/*
    * 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.hadoop.chukwa.hicc.rest;
  
  import java.util.List;
  
  import javax.annotation.PostConstruct;
  import javax.inject.Singleton;
  import javax.servlet.ServletContext;
  import javax.ws.rs.Consumes;
  import javax.ws.rs.DELETE;
  import javax.ws.rs.DefaultValue;
  import javax.ws.rs.GET;
  import javax.ws.rs.POST;
  import javax.ws.rs.PUT;
  import javax.ws.rs.Path;
  import javax.ws.rs.PathParam;
  import javax.ws.rs.Produces;
  import javax.ws.rs.QueryParam;
  import javax.ws.rs.core.Context;
  import javax.ws.rs.core.MediaType;
  import javax.ws.rs.core.Response;
  import javax.ws.rs.core.Response.Status;
  
  import org.apache.hadoop.chukwa.datastore.ChukwaHBaseStore;
  import org.apache.hadoop.chukwa.hicc.bean.Widget;
  import org.apache.log4j.Logger;
  
  import com.google.gson.Gson;
  
  @Path("widget")
  public class WidgetController {
  
    static Logger LOG = Logger.getLogger(WidgetController.class);
  
    @Context
    private ServletContext context;
  
    @PostConstruct
    @Singleton
    public void init() {
    }
  
    /**
     * List widgets
     * 
     * @param limit is number of widgets to return
     * @param offset is position in the widget list
     * @return list of widgets in HBase database
     * 
     * @response.representation.200.doc Display list of HICC supported widgets
     * @response.representation.200.mediaType application/json
     * @response.representation.200.example {@link Examples#WIDGET_LIST}
     */
    @GET
    @Path("list")
    @Produces(MediaType.APPLICATION_JSON)
    public String listWidget(@DefaultValue("1000") @QueryParam("limit") int limit, 
        @DefaultValue("0") @QueryParam("offset") int offset) {
      List<Widget> widgets = ChukwaHBaseStore.listWidget(limit, offset);
      Gson gson = new Gson();
      String json = gson.toJson(widgets);
      return json;
    }
  
    /**
     * Search for widget base on widget title
     * @param query is search critieria
     * @return list of widgets matched search critieria
     * 
     * @response.representation.200.doc Display list of HICC widget that matches query
     * @response.representation.200.mediaType application/json
     * @response.representation.200.example {@link Examples#WIDGET_LIST}
     */
    @GET
    @Path("search/{query}")
    public String searchWidget(@PathParam("query") String query) {
      List<Widget> widgets = ChukwaHBaseStore.searchWidget(query);
      Gson gson = new Gson();
      String json = gson.toJson(widgets);
      return json;
    }
  
    /**
    * View widget details
    * @param title is title of the widget
    * @return widget configuration
    * 
    * @response.representation.200.doc View widget details
    * @response.representation.200.mediaType application/json
    * @response.representation.200.example {@link Examples#SYSTEM_LOAD_AVERAGE_WIDGET}
    */
   @GET
   @Path("view/{title}")
   public String viewWidget(@PathParam("title") String title) {
     Widget w = ChukwaHBaseStore.viewWidget(title);
     Gson gson = new Gson();
     String json = gson.toJson(w);
     return json;
   }
 
   /**
    * Create a widget
    * @param buffer is widget configuration
    * @return Creation status code
    * 
    * @request.representation.example {@link Examples#WELCOME_PAGE_WIDGET}
    * @response.representation.200.doc Widget creation successful
    * @response.representation.200.mediaType text/plain
    * @response.representation.200.example 200 OK
    * @response.representation.400.doc Widget creation unsuccessful
    * @response.representation.400.mediaType text/plain
    * @response.representation.400.example 400 Bad Request
    */
   @POST
   @Path("create")
   @Consumes(MediaType.APPLICATION_JSON)
   public Response createWidget(String buffer) {
     Gson gson = new Gson();
     Widget widget = gson.fromJson(buffer, Widget.class);
     boolean result = ChukwaHBaseStore.createWidget(widget);
     if(!result) {
       return Response.status(Status.BAD_REQUEST).build();
     }
     return Response.ok().build();
   }
 
   /**
    * Update a widget
    * @param title is widget title
    * @param buffer is widget object in JSON
    * @return Update status code
    * 
    * @request.representation.example {@link Examples#WELCOME_PAGE_WIDGET}
    * @response.representation.200.doc Widget update is successful
    * @response.representation.200.mediaType text/plain
    * @response.representation.200.example 200 OK
    * @response.representation.400.doc Widget update unsuccessful
    * @response.representation.400.mediaType text/plain
    * @response.representation.400.example 400 Bad Request
    */
   @PUT
   @Path("update/{title}")
   @Consumes(MediaType.APPLICATION_JSON)
   public Response updateWidget(@PathParam("title") String title, String buffer){
     Gson gson = new Gson();
     Widget widget = gson.fromJson(buffer, Widget.class);
     boolean result = ChukwaHBaseStore.updateWidget(title, widget);
     if(!result) {
       return Response.status(Status.BAD_REQUEST).build();
     }
     return Response.ok().build();
   }
 
   /**
    * Delete a widget
    * @param title is widget title
    * @return Widget delete status code
    * 
    * @response.representation.200.doc Widget deletion successful
    * @response.representation.200.mediaType text/plain
    * @response.representation.200.example 200 OK
    * @response.representation.400.doc Widget deletion unsuccessful
    * @response.representation.400.mediaType text/plain
    * @response.representation.400.example 400 Bad Request
    */
   @DELETE
   @Path("delete/{title}")
   public Response deleteWidget(@PathParam("title") String title) {
     boolean result = ChukwaHBaseStore.deleteWidget(title);
     if(!result) {
       return Response.status(Status.BAD_REQUEST).build();
     }
     return Response.ok().build();
   }
 }