/*
 * 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.rest.client.assertion;

import org.apache.juneau.rest.client.*;

/**
 * A fluent assertion class for a named HTTP response header.
 *
 * <p>
 * Obtain instances via {@link ResponseAssertion#header(String)}.
 *
 * <h5 class='section'>See Also:</h5><ul>
 *    <li class='link'><a class="doclink" href="https://juneau.apache.org/docs/topics/NextGenRestClient">Next-Generation REST Client</a>
 * </ul>
 *
 * @since 9.2.1
 */
@SuppressWarnings({
   "resource" // Eclipse resource analysis: response is borrowed; caller closes it
})
public final class ResponseHeaderAssertion {

   private final String name;

   private final RestResponse response;
   private final ResponseAssertion parent;

   ResponseHeaderAssertion(String name, RestResponse response, ResponseAssertion parent) {
      this.name = name;
      this.response = response;
      this.parent = parent;
   }

   /**
    * Asserts that this header is present in the response.
    *
    * @return This object (for chaining).
    * @throws AssertionError If the header is absent.
    */
   public ResponseHeaderAssertion isPresent() {
      if (response.getFirstHeader(name) == null)
         throw new AssertionError("Expected header '" + name + "' to be present but was absent");
      return this;
   }

   /**
    * Asserts that this header is absent from the response.
    *
    * @return This object (for chaining).
    * @throws AssertionError If the header is present.
    */
   public ResponseHeaderAssertion isAbsent() {
      var h = response.getFirstHeader(name);
      if (h != null)
         throw new AssertionError("Expected header '" + name + "' to be absent but was present with value: " + h.value());
      return this;
   }

   /**
    * Asserts that this header's value equals the expected value (case-sensitive).
    *
    * @param expected The expected value. Must not be <jk>null</jk>.
    * @return This object (for chaining).
    * @throws AssertionError If the value does not match.
    */
   @SuppressWarnings({
      "java:S1201" // 'equals(String)' is an intentional fluent-assertion DSL method (asserts header equality), not an override of Object.equals(Object); renaming would break this public API.
   })
   public ResponseHeaderAssertion equals(String expected) {
      var h = response.getFirstHeader(name);
      var actual = h != null ? h.value() : null;
      if (!expected.equals(actual))
         throw new AssertionError("Header '" + name + "': expected '" + expected + "' but got '" + actual + "'");
      return this;
   }

   /**
    * Asserts that this header's value contains the given substring.
    *
    * @param substring The substring to look for. Must not be <jk>null</jk>.
    * @return This object (for chaining).
    * @throws AssertionError If the value is absent or does not contain the substring.
    */
   public ResponseHeaderAssertion contains(String substring) {
      var h = response.getFirstHeader(name);
      var actual = h != null ? h.value() : null;
      if (actual == null || !actual.contains(substring))
         throw new AssertionError("Header '" + name + "' value '" + actual + "' does not contain '" + substring + "'");
      return this;
   }

   /**
    * Asserts that this header's value starts with the given prefix.
    *
    * @param prefix The expected prefix. Must not be <jk>null</jk>.
    * @return This object (for chaining).
    * @throws AssertionError If the value is absent or does not start with the prefix.
    */
   public ResponseHeaderAssertion startsWith(String prefix) {
      var h = response.getFirstHeader(name);
      var actual = h != null ? h.value() : null;
      if (actual == null || !actual.startsWith(prefix))
         throw new AssertionError("Header '" + name + "' value '" + actual + "' does not start with '" + prefix + "'");
      return this;
   }

   /**
    * Asserts that this header's integer value equals the expected value.
    *
    * @param expected The expected integer value.
    * @return This object (for chaining).
    * @throws AssertionError If the value is absent, not a number, or does not match.
    */
   public ResponseHeaderAssertion integerEquals(int expected) {
      var h = response.getFirstHeader(name);
      if (h == null)
         throw new AssertionError("Header '" + name + "' is absent");
      int actual;
      try {
         actual = Integer.parseInt(h.value().trim());
      } catch (NumberFormatException e) {
         throw new AssertionError("Header '" + name + "' value '" + h.value() + "' is not a valid integer");
      }
      if (actual != expected)
         throw new AssertionError("Header '" + name + "': expected " + expected + " but got " + actual);
      return this;
   }

   /**
    * Returns the parent {@link ResponseAssertion} to continue assertion chaining.
    *
    * @return The parent assertion. Never <jk>null</jk>.
    */
   public ResponseAssertion and() {
      return parent;
   }
}