Server

Persistence.cs

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+namespace GeoSus.Server;
+
+using System.Security.Cryptography;
+using System.Text;
+using System.Text.Json;
+using Microsoft.Extensions.Logging;
+
+// Write-Ahead Log a Snapshoty pro persistenci
+public class Persistence
+{
+    private readonly ServerConfig _config;
+    private readonly ILogger<Persistence> _logger;
+    private readonly object _walLock = new();
+    
+    public Persistence(ServerConfig config, ILogger<Persistence> logger)
+    {
+        _config = config;
+        _logger = logger;
+        
+        // Vytvoříme adresář pro data
+        Directory.CreateDirectory(_config.DataPath);
+    }
+    
+    #region WAL
+    
+    public void AppendToWal(string lobbyId, GameEvent evt)
+    {
+        var lobbyDir = GetLobbyDir(lobbyId);
+        Directory.CreateDirectory(lobbyDir);
+        
+        var walPath = GetCurrentWalPath(lobbyDir);
+        var json = JsonSerializer.Serialize(evt, JsonOptions.Default);
+        
+        lock (_walLock)
+        {
+            // Kontrola velikosti WAL
+            if (File.Exists(walPath))
+            {
+                var fileInfo = new FileInfo(walPath);
+                if (fileInfo.Length > _config.WalMaxSizeMb * 1024 * 1024)
+                {
+                    // Rotace - nový soubor
+                    var newWalPath = Path.Combine(lobbyDir, $"wal_{DateTime.UtcNow:yyyyMMddHHmmss}.ndjson");
+                    walPath = newWalPath;
+                }
+            }
+            
+            using var fs = new FileStream(walPath, FileMode.Append, FileAccess.Write, FileShare.Read);
+            using var writer = new StreamWriter(fs, Encoding.UTF8);
+            writer.WriteLine(json);
+            writer.Flush();
+            fs.Flush(true); // fsync
+        }
+    }
+    
+    public List<GameEvent> ReadWal(string lobbyId, long fromEventId = 0)
+    {
+        var lobbyDir = GetLobbyDir(lobbyId);
+        var events = new List<GameEvent>();
+        
+        if (!Directory.Exists(lobbyDir))
+            return events;
+            
+        // Načteme všechny WAL soubory seřazené podle času
+        var walFiles = Directory.GetFiles(lobbyDir, "wal_*.ndjson")
+            .OrderBy(f => f)
+            .ToList();
+            
+        foreach (var walPath in walFiles)
+        {
+            try
+            {
+                var lines = File.ReadAllLines(walPath, Encoding.UTF8);
+                foreach (var line in lines)
+                {
+                    if (string.IsNullOrWhiteSpace(line)) continue;
+                    
+                    var evt = JsonSerializer.Deserialize<GameEvent>(line, JsonOptions.Default);
+                    if (evt != null && evt.EventId > fromEventId)
+                    {
+                        events.Add(evt);
+                    }
+                }
+            }
+            catch (Exception ex)
+            {
+                _logger.LogError(ex, "Chyba při čtení WAL {Path}", walPath);
+            }
+        }
+        
+        return events.OrderBy(e => e.EventId).ToList();
+    }
+    
+    private string GetCurrentWalPath(string lobbyDir)
+    {
+        // Najdeme nejnovější WAL nebo vytvoříme nový
+        var walFiles = Directory.GetFiles(lobbyDir, "wal_*.ndjson");
+        if (walFiles.Length == 0)
+        {
+            return Path.Combine(lobbyDir, $"wal_{DateTime.UtcNow:yyyyMMddHHmmss}.ndjson");
+        }
+        return walFiles.OrderByDescending(f => f).First();
+    }
+    
+    #endregion
+    
+    #region Snapshots
+    
+    public void SaveSnapshot(string lobbyId, LobbySnapshot snapshot)
+    {
+        var lobbyDir = GetLobbyDir(lobbyId);
+        Directory.CreateDirectory(lobbyDir);
+        
+        // Serializujeme bez checksumu
+        snapshot.Timestamp = DateTime.UtcNow;
+        var json = JsonSerializer.Serialize(snapshot, JsonOptions.Indented);
+        
+        // Spočítáme checksum
+        var checksum = ComputeChecksum(json);
+        snapshot.Checksum = checksum;
+        
+        // Serializujeme znovu s checksumem
+        json = JsonSerializer.Serialize(snapshot, JsonOptions.Indented);
+        
+        var snapshotPath = Path.Combine(lobbyDir, $"snapshot_{snapshot.LastEventId}.json");
+        var tempPath = snapshotPath + ".tmp";
+        
+        // Atomic write - temp + rename
+        File.WriteAllText(tempPath, json, Encoding.UTF8);
+        File.Move(tempPath, snapshotPath, overwrite: true);
+        
+        _logger.LogInformation("Snapshot uložen: {Path}, eventId: {EventId}", snapshotPath, snapshot.LastEventId);
+        
+        // Čištění starých snapshotů
+        CleanupOldSnapshots(lobbyDir);
+    }
+    
+    public LobbySnapshot? LoadLatestSnapshot(string lobbyId)
+    {
+        var lobbyDir = GetLobbyDir(lobbyId);
+        
+        if (!Directory.Exists(lobbyDir))
+            return null;
+            
+        var snapshotFiles = Directory.GetFiles(lobbyDir, "snapshot_*.json")
+            .OrderByDescending(f => f)
+            .ToList();
+            
+        foreach (var snapshotPath in snapshotFiles)
+        {
+            try
+            {
+                var json = File.ReadAllText(snapshotPath, Encoding.UTF8);
+                var snapshot = JsonSerializer.Deserialize<LobbySnapshot>(json, JsonOptions.Default);
+                
+                if (snapshot == null) continue;
+                
+                // Validace checksumu
+                var storedChecksum = snapshot.Checksum;
+                snapshot.Checksum = "";
+                var jsonWithoutChecksum = JsonSerializer.Serialize(snapshot, JsonOptions.Indented);
+                var computedChecksum = ComputeChecksum(jsonWithoutChecksum);
+                
+                if (storedChecksum != computedChecksum)
+                {
+                    _logger.LogWarning("Checksum mismatch pro snapshot {Path}", snapshotPath);
+                    continue;
+                }
+                
+                snapshot.Checksum = storedChecksum;
+                return snapshot;
+            }
+            catch (Exception ex)
+            {
+                _logger.LogError(ex, "Chyba při čtení snapshot {Path}", snapshotPath);
+            }
+        }
+        
+        return null;
+    }
+    
+    private void CleanupOldSnapshots(string lobbyDir, int keepCount = 5)
+    {
+        var snapshotFiles = Directory.GetFiles(lobbyDir, "snapshot_*.json")
+            .OrderByDescending(f => f)
+            .Skip(keepCount)
+            .ToList();
+            
+        foreach (var oldSnapshot in snapshotFiles)
+        {
+            try
+            {
+                File.Delete(oldSnapshot);
+                _logger.LogDebug("Smazán starý snapshot: {Path}", oldSnapshot);
+            }
+            catch (Exception ex)
+            {
+                _logger.LogWarning(ex, "Nelze smazat snapshot {Path}", oldSnapshot);
+            }
+        }
+    }
+    
+    private static string ComputeChecksum(string content)
+    {
+        var bytes = Encoding.UTF8.GetBytes(content);
+        var hash = SHA256.HashData(bytes);
+        return Convert.ToHexString(hash).ToLowerInvariant();
+    }
+    
+    #endregion
+    
+    #region Archive
+    
+    public void ArchiveLobby(string lobbyId)
+    {
+        var lobbyDir = GetLobbyDir(lobbyId);
+        if (!Directory.Exists(lobbyDir))
+            return;
+            
+        var archiveDir = Path.Combine(_config.DataPath, "archive");
+        Directory.CreateDirectory(archiveDir);
+        
+        var archivePath = Path.Combine(archiveDir, $"{lobbyId}_{DateTime.UtcNow:yyyyMMddHHmmss}");
+        Directory.Move(lobbyDir, archivePath);
+        
+        _logger.LogInformation("Lobby archivováno: {LobbyId} -> {ArchivePath}", lobbyId, archivePath);
+    }
+    
+    public void DeleteLobbyData(string lobbyId)
+    {
+        var lobbyDir = GetLobbyDir(lobbyId);
+        if (Directory.Exists(lobbyDir))
+        {
+            Directory.Delete(lobbyDir, recursive: true);
+            _logger.LogInformation("Data lobby smazána: {LobbyId}", lobbyId);
+        }
+    }
+    
+    #endregion
+    
+    private string GetLobbyDir(string lobbyId)
+    {
+        return Path.Combine(_config.DataPath, "lobbies", lobbyId);
+    }
+}