/**

  * Copyright (c) 2011-2017, 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.http.wire;

 import com.google.common.cache.CacheBuilder;

 import com.google.common.cache.CacheLoader;

 import com.google.common.cache.LoadingCache;

 import com.jcabi.aspects.Immutable;

 import com.jcabi.aspects.Tv;

 import com.jcabi.http.Request;

 import com.jcabi.http.Response;

 import com.jcabi.http.Wire;

 import java.io.IOException;

 import java.io.InputStream;

 import java.net.URI;

 import java.util.Collection;

 import java.util.Map;

 import java.util.concurrent.ExecutionException;

 import lombok.EqualsAndHashCode;

 import lombok.ToString;

 /**

  * Wire that caches GET requests.

  *

  * <p>This decorator can be used when you want to avoid duplicate

  * GET requests to load-sensitive resources, for example:

  *

  * <pre> String html = new JdkRequest("http://goggle.com")

  *   .through(CachingWire.class)

  *   .header(HttpHeaders.ACCEPT, MediaType.TEXT_PLAIN)

  *   .fetch()

  *   .body();</pre>

  *

  * <p>Since 1.5, you can also configure it to flush the entire cache

  * on certain request URI's, for example:

  *

  * <pre>new JdkRequest(uri)

  *   .through(CachingWire.class, "GET /save/.*")

  *   .uri().path("/save/123").back()

  *   .fetch();</pre>

  *

  * <p>The regular expression provided will be used against a string

  * constructed as an HTTP method, space, path of the URI together with

  * query part.

  *

  * <p>The class is immutable and thread-safe.

  *

  * @author Yegor Bugayenko (yegor@tpc2.com)

  * @version $Id: 025f47072606e5c8840072ccef9cd097b3f93d42 $

  * @since 1.0

  */

 @Immutable

 @ToString

 @EqualsAndHashCode(of = { "origin", "regex" })

 public final class CachingWire implements Wire {

     /**

      * Loader.

      */

     private static final CacheLoader<Wire,

         LoadingCache<CachingWire.Query, Response>> LOADER =

         new CacheLoader<Wire, LoadingCache<CachingWire.Query, Response>>() {

             @Override

             public LoadingCache<CachingWire.Query, Response> load(

                 final Wire key) {

                 return CacheBuilder.newBuilder().build(

                     new CacheLoader<CachingWire.Query, Response>() {

                         @Override

                         public Response load(final CachingWire.Query query)

                             throws IOException {

                             return query.fetch();

                         }

                     }

                 );

             }

         };

     /**

      * Cache.

      */

     private static final LoadingCache<Wire,

         LoadingCache<CachingWire.Query, Response>> CACHE =

         CacheBuilder.newBuilder().build(CachingWire.LOADER);

     /**

      * Original wire.

      */

     private final transient Wire origin;

     /**

      * Flushing regular expression.

      */

     private final transient String regex;

     /**

      * Public ctor.

      * @param wire Original wire

      */

     public CachingWire(final Wire wire) {

         this(wire, "$never");

     }

     /**

      * Public ctor.

      * @param wire Original wire

      * @param flsh Flushing regular expression

      * @since 1.5

      */

     public CachingWire(final Wire wire, final String flsh) {

         this.origin = wire;

         this.regex = flsh;

     }

     // @checkstyle ParameterNumber (5 lines)

     @Override

     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 URI uri = req.uri().get();

         final StringBuilder label = new StringBuilder(Tv.HUNDRED)

             .append(method).append(' ').append(uri.getPath());

         if (uri.getQuery() != null) {

             label.append('?').append(uri.getQuery());

         }

         if (label.toString().matches(this.regex)) {

             try {

                 CachingWire.CACHE.get(this).invalidateAll();

             } catch (final ExecutionException ex) {

                 throw new IllegalStateException(ex);

             }

         }

         final Response rsp;

         if (method.equals(Request.GET)) {

             try {

                 rsp = CachingWire.CACHE.get(this).get(

                     new CachingWire.Query(

                         this.origin, req, home, headers, content,

                         connect, read

                     )

                 );

             } catch (final ExecutionException ex) {

                 throw new IOException(ex);

             }

         } else {

             rsp = this.origin.send(

                 req, home, method, headers, content,

                 connect, read

             );

         }

         return rsp;

     }

     /**

      * Invalidate the entire cache.

      * @since 1.15

      */

     public static void invalidate() {

         CachingWire.CACHE.invalidateAll();

     }

     /**

      * Query.

      */

     @ToString

     @EqualsAndHashCode(of = { "origin", "request", "uri", "headers" })

     private static final class Query {

         /**

          * Origin wire.

          */

         private final transient Wire origin;

         /**

          * Request.

          */

         private final transient Request request;

         /**

          * URI.

          */

         private final transient String uri;

         /**

          * Headers.

          */

         private final transient Collection<Map.Entry<String, String>> headers;

         /**

          * Body.

          */

         private final transient InputStream body;

         /**

          * Connect timeout.

          */

         private final transient int connect;

         /**

          * Read timeout.

          */

         private final transient int read;

         /**

          * Ctor.

          * @param wire Original wire

          * @param req Request

          * @param home URI to fetch

          * @param hdrs Headers

          * @param input Input body

          * @param cnct Connect timeout

          * @param rdd Read timeout

          * @checkstyle ParameterNumberCheck (5 lines)

          */

         Query(final Wire wire, final Request req, final String home,

             final Collection<Map.Entry<String, String>> hdrs,

             final InputStream input, final int cnct,

             final int rdd) {

             this.origin = wire;

             this.request = req;

             this.uri = home;

             this.headers = hdrs;

             this.body = input;

             this.connect = cnct;

             this.read = rdd;

         }

         /**

          * Fetch.

          * @return Response

          * @throws IOException If fails

          */

         public Response fetch() throws IOException {

             return this.origin.send(

                 this.request, this.uri, Request.GET, this.headers, this.body,

                 this.connect, this.read

             );

         }

     }

 }