/*
    * Copyright 2011 Vincent Behar
    *
    * 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.rundeck.api;
  
  import java.io.ByteArrayInputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.security.KeyManagementException;
  import java.security.KeyStoreException;
  import java.security.NoSuchAlgorithmException;
  import java.security.UnrecoverableKeyException;
  import java.security.cert.CertificateException;
  import java.security.cert.X509Certificate;
  import java.util.ArrayList;
  import java.util.List;
  import org.apache.commons.lang.StringUtils;
  import org.apache.http.HttpResponse;
  import org.apache.http.NameValuePair;
  import org.apache.http.ParseException;
  import org.apache.http.client.HttpClient;
  import org.apache.http.client.entity.UrlEncodedFormEntity;
  import org.apache.http.client.methods.HttpDelete;
  import org.apache.http.client.methods.HttpGet;
  import org.apache.http.client.methods.HttpPost;
  import org.apache.http.client.methods.HttpRequestBase;
  import org.apache.http.conn.scheme.Scheme;
  import org.apache.http.conn.ssl.SSLSocketFactory;
  import org.apache.http.conn.ssl.TrustStrategy;
  import org.apache.http.impl.client.DefaultHttpClient;
  import org.apache.http.message.BasicNameValuePair;
  import org.apache.http.protocol.HTTP;
  import org.apache.http.util.EntityUtils;
  import org.dom4j.Document;
  import org.rundeck.api.RundeckApiException.RundeckApiLoginException;
  import org.rundeck.api.parser.ParserHelper;
  import org.rundeck.api.parser.XmlNodeParser;
  import org.rundeck.api.util.AssertUtil;
  
  /**
   * Class responsible for making the HTTP API calls
   * 
   * @author Vincent Behar
   */
  class ApiCall {
  
      private final RundeckClient client;
  
      /**
       * Build a new instance, linked to the given RunDeck client
       * 
       * @param client holding the RunDeck url and the credentials
       * @throws IllegalArgumentException if client is null
       */
      public ApiCall(RundeckClient client) throws IllegalArgumentException {
          super();
          this.client = client;
          AssertUtil.notNull(client, "The RunDeck Client must not be null !");
      }
  
      /**
       * Try to "ping" the RunDeck instance to see if it is alive
       * 
       * @throws RundeckApiException if the ping fails
       */
      public void ping() throws RundeckApiException {
          HttpClient httpClient = instantiateHttpClient();
          try {
              HttpResponse response = httpClient.execute(new HttpGet(client.getUrl()));
              if (response.getStatusLine().getStatusCode() / 100 != 2) {
                  throw new RundeckApiException("Invalid HTTP response '" + response.getStatusLine() + "' when pinging "
                                                + client.getUrl());
              }
          } catch (IOException e) {
              throw new RundeckApiException("Failed to ping RunDeck instance at " + client.getUrl(), e);
          } finally {
              httpClient.getConnectionManager().shutdown();
          }
      }
  
      /**
       * Test the credentials (login/password) on the RunDeck instance
       * 
       * @throws RundeckApiLoginException if the login fails
       */
      public void testCredentials() throws RundeckApiLoginException {
          HttpClient httpClient = instantiateHttpClient();
         try {
             login(httpClient);
         } finally {
             httpClient.getConnectionManager().shutdown();
         }
     }
 
     /**
      * Execute an HTTP GET request to the RunDeck instance, on the given path. We will login first, and then execute the
      * API call. At the end, the given parser will be used to convert the response to a more useful result object.
      * 
      * @param apiPath on which we will make the HTTP request - see {@link ApiPathBuilder}
      * @param parser used to parse the response
      * @return the result of the call, as formatted by the parser
      * @throws RundeckApiException in case of error when calling the API
      * @throws RundeckApiLoginException if the login fails
      */
     public <T> T get(ApiPathBuilder apiPath, XmlNodeParser<T> parser) throws RundeckApiException,
             RundeckApiLoginException {
         return execute(new HttpGet(client.getUrl() + RundeckClient.API_ENDPOINT + apiPath), parser);
     }
 
     /**
      * Execute an HTTP GET request to the RunDeck instance, on the given path. We will login first, and then execute the
      * API call.
      * 
      * @param apiPath on which we will make the HTTP request - see {@link ApiPathBuilder}
      * @return a new {@link InputStream} instance, not linked with network resources
      * @throws RundeckApiException in case of error when calling the API
      * @throws RundeckApiLoginException if the login fails
      */
     public InputStream get(ApiPathBuilder apiPath) throws RundeckApiException, RundeckApiLoginException {
         ByteArrayInputStream response = execute(new HttpGet(client.getUrl() + RundeckClient.API_ENDPOINT + apiPath));
 
         // try to load the document, to throw an exception in case of error
         ParserHelper.loadDocument(response);
         response.reset();
 
         return response;
     }
 
     /**
      * Execute an HTTP DELETE request to the RunDeck instance, on the given path. We will login first, and then execute
      * the API call. At the end, the given parser will be used to convert the response to a more useful result object.
      * 
      * @param apiPath on which we will make the HTTP request - see {@link ApiPathBuilder}
      * @param parser used to parse the response
      * @return the result of the call, as formatted by the parser
      * @throws RundeckApiException in case of error when calling the API
      * @throws RundeckApiLoginException if the login fails
      */
     public <T> T delete(ApiPathBuilder apiPath, XmlNodeParser<T> parser) throws RundeckApiException,
             RundeckApiLoginException {
         return execute(new HttpDelete(client.getUrl() + RundeckClient.API_ENDPOINT + apiPath), parser);
     }
 
     /**
      * Execute an HTTP request to the RunDeck instance. We will login first, and then execute the API call. At the end,
      * the given parser will be used to convert the response to a more useful result object.
      * 
      * @param request to execute. see {@link HttpGet}, {@link HttpDelete}, and so on...
      * @param parser used to parse the response
      * @return the result of the call, as formatted by the parser
      * @throws RundeckApiException in case of error when calling the API
      * @throws RundeckApiLoginException if the login fails
      */
     private <T> T execute(HttpRequestBase request, XmlNodeParser<T> parser) throws RundeckApiException,
             RundeckApiLoginException {
         // execute the request
         InputStream response = execute(request);
 
         // read and parse the response
         Document xmlDocument = ParserHelper.loadDocument(response);
         return parser.parseXmlNode(xmlDocument);
     }
 
     /**
      * Execute an HTTP request to the RunDeck instance. We will login first, and then execute the API call.
      * 
      * @param request to execute. see {@link HttpGet}, {@link HttpDelete}, and so on...
      * @return a new {@link InputStream} instance, not linked with network resources
      * @throws RundeckApiException in case of error when calling the API
      * @throws RundeckApiLoginException if the login fails
      */
     private ByteArrayInputStream execute(HttpRequestBase request) throws RundeckApiException, RundeckApiLoginException {
         HttpClient httpClient = instantiateHttpClient();
         try {
             login(httpClient);
 
             // execute the HTTP request
             HttpResponse response = null;
             try {
                 response = httpClient.execute(request);
             } catch (IOException e) {
                 throw new RundeckApiException("Failed to execute an HTTP " + request.getMethod() + " on url : "
                                               + request.getURI(), e);
             }
 
             // HTTP client refuses to handle redirects (code 3xx) for DELETE, so we have to do it manually...
             // See http://rundeck.lighthouseapp.com/projects/59277/tickets/248
             if (response.getStatusLine().getStatusCode() / 100 == 3
                 && HttpDelete.METHOD_NAME.equals(request.getMethod())) {
                 String newLocation = response.getFirstHeader("Location").getValue();
                 try {
                     EntityUtils.consume(response.getEntity());
                 } catch (IOException e) {
                     throw new RundeckApiException("Failed to consume entity (release connection)", e);
                 }
                 request = new HttpDelete(newLocation);
                 try {
                     response = httpClient.execute(request);
                 } catch (IOException e) {
                     throw new RundeckApiException("Failed to execute an HTTP " + request.getMethod() + " on url : "
                                                   + request.getURI(), e);
                 }
             }
 
             // check the response code (should be 2xx, even in case of error : error message is in the XML result)
             if (response.getStatusLine().getStatusCode() / 100 != 2) {
                 throw new RundeckApiException("Invalid HTTP response '" + response.getStatusLine() + "' for "
                                               + request.getURI());
             }
             if (response.getEntity() == null) {
                 throw new RundeckApiException("Empty RunDeck response ! HTTP status line is : "
                                               + response.getStatusLine());
             }
 
             // return a new inputStream, so that we can close all network resources
             try {
                 return new ByteArrayInputStream(EntityUtils.toByteArray(response.getEntity()));
             } catch (IOException e) {
                 throw new RundeckApiException("Failed to consume entity and convert the inputStream", e);
             }
         } finally {
             httpClient.getConnectionManager().shutdown();
         }
     }
 
     /**
      * Do the actual work of login, using the given {@link HttpClient} instance. You'll need to re-use this instance
      * when making API calls (such as running a job).
      * 
      * @param httpClient pre-instantiated
      * @throws RundeckApiLoginException if the login failed
      */
     private void login(HttpClient httpClient) throws RundeckApiLoginException {
         String location = client.getUrl() + "/j_security_check";
 
         while (true) {
             HttpPost postLogin = new HttpPost(location);
             List<NameValuePair> params = new ArrayList<NameValuePair>();
             params.add(new BasicNameValuePair("j_username", client.getLogin()));
             params.add(new BasicNameValuePair("j_password", client.getPassword()));
             params.add(new BasicNameValuePair("action", "login"));
 
             HttpResponse response = null;
             try {
                 postLogin.setEntity(new UrlEncodedFormEntity(params, HTTP.UTF_8));
                 response = httpClient.execute(postLogin);
             } catch (IOException e) {
                 throw new RundeckApiLoginException("Failed to post login form on " + location, e);
             }
 
             if (response.getStatusLine().getStatusCode() / 100 == 3) {
                 // HTTP client refuses to handle redirects (code 3xx) for POST, so we have to do it manually...
                 location = response.getFirstHeader("Location").getValue();
                 try {
                     EntityUtils.consume(response.getEntity());
                 } catch (IOException e) {
                     throw new RundeckApiLoginException("Failed to consume entity (release connection)", e);
                 }
                 continue;
             }
             if (response.getStatusLine().getStatusCode() / 100 != 2) {
                 throw new RundeckApiLoginException("Invalid HTTP response '" + response.getStatusLine() + "' for "
                                                    + location);
             }
             try {
                 String content = EntityUtils.toString(response.getEntity(), HTTP.UTF_8);
                 if (StringUtils.contains(content, "j_security_check")) {
                     throw new RundeckApiLoginException("Login failed for user " + client.getLogin());
                 }
                 try {
                     EntityUtils.consume(response.getEntity());
                 } catch (IOException e) {
                     throw new RundeckApiLoginException("Failed to consume entity (release connection)", e);
                 }
             } catch (IOException io) {
                 throw new RundeckApiLoginException("Failed to read RunDeck result", io);
             } catch (ParseException p) {
                 throw new RundeckApiLoginException("Failed to parse RunDeck response", p);
             }
             break;
         }
     }
 
     /**
      * Instantiate a new {@link HttpClient} instance, configured to accept all SSL certificates
      * 
      * @return an {@link HttpClient} instance - won't be null
      */
     private HttpClient instantiateHttpClient() {
         SSLSocketFactory socketFactory = null;
         try {
             socketFactory = new SSLSocketFactory(new TrustStrategy() {
 
                 @Override
                 public boolean isTrusted(X509Certificate[] chain, String authType) throws CertificateException {
                     return true;
                 }
             }, SSLSocketFactory.ALLOW_ALL_HOSTNAME_VERIFIER);
         } catch (KeyManagementException e) {
             throw new RuntimeException(e);
         } catch (UnrecoverableKeyException e) {
             throw new RuntimeException(e);
         } catch (NoSuchAlgorithmException e) {
             throw new RuntimeException(e);
         } catch (KeyStoreException e) {
             throw new RuntimeException(e);
         }
 
         HttpClient httpClient = new DefaultHttpClient();
         httpClient.getConnectionManager().getSchemeRegistry().register(new Scheme("https", 443, socketFactory));
         return httpClient;
     }
 }