using System.Text.Json;

namespace RadicadeServer.Auth;







public static class SteamWhitelist
{
	public sealed class WhitelistFile
	{
		public bool Enabled { get; set; }
		public List<string> SteamIds { get; set; } = new();
	}

	private static readonly JsonSerializerOptions CaseInsensitive = new()
	{
		PropertyNameCaseInsensitive = true
	};

	private static readonly object Lock = new();
	private static WhitelistFile? _data;
	private static string _filePath = "";
	private static bool _loaded;
	private static DateTime _lastWriteUtc = DateTime.MinValue;


	public static string FilePath => _filePath;





	public static bool CreatedEmptyConfig { get; private set; }


	public static void Load()
	{
		lock (Lock)
		{
			if (_loaded) return;

			_filePath = Path.GetFullPath(Path.Join(DBConfig.PrivateData, "steamwhitelist.json"));
			_loaded = true;
			CreatedEmptyConfig = !File.Exists(_filePath);

			try
			{
				if (CreatedEmptyConfig)
				{




					_data = new WhitelistFile { Enabled = false, SteamIds = new List<string>() };
				}
				else
				{
					var raw = File.ReadAllText(_filePath);
					_data = JsonSerializer.Deserialize<WhitelistFile>(raw, CaseInsensitive) ?? new WhitelistFile();
					_data.SteamIds ??= new List<string>();
					_lastWriteUtc = File.GetLastWriteTimeUtc(_filePath);
				}
			}
			catch (Exception)
			{
				_data = new WhitelistFile { Enabled = false, SteamIds = new List<string>() };
			}
		}
	}


	public static bool Enabled
	{
		get { EnsureLoaded(); lock (Lock) return _data!.Enabled; }
		set { EnsureLoaded(); lock (Lock) { _data!.Enabled = value; SaveLocked(); } }
	}


	public static IReadOnlyCollection<string> SteamIds
	{
		get { EnsureLoaded(); lock (Lock) return _data!.SteamIds.ToList(); }
	}


	public static void SetSteamIds(IEnumerable<string> steamIds)
	{
		EnsureLoaded();
		lock (Lock)
		{
			_data!.SteamIds = steamIds
				.Where(id => !string.IsNullOrWhiteSpace(id))
				.Select(id => id.Trim())
				.Distinct()
				.ToList();
			SaveLocked();
		}
	}


	public static bool Contains(string steamId)
	{
		if (string.IsNullOrWhiteSpace(steamId)) return false;
		EnsureLoaded();
		lock (Lock) return _data!.SteamIds.Contains(steamId.Trim());
	}


	public static bool Add(string steamId)
	{
		if (string.IsNullOrWhiteSpace(steamId)) return false;
		steamId = steamId.Trim();

		EnsureLoaded();
		lock (Lock)
		{
			if (_data!.SteamIds.Contains(steamId)) return false;
			_data.SteamIds.Add(steamId);
			SaveLocked();
			return true;
		}
	}


	public static bool Remove(string steamId)
	{
		if (string.IsNullOrWhiteSpace(steamId)) return false;
		steamId = steamId.Trim();

		EnsureLoaded();
		lock (Lock)
		{
			var removed = _data!.SteamIds.Remove(steamId);
			if (removed) SaveLocked();
			return removed;
		}
	}

	private static void EnsureLoaded()
	{
		if (!_loaded) { Load(); return; }





		lock (Lock)
		{
			DateTime lastWriteUtc;
			try { lastWriteUtc = File.GetLastWriteTimeUtc(_filePath); }
			catch { return; }

			if (lastWriteUtc > _lastWriteUtc)
			{
				try
				{
					var raw = File.ReadAllText(_filePath);
					var reloaded = JsonSerializer.Deserialize<WhitelistFile>(raw, CaseInsensitive);
					if (reloaded != null)
					{
						reloaded.SteamIds ??= new List<string>();
						_data = reloaded;
						_lastWriteUtc = lastWriteUtc;
					}
				}
				catch (Exception)
				{
				}
			}
		}
	}

	private static void SaveLocked()
	{
		try
		{
			var dir = Path.GetDirectoryName(_filePath);
			if (!string.IsNullOrEmpty(dir))
				Directory.CreateDirectory(dir);

			var options = new JsonSerializerOptions { WriteIndented = true };
			File.WriteAllText(_filePath, JsonSerializer.Serialize(_data, options));
			_lastWriteUtc = File.GetLastWriteTimeUtc(_filePath);
		}
		catch (Exception)
		{
		}
	}
}