
+        }
+
+        public static FindBestRoomResponse FindBestRoomResponse(string username, string otherUsername, string location, string otherLocation)
+            => new()
+            {
+                Players = new List<Player>
+                {
+                    new()
+                    {
+                        MatchingRes = 0,
+                        PlayerId = otherUsername,
+                    },
+                    new()
+                    {
+                        MatchingRes = 1,
+                        PlayerId = username,
+                    },
+                },
+                Locations = new List<string>
+                {
+                    location,
+                    otherLocation,
+                },
+                Slots = new List<List<int>>
+                {
+                    new()
+                    {
+                        5,
+                        0,
+                    },
+                },
+            };
 
         public static IMatchData? Deserialize(string data)
         {