/*
 * 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.
 */

package org.elasticsearch.rest.action.admin.indices;

import com.carrotsearch.hppc.cursors.ObjectObjectCursor;

import org.elasticsearch.action.admin.indices.settings.get.GetSettingsRequest;
import org.elasticsearch.action.admin.indices.settings.get.GetSettingsResponse;
import org.elasticsearch.action.support.IndicesOptions;
import org.elasticsearch.client.node.NodeClient;
import org.elasticsearch.common.Strings;
import org.elasticsearch.common.settings.IndexScopedSettings;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.settings.SettingsFilter;
import org.elasticsearch.common.xcontent.XContentBuilder;
import org.elasticsearch.rest.BaseRestHandler;
import org.elasticsearch.rest.BytesRestResponse;
import org.elasticsearch.rest.RestController;
import org.elasticsearch.rest.RestRequest;
import org.elasticsearch.rest.RestResponse;
import org.elasticsearch.rest.action.RestBuilderListener;

import java.io.IOException;

import static org.elasticsearch.rest.RestRequest.Method.GET;
import static org.elasticsearch.rest.RestStatus.OK;

public class RestGetSettingsAction extends BaseRestHandler {

    private final IndexScopedSettings indexScopedSettings;
    private final SettingsFilter settingsFilter;

    public RestGetSettingsAction(Settings settings, RestController controller, IndexScopedSettings indexScopedSettings,
            final SettingsFilter settingsFilter) {
        super(settings);
        this.indexScopedSettings = indexScopedSettings;
        controller.registerHandler(GET, "/{index}/_settings/{name}", this);
        controller.registerHandler(GET, "/_settings/{name}", this);
        controller.registerHandler(GET, "/{index}/_setting/{name}", this);
        this.settingsFilter = settingsFilter;
    }

    @Override
    public RestChannelConsumer prepareRequest(final RestRequest request, final NodeClient client) throws IOException {
        final String[] names = request.paramAsStringArrayOrEmptyIfAll("name");
        final boolean renderDefaults = request.paramAsBoolean("include_defaults", false);
        GetSettingsRequest getSettingsRequest = new GetSettingsRequest()
                .indices(Strings.splitStringByCommaToArray(request.param("index")))
                .indicesOptions(IndicesOptions.fromRequest(request, IndicesOptions.strictExpandOpen()))
                .humanReadable(request.hasParam("human"))
                .names(names);
        getSettingsRequest.local(request.paramAsBoolean("local", getSettingsRequest.local()));

        return channel -> client.admin().indices().getSettings(getSettingsRequest, new RestBuilderListener<GetSettingsResponse>(channel) {

            @Override
            public RestResponse buildResponse(GetSettingsResponse getSettingsResponse, XContentBuilder builder) throws Exception {
                builder.startObject();
                for (ObjectObjectCursor<String, Settings> cursor : getSettingsResponse.getIndexToSettings()) {
                    // no settings, jump over it to shorten the response data
                    if (cursor.value.isEmpty()) {
                        continue;
                    }
                    builder.startObject(cursor.key);
                    builder.startObject("settings");
                    cursor.value.toXContent(builder, request);
                    builder.endObject();
                    if (renderDefaults) {
                        builder.startObject("defaults");
                        settingsFilter.filter(indexScopedSettings.diff(cursor.value, settings)).toXContent(builder, request);
                        builder.endObject();
                    }
                    builder.endObject();
                }
                builder.endObject();
                return new BytesRestResponse(OK, builder);
            }
        });
    }

}