/*
 * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
 * Copyright (C) 2016-2021 ViaVersion and contributors
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package com.viaversion.viaversion.api.protocol;

import it.unimi.dsi.fastutil.ints.IntSortedSet;

public interface ServerProtocolVersion {

    /**
     * Returns the lowest supported protocol version by this server.
     * This and {@link #highestSupportedVersion()} should only differ on proxy servers supporting multiple versions.
     *
     * @return lowest supported protocol version
     */
    int lowestSupportedVersion();

    /**
     * Returns the lowest supported protocol version by this server.
     * This and {@link #lowestSupportedVersion()} should only differ on proxy servers supporting multiple versions.
     *
     * @return highest supported protocol version
     */
    int highestSupportedVersion();

    /**
     * Returns a sorted set of all supported protocol version by this server.
     * For non-proxy servers, this should return a singleton set.
     *
     * @return sorted set of supported protocol versions
     */
    IntSortedSet supportedVersions();

    /**
     * Returns true if the actual protocol version has not yet been identified.
     * In that case, all methods above will returns -1.
     *
     * @return true if set, false if unknown (yet)
     */
    default boolean isKnown() {
        return lowestSupportedVersion() != -1 && highestSupportedVersion() != -1;
    }
}
