/**
    * Copyright (c) 2013-2023, jcabi.com
    * All rights reserved.
    *
    * Redistribution and use in source and binary forms, with or without
    * modification, are permitted provided that the following conditions
    * are met: 1) Redistributions of source code must retain the above
    * copyright notice, this list of conditions and the following
    * disclaimer. 2) Redistributions in binary form must reproduce the above
   * copyright notice, this list of conditions and the following
   * disclaimer in the documentation and/or other materials provided
   * with the distribution. 3) Neither the name of the jcabi.com nor
   * the names of its contributors may be used to endorse or promote
   * products derived from this software without specific prior written
   * permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT
   * NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
   * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
   * THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
   * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
   * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
   * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
   * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
   * OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  package com.jcabi.github.wire;
  
  import com.jcabi.aspects.Immutable;
  import com.jcabi.http.Request;
  import com.jcabi.http.Response;
  import com.jcabi.http.Wire;
  import com.jcabi.log.Logger;
  import java.io.IOException;
  import java.io.InputStream;
  import java.util.Collection;
  import java.util.List;
  import java.util.Map;
  import java.util.concurrent.TimeUnit;
  import lombok.EqualsAndHashCode;
  import lombok.ToString;
  
  /**
   * Wire that waits if number of remaining request per hour is less than
   * a given threshold.
   *
   * <p>Github sets following headers in each response:
   * {@code X-RateLimit-Limit}, {@code X-RateLimit-Remaining}, and
   * {@code X-RateLimit-Reset}. If {@code X-RateLimit-Remaining} is
   * less than a given threshold, {@code CarefulWire} will sleep until a time
   * specified in the {@code X-RateLimit-Reset} header. For further information
   * about the Github rate limiting see
   * <a href="https://developer.github.com/v3/#rate-limiting">API
   * documentation</a>.
   *
   * <p>You can use {@code CarefulWire} with a {@link com.jcabi.github.Github}
   * object:
   * <pre>
   * {@code
   * Github github = new RtGithub(
   *     new RtGithub().entry().through(CarefulWire.class, 50)
   * );
   * }
   * </pre>
   *
   * @author Alexander Sinyagin (sinyagin.alexander@gmail.com)
   * @version $Id: cb6ac78caff6221a20b35c8a3656f45c91156a7f $
   */
  @Immutable
  @ToString
  @EqualsAndHashCode(of = { "origin", "threshold" })
  @SuppressWarnings("PMD.AvoidDuplicateLiterals")
  public final class CarefulWire implements Wire {
  
      /**
       * Original wire.
       */
      private final transient Wire origin;
  
      /**
       * Threshold of number of remaining requests, below which requests are
       * blocked until reset.
       */
      private final transient int threshold;
  
      /**
       * Public ctor.
       *
       * @param wire Original wire
       * @param thrshld Threshold of number of remaining requests, below which
       *  requests are blocked until reset
       */
      public CarefulWire(final Wire wire, final int thrshld) {
          this.origin = wire;
          this.threshold = thrshld;
      }
 
     @Override
     // @checkstyle ParameterNumber (8 lines)
     public Response send(
         final Request req,
         final String home,
         final String method,
         final Collection<Map.Entry<String, String>> headers,
         final InputStream content,
         final int connect, final int read
     ) throws IOException {
         final Response resp = this.origin
             .send(req, home, method, headers, content, connect, read);
         final int remaining = this.remainingHeader(resp);
         if (remaining < this.threshold) {
             final long reset = this.resetHeader(resp);
             final long now = TimeUnit.MILLISECONDS
                 .toSeconds(System.currentTimeMillis());
             if (reset > now) {
                 final long length = reset - now;
                 Logger.info(
                     this,
                     // @checkstyle LineLength (1 line)
                     "Remaining number of requests per hour is less than %d. Waiting for %d seconds.",
                     this.threshold, length
                 );
                 try {
                     TimeUnit.SECONDS.sleep(length);
                 } catch (final InterruptedException ex) {
                     Thread.currentThread().interrupt();
                     throw new IllegalStateException(ex);
                 }
             }
         }
         return resp;
     }
 
     /**
      * Get the header with the given name from the response.
      * If there is no such header, returns null.
      * @param resp Response to get header from
      * @param headername Name of header to get
      * @return The value of the first header with the given name, or null.
      */
     private String headerOrNull(
         final Response resp,
         final String headername) {
         final List<String> values = resp.headers().get(headername);
         String value = null;
         if (values != null && !values.isEmpty()) {
             value = values.get(0);
         }
         return value;
     }
 
     /**
      * Returns the value of the X-RateLimit-Remaining header.
      * If there is no such header, returns Integer.MAX_VALUE (no rate limit).
      * @param resp Response to get header from
      * @return Number of requests remaining before the rate limit will be hit
      */
     private int remainingHeader(
         final Response resp) {
         final String remainingstr = this.headerOrNull(
             resp,
             "X-RateLimit-Remaining"
         );
         int remaining = Integer.MAX_VALUE;
         if (remainingstr != null) {
             remaining = Integer.parseInt(remainingstr);
         }
         return remaining;
     }
 
     /**
      * Returns the value of the X-RateLimit-Reset header.
      * If there is no such header, returns 0 (reset immediately).
      * @param resp Response to get header from
      * @return Timestamp (in seconds) at which the rate limit will reset
      */
     private long resetHeader(
         final Response resp) {
         final String resetstr = this.headerOrNull(resp, "X-RateLimit-Reset");
         long reset = 0;
         if (resetstr != null) {
             reset = Long.parseLong(resetstr);
         }
         return reset;
     }
 
 }