// ***************************************************************************************************************************
// * 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;

import java.text.*;
import java.util.logging.*;

import javax.servlet.http.*;

import org.apache.juneau.dto.swagger.*;
import org.apache.juneau.html.annotation.*;
import org.apache.juneau.internal.*;
import org.apache.juneau.rest.annotation.*;
import org.apache.juneau.http.exception.*;

/**
 * Identical to {@link BasicRestServlet} but doesn't extend from {@link HttpServlet}.
 *
 * <ul class='seealso'>
 *    <li class='link'>{@doc juneau-rest-server.Instantiation.BasicRest}
 * </ul>
 */
@Rest(
   // Allow OPTIONS requests to be simulated using ?method=OPTIONS query parameter.
   allowedMethodParams="OPTIONS"
)
@HtmlDocConfig(
   // Basic page navigation links.
   navlinks={
      "up: request:/..",
      "options: servlet:/?method=OPTIONS",
      "stats: servlet:/stats"
   }
)
public abstract class BasicRest implements BasicRestConfig {

   private JuneauLogger logger = JuneauLogger.getLogger(getClass());
   private volatile RestContext context;

   /**
    * Post-initialization hook to retrieve the {@link RestContext} object for this resource.
    *
    * @param context The context for this resource.
    */
   @RestHook(HookEvent.POST_INIT)
   public synchronized void onPostInit(RestContext context) {
      this.context = context;
   }

   /**
    * [OPTIONS /*] - Show resource options.
    *
    * @param req The HTTP request.
    * @return A bean containing the contents for the OPTIONS page.
    */
   @Override /* BasicRestConfig */
   public Swagger getOptions(RestRequest req) {
      // Localized Swagger for this resource is available through the RestRequest object.
      return req.getSwagger();
   }

   /**
    * [* /error] - Error occurred.
    *
    * <p>
    * Servlet chains will often automatically redirect to <js>"/error"</js> when any sort of error condition occurs
    * (such as failed authentication) and will set appropriate response parameters (such as an <c>WWW-Authenticate</c>
    * response header).
    *
    * <p>
    * These responses should be left as-is without any additional processing.
    */
   @Override /* BasicRestConfig */
   public void error() {}

   /**
    * [GET /stats] - Timing statistics.
    *
    * <p>
    * Timing statistics for method invocations on this resource.
    *
    * @return A collection of timing statistics for each annotated method on this resource.
    */
   @Override /* BasicRestConfig */
   public RestContextStats getStats(RestRequest req) {
      return req.getContext().getStats();
   }

   //-----------------------------------------------------------------------------------------------------------------
   // Context methods.
   //-----------------------------------------------------------------------------------------------------------------

   /**
    * Returns the read-only context object that contains all the configuration information about this resource.
    *
    * @return The context information on this servlet.
    */
   protected synchronized RestContext getContext() {
      if (context == null)
         throw new InternalServerError("RestContext object not set on resource.");
      return context;
   }

   //-----------------------------------------------------------------------------------------------------------------
   // Convenience logger methods
   //-----------------------------------------------------------------------------------------------------------------

   /**
    * Log a message.
    *
    * @param msg The message to log.
    */
   public void log(String msg) {
      logger.info(msg);
   }

   /**
    * Log a message.
    *
    * @param msg The message to log.
    * @param cause The cause.
    */
   public void log(String msg, Throwable cause) {
      logger.info(cause, msg);
   }

   /**
    * Log a message.
    *
    * @param level The log level.
    * @param msg The message to log.
    * @param args Optional {@link MessageFormat}-style arguments.
    */
   public void log(Level level, String msg, Object...args) {
      logger.log(level, msg, args);
   }

   /**
    * Log a message.
    *
    * @param level The log level.
    * @param msg The message to log.
    * @param args Optional {@link MessageFormat}-style arguments.
    */
   public void logObjects(Level level, String msg, Object...args) {
      logger.logObjects(level, msg, args);
   }

   /**
    * Log a message.
    *
    * @param level The log level.
    * @param cause The cause.
    * @param msg The message to log.
    * @param args Optional {@link MessageFormat}-style arguments.
    */
   public void log(Level level, Throwable cause, String msg, Object...args) {
      logger.log(level, cause, msg, args);
   }

   //-----------------------------------------------------------------------------------------------------------------
   // Request-time methods.
   //-----------------------------------------------------------------------------------------------------------------

   /**
    * Returns the current HTTP request.
    *
    * @return The current HTTP request.
    */
   public synchronized RestRequest getRequest() {
      return getContext().getRequest();
   }

   /**
    * Returns the current HTTP response.
    *
    * @return The current HTTP response
    */
   public synchronized RestResponse getResponse() {
      return getContext().getResponse();
   }
}