/*
 * 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.juneau.http.header;

import java.util.*;
import java.util.function.*;

import org.apache.juneau.*;
import org.apache.juneau.assertions.*;
import org.apache.juneau.common.utils.*;
import org.apache.juneau.http.annotation.*;
import org.apache.juneau.internal.*;

/**
 * Represents a parsed <l>Client-Version</l> HTTP request header.
 *
 * <p>
 * Specifies a client-side version number.
 *
 * <h5 class='figure'>Example</h5>
 * <p class='bcode'>
 *    Client-Version: 2.0.1
 * </p>
 *
 * <p>
 * Not part of the RFC2616 specification, but provided to allow for HTTP responses to be tailored to specified
 * known client versions.
 *
 * <h5 class='section'>See Also:</h5><ul>
 *    <li class='link'><a class="doclink" href="https://juneau.apache.org/docs/topics/JuneauRestCommonBasics">juneau-rest-common Basics</a>
 * </ul>
 *
 * @serial exclude
 */
@Header("Client-Version")
public class ClientVersion extends BasicStringHeader {

   //-----------------------------------------------------------------------------------------------------------------
   // Static
   //-----------------------------------------------------------------------------------------------------------------

   private static final long serialVersionUID = 1L;
   private static final String NAME = "Client-Version";

   private static final Cache<String,ClientVersion> CACHE = Cache.of(String.class, ClientVersion.class).build();

   /**
    * Static creator.
    *
    * @param value
    *    The header value.
    *    <br>Must be parsable by {@link Version#of(String)}
    *    <br>Can be <jk>null</jk>.
    * @return A new header bean, or <jk>null</jk> if the value is <jk>null</jk>.
    */
   public static ClientVersion of(String value) {
      return value == null ? null : CACHE.get(value, ()->new ClientVersion(value));
   }

   /**
    * Static creator.
    *
    * @param value
    *    The header value.
    *    <br>Can be <jk>null</jk>.
    * @return A new header bean, or <jk>null</jk> if the value is <jk>null</jk>.
    */
   public static ClientVersion of(Version value) {
      return value == null ? null : new ClientVersion(value);
   }

   /**
    * Static creator with delayed value.
    *
    * <p>
    * Header value is re-evaluated on each call to {@link #getValue()}.
    *
    * @param value
    *    The supplier of the header value.
    *    <br>Can be <jk>null</jk>.
    * @return A new header bean, or <jk>null</jk> if the value is <jk>null</jk>.
    */
   public static ClientVersion of(Supplier<Version> value) {
      return value == null ? null : new ClientVersion(value);
   }

   //-----------------------------------------------------------------------------------------------------------------
   // Instance
   //-----------------------------------------------------------------------------------------------------------------

   private final Version value;
   private final Supplier<Version> supplier;

   /**
    * Constructor.
    *
    * @param value
    *    The header value.
    *    <br>Must be parsable by {@link Version#of(String)}
    *    <br>Can be <jk>null</jk>.
    */
   public ClientVersion(String value) {
      super(NAME, value);
      this.value = Version.of(value);
      this.supplier = null;
   }

   /**
    * Constructor.
    *
    * @param value
    *    The header value.
    *    <br>Can be <jk>null</jk>.
    */
   public ClientVersion(Version value) {
      super(NAME, Utils.s(value));
      this.value = value;
      this.supplier = null;
   }

   /**
    * Constructor with delayed value.
    *
    * <p>
    * Header value is re-evaluated on each call to {@link #getValue()}.
    *
    * @param value
    *    The supplier of the header value.
    *    <br>Can be <jk>null</jk>.
    */
   public ClientVersion(Supplier<Version> value) {
      super(NAME, (String)null);
      this.value = null;
      this.supplier = value;
   }

   @Override /* Header */
   public String getValue() {
      if (supplier != null)
         return Utils.s(supplier.get());
      return super.getValue();
   }

   /**
    * Returns the header value as a {@link Version} object.
    *
    * @return The header value as a {@link Version} object, or {@link Optional#empty()} if the value is <jk>null</jk>.
    */
   public Optional<Version> asVersion() {
      return Utils.opt(value);
   }

   /**
    * Provides the ability to perform fluent-style assertions on this header.
    *
    * <h5 class='section'>Examples:</h5>
    * <p class='bjava'>
    *    <jc>// Validates the response content is older than 1.</jc>
    *    <jv>client</jv>
    *       .get(<jsf>URL</jsf>)
    *       .run()
    *       .getHeader(ClientVersion.<jk>class</jk>).assertVersion().major().isGreaterThan(1);
    * </p>
    *
    * @return A new fluent assertion object.
    * @throws AssertionError If assertion failed.
    */
   public FluentVersionAssertion<ClientVersion> assertVersion() {
      return new FluentVersionAssertion<>(asVersion().orElse(null), this);
   }
}