/*******************************************************************************
 * 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:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * 3. All advertising materials mentioning features or use of this software must
 *    display the following acknowledgement:
 *    This product includes software developed by the Egothor project.
 *
 * 4. Neither the name of the copyright holder nor the names of its contributors
 *    may be used to endorse or promote products derived from this software without
 *    specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 ******************************************************************************/
package zeroecho.core.storage;

/**
 * Operational limits applied while opening an encrypted software keyring.
 *
 * @param operationalIterationMaximum maximum accepted PBKDF2 iteration count;
 *                                    it may restrict but never exceed the
 *                                    absolute decoded maximum
 */
public record KeyringProtection(int operationalIterationMaximum) {
    /** Iterations used when a new keyring is created. */
    public static final int CREATION_ITERATIONS = 600_000;
    /** Largest operationally accepted PBKDF2 iteration count. */
    public static final int MAX_OPERATIONAL_ITERATIONS = 1_000_000;
    /** Absolute safety ceiling for decoded PBKDF2 iteration counts. */
    public static final int MAX_DECODED_ITERATIONS = 10_000_000;

    /**
     * Validates the operational limit.
     *
     * @throws IllegalArgumentException if the limit is below the creation setting
     *                                  or above the absolute operational maximum
     */
    public KeyringProtection {
        if (operationalIterationMaximum < CREATION_ITERATIONS
                || operationalIterationMaximum > MAX_OPERATIONAL_ITERATIONS) {
            throw new IllegalArgumentException("operationalIterationMaximum must be in [600000,1000000]");
        }
    }

    /**
     * Returns the standard protection policy.
     *
     * @return policy accepting up to one million iterations
     */
    public static KeyringProtection standard() {
        return new KeyringProtection(MAX_OPERATIONAL_ITERATIONS);
    }
}
