/*
    * 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.io.StringWriter;
  import java.lang.reflect.Type;
  import java.text.SimpleDateFormat;
  import java.util.ArrayList;
  import java.util.List;
  
  import javax.servlet.http.HttpServletRequest;
  import javax.ws.rs.Consumes;
  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.core.Context;
  import javax.ws.rs.core.MediaType;
  import javax.ws.rs.core.Response;
  
  import org.apache.hadoop.chukwa.datastore.ChukwaHBaseStore;
  import org.apache.hadoop.chukwa.hicc.TimeHandler;
  import org.apache.hadoop.chukwa.hicc.bean.Chart;
  import org.apache.hadoop.chukwa.hicc.bean.SeriesMetaData;
  import org.apache.log4j.Logger;
  import org.apache.velocity.Template;
  import org.apache.velocity.VelocityContext;
  import org.apache.velocity.app.VelocityEngine;
  
  import com.google.gson.Gson;
  import com.google.gson.reflect.TypeToken;
  import com.sun.jersey.api.Responses;
  
  @Path("/chart")
  public class ChartController {
    static Logger LOG = Logger.getLogger(ChartController.class);
    SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMddHHmmss");
  
    @Context
    VelocityEngine velocity;
    
    /**
     * Render chart using flot.js
     * 
     * @param id Reference ID of Chart stored in HBase chukwa_meta table.
     * @return chart widget
     * 
     */
    @GET
    @Path("draw/{id}")
    @Produces(MediaType.TEXT_HTML)
    public String draw(@PathParam("id") String id) {
      VelocityContext context = new VelocityContext();
      StringWriter sw = null;
      try {
        Chart chart = ChukwaHBaseStore.getChart(id);
        List<SeriesMetaData> series = chart.getSeries();
        Gson gson = new Gson();
        String seriesMetaData = gson.toJson(series);
  
        context.put("chart", chart);
        context.put("seriesMetaData", seriesMetaData);
        Template template = velocity.getTemplate("chart.vm");
        sw = new StringWriter();
        template.merge(context, sw);
      } catch (Exception e) {
        e.printStackTrace();
        return e.getMessage();
      }
      return sw.toString();
    }
  
    /**
     * Describe chart meta data
     * 
     * @param id Chart ID
     * @return chart meta data
     * 
     * @response.representation.200.doc Display chart configuration options
     * @response.representation.200.mediaType application/json
     * @response.representation.200.example {@link Examples#CPU_UTILIZATION}
     * 
    */
   @GET
   @Path("describe/{id}")
   @Produces(MediaType.APPLICATION_JSON)
   public String describe(@PathParam("id") String id) {
     Chart chart = ChukwaHBaseStore.getChart(id);
     Gson gson = new Gson();
     String buffer = gson.toJson(chart);
     return buffer;
   }
 
   /**
    * Create a new chart meta data
    * 
    * @param buffer holds incoming JSON of Chart object
    * @return Web response code
    * 
    * @request.representation.example {@link Examples#MEMORY_UTILIZATION}
    * 
    */
   @POST
   @Path("save")
   @Consumes(MediaType.APPLICATION_JSON)
   public Response create(String buffer) {
     Gson gson = new Gson();
     Chart chart = gson.fromJson(buffer, Chart.class);
     String id = ChukwaHBaseStore.createChart(chart);
     if (id != null) {
       return Response.ok(id).build();
     }
     return Responses.notAcceptable().build();
   }
 
   /**
    * Save chart meta data
    * 
    * @param id is unique identifier of Chart object
    * @param buffer holds incoming JSON of Chart object
    * @return Web response code
    * 
    * @request.representation.example {@link Examples#DISK_UTILIZATION}
    * 
    */
   @PUT
   @Path("save/{id}")
   @Consumes(MediaType.APPLICATION_JSON)
   public Response save(@PathParam("id") String id, String buffer) {
     Gson gson = new Gson();
     Chart chart = gson.fromJson(buffer, Chart.class);
     ChukwaHBaseStore.putChart(id, chart);
     return Response.ok().build();
     
   }
 
   /**
    * Display a chart base on chart configuration from REST API input
    * 
    * @param buffer holds incoming JSON of Chart object
    * @return segment of chart HTML output
    * 
    * @request.representation.example {@link Examples#NETWORK_UTILIZATION}
    *
    */
   @PUT
   @Path("preview")
   @Consumes(MediaType.APPLICATION_JSON)
   @Produces(MediaType.TEXT_HTML)
   public String preview(String buffer) {
     VelocityContext context = new VelocityContext();
     StringWriter sw = null;
     try {
       Gson gson = new Gson();
       Chart chart = gson.fromJson(buffer, Chart.class);
       List<SeriesMetaData> series = chart.getSeries();
       String seriesMetaData = gson.toJson(series);
 
       context.put("chart", chart);
       context.put("seriesMetaData", seriesMetaData);
       Template template = velocity.getTemplate("chart.vm");
       sw = new StringWriter();
       template.merge(context, sw);
     } catch (Exception e) {
       e.printStackTrace();
       return e.getMessage();
     }
     return sw.toString();
   }
 
   /**
    * Display metrics series in JSON
    * 
    * @param request HTTP request object
    * @param buffer list of SeriesMetaData
    * @return metrics JSON
    * 
    * @request.representation.example {@link Examples#CPU_SERIES_METADATA}
    * @response.representation.200.doc Display series data in JSON
    * @response.representation.200.mediaType application/json
    * 
    */
   @PUT
   @Path("preview/series")
   @Consumes(MediaType.APPLICATION_JSON)
   @Produces("application/json")
   public String previewSeries(@Context HttpServletRequest request, String buffer) {
     Type listType = new TypeToken<ArrayList<SeriesMetaData>>() {
     }.getType();
     long startTime = 0;
     long endTime = 0;
     TimeHandler time = new TimeHandler(request);
     startTime = time.getStartTime();
     endTime = time.getEndTime();
     Gson gson = new Gson();
     ArrayList<SeriesMetaData> series = gson.fromJson(buffer, listType);
     series = ChukwaHBaseStore.getChartSeries(series, startTime, endTime);
     String result = gson.toJson(series);
     return result;
   }
 
 }