/*
 * Licensed to Crate under one or more contributor license agreements.
 * See the NOTICE file distributed with this work for additional
 * information regarding copyright ownership.  Crate licenses this file
 * to you under the Apache License, Version 2.0 (the "License"); you may
 * not use this file except in compliance with the License.  You may
 * obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
 * implied.  See the License for the specific language governing
 * permissions and limitations under the License.
 *
 * However, if you have executed another commercial license agreement
 * with Crate these terms will supersede the license and you may use the
 * software solely pursuant to the terms of the relevant commercial
 * agreement.
 */

package io.crate.operation.reference.sys.check;


import org.apache.lucene.util.BytesRef;

import javax.annotation.concurrent.ThreadSafe;
import java.util.concurrent.CompletableFuture;

@ThreadSafe
public interface SysCheck {

    enum Severity {
        LOW(1),
        MEDIUM(2),
        HIGH(3);

        private int value;

        Severity(int value) {
            this.value = value;
        }

        public int value() {
            return value;
        }
    }

    /**
     * Returns the unique id of the check.
     */
    int id();

    /**
     * Returns the message description relevant for the check.
     */
    BytesRef description();

    /**
     * Returns the level of {@link Severity} for the check.
     */
    Severity severity();

    /**
     * The validator method, used for e.g. validation of a setting.
     *
     * @return true if validation is passed.
     */
    boolean validate();

    /**
     * Start the checks in an async manner and returns a future
     * which the caller can use as a callback.
     */
    CompletableFuture<?> computeResult();
}