/**
 * Copyright 2017 ZTE Corporation.
 *
 * 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.
 */
package org.onap.workflow.activitiext.restservicetask;

import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpMethod;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.alibaba.fastjson.JSON;

/**
 * This static-class eases HTTP-method execution by self-managed fault-handling
 * and automated Response-information processing
 */
public class LowLevelRestApi {

	private static final Logger logger = LoggerFactory.getLogger(LowLevelRestApi.class);

	// Local HttpClient used for every communication (Singleton implementation)
	private static HttpClient httpClient = new HttpClient();

	/**
	 * Executes a passed HttpMethod (Method type is either PUT, POST, GET or
	 * DELETE) and returns a HttpResponseMessage
	 * 
	 * @param method
	 *            Method to execute
	 * @return HttpResponseMessage which contains all information about the
	 *         execution
	 */
	public static HttpResponseMessage executeHttpMethod(HttpMethod method) throws Exception {

		HttpResponseMessage responseMessage = null;

		try {

			// Execute Request
			LowLevelRestApi.httpClient.executeMethod(method);
			responseMessage = LowLevelRestApi.extractResponseInformation(method);
			
			logger.info("statusCode: {}", method.getStatusCode());
			logger.info("responseBody: {}", method.getResponseBodyAsString());
		} catch (Exception e) {
			logger.error("visit interface failed!", e);
			throw e;
		} finally {

			// Release Connection anyway
			method.releaseConnection();
		}

		// Extract response information and return
		return responseMessage;
	}

	/**
	 * Extracts the response information from an executed HttpMethod
	 * 
	 * @param method
	 *            Executed Method
	 * @return Packaged response information
	 */
	private static HttpResponseMessage extractResponseInformation(HttpMethod method) {
		// Create and return HttpResponseMethod
		HttpResponseMessage responseMessage = new HttpResponseMessage();
		responseMessage.setStatusCode(method.getStatusCode());
		try {
			JSON json = (JSON) JSON.parse(method.getResponseBodyAsString());
			responseMessage.setResponseBody(json);
			json.toJSONString();
		} catch (Exception e) {
			logger.info("response is not a json!");
		}
		return responseMessage;
	}

}