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

import java.util.*;

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

/**
 * This is the root document object for the OpenAPI specification.
 *
 * <p>
 * The OpenAPI Object is the root document that describes an entire API. It contains metadata about the API,
 * available paths and operations, parameters, responses, authentication methods, and other information.
 *
 * <h5 class='section'>OpenAPI Specification:</h5>
 * <p>
 * The OpenAPI Object is composed of the following fields:
 * <ul class='spaced-list'>
 *    <li><c>openapi</c> (string, REQUIRED) - The OpenAPI Specification version (e.g., "3.0.0")
 *    <li><c>info</c> ({@link Info}, REQUIRED) - Provides metadata about the API
 *    <li><c>servers</c> (array of {@link Server}) - An array of Server Objects providing connectivity information
 *    <li><c>paths</c> (map of {@link PathItem}) - The available paths and operations for the API
 *    <li><c>components</c> ({@link Components}) - An element to hold various schemas for reuse
 *    <li><c>security</c> (array of {@link SecurityRequirement}) - Security mechanisms applied to all operations
 *    <li><c>tags</c> (array of {@link Tag}) - A list of tags for API documentation control
 *    <li><c>externalDocs</c> ({@link ExternalDocumentation}) - Additional external documentation
 * </ul>
 *
 * <h5 class='section'>Example:</h5>
 * <p class='bjava'>
 *    <jc>// Create an OpenAPI document</jc>
 *    OpenApi <jv>doc</jv> = <jk>new</jk> OpenApi()
 *       .setOpenapi(<js>"3.0.0"</js>)
 *       .setInfo(
 *          <jk>new</jk> Info()
 *             .setTitle(<js>"My API"</js>)
 *             .setVersion(<js>"1.0.0"</js>)
 *       )
 *       .setPaths(
 *          JsonMap.<jsm>of</jsm>(
 *             <js>"/pets"</js>, <jk>new</jk> PathItem()
 *                .setGet(<jk>new</jk> Operation()
 *                   .setSummary(<js>"List all pets"</js>)
 *                )
 *          )
 *       );
 * </p>
 *
 * <h5 class='section'>See Also:</h5><ul>
 *    <li class='link'><a class="doclink" href="https://spec.openapis.org/oas/v3.0.0#openapi-object">OpenAPI Specification &gt; OpenAPI Object</a>
 *    <li class='link'><a class="doclink" href="https://swagger.io/docs/specification/basic-structure/">OpenAPI Basic Structure</a>
 *    <li class='link'><a class="doclink" href="https://juneau.apache.org/docs/topics/JuneauBeanOpenApi3">juneau-bean-openapi-v3</a>
 * </ul>
 */
public class OpenApi extends OpenApiElement {

   /** Represents a null OpenAPI document */
   public static final OpenApi NULL = new OpenApi();

   private static final Comparator<String> PATH_COMPARATOR = (o1, o2) -> o1.replace('{', '@').compareTo(o2.replace('{', '@'));

   private String openapi = "3.0.0";
   private Info info;
   private List<Server> servers = list();
   private Map<String,PathItem> paths;
   private Components components;
   private List<SecurityRequirement> security = list();
   private List<Tag> tags = list();
   private ExternalDocumentation externalDocs;

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

   /**
    * Copy constructor.
    *
    * @param copyFrom The object to copy.
    */
   public OpenApi(OpenApi copyFrom) {
      super(copyFrom);
      this.openapi = copyFrom.openapi;
      this.info = copyFrom.info;
      if (nn(copyFrom.servers))
         this.servers.addAll(copyOf(copyFrom.servers, Server::copy));
      this.paths = copyOf(copyFrom.paths);
      this.components = copyFrom.components;
      if (nn(copyFrom.security))
         this.security.addAll(copyOf(copyFrom.security, SecurityRequirement::copy));
      if (nn(copyFrom.tags))
         this.tags.addAll(copyOf(copyFrom.tags, Tag::copy));
      this.externalDocs = copyFrom.externalDocs;
   }

   /**
    * Adds a path to this OpenAPI document.
    *
    * @param path The path string.  Must not be <jk>null</jk>.
    * @param pathItem The path item.  Must not be <jk>null</jk>.
    * @return This object.
    */
   public OpenApi addPath(String path, PathItem pathItem) {
      assertArgNotNull("path", path);
      assertArgNotNull("pathItem", pathItem);
      if (paths == null)
         paths = new TreeMap<>(PATH_COMPARATOR);
      getPaths().put(path, pathItem);
      return this;
   }

   /**
    * Bean property fluent setter:  <property>security</property>.
    *
    * <p>
    * A declaration of which security mechanisms can be used across the API.
    *
    * @param values
    *    The values to add to this property.
    *    <br>Ignored if <jk>null</jk>.
    * @return This object.
    */
   public OpenApi addSecurity(Collection<SecurityRequirement> values) {
      security = listb(SecurityRequirement.class).sparse().addAny(security, values).build();
      return this;
   }

   /**
    * Bean property fluent setter:  <property>security</property>.
    *
    * <p>
    * A declaration of which security mechanisms can be used across the API.
    *
    * @param values
    *    The values to add to this property.
    *    <br>Ignored if <jk>null</jk>.
    * @return This object.
    */
   public OpenApi addSecurity(SecurityRequirement...values) {
      security = listb(SecurityRequirement.class).sparse().addAll(security).addAny((Object)values).build();
      return this;
   }

   /**
    * Bean property fluent setter:  <property>servers</property>.
    *
    * <p>
    * An array of Server Objects, which provide connectivity information to a target server.
    *
    * @param values
    *    The values to add to this property.
    *    <br>Ignored if <jk>null</jk>.
    * @return This object.
    */
   public OpenApi addServers(Collection<Server> values) {
      if (nn(values))
         servers.addAll(values);
      return this;
   }

   /**
    * Bean property fluent setter:  <property>servers</property>.
    *
    * <p>
    * An array of Server Objects, which provide connectivity information to a target server.
    *
    * @param values
    *    The values to add to this property.
    *    <br>Ignored if <jk>null</jk>.
    * @return This object.
    */
   public OpenApi addServers(Server...values) {
      if (nn(values))
         for (var v : values)
            if (nn(v))
               servers.add(v);
      return this;
   }

   /**
    * Bean property appender:  <property>tags</property>.
    *
    * <p>
    * A list of tags used by the specification with additional metadata.
    *
    * @param values
    *    The values to add to this property.
    *    <br>Ignored if <jk>null</jk>.
    * @return This object.
    */
   public OpenApi addTags(Collection<Tag> values) {
      if (nn(values))
         tags.addAll(values);
      return this;
   }

   /**
    * Bean property appender:  <property>tags</property>.
    *
    * <p>
    * A list of tags used by the specification with additional metadata.
    *
    * @param values
    *    The values to add to this property.
    *    <br>Ignored if <jk>null</jk>.
    * @return This object.
    */
   public OpenApi addTags(Tag...values) {
      if (nn(values))
         for (var v : values)
            if (nn(v))
               tags.add(v);
      return this;
   }

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

   /**
    * Finds a reference within this OpenAPI document.
    *
    * @param ref The reference string (e.g., <js>"#/components/schemas/User"</js>).  Must not be <jk>null</jk> or blank.
    * @param c The expected class type.  Must not be <jk>null</jk>.
    * @return The referenced node, or <jk>null</jk> if not found.
    */
   public <T> T findRef(String ref, Class<T> c) {
      assertArgNotNullOrBlank("ref", ref);
      assertArgNotNull("c", c);
      if (! ref.startsWith("#/"))
         throw rex("Unsupported reference:  ''{0}''", ref);
      try {
         return new ObjectRest(this).get(ref.substring(1), c);
      } catch (Exception e) {
         throw bex(e, c, "Reference ''{0}'' could not be converted to type ''{1}''.", ref, cn(c));
      }
   }

   @Override /* Overridden from OpenApiElement */
   public <T> T get(String property, Class<T> type) {
      assertArgNotNull("property", property);
      return switch (property) {
         case "openapi" -> toType(getOpenapi(), type);
         case "info" -> toType(getInfo(), type);
         case "servers" -> toType(getServers(), type);
         case "paths" -> toType(getPaths(), type);
         case "components" -> toType(getComponents(), type);
         case "security" -> toType(getSecurity(), type);
         case "tags" -> toType(getTags(), type);
         case "externalDocs" -> toType(getExternalDocs(), type);
         default -> super.get(property, type);
      };
   }

   /**
    * Returns the components object.
    *
    * @return The components object.
    */
   public Components getComponents() { return components; }

   /**
    * Returns the external documentation.
    *
    * @return The external documentation.
    */
   public ExternalDocumentation getExternalDocs() { return externalDocs; }

   /**
    * Returns the info object.
    *
    * @return The info object.
    */
   public Info getInfo() { return info; }

   /**
    * Returns the OpenAPI version.
    *
    * @return The OpenAPI version.
    */
   public String getOpenapi() { return openapi; }

   /**
    * Returns the paths map.
    *
    * @return The paths map.
    */
   public Map<String,PathItem> getPaths() { return paths; }

   /**
    * Returns the security requirements list.
    *
    * @return The security requirements list.
    */
   public List<SecurityRequirement> getSecurity() { return nullIfEmpty(security); }

   /**
    * Returns the servers list.
    *
    * @return The servers list.
    */
   public List<Server> getServers() { return nullIfEmpty(servers); }

   /**
    * Returns the tags list.
    *
    * @return The tags list.
    */
   public List<Tag> getTags() { return nullIfEmpty(tags); }

   @Override /* Overridden from OpenApiElement */
   public Set<String> keySet() {
      // @formatter:off
      var s = setb(String.class)
         .addIf(nn(components), "components")
         .addIf(nn(externalDocs), "externalDocs")
         .addIf(nn(info), "info")
         .addIf(nn(openapi), "openapi")
         .addIf(nn(paths), "paths")
         .addIf(ne(security), "security")
         .addIf(ne(servers), "servers")
         .addIf(ne(tags), "tags")
         .build();
      // @formatter:on
      return new MultiSet<>(s, super.keySet());
   }

   @Override /* Overridden from OpenApiElement */
   public OpenApi set(String property, Object value) {
      assertArgNotNull("property", property);
      return switch (property) {
         case "components" -> setComponents(toType(value, Components.class));
         case "externalDocs" -> setExternalDocs(toType(value, ExternalDocumentation.class));
         case "info" -> setInfo(toType(value, Info.class));
         case "openapi" -> setOpenapi(s(value));
         case "paths" -> setPaths(toMapBuilder(value, String.class, PathItem.class).sparse().build());
         case "security" -> setSecurity(listb(SecurityRequirement.class).addAny(value).sparse().build());
         case "servers" -> setServers(listb(Server.class).addAny(value).sparse().build());
         case "tags" -> setTags(listb(Tag.class).addAny(value).sparse().build());
         default -> {
            super.set(property, value);
            yield this;
         }
      };
   }

   /**
    * Sets the components object.
    *
    * @param value The new value for this property.
    * @return This object.
    */
   public OpenApi setComponents(Components value) {
      components = value;
      return this;
   }

   /**
    * Sets the external documentation.
    *
    * @param value The new value for this property.
    * @return This object.
    */
   public OpenApi setExternalDocs(ExternalDocumentation value) {
      externalDocs = value;
      return this;
   }

   /**
    * Sets the info object.
    *
    * @param value The new value for this property.
    * @return This object.
    */
   public OpenApi setInfo(Info value) {
      info = value;
      return this;
   }

   /**
    * Sets the OpenAPI version.
    *
    * @param value The new value for this property.
    * @return This object.
    */
   public OpenApi setOpenapi(String value) {
      openapi = value;
      return this;
   }

   /**
    * Sets the paths map.
    *
    * @param value The new value for this property.
    * @return This object.
    */
   public OpenApi setPaths(Map<String,PathItem> value) {
      this.paths = toMapBuilder(value, String.class, PathItem.class).sparse().sorted(PATH_COMPARATOR).build();
      return this;
   }

   /**
    * Sets the security requirements list.
    *
    * @param value The new value for this property.
    * @return This object.
    */
   public OpenApi setSecurity(List<SecurityRequirement> value) {
      security.clear();
      if (nn(value))
         security.addAll(value);
      return this;
   }

   /**
    * Sets the servers list.
    *
    * @param value The new value for this property.
    * @return This object.
    */
   public OpenApi setServers(List<Server> value) {
      servers.clear();
      if (nn(value))
         servers.addAll(value);
      return this;
   }

   /**
    * Sets the tags list.
    *
    * @param value The new value for this property.
    * @return This object.
    */
   public OpenApi setTags(List<Tag> value) {
      tags.clear();
      if (nn(value))
         tags.addAll(value);
      return this;
   }

   /**
    * Bean property setter:  <property>tags</property>.
    *
    * <p>
    * A list of tags used by the specification with additional metadata.
    *
    * @param value
    *    The new value for this property.
    *    <br>Ignored if <jk>null</jk>.
    * @return This object.
    */
   public OpenApi setTags(Tag...value) {
      setTags(listb(Tag.class).add(value).sparse().build());
      return this;
   }

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

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

   @Override
   public String toString() {
      return JsonSerializer.DEFAULT.toString(this);
   }
}