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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.pki.api.audit;

import java.util.Optional;

import zeroecho.pki.api.attr.AttributeCatalogue;
import zeroecho.pki.api.attr.AttributeId;
import zeroecho.pki.api.attr.AttributeSet;
import zeroecho.pki.api.attr.AttributeValue;

/**
 * Policy enforcement point for attribute access with mandatory auditing.
 *
 * <p>
 * All attribute read/write/export/derive operations should be performed through
 * this service to ensure: (1) consistent ACL evaluation and (2) consistent
 * audit event emission.
 * </p>
 */
public interface AttributeGovernanceService {

    /**
     * Reads an attribute value after applying access control.
     *
     * @param catalogue attribute catalogue used to resolve definitions
     * @param set       attribute set being accessed
     * @param id        attribute id
     * @param context   access context
     * @return value if present and access is allowed; empty otherwise
     * @throws IllegalArgumentException if inputs are null
     */
    Optional<AttributeValue> read(AttributeCatalogue catalogue, AttributeSet set, AttributeId id,
            AccessContext context);

    /**
     * Writes an attribute value after applying access control.
     *
     * @param catalogue attribute catalogue used to resolve definitions
     * @param set       attribute set being modified
     * @param id        attribute id
     * @param value     value to write
     * @param context   access context
     * @return new attribute set instance containing the updated value
     * @throws IllegalArgumentException if inputs are null
     */
    AttributeSet write(AttributeCatalogue catalogue, AttributeSet set, AttributeId id, AttributeValue value,
            AccessContext context);

    /**
     * Exports an attribute value after applying access control.
     *
     * <p>
     * Export may imply redaction. The exact redaction rules are
     * implementation-defined and should take attribute sensitivity and export
     * target into account.
     * </p>
     *
     * @param catalogue attribute catalogue used to resolve definitions
     * @param set       attribute set being exported from
     * @param id        attribute id
     * @param context   access context
     * @return exported value if present and allowed; empty otherwise
     * @throws IllegalArgumentException if inputs are null
     */
    Optional<AttributeValue> export(AttributeCatalogue catalogue, AttributeSet set, AttributeId id,
            AccessContext context);

    /**
     * Derives an attribute value from other inputs after applying access control.
     *
     * <p>
     * Derivation may be used to compute attributes such as fingerprints or
     * normalized identity fields.
     * </p>
     *
     * @param catalogue attribute catalogue used to resolve definitions
     * @param set       attribute set being modified
     * @param id        attribute id
     * @param context   access context
     * @return new attribute set instance containing the derived value
     *         (implementation-defined)
     * @throws IllegalArgumentException if inputs are null
     */
    AttributeSet derive(AttributeCatalogue catalogue, AttributeSet set, AttributeId id, AccessContext context);
}
