/*
 * 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.bean.swagger;

import static org.apache.juneau.commons.utils.AssertionUtils.*;
import static org.apache.juneau.commons.utils.CollectionUtils.*;
import static org.apache.juneau.commons.utils.Utils.*;
import static org.apache.juneau.internal.ConverterUtils.*;

import java.util.*;

import org.apache.juneau.commons.collections.*;

/**
 * Describes a single response from an API operation.
 *
 * <p>
 * The Response Object describes a single response from a Swagger 2.0 API operation, including a description,
 * schema, headers, and examples. Responses are associated with HTTP status codes (e.g., 200, 404, 500).
 *
 * <h5 class='section'>Swagger Specification:</h5>
 * <p>
 * The Response Object is composed of the following fields:
 * <ul class='spaced-list'>
 *    <li><c>description</c> (string, REQUIRED) - A short description of the response
 *    <li><c>schema</c> ({@link SchemaInfo}) - A definition of the response structure
 *    <li><c>headers</c> (map of {@link HeaderInfo}) - Maps a header name to its definition
 *    <li><c>examples</c> (map of any) - An example of the response message (keys are media types)
 * </ul>
 *
 * <h5 class='section'>Example:</h5>
 * <p class='bjava'>
 *    <jc>// Construct using SwaggerBuilder.</jc>
 *    ResponseInfo <jv>info</jv> = <jsm>responseInfo</jsm>(<js>"A complex object array response"</js>)
 *       .schema(
 *          <jsm>schemaInfo</jsm>
 *             .type(<js>"array"</js>)
 *             .items(
 *                <jsm>items</jsm>()
 *                   .set(<js>"$ref"</js>, <js>"#/definitions/VeryComplexType"</js>)
 *             )
 *       );
 *
 *    <jc>// Serialize using JsonSerializer.</jc>
 *    String <jv>json</jv> = Json.<jsm>from</jsm>(<jv>info</jv>);
 *
 *    <jc>// Or just use toString() which does the same as above.</jc>
 *    <jv>json</jv> = <jv>info</jv>.toString();
 * </p>
 * <p class='bjson'>
 *    <jc>// Output</jc>
 *    {
 *       <js>"description"</js>: <js>"A complex object array response"</js>,
 *       <js>"schema"</js>: {
 *          <js>"type"</js>: <js>"array"</js>,
 *          <js>"items"</js>: {
 *             <js>"$ref"</js>: <js>"#/definitions/VeryComplexType"</js>
 *          }
 *       }
 *    }
 * </p>
 *
 * <h5 class='section'>See Also:</h5><ul>
 *    <li class='link'><a class="doclink" href="https://swagger.io/specification/v2/#response-object">Swagger 2.0 Specification &gt; Response Object</a>
 *    <li class='link'><a class="doclink" href="https://swagger.io/docs/specification/2-0/describing-responses/">Swagger Describing Responses</a>
 *    <li class='link'><a class="doclink" href="https://juneau.apache.org/docs/topics/JuneauBeanSwagger2">juneau-bean-swagger-v2</a>
 * </ul>
 */
public class ResponseInfo extends SwaggerElement {

   private String description;
   private SchemaInfo schema;
   private Map<String,HeaderInfo> headers = map();
   private Map<String,Object> examples = map();

   /**
    * Default constructor.
    */
   public ResponseInfo() {}

   /**
    * Copy constructor.
    *
    * @param copyFrom The object to copy.
    */
   public ResponseInfo(ResponseInfo copyFrom) {
      super(copyFrom);

      this.description = copyFrom.description;
      this.schema = copyFrom.schema == null ? null : copyFrom.schema.copy();
      if (nn(copyFrom.examples))
         examples.putAll(copyOf(copyFrom.examples));
      if (nn(copyFrom.headers))
         headers.putAll(copyOf(copyFrom.headers, HeaderInfo::copy));
   }

   /**
    * Bean property appender:  <property>examples</property>.
    *
    * <p>
    * Adds a single value to the <property>examples</property> property.
    *
    * @param mimeType The mime-type string.  Must not be <jk>null</jk>.
    * @param example The example.  Must not be <jk>null</jk>.
    * @return This object.
    */
   public ResponseInfo addExample(String mimeType, Object example) {
      assertArgNotNull("mimeType", mimeType);
      assertArgNotNull("example", example);
      examples.put(mimeType, example);
      return this;
   }

   /**
    * Bean property appender:  <property>headers</property>.
    *
    * @param name The header name.  Must not be <jk>null</jk>.
    * @param header The header descriptions  Must not be <jk>null</jk>.
    * @return This object.
    */
   public ResponseInfo addHeader(String name, HeaderInfo header) {
      assertArgNotNull("name", name);
      assertArgNotNull("header", header);
      headers.put(name, header);
      return this;
   }

   /**
    * Make a deep copy of this object.
    *
    * @return A deep copy of this object.
    */
   public ResponseInfo copy() {
      return new ResponseInfo(this);
   }

   /**
    * Copies any non-null fields from the specified object to this object.
    *
    * @param r
    *    The object to copy fields from.
    *    <br>Can be <jk>null</jk>.
    * @return This object.
    */
   public ResponseInfo copyFrom(ResponseInfo r) {
      if (nn(r)) {
         if (nn(r.description))
            description = r.description;
         if (nn(r.schema))
            schema = r.schema;
         if (nn(r.headers))
            headers = r.headers;
         if (nn(r.examples))
            examples = r.examples;
      }
      return this;
   }

   @Override /* Overridden from SwaggerElement */
   public <T> T get(String property, Class<T> type) {
      assertArgNotNull("property", property);
      return switch (property) {
         case "description" -> toType(getDescription(), type);
         case "examples" -> toType(getExamples(), type);
         case "headers" -> toType(getHeaders(), type);
         case "schema" -> toType(getSchema(), type);
         default -> super.get(property, type);
      };
   }

   /**
    * Bean property getter:  <property>description</property>.
    *
    * <p>
    * A short description of the response.
    *
    * @return The property value, or <jk>null</jk> if it is not set.
    */
   public String getDescription() { return description; }

   /**
    * Bean property getter:  <property>examples</property>.
    *
    * <p>
    * An example of the response message.
    *
    * @return The property value, or <jk>null</jk> if it is not set.
    */
   public Map<String,Object> getExamples() { return nullIfEmpty(examples); }

   /**
    * Returns the header information with the specified name.
    *
    * @param name The header name.  Must not be <jk>null</jk>.
    * @return The header info, or <jk>null</jk> if not found.
    */
   public HeaderInfo getHeader(String name) {
      assertArgNotNull("name", name);
      return headers.get(name);
   }

   /**
    * Bean property getter:  <property>headers</property>.
    *
    * <p>
    * A list of headers that are sent with the response.
    *
    * @return The property value, or <jk>null</jk> if it is not set.
    */
   public Map<String,HeaderInfo> getHeaders() { return nullIfEmpty(headers); }

   /**
    * Bean property getter:  <property>schema</property>.
    *
    * <p>
    * A definition of the response structure.
    *
    * @return The property value, or <jk>null</jk> if it is not set.
    */
   public SchemaInfo getSchema() { return schema; }

   @Override /* Overridden from SwaggerElement */
   public Set<String> keySet() {
      // @formatter:off
      var s = setb(String.class)
         .addIf(nn(description), "description")
         .addIf(ne(examples), "examples")
         .addIf(ne(headers), "headers")
         .addIf(nn(schema), "schema")
         .build();
      // @formatter:on
      return new MultiSet<>(s, super.keySet());
   }

   /**
    * Resolves any <js>"$ref"</js> attributes in this element.
    *
    * @param swagger The swagger document containing the definitions.
    * @param refStack Keeps track of previously-visited references so that we don't cause recursive loops.
    * @param maxDepth
    *    The maximum depth to resolve references.
    *    <br>After that level is reached, <c>$ref</c> references will be left alone.
    *    <br>Useful if you have very complex models and you don't want your swagger page to be overly-complex.
    * @return
    *    This object with references resolved.
    *    <br>May or may not be the same object.
    */
   public ResponseInfo resolveRefs(Swagger swagger, Deque<String> refStack, int maxDepth) {

      if (nn(schema))
         schema = schema.resolveRefs(swagger, refStack, maxDepth);

      headers.entrySet().forEach(x -> x.setValue(x.getValue().resolveRefs(swagger, refStack, maxDepth)));

      return this;
   }

   @Override /* Overridden from SwaggerElement */
   public ResponseInfo set(String property, Object value) {
      assertArgNotNull("property", property);
      return switch (property) {
         case "description" -> setDescription(s(value));
         case "examples" -> setExamples(toMapBuilder(value, String.class, Object.class).sparse().build());
         case "headers" -> setHeaders(toMapBuilder(value, String.class, HeaderInfo.class).sparse().build());
         case "schema" -> setSchema(toType(value, SchemaInfo.class));
         default -> {
            super.set(property, value);
            yield this;
         }
      };
   }

   /**
    * Bean property setter:  <property>description</property>.
    *
    * <p>
    * A short description of the response.
    *
    * @param value
    *    The new value for this property.
    *    <br><a class="doclink" href="https://help.github.com/articles/github-flavored-markdown">GFM syntax</a> can be used for rich text representation.
    *    <br>Property value is required.
    *    <br>Can be <jk>null</jk> to unset the property.
    * @return This object.
    */
   public ResponseInfo setDescription(String value) {
      description = value;
      return this;
   }

   /**
    * Bean property setter:  <property>examples</property>.
    *
    * <p>
    * An example of the response message.
    *
    * @param value
    *    The new value for this property.
    *    <br>Keys must be MIME-type strings.
    *    <br>Can be <jk>null</jk> to unset the property.
    * @return This object.
    */
   public ResponseInfo setExamples(Map<String,Object> value) {
      examples.clear();
      if (nn(value))
         examples.putAll(value);
      return this;
   }

   /**
    * Bean property setter:  <property>headers</property>.
    *
    * <p>
    * A list of headers that are sent with the response.
    *
    * @param value
    *    The new value for this property.
    *    <br>Can be <jk>null</jk> to unset the property.
    * @return This object.
    */
   public ResponseInfo setHeaders(Map<String,HeaderInfo> value) {
      headers.clear();
      if (nn(value))
         headers.putAll(value);
      return this;
   }

   /**
    * Bean property setter:  <property>schema</property>.
    *
    * <p>
    * A definition of the response structure.
    *
    * @param value
    *    The new value for this property.
    *    <br>It can be a primitive, an array or an object.
    *    <br>Can be <jk>null</jk> to unset the property.
    * @return This object.
    */
   public ResponseInfo setSchema(SchemaInfo value) {
      schema = value;
      return this;
   }

   /**
    * Sets strict mode on this bean.
    *
    * @return This object.
    */
   @Override
   public ResponseInfo strict() {
      super.strict();
      return this;
   }

   /**
    * Sets strict mode on this bean.
    *
    * @param value
    *    The new value for this property.
    *    <br>Non-boolean values will be converted to boolean using <code>Boolean.<jsm>valueOf</jsm>(value.toString())</code>.
    *    <br>Can be <jk>null</jk> (interpreted as <jk>false</jk>).
    * @return This object.
    */
   @Override
   public ResponseInfo strict(Object value) {
      super.strict(value);
      return this;
   }
}