using TH1_Logic.Chat;

namespace TH1_UI.View.Outside
{
	internal static class RoomNameInputValidator
	{
		public const int MinRoomNameLength = 2;
		public const int MaxRoomNameLength = 20;
		public const string InvalidRoomNameHint = "房间名称包含不适当内容，请修改后再确认。禁止使用辱骂、歧视、色情、广告、冒充官方或泄露隐私等内容。";
		public const string InvalidCharactersHint = "房间名称只能使用中文、英文字母、数字、下划线、中划线和点。";

		public enum ErrorType
		{
			None,
			Illegal,
			TooShort
		}

		public static string SanitizeAllowedCharacters(string input)
		{
			if (string.IsNullOrEmpty(input)) return string.Empty;

			var result = new System.Text.StringBuilder();
			foreach (char c in input.Trim())
			{
				bool isChinese = c >= '\u4e00' && c <= '\u9fff';
				bool isLetter = (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z');
				bool isDigit = c >= '0' && c <= '9';
				bool isAllowedSymbol = c == '_' || c == '-' || c == '.';

				if (isChinese || isLetter || isDigit || isAllowedSymbol)
				{
					result.Append(c);
				}

				if (result.Length >= MaxRoomNameLength) break;
			}

			return result.ToString();
		}

		public static bool TryValidateForSubmit(string input, string fallbackRoomName, out string roomName, out string hint)
		{
			ErrorType errorType;
			if (TryValidateForSubmitWithErrorType(input, fallbackRoomName, out roomName, out errorType))
			{
				hint = null;
				return true;
			}

			hint = errorType == ErrorType.TooShort ? string.Empty : InvalidRoomNameHint;
			return false;
		}

		public static bool TryValidateForSubmitWithErrorType(string input, string fallbackRoomName, out string roomName, out ErrorType errorType)
		{
			roomName = SanitizeAllowedCharacters(input);
			if (string.IsNullOrEmpty(roomName)) roomName = SanitizeAllowedCharacters(fallbackRoomName);
			if (roomName.Length < MinRoomNameLength)
			{
				errorType = ErrorType.TooShort;
				return false;
			}

			var filtered = BannedWordFilter.Filter(roomName, BannedTextContext.Name);
			if (filtered != roomName)
			{
				errorType = ErrorType.Illegal;
				return false;
			}

			errorType = ErrorType.None;
			return true;
		}

	}
}