/*
    *
    * 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 java.io.IOException;
  
  import javax.ws.rs.DELETE;
  import javax.ws.rs.GET;
  import javax.ws.rs.Produces;
  import javax.ws.rs.QueryParam;
  import javax.ws.rs.core.CacheControl;
  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 org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.hbase.Cell;
  import org.apache.hadoop.hbase.CellUtil;
  import org.apache.hadoop.hbase.KeyValue;
  import org.apache.hadoop.hbase.TableNotFoundException;
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.rest.model.CellModel;
  import org.apache.hadoop.hbase.rest.model.CellSetModel;
  import org.apache.hadoop.hbase.rest.model.RowModel;
  import org.apache.hadoop.hbase.util.Base64;
  import org.apache.hadoop.hbase.util.Bytes;
  
  @InterfaceAudience.Private
  public class ScannerInstanceResource extends ResourceBase {
    private static final Log LOG =
      LogFactory.getLog(ScannerInstanceResource.class);
  
    static CacheControl cacheControl;
    static {
      cacheControl = new CacheControl();
      cacheControl.setNoCache(true);
      cacheControl.setNoTransform(false);
    }
  
    ResultGenerator generator = null;
    String id = null;
    int batch = 1;
  
    public ScannerInstanceResource() throws IOException { }
  
    public ScannerInstanceResource(String table, String id,
        ResultGenerator generator, int batch) throws IOException {
      this.id = id;
      this.generator = generator;
      this.batch = batch;
    }
  
    @GET
    @Produces({MIMETYPE_XML, MIMETYPE_JSON, MIMETYPE_PROTOBUF,
      MIMETYPE_PROTOBUF_IETF})
    public Response get(final @Context UriInfo uriInfo,
        @QueryParam("n") int maxRows, final @QueryParam("c") int maxValues) {
      if (LOG.isTraceEnabled()) {
        LOG.trace("GET " + uriInfo.getAbsolutePath());
      }
      servlet.getMetrics().incrementRequests(1);
      if (generator == null) {
        servlet.getMetrics().incrementFailedGetRequests(1);
        return Response.status(Response.Status.NOT_FOUND)
          .type(MIMETYPE_TEXT).entity("Not found" + CRLF)
          .build();
      } else {
        // Updated the connection access time for each client next() call
        RESTServlet.getInstance().getConnectionCache().updateConnectionAccessTime();
      }
      CellSetModel model = new CellSetModel();
      RowModel rowModel = null;
      byte[] rowKey = null;
      int limit = batch;
      if (maxValues > 0) {
        limit = maxValues;
      }
      int count = limit;
      do {
        Cell value = null;
       try {
         value = generator.next();
       } catch (IllegalStateException e) {
         if (ScannerResource.delete(id)) {
           servlet.getMetrics().incrementSucessfulDeleteRequests(1);
         } else {
           servlet.getMetrics().incrementFailedDeleteRequests(1);
         }
         servlet.getMetrics().incrementFailedGetRequests(1);
         return Response.status(Response.Status.GONE)
           .type(MIMETYPE_TEXT).entity("Gone" + CRLF)
           .build();
       } catch (IllegalArgumentException e) {
         Throwable t = e.getCause();
         if (t instanceof TableNotFoundException) {
           return Response.status(Response.Status.NOT_FOUND)
               .type(MIMETYPE_TEXT).entity("Not found" + CRLF)
               .build();
         }
         throw e;
       }
       if (value == null) {
         if (LOG.isTraceEnabled()) {
           LOG.trace("generator exhausted");
         }
         // respond with 204 (No Content) if an empty cell set would be
         // returned
         if (count == limit) {
           return Response.noContent().build();
         }
         break;
       }
       if (rowKey == null) {
         rowKey = CellUtil.cloneRow(value);
         rowModel = new RowModel(rowKey);
       }
       if (!Bytes.equals(CellUtil.cloneRow(value), rowKey)) {
         // if maxRows was given as a query param, stop if we would exceed the
         // specified number of rows
         if (maxRows > 0) {
           if (--maxRows == 0) {
             generator.putBack(value);
             break;
           }
         }
         model.addRow(rowModel);
         rowKey = CellUtil.cloneRow(value);
         rowModel = new RowModel(rowKey);
       }
       rowModel.addCell(
         new CellModel(CellUtil.cloneFamily(value), CellUtil.cloneQualifier(value),
           value.getTimestamp(), CellUtil.cloneValue(value)));
     } while (--count > 0);
     model.addRow(rowModel);
     ResponseBuilder response = Response.ok(model);
     response.cacheControl(cacheControl);
     servlet.getMetrics().incrementSucessfulGetRequests(1);
     return response.build();
   }
 
   @GET
   @Produces(MIMETYPE_BINARY)
   public Response getBinary(final @Context UriInfo uriInfo) {
     if (LOG.isTraceEnabled()) {
       LOG.trace("GET " + uriInfo.getAbsolutePath() + " as " +
         MIMETYPE_BINARY);
     }
     servlet.getMetrics().incrementRequests(1);
     try {
       Cell value = generator.next();
       if (value == null) {
         if (LOG.isTraceEnabled()) {
           LOG.trace("generator exhausted");
         }
         return Response.noContent().build();
       }
       ResponseBuilder response = Response.ok(CellUtil.cloneValue(value));
       response.cacheControl(cacheControl);
       response.header("X-Row", Base64.encodeBytes(CellUtil.cloneRow(value)));
       response.header("X-Column",
         Base64.encodeBytes(
           KeyValue.makeColumn(CellUtil.cloneFamily(value), CellUtil.cloneQualifier(value))));
       response.header("X-Timestamp", value.getTimestamp());
       servlet.getMetrics().incrementSucessfulGetRequests(1);
       return response.build();
     } catch (IllegalStateException e) {
       if (ScannerResource.delete(id)) {
         servlet.getMetrics().incrementSucessfulDeleteRequests(1);
       } else {
         servlet.getMetrics().incrementFailedDeleteRequests(1);
       }
       servlet.getMetrics().incrementFailedGetRequests(1);
       return Response.status(Response.Status.GONE)
         .type(MIMETYPE_TEXT).entity("Gone" + CRLF)
         .build();
     }
   }
 
   @DELETE
   public Response delete(final @Context UriInfo uriInfo) {
     if (LOG.isTraceEnabled()) {
       LOG.trace("DELETE " + uriInfo.getAbsolutePath());
     }
     servlet.getMetrics().incrementRequests(1);
     if (servlet.isReadOnly()) {
       return Response.status(Response.Status.FORBIDDEN)
         .type(MIMETYPE_TEXT).entity("Forbidden" + CRLF)
         .build();
     }
     if (ScannerResource.delete(id)) {
       servlet.getMetrics().incrementSucessfulDeleteRequests(1);
     } else {
       servlet.getMetrics().incrementFailedDeleteRequests(1);
     }
     return Response.ok().build();
   }
 }