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 * Copyright (C) 2026, Leo Galambos
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 *    This product includes software developed by the Egothor project.
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package zeroecho.sdk.util;

import zeroecho.core.util.RandomSupport;

/**
 * Utility class for generating random passwords and secure random byte arrays.
 * <p>
 * This class provides methods to:
 * <ul>
 * <li>Generate cryptographically secure random byte arrays of specified
 * length.</li>
 * <li>Generate random passwords composed of characters derived from random
 * bytes.</li>
 * </ul>
 * <p>
 * Randomness is supplied by the shared thread-safe source in
 * {@link RandomSupport}.
 *
 * @author Leo Galambos
 */
public final class Password {
    /**
     * Private constructor to prevent instantiation of this utility class.
     */
    private Password() {
        // this is a utility class
    }

    /**
     * Fills the supplied array with cryptographically strong random bytes.
     *
     * @param password array to fill; must not be {@code null}
     * @return {@code password}
     * @throws NullPointerException if {@code password} is {@code null}
     */
    public static byte[] generateRandom(final byte[] password) {
        return RandomSupport.generateRandom(password);
    }

    /**
     * Generates a printable password in a caller-owned character array.
     *
     * @param length desired password length; must be positive
     * @return a newly allocated printable password
     * @throws IllegalArgumentException if {@code length} is not positive
     */
    public static char[] generatePrintablePasswordChars(final int length) {
        if (length <= 0) {
            throw new IllegalArgumentException("Password length must be greater than zero");
        }

        final char[] password = new char[length];
        for (int i = 0; i < length; i++) {
            password[i] = (char) (RandomSupport.nextInt('~' - '!' + 1) + '!');
        }
        return password;
    }

}
