/*
    * Licensed to The Apereo Foundation under one or more contributor license
    * agreements. See the NOTICE file distributed with this work for additional
    * information regarding copyright ownership.
    *
    *
    * The Apereo Foundation licenses this file to you under the Educational
    * Community 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://opensource.org/licenses/ecl2.txt
   *
   * 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.opencastproject.util;
  
  import static org.opencastproject.util.data.Collections.list;
  import static org.opencastproject.util.data.Either.left;
  import static org.opencastproject.util.data.Either.right;
  import static org.opencastproject.util.data.Monadics.mlist;
  import static org.opencastproject.util.data.Prelude.sleep;
  import static org.opencastproject.util.data.functions.Misc.chuck;
  
  import org.opencastproject.security.api.TrustedHttpClient;
  import org.opencastproject.util.data.Either;
  import org.opencastproject.util.data.Function;
  import org.opencastproject.util.data.Tuple;
  
  import org.apache.http.HttpEntityEnclosingRequest;
  import org.apache.http.HttpResponse;
  import org.apache.http.HttpStatus;
  import org.apache.http.NameValuePair;
  import org.apache.http.client.entity.UrlEncodedFormEntity;
  import org.apache.http.client.methods.HttpGet;
  import org.apache.http.client.methods.HttpHead;
  import org.apache.http.client.methods.HttpPost;
  import org.apache.http.message.BasicNameValuePair;
  
  import java.io.UnsupportedEncodingException;
  import java.net.URI;
  import java.net.URLEncoder;
  import java.util.List;
  
  /** Functions to support Apache httpcomponents and HTTP related operations in general. */
  
  /** Functions to support Apache httpcomponents. */
  public final class HttpUtil {
    private HttpUtil() {
    }
  
    public static HttpPost post(NameValuePair... formParams) {
      final HttpPost post = new HttpPost();
      setFormParams(post, formParams);
      return post;
    }
  
    public static HttpPost post(String uri, NameValuePair... formParams) {
      final HttpPost post = new HttpPost(uri);
      setFormParams(post, formParams);
      return post;
    }
  
    public static HttpGet get(String path, Tuple<String, String>... queryParams) {
      final String url = mlist(path, mlist(queryParams).map(new Function<Tuple<String, String>, String>() {
        @Override
        public String apply(Tuple<String, String> a) {
          try {
            return a.getA() + "=" + URLEncoder.encode(a.getB(), "UTF-8");
          } catch (UnsupportedEncodingException e) {
            return chuck(e);
          }
        }
      }).mkString("&")).mkString("?");
      return new HttpGet(url);
    }
  
    private static void setFormParams(HttpEntityEnclosingRequest r, NameValuePair[] formParams) {
      final List<NameValuePair> params = list(formParams);
      try {
        r.setEntity(new UrlEncodedFormEntity(params, "UTF-8"));
      } catch (UnsupportedEncodingException e) {
        chuck(e);
      }
    }
  
    public static NameValuePair param(String name, String value) {
      return new BasicNameValuePair(name, value);
    }
  
    public static final Function<HttpResponse, Integer> getStatusCode = new Function<HttpResponse, Integer>() {
      @Override
      public Integer apply(HttpResponse response) {
       return response.getStatusLine().getStatusCode();
     }
   };
 
   public static boolean isOk(HttpResponse res) {
     return res.getStatusLine().getStatusCode() == HttpStatus.SC_OK;
   }
 
   /**
    * Wait for a certain status of a resource.
    *
    * @return either an exception or the status code of the last http response
    */
   public static Either<Exception, Integer> waitForResource(final TrustedHttpClient http, final URI resourceUri,
           final int expectedStatus, final long timeout, final long pollingInterval) {
     long now = 0L;
     while (true) {
       final HttpHead head = new HttpHead(resourceUri);
       HttpResponse response = null;
       final int status;
       try {
         try {
           response = http.execute(head);
           status = response.getStatusLine().getStatusCode();
         } finally {
           http.close(response);
         }
         if (status == expectedStatus || now >= timeout) {
           return right(status);
         } else {
           if (!sleep(pollingInterval)) {
             return left(new Exception("Interrupted"));
           } else {
             now = now + pollingInterval;
           }
         }
       } catch (Exception e) {
         return left(e);
       }
     }
   }
 }