Experimental convoluted rain refactor to use Redis instead of semaphores

KfChatDotNetBot/Services/KasinoRain.cs

@@ -0,0 +1,145 @@
+using System.Text.Json;
+using KfChatDotNetBot.Extensions;
+using KfChatDotNetBot.Models.DbModels;
+using KfChatDotNetBot.Settings;
+using Microsoft.EntityFrameworkCore;
+using NLog;
+using StackExchange.Redis;
+
+namespace KfChatDotNetBot.Services;
+
+public class KasinoRain : IDisposable
+{
+    private readonly Logger _logger = LogManager.GetCurrentClassLogger();
+    private Task? _rainTimerTask;
+    private IDatabase? _redisDb;
+    private ChatBot _kfChatBot;
+    private CancellationToken _ct;
+    private CancellationTokenSource _rainCts = new();
+
+    public KasinoRain(ChatBot kfChatBot, CancellationToken ct = default)
+    {
+        _kfChatBot = kfChatBot;
+        _ct = ct;
+        var connectionString = SettingsProvider.GetValueAsync(BuiltIn.Keys.BotRedisConnectionString).Result;
+        if (string.IsNullOrEmpty(connectionString.Value))
+        {
+            _logger.Error($"Can't initialize the Kasino Rain service as Redis isn't configured in {BuiltIn.Keys.BotRedisConnectionString}");
+            return;
+        }
+
+        var redis = ConnectionMultiplexer.Connect(connectionString.Value);
+        _redisDb = redis.GetDatabase();
+        _rainTimerTask = Task.Run(RainTimerTask, ct);
+    }
+
+    public bool IsInitialized()
+    {
+        return _redisDb != null;
+    }
+
+    public async Task AddParticipant(int userId)
+    {
+        var data = await GetRainState();
+        if (data == null) throw new InvalidOperationException("Failed to retrieve state or no rain is in progress");
+        if (data.Participants.Contains(userId)) return;
+        data.Participants.Add(userId);
+        await SaveRainState(data);
+    }
+
+    public async Task RemoveRainState()
+    {
+        if (_redisDb == null) throw new InvalidOperationException("Kasino Rain service isn't initialized");
+        await _redisDb.KeyDeleteAsync("Rain.State");
+    }
+
+    public async Task<KasinoRainModel?> GetRainState()
+    {
+        if (_redisDb == null) throw new InvalidOperationException("Kasino Rain service isn't initialized");
+        var json = await _redisDb.StringGetAsync("Rain.State");
+        if (string.IsNullOrEmpty(json)) return null;
+        var data = JsonSerializer.Deserialize<KasinoRainModel>(json.ToString());
+        return data;
+    }
+
+    public async Task SaveRainState(KasinoRainModel rain)
+    {
+        if (_redisDb == null) throw new InvalidOperationException("Kasino Rain service isn't initialized");
+        var json = JsonSerializer.Serialize(rain);
+        await _redisDb.StringSetAsync("Rain.State", json, null, When.Always);
+    }
+
+    private async Task RainTimerTask()
+    {
+        var interval = TimeSpan.FromSeconds(1);
+        using var timer = new PeriodicTimer(interval);
+        while (await timer.WaitForNextTickAsync(_ct))
+        {
+            var rain = await GetRainState();
+            if (rain == null) continue;
+            if (DateTimeOffset.UtcNow < rain.PayoutWhen) continue;
+            var creator = await Money.GetGamblerEntityAsync(rain.Creator, ct: _ct);
+            if (creator == null)
+            {
+                _logger.Error($"Somehow this rain was created by a non-existent (or banned) gambler with user ID {rain.Creator}? Wiping this fucked up state");
+                await RemoveRainState();
+                continue;
+            }
+            
+            if (rain.Participants.Count == 0)
+            {
+                await _kfChatBot.SendChatMessageAsync(
+                    $"Nobody participated in {creator.User.FormatUsername()}'s rain!",
+                    true, autoDeleteAfter: TimeSpan.FromSeconds(30));
+                continue;
+            }
+
+            if (rain.RainAmount > creator.Balance)
+            {
+                await _kfChatBot.SendChatMessageAsync(
+                    $"{creator.User.FormatUsername()} lost it all before he could bless everyone! The giveaway is canceled! :lossmanjack:",
+                    true, autoDeleteAfter: TimeSpan.FromSeconds(30));
+                await RemoveRainState();
+                continue;
+            }
+            
+            List<string> participantNames = [];
+            var payout = rain.RainAmount / rain.Participants.Count;
+            decimal failedPayoutAmount = 0;
+            foreach (var participant in rain.Participants)
+            {
+                var gambler = await Money.GetGamblerEntityAsync(participant, ct: _ct);
+                if (gambler == null)
+                {
+                    _logger.Error($"Somehow this participant ({participant}) does not have a gambler entity or has been banned");
+                    failedPayoutAmount += payout;
+                    continue;
+                }
+                participantNames.Add(gambler.User.FormatUsername());
+                await Money.ModifyBalanceAsync(gambler.Id, payout, TransactionSourceEventType.Rain,
+                    "Payout from rain event", creator.Id, _ct);
+            }
+
+            await Money.ModifyBalanceAsync(creator.Id, -rain.RainAmount + failedPayoutAmount, TransactionSourceEventType.Rain,
+                $"Rained on {participantNames.Count} people", ct: _ct);
+            await _kfChatBot.SendChatMessageAsync(
+                $"{creator.User.FormatUsername()} made it rain {await payout.FormatKasinoCurrencyAsync()} on {string.Join(' ', participantNames)}",
+                true, autoDeleteAfter: TimeSpan.FromSeconds(30));
+            await RemoveRainState();
+        }
+    }
+    public void Dispose()
+    {
+        _rainTimerTask?.Dispose();
+        GC.SuppressFinalize(this);
+    }
+}
+
+public class KasinoRainModel
+{
+    public required List<int> Participants { get; set; } = [];
+    public required int Creator { get; set; }
+    public required DateTimeOffset Started { get; set; }
+    public required decimal RainAmount { get; set; }
+    public required DateTimeOffset PayoutWhen { get; set; }
+}