package jnpf.audit;

/** 由后端签发的 biz_sign 派生稳定的审计操作分组键。 */
public final class AuditOperationIds {

    private static final String PREFIX = "BS-";
    private static final int MAX_SIGN_LENGTH = 40;

    public static String correlation(String bizSign) {
        String normalized = normalize(bizSign);
        return normalized == null ? null : PREFIX + normalized;
    }

    private static String normalize(String bizSign) {
        if (bizSign == null) {
            return null;
        }
        String value = bizSign.trim();
        if (value.isEmpty() || value.length() > MAX_SIGN_LENGTH) {
            return null;
        }
        for (int i = 0; i < value.length(); i++) {
            char ch = value.charAt(i);
            boolean asciiLetter = (ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z');
            if (!asciiLetter && (ch < '0' || ch > '9') && ch != '-' && ch != '_') {
                return null;
            }
        }
        return value;
    }

    private AuditOperationIds() {
    }
}