package com.atlassian.sal.core.net;
   
   import com.atlassian.sal.api.net.Request;
   import com.atlassian.sal.api.net.RequestFilePart;
   import com.atlassian.sal.api.net.Response;
   import com.atlassian.sal.api.net.ResponseException;
   import com.atlassian.sal.api.net.ResponseHandler;
   import com.atlassian.sal.api.net.ResponseProtocolException;
   import com.atlassian.sal.api.net.ResponseStatusException;
  import com.atlassian.sal.api.net.ReturningResponseHandler;
  import com.google.common.base.Preconditions;
  import org.apache.http.HttpHost;
  import org.apache.http.NameValuePair;
  import org.apache.http.auth.AuthScope;
  import org.apache.http.auth.UsernamePasswordCredentials;
  import org.apache.http.client.ClientProtocolException;
  import org.apache.http.client.config.CookieSpecs;
  import org.apache.http.client.config.RequestConfig;
  import org.apache.http.client.entity.UrlEncodedFormEntity;
  import org.apache.http.client.methods.CloseableHttpResponse;
  import org.apache.http.client.methods.HttpPost;
  import org.apache.http.client.methods.HttpPut;
  import org.apache.http.client.methods.HttpUriRequest;
  import org.apache.http.client.methods.RequestBuilder;
  import org.apache.http.client.protocol.HttpClientContext;
  import org.apache.http.entity.ContentType;
  import org.apache.http.entity.StringEntity;
  import org.apache.http.entity.mime.MultipartEntityBuilder;
  import org.apache.http.impl.auth.BasicScheme;
  import org.apache.http.impl.client.CloseableHttpClient;
  import org.apache.http.message.BasicNameValuePair;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.io.IOException;
  import java.nio.charset.StandardCharsets;
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.LinkedList;
  import java.util.List;
  import java.util.Map;
  
  /**
   * HttpClient implementation of Request interface
   */
  public class HttpClientRequest<T extends Request<?, ?>, RESP extends Response> implements Request<HttpClientRequest<?, ?>, HttpClientResponse> {
      private static final Logger log = LoggerFactory.getLogger(HttpClientRequest.class);
  
      private final CloseableHttpClient httpClient;
      private final List<NameValuePair> requestParameters;
      protected final HttpClientContext httpClientContext;
      final RequestBuilder requestBuilder;
      final RequestConfig.Builder requestConfigBuilder;
  
      // Unfortunately we need to keep a list of the headers
      private final Map<String, List<String>> headers = new HashMap<>();
  
      public HttpClientRequest(CloseableHttpClient httpClient, HttpClientContext httpClientContext, MethodType initialMethodType, String initialUrl) {
          this.httpClient = httpClient;
          this.httpClientContext = httpClientContext;
          this.requestBuilder = RequestBuilder.create(initialMethodType.toString()).setUri(initialUrl);
          this.requestParameters = new LinkedList<>();
  
          final ConnectionConfig connectionConfig = new SystemPropertiesConnectionConfig();
          this.requestConfigBuilder = RequestConfig.custom()
                  .setConnectTimeout(connectionConfig.getConnectionTimeout())
                  .setSocketTimeout(connectionConfig.getSocketTimeout())
                  .setMaxRedirects(connectionConfig.getMaxRedirects())
                  .setCookieSpec(CookieSpecs.STANDARD);
      }
  
      @Override
      public String execute() throws ResponseException {
          return executeAndReturn(response -> {
              if (!response.isSuccessful()) {
                  throw new ResponseStatusException("Unexpected response received. Status code: " + response.getStatusCode(),
                          response);
              }
              return response.getResponseBodyAsString();
          });
      }
  
      @Override
      public void execute(final ResponseHandler<? super HttpClientResponse> responseHandler) throws ResponseException {
          executeAndReturn((ReturningResponseHandler<HttpClientResponse, Void>) response -> {
              responseHandler.handle(response);
              return null;
          });
      }
  
      @Override
      public <RET> RET executeAndReturn(final ReturningResponseHandler<? super HttpClientResponse, RET> responseHandler)
              throws ResponseException {
          if (!requestParameters.isEmpty()) {
              requestBuilder.setEntity(new UrlEncodedFormEntity(requestParameters, StandardCharsets.UTF_8));
          }
          final HttpUriRequest request = requestBuilder.setConfig(requestConfigBuilder.build()).build();
          log.debug("Executing request:{}", request);
 
         try (final CloseableHttpResponse response = httpClient.execute(request, httpClientContext)) {
             return responseHandler.handle(new HttpClientResponse(response));
         } catch (ClientProtocolException cpe) {
             throw new ResponseProtocolException(cpe);
         } catch (IOException e) {
             throw new ResponseException(e);
         }
     }
 
     @Override
     public Map<String, List<String>> getHeaders() {
         return Collections.unmodifiableMap(headers);
     }
 
     @Override
     public HttpClientRequest addBasicAuthentication(final String hostname, final String username, final String password) {
         httpClientContext.getCredentialsProvider().setCredentials(
                 new AuthScope(hostname, AuthScope.ANY_PORT),
                 new UsernamePasswordCredentials(username, password));
         httpClientContext.getAuthCache().put(new HttpHost(hostname), new BasicScheme());
         return this;
     }
 
     @Override
     public HttpClientRequest setConnectionTimeout(final int connectionTimeout) {
         requestConfigBuilder.setConnectionRequestTimeout(connectionTimeout);
         return this;
     }
 
     @Override
     public HttpClientRequest setSoTimeout(final int soTimeout) {
         requestConfigBuilder.setSocketTimeout(soTimeout);
         return this;
     }
 
     @Override
     public HttpClientRequest setUrl(final String url) {
         requestBuilder.setUri(url);
         return this;
     }
 
     @Override
     public HttpClientRequest setRequestBody(final String requestBody) {
         return setRequestBody(requestBody, ContentType.TEXT_PLAIN.getMimeType());
     }
 
     @Override
     public HttpClientRequest setRequestBody(final String requestBodyString, final String contentTypeString) {
         Preconditions.checkNotNull(requestBodyString);
         Preconditions.checkNotNull(contentTypeString);
         Preconditions.checkState(isRequestBodyMethod(), "Only PUT or POST methods accept a request body.");
 
         requestBuilder.setEntity(new StringEntity(requestBodyString, ContentType.create(contentTypeString, StandardCharsets.UTF_8)));
         return this;
     }
 
     @Override
     public HttpClientRequest setFiles(final List<RequestFilePart> requestBodyFiles) {
         Preconditions.checkNotNull(requestBodyFiles);
         Preconditions.checkState(isRequestBodyMethod(), "Only PUT or POST methods accept a request body.");
 
         final MultipartEntityBuilder multipartEntityBuilder = MultipartEntityBuilder.create();
 
         for (RequestFilePart requestBodyFile : requestBodyFiles) {
             final ContentType fileContentType = ContentType.create(requestBodyFile.getContentType());
             multipartEntityBuilder.addBinaryBody(requestBodyFile.getParameterName(), requestBodyFile.getFile(), fileContentType, requestBodyFile.getFileName());
         }
 
         requestBuilder.setEntity(multipartEntityBuilder.build());
         return this;
     }
 
     @Override
     public HttpClientRequest addRequestParameters(final String... params) {
         Preconditions.checkNotNull(params);
         Preconditions.checkState(isRequestBodyMethod(), "Only PUT or POST methods accept a request body.");
 
         if (params.length % 2 != 0) {
             throw new IllegalArgumentException("You must enter an even number of arguments.");
         }
 
         for (int i = 0; i < params.length; i += 2) {
             final String name = params[i];
             final String value = params[i + 1];
             requestParameters.add(new BasicNameValuePair(name, value));
         }
 
         return this;
     }
 
     private boolean isRequestBodyMethod() {
         final String methodType = requestBuilder.getMethod();
         return HttpPost.METHOD_NAME.equals(methodType) || HttpPut.METHOD_NAME.equals(methodType);
     }
 
     @Override
     public HttpClientRequest addHeader(final String headerName, final String headerValue) {
         headers.computeIfAbsent(headerName, k -> new ArrayList<>())
                 .add(headerValue);
         requestBuilder.addHeader(headerName, headerValue);
         return this;
     }
 
     @Override
     public HttpClientRequest setHeader(final String headerName, final String headerValue) {
         headers.put(headerName, new ArrayList<>(Collections.singletonList(headerValue)));
         requestBuilder.setHeader(headerName, headerValue);
         return this;
     }
 
     @Override
     public HttpClientRequest setFollowRedirects(final boolean follow) {
         requestConfigBuilder.setRedirectsEnabled(follow);
         return this;
     }
 
     @Override
     public HttpClientRequest setEntity(final Object entity) {
         throw new UnsupportedOperationException("This SAL request does not support object marshalling. Use the RequestFactory component instead.");
     }
 }