niko
44 lines
1.9 KiB
C#
44 lines
1.9 KiB
C#
using System.Collections.Concurrent;
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namespace Campus_live_rewrite.api.server
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{
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/// <summary>
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/// One gift of the same item from the same buyer to the same player per Window (2026-09-27
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/// request). The gift button is easy to hit twice, and two taps both passed the "they already
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/// have it" check before either box existed - consumables are never checked at all - so the
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/// buyer paid twice. The reservation is taken atomically before anything is charged; a line
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/// that ends up unbought gives it back.
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/// </summary>
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public static class GiftGuard
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{
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public static TimeSpan Window = TimeSpan.FromSeconds(60);
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public const string Message = "You just gifted them that - wait a minute before sending it again.";
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private static readonly ConcurrentDictionary<string, DateTime> _recent = new();
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public static string Key(ulong buyer, ulong recipient, string item) => $"{buyer}>{recipient}:{item.ToLowerInvariant()}";
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/// <summary>True when this gift may go ahead (and it is now reserved), false inside the window.</summary>
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public static bool TryReserve(string key)
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{
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var now = DateTime.UtcNow;
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if (_recent.Count > 5000)
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foreach (var kv in _recent)
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if (now - kv.Value >= Window) _recent.TryRemove(kv.Key, out _);
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while (true)
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{
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if (_recent.TryAdd(key, now)) return true;
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if (!_recent.TryGetValue(key, out var at)) continue;
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if (now - at < Window) return false;
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if (_recent.TryUpdate(key, now, at)) return true;
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}
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}
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/// <summary>Give a reservation back (the gift was not bought after all).</summary>
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public static void Release(string? key)
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{
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if (!string.IsNullOrEmpty(key)) _recent.TryRemove(key, out _);
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}
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}
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}
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