import com.google.api.client.http.ByteArrayContent;

import com.google.api.client.http.GenericUrl;

import com.google.api.client.http.HttpBackOffUnsuccessfulResponseHandler;

import com.google.api.client.http.HttpContent;

import com.google.api.client.http.HttpHeaders;

import com.google.api.client.http.HttpRequest;

import com.google.api.client.http.HttpRequestFactory;

import com.google.api.client.http.HttpResponse;

import com.google.api.client.http.HttpStatusCodes;

import com.google.api.client.http.HttpTransport;

import com.google.api.client.http.apache.ApacheHttpTransport;

import com.google.api.client.util.BackOff;

import java.io.IOException;

import java.io.InputStream;

import java.net.ProxySelector;

import java.util.Map;

import java.util.Timer;

import java.util.TimerTask;

import java.util.concurrent.TimeUnit;

import javax.annotation.PreDestroy;

import lombok.Data;

import lombok.extern.slf4j.Slf4j;

import org.apache.http.HeaderElement;

import org.apache.http.HeaderElementIterator;

import org.apache.http.HttpHost;

import org.apache.http.conn.ClientConnectionManager;

import org.apache.http.conn.ConnectionKeepAliveStrategy;

import org.apache.http.conn.params.ConnManagerParams;

import org.apache.http.conn.params.ConnPerRouteBean;

import org.apache.http.conn.scheme.PlainSocketFactory;

import org.apache.http.conn.scheme.Scheme;

import org.apache.http.conn.scheme.SchemeRegistry;

import org.apache.http.conn.ssl.SSLSocketFactory;

import org.apache.http.impl.client.DefaultHttpClient;

import org.apache.http.impl.client.DefaultHttpRequestRetryHandler;

import org.apache.http.impl.conn.ProxySelectorRoutePlanner;

import org.apache.http.impl.conn.tsccm.ThreadSafeClientConnManager;

import org.apache.http.message.BasicHeaderElementIterator;

import org.apache.http.params.BasicHttpParams;

import org.apache.http.params.HttpConnectionParams;

import org.apache.http.params.HttpParams;

import org.apache.http.protocol.HTTP;

import org.apache.http.protocol.HttpContext;

/**

 * @author Li Sheng

 */

@Slf4j

public class HttpClientUtils {

  private static HttpRequestFactory requestFactory;

  private static HttpTransport httpTransport;

  private static final String CONTENT_TYPE_JSON = "application/json";

  private static final int CACHE_SIZE = 4096;

  static {

    HttpParams params = new BasicHttpParams();

    HttpConnectionParams.setStaleCheckingEnabled(params, false);

    HttpConnectionParams.setSocketBufferSize(params, 245760); // 8k(8192) * 30

    ConnManagerParams.setMaxTotalConnections(params, 400);

    ConnManagerParams.setMaxConnectionsPerRoute(params, new ConnPerRouteBean(200));

    SchemeRegistry registry = new SchemeRegistry();

    registry.register(new Scheme("http", PlainSocketFactory.getSocketFactory(), 80));

    registry.register(new Scheme("https", SSLSocketFactory.getSocketFactory(), 443));

    ClientConnectionManager connectionManager = new ThreadSafeClientConnManager(params, registry);

    DefaultHttpClient defaultHttpClient = new DefaultHttpClient(connectionManager, params);

    defaultHttpClient.setHttpRequestRetryHandler(new DefaultHttpRequestRetryHandler(0, false));

    defaultHttpClient

        .setRoutePlanner(new ProxySelectorRoutePlanner(registry, ProxySelector.getDefault()));

    ConnectionKeepAliveStrategy connectionKeepAliveStrategy = new ConnectionKeepAliveStrategy() {

      @Override

      public long getKeepAliveDuration(org.apache.http.HttpResponse httpResponse,

          HttpContext httpContext) {

        return 20 * 1000; // 20 seconds,because tomcat default keep-alive timeout is 20s

      }

    };

    defaultHttpClient.setKeepAliveStrategy(connectionKeepAliveStrategy);

    httpTransport = new ApacheHttpTransport(defaultHttpClient);

    requestFactory = httpTransport.createRequestFactory();

  }

  @Data

  public static class PostParam {

    private Integer connectTimeoutMills;  // 可选,默认 20s

    private Integer readTimeoutMills;  // 可选，默认 20s

    private Map<String, String> headers; // 可选

    private String url; //必填

    private String postJson; //必填

    private Boolean readResponseData; //必填：是否需要读取数据。如果不需要返回结果,设置 false

    private BackOff backOff; //可选,重试机制策略

    private String authorization; //可选

    public PostParam(String url, String postJson, boolean readResponseData) {

      this.url = url;

      this.postJson = postJson;

      this.readResponseData = readResponseData;

    }

  }

  public static String postWithJson(PostParam postParam) {

    GenericUrl genericUrl = new GenericUrl(postParam.getUrl());

    HttpContent httpContent = ByteArrayContent.fromString(null, postParam.getPostJson());

    HttpResponse httpResponse = null;

    try {

      HttpRequest httpRequest = requestFactory.buildPostRequest(genericUrl, httpContent);

      if (postParam.getConnectTimeoutMills() != null) {

        httpRequest.setConnectTimeout(postParam.getConnectTimeoutMills());

      }

      if (postParam.getReadTimeoutMills() != null) {

        httpRequest.setReadTimeout(postParam.getReadTimeoutMills());

      }

      if (postParam.getBackOff() != null) {

        httpRequest.setUnsuccessfulResponseHandler(

            new HttpBackOffUnsuccessfulResponseHandler(postParam.getBackOff()));

      }

      HttpHeaders httpHeaders = new HttpHeaders();

      httpHeaders.setContentType(CONTENT_TYPE_JSON);

      Map<String, String> headers = postParam.getHeaders();

      if (headers != null && headers.size() > 0) {

        headers.forEach(httpHeaders::set);

      }

      if (postParam.getAuthorization() != null && !postParam.equals("")) {

        httpHeaders.setAuthorization(postParam.getAuthorization());

      }

      httpRequest.setHeaders(httpHeaders);

      httpResponse = httpRequest.execute();

      if (httpResponse.getStatusCode() != HttpStatusCodes.STATUS_CODE_OK) {

        log.error("http status not 200. param:{},status:{},msg:{}", postParam,

            httpResponse.getStatusCode(), httpResponse.getStatusMessage());

        return null;

      }

      Boolean readResponseData = postParam.getReadResponseData();

      if (readResponseData != null && readResponseData) {

        InputStream inputStream = httpResponse.getContent();

        if (inputStream != null) {

          StringBuffer out = new StringBuffer();

          byte[] b = new byte[CACHE_SIZE];

          for (int n; (n = inputStream.read(b)) != -1; ) {

            out.append(new String(b, 0, n));

          }

          return out.toString();

        }

      }

    } catch (Exception e) {

      log.error("post exception,param:{}", postParam, e);

    } finally {

      try {

        if (httpResponse != null) {

          httpResponse.disconnect();

        }

      } catch (Exception e) {

        log.error("httpResponse disconnect exception", e);

      }

    }

    return null;

  }

  @PreDestroy

  public static void destory() {

    try {

      log.info("httpTransport shutdown now....");

      httpTransport.shutdown();

    } catch (IOException e) {

      log.error("shut down httpTransport exception", e);

    }

  }

}