/*
 * SPDX-License-Identifier: Apache-2.0
 *
 * The OpenSearch Contributors require contributions made to
 * this file be licensed under the Apache-2.0 license or a
 * compatible open source license.
 */

/*
 * Licensed to Elasticsearch under one or more contributor
 * license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright
 * ownership. Elasticsearch 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.
 */
/*
 * Modifications Copyright OpenSearch Contributors. See
 * GitHub history for details.
 */

package org.opensearch.discovery;

import org.opensearch.common.settings.Settings;
import org.opensearch.core.common.transport.TransportAddress;
import org.opensearch.common.util.set.Sets;
import org.opensearch.discovery.SeedHostsProvider.HostsResolver;
import org.opensearch.test.OpenSearchTestCase;
import org.opensearch.transport.TransportService;

import java.util.Arrays;
import java.util.List;
import java.util.Set;

import static java.util.Collections.emptyList;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.when;

public class SettingsBasedSeedHostsProviderTests extends OpenSearchTestCase {

    private class AssertingHostsResolver implements HostsResolver {
        private final Set<String> expectedHosts;

        private boolean resolvedHosts;

        AssertingHostsResolver(String... expectedHosts) {
            this.expectedHosts = Sets.newHashSet(expectedHosts);
        }

        @Override
        public List<TransportAddress> resolveHosts(List<String> hosts) {
            assertEquals(expectedHosts, Sets.newHashSet(hosts));
            resolvedHosts = true;
            return emptyList();
        }

        boolean getResolvedHosts() {
            return resolvedHosts;
        }
    }

    public void testScansPortsByDefault() {
        final AssertingHostsResolver hostsResolver = new AssertingHostsResolver(
            "[::1]:9300",
            "[::1]:9301",
            "127.0.0.1:9300",
            "127.0.0.1:9301"
        );
        final TransportService transportService = mock(TransportService.class);
        when(transportService.getDefaultSeedAddresses()).thenReturn(
            Arrays.asList("[::1]:9300", "[::1]:9301", "127.0.0.1:9300", "127.0.0.1:9301")
        );
        new SettingsBasedSeedHostsProvider(Settings.EMPTY, transportService).getSeedAddresses(hostsResolver);
        assertTrue(hostsResolver.getResolvedHosts());
    }

    public void testGetsHostsFromSetting() {
        final AssertingHostsResolver hostsResolver = new AssertingHostsResolver("bar", "foo");
        new SettingsBasedSeedHostsProvider(
            Settings.builder().putList(SettingsBasedSeedHostsProvider.DISCOVERY_SEED_HOSTS_SETTING.getKey(), "foo", "bar").build(),
            null
        ).getSeedAddresses(hostsResolver);
        assertTrue(hostsResolver.getResolvedHosts());
    }

    public void testGetsHostsFromLegacySetting() {
        final AssertingHostsResolver hostsResolver = new AssertingHostsResolver("bar", "foo");
        new SettingsBasedSeedHostsProvider(
            Settings.builder()
                .putList(SettingsBasedSeedHostsProvider.LEGACY_DISCOVERY_ZEN_PING_UNICAST_HOSTS_SETTING.getKey(), "foo", "bar")
                .build(),
            null
        ).getSeedAddresses(hostsResolver);
        assertTrue(hostsResolver.getResolvedHosts());
        assertWarnings(
            "[discovery.zen.ping.unicast.hosts] setting was deprecated in OpenSearch and will be removed in a future "
                + "release! See the breaking changes documentation for the next major version."
        );
    }

    public void testForbidsBothSettingsAtTheSameTime() {
        expectThrows(
            IllegalArgumentException.class,
            () -> new SettingsBasedSeedHostsProvider(
                Settings.builder()
                    .putList(SettingsBasedSeedHostsProvider.LEGACY_DISCOVERY_ZEN_PING_UNICAST_HOSTS_SETTING.getKey())
                    .putList(SettingsBasedSeedHostsProvider.DISCOVERY_SEED_HOSTS_SETTING.getKey())
                    .build(),
                null
            )
        );
    }
}