/*
 * 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.ingest.common;

import org.elasticsearch.ElasticsearchParseException;
import org.elasticsearch.common.xcontent.XContentHelper;
import org.elasticsearch.common.xcontent.json.JsonXContent;
import org.elasticsearch.ingest.AbstractProcessor;
import org.elasticsearch.ingest.ConfigurationUtils;
import org.elasticsearch.ingest.IngestDocument;
import org.elasticsearch.ingest.Processor;

import java.util.Map;

import static org.elasticsearch.ingest.ConfigurationUtils.newConfigurationException;

/**
 * Processor that serializes a string-valued field into a
 * map of maps.
 */
public final class JsonProcessor extends AbstractProcessor {

    public static final String TYPE = "json";

    private final String field;
    private final String targetField;
    private final boolean addToRoot;

    JsonProcessor(String tag, String field, String targetField, boolean addToRoot) {
        super(tag);
        this.field = field;
        this.targetField = targetField;
        this.addToRoot = addToRoot;
    }

    public String getField() {
        return field;
    }

    public String getTargetField() {
        return targetField;
    }

    boolean isAddToRoot() {
        return addToRoot;
    }

    @Override
    public void execute(IngestDocument document) throws Exception {
        String stringValue = document.getFieldValue(field, String.class);
        try {
            Map<String, Object> mapValue = XContentHelper.convertToMap(JsonXContent.jsonXContent, stringValue, false);
            if (addToRoot) {
                for (Map.Entry<String, Object> entry : mapValue.entrySet()) {
                    document.setFieldValue(entry.getKey(), entry.getValue());
                }
            } else {
                document.setFieldValue(targetField, mapValue);
            }
        } catch (ElasticsearchParseException e) {
            throw new IllegalArgumentException(e);
        }
    }

    @Override
    public String getType() {
        return TYPE;
    }

    public static final class Factory implements Processor.Factory {
        @Override
        public JsonProcessor create(Map<String, Processor.Factory> registry, String processorTag,
                                    Map<String, Object> config) throws Exception {
            String field = ConfigurationUtils.readStringProperty(TYPE, processorTag, config, "field");
            String targetField = ConfigurationUtils.readOptionalStringProperty(TYPE, processorTag, config, "target_field");
            boolean addToRoot = ConfigurationUtils.readBooleanProperty(TYPE, processorTag, config, "add_to_root", false);

            if (addToRoot && targetField != null) {
                throw newConfigurationException(TYPE, processorTag, "target_field",
                    "Cannot set a target field while also setting `add_to_root` to true");
            }

            if (targetField == null) {
                targetField = field;
            }

            return new JsonProcessor(processorTag, field, targetField, addToRoot);
        }
    }
}