/*
 * #%L
 * Wikidata Toolkit Wikibase API
 * %%
 * Copyright (C) 2014 - 2015 Wikidata Toolkit Developers
 * %%
 * Licensed 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.
 * #L%
 */

package org.wikidata.wdtk.wikibaseapi;

import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.wikidata.wdtk.wikibaseapi.apierrors.MediaWikiApiErrorException;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;

/**
 * Java implementation of the wbsearchentities action.
 *
 * @author Sören Brunk
 *
 */
public class WbSearchEntitiesAction {

	/**
	 * Connection to a Wikibase API.
	 */
	private final ApiConnection connection;

	/**
	 * Mapper object used for deserializing JSON data.
	 */
	private final ObjectMapper mapper = new ObjectMapper();

	/**
	 * Creates an object to fetch data from the given ApiConnection. The site
	 * URI is necessary since it is not contained in the data retrieved from the
	 * API.
	 *
	 * @param connection
	 *            {@link ApiConnection} Object to send the requests
	 * @param siteUri
	 *            the URI identifying the site that is accessed (usually the
	 *            prefix of entity URIs), e.g.,
	 *            "http://www.wikidata.org/entity/"
	 */
	public WbSearchEntitiesAction(ApiConnection connection, String siteUri) {
		this.connection = connection;
	}

	public List<WbSearchEntitiesResult> wbSearchEntities(WbGetEntitiesSearchData properties)
			throws MediaWikiApiErrorException, IOException {
		return wbSearchEntities(properties.search, properties.language,
				properties.strictlanguage, properties.type, properties.limit, properties.offset);
	}

	/**
	 * Executes the API action "wbsearchentity" for the given parameters.
	 * Searches for entities using labels and aliases. Returns a label and
	 * description for the entity in the user language if possible. Returns
	 * details of the matched term. The matched term text is also present in the
	 * aliases key if different from the display label.
	 *
	 * <p>
	 * See the <a href=
	 * "https://www.wikidata.org/w/api.php?action=help&modules=wbsearchentity"
	 * >online API documentation</a> for further information.
	 * <p>
	 *
	 * @param search
	 *            (required) search for this text
	 * @param language
	 *            (required) search in this language
	 * @param strictLanguage
	 *            (optional) whether to disable language fallback
	 * @param type
	 *            (optional) search for this type of entity
	 *            One of the following values: item, property
	 *            Default: item
	 * @param limit
	 *            (optional) maximal number of results
	 *            no more than 50 (500 for bots) allowed
	 *            Default: 7
	 * @param offset
	 *            (optional) offset where to continue a search
	 *            Default: 0
	 *            this parameter is called "continue" in the API (which is a Java keyword)
	 *
	 * @return list of matching entities retrieved via the API URL
	 * @throws MediaWikiApiErrorException
	 *             if the API returns an error
	 * @throws IllegalArgumentException
	 *             if the given combination of parameters does not make sense
	 * @throws MalformedResponseException
	 *             if response JSON cannot be parsed
	 */
	public List<WbSearchEntitiesResult> wbSearchEntities(String search, String language,
			Boolean strictLanguage, String type, Long limit, Long offset)
					throws MediaWikiApiErrorException, IOException {

		Map<String, String> parameters = new HashMap<>();
		parameters.put(ApiConnection.PARAM_ACTION, "wbsearchentities");

		if (search != null) {
			parameters.put("search", search);
		} else {
			throw new IllegalArgumentException(
					"Search parameter must be specified for this action.");
		}

		if (language != null) {
			parameters.put("language", language);
		} else {
			throw new IllegalArgumentException(
					"Language parameter must be specified for this action.");
		}
		if (strictLanguage != null) {
			parameters.put("strictlanguage", Boolean.toString(strictLanguage));
		}

		if (type != null) {
			parameters.put("type", type);
		}

		if (limit != null) {
			parameters.put("limit", Long.toString(limit));
		}

		if (offset != null) {
			parameters.put("continue", Long.toString(offset));
		}

		List<WbSearchEntitiesResult> results = new ArrayList<>();

		JsonNode root = this.connection.sendJsonRequest("POST", parameters);
		JsonNode entities = root.path("search");
		for (JsonNode entityNode : entities) {
			try {
				JacksonWbSearchEntitiesResult ed = mapper.treeToValue(entityNode,
						JacksonWbSearchEntitiesResult.class);
				results.add(ed);
			} catch (JsonProcessingException e) {
				throw new MalformedResponseException(
						"Error when reading JSON for entity " + entityNode.path("id").asText("UNKNOWN"), e);
			}
		}

		return results;
	}

}
