/*******************************************************************************
    * Copyright (c) 2007, 2014 Massimiliano Ziccardi
    *
    * 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 it.jnrpe.plugin.utils;
  
  import java.io.BufferedReader;
  import java.io.DataOutputStream;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.net.HttpURLConnection;
  import java.net.URL;
  import java.util.Map.Entry;
  import java.util.Properties;
  
  /**
   * Utility class for various HTTP operations.
   * 
   * @author Frederico Campos
   * 
   */
  public class HttpUtils {
  
  	/**
  	 * Do a http get request and return response
  	 * 
  	 * @param url
  	 * @param requestProps
  	 * @param timeout
  	 * @param includeHeaders
  	 * @param ignoreBody
  	 * @return
  	 * @throws Exception
  	 */
  	public static String doGET(final URL url, final Properties requestProps,
  			final Integer timeout, boolean includeHeaders, boolean ignoreBody)
  			throws Exception {
  		return doRequest(url, requestProps, timeout, includeHeaders,
  				ignoreBody, "GET");
  	}
  
  	/**
  	 * Do a http head request and return response
  	 * 
  	 * @param url
  	 * @param requestProps
  	 * @param timeout
  	 * @param includeHeaders
  	 * @param ignoreBody
  	 * @return
  	 * @throws Exception
  	 */
  	public static String doHEAD(final URL url, final Properties requestProps,
  			final Integer timeout, boolean includeHeaders, boolean ignoreBody)
  			throws Exception {
  		return doRequest(url, requestProps, timeout, includeHeaders,
  				ignoreBody, "HEAD");
  	}
  
  	/**
  	 * Do a http post request and return response
  	 * 
  	 * @param url
  	 * @param requestProps
  	 * @param timeout
  	 * @param encodedData
  	 * @param includeHeaders
  	 * @param ignoreBody
  	 * @return
  	 * @throws IOException
  	 */
  	public static String doPOST(final URL url, final Properties requestProps,
  			final Integer timeout, final String encodedData,
  			boolean includeHeaders, boolean ignoreBody) throws IOException {
  		HttpURLConnection conn = (HttpURLConnection) url.openConnection();
  		setRequestProperties(requestProps, conn, timeout);
  		sendPostData(conn, encodedData);
  		return parseHttpResponse(conn, includeHeaders, ignoreBody);
  	}
  
  	/**
  	 * Submits http post data to an HttpURLConnection
  	 * 
  	 * @param conn
  	 * @param encodedData
  	 * @throws IOException
  	 */
  	public static void sendPostData(HttpURLConnection conn, String encodedData)
 			throws IOException {
 		conn.setDoOutput(true);
 		conn.setRequestMethod("POST");
 		if (conn.getRequestProperty("Content-Type") == null) {
 			conn.setRequestProperty("Content-Type",
 					"application/x-www-form-urlencoded");
 		}
 		if (encodedData != null) {
 			if (conn.getRequestProperty("Content-Length") == null) {
 				conn.setRequestProperty("Content-Length",
 						"" + encodedData.getBytes("UTF-8").length);
 			}
 			DataOutputStream out = new DataOutputStream(conn.getOutputStream());
 			out.write(encodedData.getBytes());
 			out.close();
 		}
 	}
 
 	private static String doRequest(final URL url,
 			final Properties requestProps, final Integer timeout,
 			boolean includeHeaders, boolean ignoreBody, String method)
 			throws Exception {
 		if (method.toUpperCase().equals("POST")) {
 			throw new Exception(
 					"use it.jnrpe.plugin.utils.HttpUtils.doPOST instead.");
 		}
 		HttpURLConnection conn = (HttpURLConnection) url.openConnection();
 		setRequestProperties(requestProps, conn, timeout);
 		conn.setRequestMethod("GET");
 		String response = parseHttpResponse(conn, includeHeaders, ignoreBody);
 		return response;
 	}
 
 	/**
 	 * Sets request headers for an http connection
 	 * 
 	 * @param props
 	 * @param conn
 	 * @param timeout
 	 */
 	public static void setRequestProperties(final Properties props,
 			HttpURLConnection conn, Integer timeout) {
 		if (props != null) {
 			if (props.get("User-Agent") == null) {
 				conn.setRequestProperty("User-Agent", "Java");
 			}
 
 			for (Entry entry : props.entrySet()) {
 				conn.setRequestProperty(String.valueOf(entry.getKey()),
 						String.valueOf(entry.getValue()));
 			}
 		}
 
 		if (timeout != null) {
 			conn.setConnectTimeout(timeout * 1000);
 		}
 
 	}
 
 	/**
 	 * Parses an http request response
 	 * 
 	 * @param conn
 	 * @param includeHeaders
 	 * @param ignoreBody
 	 * @return
 	 * @throws IOException
 	 */
 	public static String parseHttpResponse(HttpURLConnection conn,
 			boolean includeHeaders, boolean ignoreBody) throws IOException {
 		StringBuffer buff = new StringBuffer();
 		if (includeHeaders) {
 			buff.append(conn.getResponseCode() + " "
 					+ conn.getResponseMessage() + "\n");
 			int idx = (conn.getHeaderFieldKey(0) == null) ? 1 : 0;
 			while (true) {
 				String key = conn.getHeaderFieldKey(idx);
 				if (key == null) {
 					break;
 				}
 				buff.append(key + ": " + conn.getHeaderField(idx) + "\n");
 				++idx;
 			}
 		}
 		if (!ignoreBody) {
 			BufferedReader in = new BufferedReader(new InputStreamReader(
 					conn.getInputStream()));
 			String inputLine;
 			while ((inputLine = in.readLine()) != null) {
 				buff.append(inputLine);
 			}
 			in.close();
 		}
 		return buff.toString();
 	}
 
 }