/*
    * 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.util.Set;
  import java.net.InetAddress;
  
  import javax.servlet.ServletContext;
  import javax.servlet.http.HttpServletRequest;
  import javax.ws.rs.Consumes;
  import javax.ws.rs.GET;
  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 javax.ws.rs.core.Response.Status;
  
  import org.apache.hadoop.chukwa.datastore.ChukwaHBaseStore;
  import org.apache.hadoop.chukwa.hicc.bean.Dashboard;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.hbase.HBaseConfiguration;
  import org.apache.hadoop.hbase.HConstants;
  import org.apache.hadoop.hdfs.DFSConfigKeys;
  import org.apache.hadoop.yarn.conf.YarnConfiguration;
  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;
  
  @Path("dashboard")
  public class DashboardController {
    static Logger LOG = Logger.getLogger(DashboardController.class);
  
    @Context
    private ServletContext context;
    @Context
    VelocityEngine velocity;
  
    /**
     * Load a dashboard view
     * 
     * @param request HTTP request object
     * @param id is dashboard unique identifier
     * @return Dashboard view in JSON structure
     * 
     * @response.representation.200.doc Display dashboard JSON structure
     * @response.representation.200.mediaType application/json
     * @response.representation.200.example {@link Examples#SYSTEM_DASHBOARD}
     */
    @GET
    @Produces(MediaType.APPLICATION_JSON)
    @Path("load/{id}")
    public String load(@Context HttpServletRequest request, @PathParam("id") String id) {
      Gson gson = new Gson();
      Dashboard dash = ChukwaHBaseStore.getDashboard(id, request.getRemoteUser());
      String json = gson.toJson(dash);
      return json;
    }
    
    /**
     * Save a dashboard view
     * 
     * @param request HTTP request object
     * @param id is dashboard unique identifier
     * @param buffer is JSON structure of dashboard view
     * @return Status of the dashboard save
     * 
     * @request.representation.example {@link Examples#USER_DASHBOARD}
     * @response.representation.200.doc Display save status code
     * @response.representation.200.mediaType text/plain
     */
    @PUT
    @Path("save/{id}")
    @Consumes(MediaType.APPLICATION_JSON)
    public Response save(@Context HttpServletRequest request, @PathParam("id") String id, String buffer) {
      Gson gson = new Gson();
      Dashboard dash = gson.fromJson(buffer, Dashboard.class);
      boolean result = ChukwaHBaseStore.updateDashboard(id, request.getRemoteUser(), dash);
     if(!result) {
       return Response.status(Status.BAD_REQUEST).build();
     }
     return Response.ok().build();
   }
   
   /**
    * Return HTTP request connection user name
    * 
    * @param request HTTP request object
    * @return username
    * 
    * @response.representation.200.doc Username
    * @response.representation.200.mediaType text/plain
    * @response.representation.200.example admin
    */
   @GET
   @Path("whoami")
   @Produces(MediaType.TEXT_PLAIN)
   public String whoami(@Context HttpServletRequest request) {
     return request.getRemoteUser();
   }
   
   /**
    * Render Quick links to various services web portals
    * 
    * @return HTML page of quick links
    * 
    * @response.representation.200.doc Display quick link widget
    * @response.representation.200.mediaType text/html
    * @response.representation.200.example Example is availabe on HICC UI
    */
   @GET
   @Path("quicklinks")
   @Produces(MediaType.TEXT_HTML)
   public String quicklinks() {
     VelocityContext context = new VelocityContext();
     StringWriter sw = null;
     Configuration hconf = HBaseConfiguration.create();
     Configuration hadoop = new Configuration();
     String nn = "";
     String rm = "";
     String hm = "";
     Set<String> sourceNames = ChukwaHBaseStore.getSourceNames("");
     for (String source : sourceNames) {
       String[] sourceParts = source.split(":");
       if(sourceParts.length<2) {
         continue;
       }
       if(sourceParts[1].equals("NameNode")) {
         String[] parts = hadoop.get(DFSConfigKeys.DFS_NAMENODE_HTTP_ADDRESS_KEY).split(":");
         StringBuilder buffer = new StringBuilder();
         try {
           InetAddress address = InetAddress.getByName(sourceParts[0]);
           buffer.append(address.getHostAddress());
         } catch (Exception e) {
           buffer.append(sourceParts[0]);
         } 
         buffer.append(":");
         buffer.append(parts[1]);
         nn = buffer.toString();
       } else if(sourceParts[1].equals("ResourceManager")) {
         String[] parts = hadoop.get(YarnConfiguration.RM_WEBAPP_ADDRESS).split(":");
         StringBuilder buffer = new StringBuilder();
         try {
           InetAddress address = InetAddress.getByName(sourceParts[0]);
           buffer.append(address.getHostAddress());
         } catch (Exception e) {
           buffer.append(sourceParts[0]);
         } 
         buffer.append(":");
         buffer.append(parts[1]);
         rm = buffer.toString();
       } else if(sourceParts[1].equals("Master")) {
         StringBuilder buffer = new StringBuilder();
         try {
           InetAddress address = InetAddress.getByName(sourceParts[0]);
           buffer.append(address.getHostAddress());
         } catch (Exception e) {
           buffer.append(sourceParts[0]);
         } 
         buffer.append(":");
         buffer.append(hconf.getInt("hbase.master.info.port", HConstants.DEFAULT_MASTER_INFOPORT));
         hm = buffer.toString();
       }
     }
     try {
       context.put("nn", nn);
       context.put("rm", rm);
       context.put("hm", hm);
       Template template = velocity.getTemplate("quick-links.vm");
       sw = new StringWriter();
       template.merge(context, sw);
     } catch (Exception e) {
       e.printStackTrace();
       return e.getMessage();
     }
     return sw.toString();
   }
 }