/*******************************************************************************
 * Copyright (C) 2026, Leo Galambos
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
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 * 1. Redistributions of source code must retain the above copyright notice, this
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 *    This product includes software developed by the Egothor project.
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package zeroecho.pki.api.attr;

import java.util.List;
import java.util.Optional;
import java.util.Set;

/**
 * Immutable set of typed attributes.
 *
 * <p>
 * This is a passive container. Production code is expected to mediate
 * read/write/export/derive operations through a governance/enforcement layer
 * that performs ACL checks and emits audit events.
 * </p>
 */
public interface AttributeSet {

    /**
     * Returns all attribute identifiers present in this set.
     *
     * @return set of attribute ids
     */
    Set<AttributeId> ids();

    /**
     * Reads a single-valued attribute.
     *
     * <p>
     * If the attribute is multi-valued, implementations may return empty or one
     * chosen value; callers should prefer {@link #getAll(AttributeId)} when
     * multi-valued is expected.
     * </p>
     *
     * @param id attribute id
     * @return attribute value if present
     * @throws IllegalArgumentException if {@code id} is null
     */
    Optional<AttributeValue> get(AttributeId id);

    /**
     * Reads a potentially multi-valued attribute.
     *
     * @param id attribute id
     * @return list of values (empty if absent)
     * @throws IllegalArgumentException if {@code id} is null
     */
    List<AttributeValue> getAll(AttributeId id);
}
