// Name and filename sanitizing helpers.

string normalize_name_whitespace(string name) {
	string result = "";
	bool lastWasSpace = true;

	for (uint charIndex = 0; charIndex < name.length(); charIndex++) {
		string ch = name.substr(charIndex, 1);
		bool isSpace = (ch == " " || ch == "\t" || ch == "\r" || ch == "\n");
		if (isSpace) {
			if (!lastWasSpace) {
				result += " ";
				lastWasSpace = true;
			}
			continue;
		}

		result += ch;
		lastWasSpace = false;
	}

	if (result.length() > 0 && result.substr(result.length() - 1) == " ") {
		result = result.substr(0, result.length() - 1);
	}

	return result;
}

bool is_windows_reserved_filename(const string&in upperName) {
	if (upperName == "CON" || upperName == "PRN" || upperName == "AUX" || upperName == "NUL") return true;

	if (upperName.length() == 4 && upperName.substr(0, 3) == "COM") {
		int num = parse_int(upperName.substr(3));
		if (num >= 1 && num <= 9) return true;
	}

	if (upperName.length() == 4 && upperName.substr(0, 3) == "LPT") {
		int num = parse_int(upperName.substr(3));
		if (num >= 1 && num <= 9) return true;
	}

	return false;
}

string sanitize_filename_base(string name, const int maxLength = 40, const string fallback = "item") {
	string normalized = normalize_name_whitespace(name);
	string result = "";
	bool lastSeparator = false;

	for (uint charIndex = 0; charIndex < normalized.length(); charIndex++) {
		string ch = normalized.substr(charIndex, 1);
		bool isUpper = (ch >= "A" && ch <= "Z");
		bool isLower = (ch >= "a" && ch <= "z");
		bool isDigit = (ch >= "0" && ch <= "9");

		if (isUpper || isLower || isDigit) {
			result += ch;
			lastSeparator = false;
			continue;
		}

		if (ch == " " || ch == "_" || ch == "-") {
			if (!lastSeparator && result.length() > 0) {
				result += "_";
				lastSeparator = true;
			}
		}
	}

	while (result.length() > 0 && result.substr(result.length() - 1) == "_") {
		result = result.substr(0, result.length() - 1);
	}

	if (result.length() == 0) {
		result = fallback;
	}

	if (result.length() > maxLength) {
		result = result.substr(0, maxLength);
	}

	while (result.length() > 0 && result.substr(result.length() - 1) == "_") {
		result = result.substr(0, result.length() - 1);
	}

	string upperName = result.upper();
	if (upperName == "." || upperName == "..") {
		result = fallback;
		upperName = result.upper();
	}

	if (is_windows_reserved_filename(upperName)) {
		result = "file_" + result;
	}

	return result;
}

string build_filename_from_name(const string&in name, const string&in extension = ".dat", const int maxBaseLength = 40, const string fallback = "item") {
	return sanitize_filename_base(name, maxBaseLength, fallback) + extension;
}