/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you 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.apache.chemistry.opencmis.client.bindings.spi.http;
  
  import static org.apache.chemistry.opencmis.commons.impl.CollectionsHelper.isNotEmpty;
  
  import java.io.BufferedOutputStream;
  import java.io.ByteArrayInputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.math.BigInteger;
  import java.net.Socket;
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  import java.util.zip.GZIPOutputStream;
  
  import javax.net.ssl.HostnameVerifier;
  import javax.net.ssl.SSLException;
  import javax.net.ssl.SSLSocket;
  
  import org.apache.chemistry.opencmis.client.bindings.impl.ClientVersion;
  import org.apache.chemistry.opencmis.client.bindings.impl.CmisBindingsHelper;
  import org.apache.chemistry.opencmis.client.bindings.spi.BindingSession;
  import org.apache.chemistry.opencmis.commons.SessionParameter;
  import org.apache.chemistry.opencmis.commons.exceptions.CmisConnectionException;
  import org.apache.chemistry.opencmis.commons.exceptions.CmisRuntimeException;
  import org.apache.chemistry.opencmis.commons.impl.IOUtils;
  import org.apache.chemistry.opencmis.commons.impl.UrlBuilder;
  import org.apache.chemistry.opencmis.commons.spi.AuthenticationProvider;
  import org.apache.http.Header;
  import org.apache.http.HttpEntity;
  import org.apache.http.HttpResponse;
  import org.apache.http.HttpVersion;
  import org.apache.http.client.HttpClient;
  import org.apache.http.client.methods.HttpDelete;
  import org.apache.http.client.methods.HttpEntityEnclosingRequestBase;
  import org.apache.http.client.methods.HttpGet;
  import org.apache.http.client.methods.HttpPost;
  import org.apache.http.client.methods.HttpPut;
  import org.apache.http.client.methods.HttpRequestBase;
  import org.apache.http.conn.ssl.X509HostnameVerifier;
  import org.apache.http.entity.AbstractHttpEntity;
  import org.apache.http.impl.client.DefaultHttpClient;
  import org.apache.http.params.BasicHttpParams;
  import org.apache.http.params.HttpConnectionParams;
  import org.apache.http.params.HttpParams;
  import org.apache.http.params.HttpProtocolParams;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * A {@link HttpInvoker} that uses The Apache HTTP client.
   */
  public abstract class AbstractApacheClientHttpInvoker implements HttpInvoker {
  
      protected static final Logger LOG = LoggerFactory.getLogger(AbstractApacheClientHttpInvoker.class);
  
      protected static final String HTTP_CLIENT = "org.apache.chemistry.opencmis.client.bindings.spi.http.ApacheClientHttpInvoker.httpClient";
      protected static final int BUFFER_SIZE = 2 * 1024 * 1024;
  
      @Override
      public Response invokeGET(UrlBuilder url, BindingSession session) {
          return invoke(url, "GET", null, null, null, session, null, null);
      }
  
      @Override
      public Response invokeGET(UrlBuilder url, BindingSession session, BigInteger offset, BigInteger length) {
          return invoke(url, "GET", null, null, null, session, offset, length);
      }
  
      @Override
      public Response invokePOST(UrlBuilder url, String contentType, Output writer, BindingSession session) {
          return invoke(url, "POST", contentType, null, writer, session, null, null);
      }
  
      @Override
      public Response invokePUT(UrlBuilder url, String contentType, Map<String, String> headers, Output writer,
              BindingSession session) {
          return invoke(url, "PUT", contentType, headers, writer, session, null, null);
      }
 
     @Override
     public Response invokeDELETE(UrlBuilder url, BindingSession session) {
         return invoke(url, "DELETE", null, null, null, session, null, null);
     }
 
     protected Response invoke(UrlBuilder url, String method, String contentType, Map<String, String> headers,
             final Output writer, final BindingSession session, BigInteger offset, BigInteger length) {
         int respCode = -1;
 
         try {
             // log before connect
             if (LOG.isDebugEnabled()) {
                 LOG.debug("Session {}: {} {}", session.getSessionId(), method, url);
             }
 
             // get HTTP client object from session
             DefaultHttpClient httpclient = (DefaultHttpClient) session.get(HTTP_CLIENT);
             if (httpclient == null) {
                 session.writeLock();
                 try {
                     httpclient = (DefaultHttpClient) session.get(HTTP_CLIENT);
                     if (httpclient == null) {
                         httpclient = createHttpClient(url, session);
                         session.put(HTTP_CLIENT, httpclient, true);
                     }
                 } finally {
                     session.writeUnlock();
                 }
             }
 
             HttpRequestBase request = null;
 
             if ("GET".equals(method)) {
                 request = new HttpGet(url.toString());
             } else if ("POST".equals(method)) {
                 request = new HttpPost(url.toString());
             } else if ("PUT".equals(method)) {
                 request = new HttpPut(url.toString());
             } else if ("DELETE".equals(method)) {
                 request = new HttpDelete(url.toString());
             } else {
                 throw new CmisRuntimeException("Invalid HTTP method!");
             }
 
             // set content type
             if (contentType != null) {
                 request.setHeader("Content-Type", contentType);
             }
             // set other headers
             if (headers != null) {
                 for (Map.Entry<String, String> header : headers.entrySet()) {
                     request.addHeader(header.getKey(), header.getValue());
                 }
             }
 
             // authenticate
             AuthenticationProvider authProvider = CmisBindingsHelper.getAuthenticationProvider(session);
             if (authProvider != null) {
                 Map<String, List<String>> httpHeaders = authProvider.getHTTPHeaders(url.toString());
                 if (httpHeaders != null) {
                     for (Map.Entry<String, List<String>> header : httpHeaders.entrySet()) {
                         if (header.getKey() != null && isNotEmpty(header.getValue())) {
                             String key = header.getKey();
                             if (key.equalsIgnoreCase("user-agent")) {
                                 request.setHeader("User-Agent", header.getValue().get(0));
                             } else {
                                 for (String value : header.getValue()) {
                                     if (value != null) {
                                         request.addHeader(key, value);
                                     }
                                 }
                             }
                         }
                     }
                 }
             }
 
             // range
             if ((offset != null) || (length != null)) {
                 StringBuilder sb = new StringBuilder("bytes=");
 
                 if ((offset == null) || (offset.signum() == -1)) {
                     offset = BigInteger.ZERO;
                 }
 
                 sb.append(offset.toString());
                 sb.append('-');
 
                 if ((length != null) && (length.signum() == 1)) {
                     sb.append(offset.add(length.subtract(BigInteger.ONE)).toString());
                 }
 
                 request.setHeader("Range", sb.toString());
             }
 
             // compression
             Object compression = session.get(SessionParameter.COMPRESSION);
             if ((compression != null) && Boolean.parseBoolean(compression.toString())) {
                 request.setHeader("Accept-Encoding", "gzip,deflate");
             }
 
             // locale
             if (session.get(CmisBindingsHelper.ACCEPT_LANGUAGE) instanceof String) {
                 request.setHeader("Accept-Language", session.get(CmisBindingsHelper.ACCEPT_LANGUAGE).toString());
             }
 
             // send data
             if (writer != null) {
                 Object clientCompression = session.get(SessionParameter.CLIENT_COMPRESSION);
                 final boolean clientCompressionFlag = (clientCompression != null)
                         && Boolean.parseBoolean(clientCompression.toString());
                 if (clientCompressionFlag) {
                     request.setHeader("Content-Encoding", "gzip");
                 }
 
                 AbstractHttpEntity streamEntity = new AbstractHttpEntity() {
                     @Override
                     public boolean isChunked() {
                         return true;
                     }
 
                     @Override
                     public boolean isRepeatable() {
                         return false;
                     }
 
                     @Override
                     public long getContentLength() {
                         return -1;
                     }
 
                     @Override
                     public boolean isStreaming() {
                         return false;
                     }
 
                     @Override
                     public InputStream getContent() throws IOException {
                         throw new UnsupportedOperationException();
                     }
 
                     @Override
                     public void writeTo(final OutputStream outstream) throws IOException {
                         OutputStream connOut = null;
 
                         if (clientCompressionFlag) {
                             connOut = new GZIPOutputStream(outstream, 4096);
                         } else {
                             connOut = outstream;
                         }
 
                         OutputStream out = new BufferedOutputStream(connOut, BUFFER_SIZE);
                         try {
                             writer.write(out);
                         } catch (IOException ioe) {
                             throw ioe;
                         } catch (Exception e) {
                             throw new IOException(e);
                         }
                         out.flush();
 
                         if (connOut instanceof GZIPOutputStream) {
                             ((GZIPOutputStream) connOut).finish();
                         }
                     }
                 };
                 ((HttpEntityEnclosingRequestBase) request).setEntity(streamEntity);
             }
 
             // connect
             HttpResponse response = httpclient.execute(request);
             HttpEntity entity = response.getEntity();
 
             // get stream, if present
             respCode = response.getStatusLine().getStatusCode();
             InputStream inputStream = null;
             InputStream errorStream = null;
 
             if (respCode == 200 || respCode == 201 || respCode == 203 || respCode == 206) {
                 if (entity != null) {
                     inputStream = entity.getContent();
                 } else {
                     inputStream = new ByteArrayInputStream(new byte[0]);
                 }
             } else {
                 if (entity != null) {
                     errorStream = entity.getContent();
                 } else {
                     errorStream = new ByteArrayInputStream(new byte[0]);
                 }
             }
 
             // collect headers
             Map<String, List<String>> responseHeaders = new HashMap<String, List<String>>();
             for (Header header : response.getAllHeaders()) {
                 List<String> values = responseHeaders.get(header.getName());
                 if (values == null) {
                     values = new ArrayList<String>();
                     responseHeaders.put(header.getName(), values);
                 }
                 values.add(header.getValue());
             }
 
             // log after connect
             if (LOG.isTraceEnabled()) {
                 LOG.trace("Session {}: {} {} > Headers: {}", session.getSessionId(), method, url,
                         responseHeaders.toString());
             }
 
             // forward response HTTP headers
             if (authProvider != null) {
                 authProvider.putResponseHeaders(url.toString(), respCode, responseHeaders);
             }
 
             // get the response
             return new Response(respCode, response.getStatusLine().getReasonPhrase(), responseHeaders, inputStream,
                     errorStream);
         } catch (Exception e) {
             throw new CmisConnectionException(url.toString(), respCode, e);
         }
     }
 
     /**
      * Creates default params for the Apache HTTP Client.
      */
     protected HttpParams createDefaultHttpParams(BindingSession session) {
         HttpParams params = new BasicHttpParams();
 
         HttpProtocolParams.setVersion(params, HttpVersion.HTTP_1_1);
         HttpProtocolParams.setUserAgent(params,
                 (String) session.get(SessionParameter.USER_AGENT, ClientVersion.OPENCMIS_USER_AGENT));
         HttpProtocolParams.setContentCharset(params, IOUtils.UTF8);
         HttpProtocolParams.setUseExpectContinue(params, true);
 
         HttpConnectionParams.setStaleCheckingEnabled(params, true);
 
         int connectTimeout = session.get(SessionParameter.CONNECT_TIMEOUT, -1);
         if (connectTimeout >= 0) {
             HttpConnectionParams.setConnectionTimeout(params, connectTimeout);
         }
 
         int readTimeout = session.get(SessionParameter.READ_TIMEOUT, -1);
         if (readTimeout >= 0) {
             HttpConnectionParams.setSoTimeout(params, readTimeout);
         }
 
         return params;
     }
 
     /**
      * Verifies a hostname with the given verifier.
      */
     protected void verify(HostnameVerifier verifier, String host, SSLSocket sslSocket) throws IOException {
         try {
             if (verifier instanceof X509HostnameVerifier) {
                 ((X509HostnameVerifier) verifier).verify(host, sslSocket);
             } else {
                 if (!verifier.verify(host, sslSocket.getSession())) {
                     throw new SSLException("Hostname in certificate didn't match: <" + host + ">");
                 }
             }
         } catch (IOException ioe) {
             closeSocket(sslSocket);
             throw ioe;
         }
     }
 
     /**
      * Closes the given socket and ignores exceptions.
      */
     protected void closeSocket(Socket socket) {
         try {
             socket.close();
         } catch (IOException ioe) {
             // ignore
         }
     }
 
     /**
      * Creates the {@link HttpClient} instance.
      */
     protected abstract DefaultHttpClient createHttpClient(UrlBuilder url, BindingSession session);
 }