/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF 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.
 */
package org.eclipse.aether.util.version;

import java.util.Objects;

import org.eclipse.aether.version.Version;
import org.eclipse.aether.version.VersionConstraint;
import org.eclipse.aether.version.VersionRange;

import static java.util.Objects.requireNonNull;

/**
 * A constraint on versions for a dependency.
 * <p>
 * Despite its name, this class is generic in a sense it works with any {@link Version}.
 */
final class GenericVersionConstraint implements VersionConstraint {

    private final VersionRange range;

    private final Version version;

    /**
     * Creates a version constraint from the specified version range.
     *
     * @param range the version range, must not be {@code null}
     */
    GenericVersionConstraint(VersionRange range) {
        this.range = requireNonNull(range, "version range cannot be null");
        this.version = null;
    }

    /**
     * Creates a version constraint from the specified version.
     *
     * @param version the version, must not be {@code null}
     */
    GenericVersionConstraint(Version version) {
        this.version = requireNonNull(version, "version cannot be null");
        this.range = null;
    }

    @Override
    public VersionRange getRange() {
        return range;
    }

    @Override
    public Version getVersion() {
        return version;
    }

    @Override
    public boolean containsVersion(Version version) {
        if (range == null) {
            return version.equals(this.version);
        } else {
            return range.containsVersion(version);
        }
    }

    @Override
    public String toString() {
        return String.valueOf((range == null) ? version : range);
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        if (obj == null || !getClass().equals(obj.getClass())) {
            return false;
        }

        VersionConstraint that = (VersionConstraint) obj;

        return Objects.equals(range, that.getRange()) && Objects.equals(version, that.getVersion());
    }

    @Override
    public int hashCode() {
        int hash = 17;
        hash = hash * 31 + hash(getRange());
        hash = hash * 31 + hash(getVersion());
        return hash;
    }

    private static int hash(Object obj) {
        return obj != null ? obj.hashCode() : 0;
    }
}
