/*
 * 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.openapi3;

import static org.apache.juneau.commons.utils.CollectionUtils.*;
import static org.apache.juneau.bean.openapi3.OpenApiCopyUtils.*;
import static org.apache.juneau.commons.utils.Shorts.*;
import static org.apache.juneau.marshall.internal.ConverterUtils.*;

import java.util.*;

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

/**
 * The Link object represents a possible design-time link for a response.
 *
 * <p>
 * The Link Object represents a possible design-time link for a response. The presence of a link does not guarantee
 * the caller's ability to successfully invoke it, rather it provides a known relationship and traversal mechanism
 * between responses and other operations.
 *
 * <h5 class='section'>OpenAPI Specification:</h5>
 * <p>
 * The Link Object is composed of the following fields:
 * <ul class='spaced-list'>
 *    <li><c>operationRef</c> (string) - A relative or absolute reference to an OAS operation (mutually exclusive with <c>operationId</c>)
 *    <li><c>operationId</c> (string) - The name of an existing, resolvable OAS operation (mutually exclusive with <c>operationRef</c>)
 *    <li><c>parameters</c> (map of any) - A map representing parameters to pass to an operation as specified with <c>operationId</c> or identified via <c>operationRef</c>
 *    <li><c>requestBody</c> (any) - A literal value or expression to use as a request body when calling the target operation
 *    <li><c>description</c> (string) - A description of the link (CommonMark syntax may be used)
 *    <li><c>server</c> ({@link Server}) - A server object to be used by the target operation
 * </ul>
 *
 * <h5 class='section'>Example:</h5>
 * <p class='bjava'>
 *    <jc>// Create a link to another operation</jc>
 *    Link <jv>link</jv> = <jk>new</jk> Link()
 *       .setOperationId(<js>"getUserById"</js>)
 *       .setParameters(
 *          JsonMap.<jsm>of</jsm>(<js>"userId"</js>, <js>"$response.body#/id"</js>)
 *       )
 *       .setDescription(<js>"The id value returned in the response can be used as userId parameter in GET /users/{userId}"</js>);
 * </p>
 *
 * <h5 class='section'>See Also:</h5><ul>
 *    <li class='link'><a class="doclink" href="https://spec.openapis.org/oas/v3.0.0#link-object">OpenAPI Specification &gt; Link Object</a>
 *    <li class='link'><a class="doclink" href="https://swagger.io/docs/specification/links/">OpenAPI Links</a>
 *    <li class='link'><a class="doclink" href="https://juneau.apache.org/docs/topics/JuneauBeanOpenApi3">juneau-bean-openapi-v3</a>
 * </ul>
 */
@SuppressWarnings({
   "java:S1192" // Duplicated literals (argument/property names) read more clearly inline than as constants
})
public class Link extends OpenApiElement {

   private String operationRef;
   private String operationId;
   private String description;
   private Object requestBody;
   private Server server;
   private final Map<String,Object> parameters = map();

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

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

      this.operationRef = copyFrom.operationRef;
      this.description = copyFrom.description;
      this.operationId = copyFrom.operationId;
      this.requestBody = copyFrom.requestBody;
      this.server = copyOf(copyFrom.server);
      parameters.putAll(copyFrom.parameters);
   }

   /**
    * Adds a single value to the <property>parameters</property> property.
    *
    * @param mimeType The parameter name.  Must not be <jk>null</jk>, or an {@link IllegalArgumentException} is thrown.
    * @param parameter The parameter value.  Must not be <jk>null</jk>, or an {@link IllegalArgumentException} is thrown.
    * @return This object
    */
   public Link addParameter(String mimeType, Object parameter) {
      reqnn("mimeType", mimeType);
      reqnn("parameter", parameter);
      parameters.put(mimeType, parameter);
      return this;
   }

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

   @Override /* Overridden from OpenApiElement */
   public <T> T get(String property, Class<T> type) {
      reqnn("property", property);
      return switch (property) {
         case "description" -> toType(getDescription(), type);
         case "operationRef" -> toType(getOperationRef(), type);
         case "operationId" -> toType(getOperationId(), type);
         case "requestBody" -> toType(getRequestBody(), type);
         case "parameters" -> toType(getParameters(), type);
         case "server" -> toType(getServer(), type);
         default -> super.get(property, type);
      };
   }

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

   /**
    * Bean property getter:  <property>operationId</property>.
    *
    * <p>
    * The name of an existing, resolvable OAS operation.
    *
    * @return The property value, or <jk>null</jk> if it is not set.
    */
   public String getOperationId() { return operationId; }

   /**
    * Bean property getter:  <property>operationRef</property>.
    *
    * <p>
    * A relative or absolute reference to an OAS operation.
    *
    * @return The property value, or <jk>null</jk> if it is not set.
    */
   public String getOperationRef() { return operationRef; }

   /**
    * Bean property getter:  <property>parameters</property>.
    *
    * <p>
    * A map representing parameters to pass to an operation.
    *
    * @return The property value, or <jk>null</jk> if it is not set.
    */
   public Map<String,Object> getParameters() { return nie(parameters); }

   /**
    * Bean property getter:  <property>requestBody</property>.
    *
    * <p>
    * A literal value or expression to use as a request body when calling the target operation.
    *
    * @return The property value, or <jk>null</jk> if it is not set.
    */
   public Object getRequestBody() { return requestBody; }

   /**
    * Bean property getter:  <property>server</property>.
    *
    * @return The property value, or <jk>null</jk> if it is not set.
    */
   public Server getServer() { return server; }

   @Override /* Overridden from OpenApiElement */
   public Set<String> keySet() {
      // @formatter:off
      var s = stb(String.class)
         .addIf(nn(description), "description")
         .addIf(nn(operationId), "operationId")
         .addIf(nn(operationRef), "operationRef")
         .addIf(ine(parameters), "parameters")
         .addIf(nn(requestBody), "requestBody")
         .addIf(nn(server), "server")
         .build();
      // @formatter:on
      return new MultiSet<>(s, super.keySet());
   }

   @Override /* Overridden from OpenApiElement */
   public Link set(String property, Object value) {
      reqnn("property", property);
      return switch (property) {
         case "description" -> setDescription(s(value));
         case "operationId" -> setOperationId(s(value));
         case "operationRef" -> setOperationRef(s(value));
         case "parameters" -> setParameters(toMapBuilder(value, String.class, Object.class).sparse().build());
         case "requestBody" -> setRequestBody(value);
         case "server" -> setServer(toType(value, Server.class));
         default -> {
            super.set(property, value);
            yield this;
         }
      };
   }

   /**
    * Bean property setter:  <property>description</property>.
    * @param value
    *    The new value for this property.
    *    <br>Can be <jk>null</jk> to unset the property.
    * @return This object
    */
   public Link setDescription(String value) {
      description = value;
      return this;
   }

   /**
    * Bean property setter:  <property>operationId</property>.
    *
    * <p>
    * The name of an existing, resolvable OAS operation.
    *
    * @param value
    *    The new value for this property.
    *    <br>Can be <jk>null</jk> to unset the property.
    * @return This object
    */
   public Link setOperationId(String value) {
      operationId = value;
      return this;
   }

   /**
    * Bean property setter:  <property>operationRef</property>.
    *
    * <p>
    * A relative or absolute reference to an OAS operation.
    *
    * @param value
    *    The new value for this property.
    *    <br>Can be <jk>null</jk> to unset the property.
    * @return This object
    */
   public Link setOperationRef(String value) {
      operationRef = value;
      return this;
   }

   /**
    * Bean property setter:  <property>parameters</property>.
    *
    * <p>
    * A map representing parameters to pass to an operation.
    *
    * @param value
    *    The new value for this property.
    *    <br>Can be <jk>null</jk> to unset the property.
    * @return This object
    */
   public Link setParameters(Map<String,Object> value) {
      parameters.clear();
      if (nn(value))
         parameters.putAll(value);
      return this;
   }

   /**
    * Bean property setter:  <property>requestBody</property>.
    *
    * <p>
    * A literal value or expression to use as a request body when calling the target operation.
    *
    * @param val The new value for this property.
    *    <br>Can be <jk>null</jk> to unset the property.
    * @return This object
    */
   public Link setRequestBody(Object val) {
      requestBody = val;
      return this;
   }

   /**
    * Bean property setter:  <property>server</property>.
    *
    * @param value
    *    The new value for this property.
    *    <br>Can be <jk>null</jk> to unset the property.
    * @return This object
    */
   public Link setServer(Server value) {
      server = value;
      return this;
   }

   @Override /* Overridden from OpenApiElement */
   public Link strict() {
      super.strict();
      return this;
   }

   @Override /* Overridden from OpenApiElement */
   public Link strict(Object value) {
      super.strict(value);
      return this;
   }
}