Two players cannot repeat meeting more often than once every 180 s

MomentaryMeeting/Game/InteractionManager.cs

@@ -17,6 +17,8 @@ namespace MomentaryMeeting.Game
     public class InteractionManager : IEndMeetings
     {
         private const string _entryText = "A stranger appears in front of you.{1} You feel as though you could {b}say{/b} something to them.";
+        // Two players cannot meet more than once within this interval
+        private const int _reMeetingLockoutInterval = 180;
 
         private readonly IDatabaseApi _databaseApi;
         private readonly Database _database;
@@ -25,6 +27,9 @@ namespace MomentaryMeeting.Game
         private readonly IDistributedCache _distributedCache;
         private List<Meeting> _meetings;
         private GameInstance _gameInstance;
+        // key is player discord ID, value is a dictionary whose key is another
+        // other player's discord ID and value is the UNIX timestamp when they were last together
+        private Dictionary<ulong, Dictionary<ulong, long>> _lastMetRecord;
 
         public InteractionManager(IDatabaseApi databaseApi, ILogger<InteractionManager> logger, ArrangementGenerator arrangementGenerator, IDistributedCache distributedCache)
         {
@@ -34,6 +39,42 @@ namespace MomentaryMeeting.Game
             _arrangementGenerator = arrangementGenerator;
             _distributedCache = distributedCache;
             _meetings = new List<Meeting>();
+            _lastMetRecord = new Dictionary<ulong, Dictionary<ulong, long>>();
+        }
+
+        public static long Now()
+        {
+            return new DateTimeOffset(DateTime.UtcNow).ToUnixTimeSeconds();
+        }
+
+        // This should be called when a meeting occurs, to record when a player
+        // last met another player
+        private void RecordMeetingOccurred(UserModel player, UserModel otherUser)
+        {
+            if (!_lastMetRecord.ContainsKey(player.DiscordId))
+            {
+                _lastMetRecord[player.DiscordId] = new Dictionary<ulong, long>();
+            }
+            _lastMetRecord[player.DiscordId][otherUser.DiscordId] = Now();
+        }
+
+        // Check whether player and otherUser have met within
+        // _reMeetingLockoutInterval seconds, returns true if so
+        private bool LastMeetingTooSoon(UserModel player, UserModel otherUser)
+        {
+            if (!_lastMetRecord.ContainsKey(player.DiscordId))
+            {
+                // Wow, this player has met no-one ever
+                return false;
+            }
+            if (!_lastMetRecord[player.DiscordId].ContainsKey(otherUser.DiscordId))
+            {
+                // This player has never met otherUser
+                return false;
+            }
+            long lastMetSecondsAgo = Now() - _lastMetRecord[player.DiscordId][otherUser.DiscordId];
+            //_logger.LogInformation($"Players last met {lastMetSecondsAgo} s ago");
+            return lastMetSecondsAgo < _reMeetingLockoutInterval;
         }
 
         public async Task<string> CheckForInteraction(GameInstance gameInstance, UserModel player)
@@ -43,14 +84,19 @@ namespace MomentaryMeeting.Game
             foreach (UserModel otherUser in gameInstance.GetPlayers())
             {
                 _logger.LogInformation($"ID: {player.DiscordId} {otherUser.DiscordId} {player.DiscordId != otherUser.DiscordId} object: {player != otherUser}");
-                // if someone else is in the room, and they are not me and they are not in meeting
-                if (otherUser.LocationName == player.LocationName && player.DiscordId != otherUser.DiscordId && otherUser.InMeeting == false)
+                // if someone else is in the room, and they are not me and they are not in meeting and they haven't already met recently
+                if ((otherUser.LocationName == player.LocationName)
+                    && (player.DiscordId != otherUser.DiscordId)
+                    && (otherUser.InMeeting == false)
+                    && !LastMeetingTooSoon(player, otherUser))
                 {
                     player.InMeeting = true;
                     otherUser.InMeeting = true;
                     Meeting meeting = new Meeting(this);
                     meeting._users.Add(player);
                     meeting._users.Add(otherUser);
+                    RecordMeetingOccurred(player, otherUser);
+                    RecordMeetingOccurred(otherUser, player);
                     _meetings.Add(meeting);
                     // let them know someone has entered their room
                     await _gameInstance.SendPromptToPlayer(otherUser, "<" + _entryText);
@@ -71,7 +117,7 @@ namespace MomentaryMeeting.Game
             {
                 player.InMeeting = false;
                 _meetings.Remove(meeting);
-                if (isTornApart)
+                if (isTornApart)
                 {
                     // send them several rooms away
                     ArrangementGenerator.Neighbours neighbours;