/*
    * 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.lang.reflect.Type;
  import java.text.ParseException;
  import java.text.SimpleDateFormat;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Set;
  
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpSession;
  import javax.ws.rs.GET;
  import javax.ws.rs.Path;
  import javax.ws.rs.PathParam;
  import javax.ws.rs.QueryParam;
  import javax.ws.rs.Produces;
  import javax.ws.rs.WebApplicationException;
  import javax.ws.rs.core.Context;
  import javax.ws.rs.core.Response;
  
  import org.apache.hadoop.chukwa.datacollection.agent.rest.Examples;
  import org.apache.hadoop.chukwa.datastore.ChukwaHBaseStore;
  import org.apache.hadoop.chukwa.hicc.TimeHandler;
  import org.apache.hadoop.chukwa.hicc.bean.Series;
  
  import com.google.gson.Gson;
  import com.google.gson.reflect.TypeToken;
  
  @Path("/metrics")
  public class MetricsController {
  
    /**
     * Query metrics stored in HBase table
     * 
     * @param request is HTTP request object
     * @param metric is metric name
     * @param source is data source
     * @param start is start time
     * @param end is end time
     * @return Metrics JSON
     * 
     */
    @GET
    @Path("series/{metric}/{source}")
    @Produces("application/json")
    public String getSeries(@Context HttpServletRequest request, @PathParam("metric") String metric, @PathParam("source") String source, @QueryParam("start") String start, @QueryParam("end") String end) {
      SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMddHHmmss");
      String buffer = "";
      Series series;
      long startTime = 0;
      long endTime = 0;
      TimeHandler time = new TimeHandler(request);
      try {
        if(start!=null) {
          startTime = sdf.parse(start).getTime();
        } else {
          startTime = time.getStartTime();
        }
        if(end!=null) {
          endTime = sdf.parse(end).getTime();
        } else {
          endTime = time.getEndTime();
        }
        series = ChukwaHBaseStore.getSeries(metric, source, startTime, endTime);
        buffer = series.toString();
      } catch (ParseException e) {
        throw new WebApplicationException(Response.status(Response.Status.BAD_REQUEST)
            .entity("Start/End date parse error.  Format: yyyyMMddHHmmss.").build());
      }
      return buffer;
    }
  
    /**
     * Query metric series by session key, this is useful to query same metric from
     * multiple data sources, such as multiple hosts
     * 
     * @param request is HTTP request object
     * @param metricGroup is metric group name
     * @param metric is metric name
     * @param skey is session key which maps to multiple data sources
     * @param start is start time
     * @param end is end time
    * @return List of metric series
    */
   @GET
   @Path("series/{metricGroup}/{metric}/session/{sessionKey}")
   @Produces("application/json")
   public String getSeriesBySessionAttribute(@Context HttpServletRequest request, @PathParam("metricGroup") String metricGroup, @PathParam("metric") String metric, @PathParam("sessionKey") String skey, @QueryParam("start") String start, @QueryParam("end") String end) {
     SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMddHHmmss");
     String buffer = "";
     long startTime = 0;
     long endTime = 0;
     TimeHandler time = new TimeHandler(request);
     try {
       if(start!=null) {
         startTime = sdf.parse(start).getTime();
       } else {
         startTime = time.getStartTime();
       }
       if(end!=null) {
         endTime = sdf.parse(end).getTime();
       } else {
         endTime = time.getEndTime();
       }
       if(skey!=null) {
           HttpSession session = request.getSession();
           String[] sourcekeys = (session.getAttribute(skey).toString()).split(",");
           Type seriesListType =new TypeToken<ArrayList<Series>>(){}.getType();
           ArrayList<Series> seriesList = new ArrayList<Series>();
           for(String source : sourcekeys) {
             if (source == null || source.equals("")) {
               continue;
             }
             Series output = ChukwaHBaseStore.getSeries(metricGroup, metric, source, startTime, endTime);
             seriesList.add(output);
           }
           buffer = new Gson().toJson(seriesList, seriesListType);
       } else {
         throw new WebApplicationException(Response.status(Response.Status.BAD_REQUEST)
             .entity("No session attribute key defined.").build());
       }
     } catch (ParseException e) {
       throw new WebApplicationException(Response.status(Response.Status.BAD_REQUEST)
           .entity("Start/End date parse error.  Format: yyyyMMddHHmmss.").build());
     }
     return buffer;
   }
 
   /**
    * Query all metric group names in HBase
    * 
    * @return a list of metric groups
    */
   @GET
   @Path("schema")
   @Produces("application/json")
   public String getTables() {
     Set<String> metricGroups = ChukwaHBaseStore.getMetricGroups();
     Type metricGroupsType = new TypeToken<List<String>>(){}.getType();
     String groups = new Gson().toJson(metricGroups, metricGroupsType);
     return groups;
   }
   
   /**
    * Query metric names by metric group
    * 
    * @param metricGroup is name of metric group
    * @return a list of metric names
    * 
    */
   @GET
   @Path("schema/{metricGroup}")
   @Produces("application/json")
   public String getMetrics(@PathParam("metricGroup") String metricGroup) {
     Set<String> metricNames = ChukwaHBaseStore.getMetricNames(metricGroup);
     Type metricsType = new TypeToken<List<String>>(){}.getType();
     String metrics = new Gson().toJson(metricNames, metricsType);
     return metrics;
   }
 
   /**
    * Query metrics source names by metric group
    * 
    * @param request HTTP Request object
    * @param metricGroup is name of metric group
    * @return a list of metric source names
    * 
    */
   @GET
   @Path("source/{metricGroup}")
   @Produces("application/json")
   public String getSourceNames(@Context HttpServletRequest request, @PathParam("metricGroup") String metricGroup) {
     Set<String> sourceNames = ChukwaHBaseStore.getSourceNames(metricGroup);
     Type rowsType = new TypeToken<List<String>>(){}.getType();
     String rows = new Gson().toJson(sourceNames, rowsType);
     return rows;
   }
 
 }