/*
    *
    * 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.hbase.rest;
  
  import com.fasterxml.jackson.annotation.JsonIgnore;
  import com.fasterxml.jackson.annotation.JsonProperty;
  
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.Iterator;
  import java.util.List;
  
  import javax.ws.rs.GET;
  import javax.ws.rs.HeaderParam;
  import javax.ws.rs.Produces;
  import javax.ws.rs.core.Context;
  import javax.ws.rs.core.Response;
  import javax.ws.rs.core.Response.ResponseBuilder;
  import javax.ws.rs.core.UriInfo;
  import javax.xml.bind.annotation.XmlAccessType;
  import javax.xml.bind.annotation.XmlAccessorType;
  import javax.xml.bind.annotation.XmlElement;
  import javax.xml.bind.annotation.XmlRootElement;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.Cell;
  import org.apache.hadoop.hbase.CellUtil;
  import org.apache.hadoop.hbase.client.Result;
  import org.apache.hadoop.hbase.client.ResultScanner;
  import org.apache.hadoop.hbase.rest.model.CellModel;
  import org.apache.hadoop.hbase.rest.model.RowModel;
  
  @InterfaceAudience.Private
  public class TableScanResource  extends ResourceBase {
  
    private static final Log LOG = LogFactory.getLog(TableScanResource.class);
    TableResource tableResource;
    ResultScanner results;
    int userRequestedLimit;
  
    public TableScanResource(ResultScanner scanner, int userRequestedLimit) throws IOException {
      super();
      this.results = scanner;
      this.userRequestedLimit = userRequestedLimit;
    }
  
    @GET
    @Produces({ Constants.MIMETYPE_XML, Constants.MIMETYPE_JSON })
    public CellSetModelStream get(final @Context UriInfo uriInfo) {
      if (LOG.isTraceEnabled()) {
        LOG.trace("GET " + uriInfo.getAbsolutePath());
      }
      servlet.getMetrics().incrementRequests(1);
      final int rowsToSend = userRequestedLimit;
      servlet.getMetrics().incrementSucessfulScanRequests(1);
      final Iterator<Result> itr = results.iterator();
      return new CellSetModelStream(new ArrayList<RowModel>() {
        public Iterator<RowModel> iterator() {
          return new Iterator<RowModel>() {
            int count = rowsToSend;
  
            @Override
            public boolean hasNext() {
              if (count > 0) {
                return itr.hasNext();
              } else {
                return false;
              }
            }
  
            @Override
            public void remove() {
              throw new UnsupportedOperationException(
                  "Remove method cannot be used in CellSetModelStream");
            }
  
            @Override
            public RowModel next() {
              Result rs = itr.next();
              if ((rs == null) || (count <= 0)) {
                return null;
             }
             byte[] rowKey = rs.getRow();
             RowModel rModel = new RowModel(rowKey);
             List<Cell> kvs = rs.listCells();
             for (Cell kv : kvs) {
               rModel.addCell(new CellModel(CellUtil.cloneFamily(kv), CellUtil.cloneQualifier(kv),
                   kv.getTimestamp(), CellUtil.cloneValue(kv)));
             }
             count--;
             if (count == 0) {
               results.close();
             }
             return rModel;
           }
         };
       }
     });
   }
 
   @GET
   @Produces({ Constants.MIMETYPE_PROTOBUF, Constants.MIMETYPE_PROTOBUF_IETF })
   public Response getProtobuf(
       final @Context UriInfo uriInfo,
       final @HeaderParam("Accept") String contentType) {
     if (LOG.isTraceEnabled()) {
       LOG.trace("GET " + uriInfo.getAbsolutePath() + " as " +
               MIMETYPE_BINARY);
     }
     servlet.getMetrics().incrementRequests(1);
     try {
       int fetchSize = this.servlet.getConfiguration().getInt(Constants.SCAN_FETCH_SIZE, 10);
       ProtobufStreamingUtil stream = new ProtobufStreamingUtil(this.results, contentType,
           userRequestedLimit, fetchSize);
       servlet.getMetrics().incrementSucessfulScanRequests(1);
       ResponseBuilder response = Response.ok(stream);
       response.header("content-type", contentType);
       return response.build();
     } catch (Exception exp) {
       servlet.getMetrics().incrementFailedScanRequests(1);
       processException(exp);
       LOG.warn(exp);
       return null;
     }
   }
 
   @XmlRootElement(name = "CellSet")
   @XmlAccessorType(XmlAccessType.FIELD)
   public static class CellSetModelStream {
     // JAXB needs an arraylist for streaming
     @XmlElement(name = "Row")
     @JsonIgnore
     private ArrayList<RowModel> Row;
 
     public CellSetModelStream() {
     }
 
     public CellSetModelStream(final ArrayList<RowModel> rowList) {
       this.Row = rowList;
     }
 
     // jackson needs an iterator for streaming
     @JsonProperty("Row")
     public Iterator<RowModel> getIterator() {
       return Row.iterator();
     }
   }
 }