the files

2026-10-14 06:59:51 +02:00
parent f6175893fc
commit 2040419525
1855 changed files with 6735668 additions and 0 deletions
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+using System.Collections.Concurrent;
+
+namespace Campus_live_rewrite.api.server
+{
+    /// <summary>
+    /// Short-lived codes for linking a Discord account to a Campus account.
+    ///
+    /// FLOW: the website Settings > Discord tab (SiteController, site-cookie authed) calls
+    /// <see cref="Generate"/> for the signed-in account and shows the code; the player runs
+    /// `/link &lt;code&gt;` with the Discord bot (BotCommands), which calls <see cref="TryResolve"/>
+    /// then <see cref="Consume"/> to bind their Discord id.
+    ///
+    /// This is DELIBERATELY its own single-purpose store, isolated from the admin session gate
+    /// (AdminGate) and everything else: redeeming a code ONLY records a Discord&lt;-&gt;account link
+    /// (PlayerDB.SetDiscordLink) and can never mint an admin session or grant any privilege. That is
+    /// the whole point of keeping it separate - linking Discord must never be a path into the admin
+    /// panel.
+    /// </summary>
+    public static class DiscordLinkCodes
+    {
+        private const int TtlSeconds = 600;   // 10 minutes
+        // Unambiguous alphabet (no 0/O/1/I) so a 6-char code is easy to read off a screen and type.
+        private const string Alphabet = "ABCDEFGHJKLMNPQRSTUVWXYZ23456789";
+
+        private static readonly ConcurrentDictionary<string, (ulong accountId, long expires)> _codes = new();
+        private static readonly Random _rng = new();
+
+        /// <summary>Mint a fresh code for this account (replacing any it already had), valid for 10 min.</summary>
+        public static (string code, int ttlSeconds) Generate(ulong accountId)
+        {
+            Sweep();
+            // Drop any outstanding code for this account so only the newest one works.
+            foreach (var kv in _codes)
+                if (kv.Value.accountId == accountId) _codes.TryRemove(kv.Key, out _);
+
+            string code;
+            do
+            {
+                var chars = new char[6];
+                lock (_rng)
+                    for (int i = 0; i < chars.Length; i++) chars[i] = Alphabet[_rng.Next(Alphabet.Length)];
+                code = new string(chars);
+            } while (_codes.ContainsKey(code));
+
+            long expires = DateTimeOffset.UtcNow.ToUnixTimeSeconds() + TtlSeconds;
+            _codes[code] = (accountId, expires);
+            return (code, TtlSeconds);
+        }
+
+        /// <summary>Look up (without consuming) the account a live code belongs to. False if unknown/expired.</summary>
+        public static bool TryResolve(string? code, out ulong accountId)
+        {
+            accountId = 0;
+            if (string.IsNullOrWhiteSpace(code)) return false;
+            code = code.Trim().ToUpperInvariant();
+            if (!_codes.TryGetValue(code, out var entry)) return false;
+            if (DateTimeOffset.UtcNow.ToUnixTimeSeconds() > entry.expires)
+            {
+                _codes.TryRemove(code, out _);
+                return false;
+            }
+            accountId = entry.accountId;
+            return true;
+        }
+
+        /// <summary>Burn a code after a successful link so it can't be reused.</summary>
+        public static void Consume(string? code)
+        {
+            if (string.IsNullOrWhiteSpace(code)) return;
+            _codes.TryRemove(code.Trim().ToUpperInvariant(), out _);
+        }
+
+        private static long _lastSweep;
+        private static void Sweep()
+        {
+            long now = DateTimeOffset.UtcNow.ToUnixTimeSeconds();
+            if (now - Interlocked.Read(ref _lastSweep) < 60) return;
+            Interlocked.Exchange(ref _lastSweep, now);
+            foreach (var kv in _codes)
+                if (now > kv.Value.expires) _codes.TryRemove(kv.Key, out _);
+        }
+    }
+}