/**
    * 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.protobuf;
  
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.List;
  
  import edu.umd.cs.findbugs.annotations.Nullable;
  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.CellScanner;
  import org.apache.hadoop.hbase.DoNotRetryIOException;
  import org.apache.hadoop.hbase.HRegionInfo;
  import org.apache.hadoop.hbase.ServerName;
  import org.apache.hadoop.hbase.client.Result;
  import org.apache.hadoop.hbase.ipc.ServerRpcController;
  import org.apache.hadoop.hbase.protobuf.generated.AccessControlProtos.GetUserPermissionsResponse;
  import org.apache.hadoop.hbase.protobuf.generated.AdminProtos.CloseRegionResponse;
  import org.apache.hadoop.hbase.protobuf.generated.AdminProtos.GetOnlineRegionResponse;
  import org.apache.hadoop.hbase.protobuf.generated.AdminProtos.GetServerInfoResponse;
  import org.apache.hadoop.hbase.protobuf.generated.AdminProtos.OpenRegionResponse;
  import org.apache.hadoop.hbase.protobuf.generated.AdminProtos.ServerInfo;
  import org.apache.hadoop.hbase.protobuf.generated.ClientProtos;
  import org.apache.hadoop.hbase.protobuf.generated.ClientProtos.MultiRequest;
  import org.apache.hadoop.hbase.protobuf.generated.ClientProtos.RegionAction;
  import org.apache.hadoop.hbase.protobuf.generated.ClientProtos.RegionActionResult;
  import org.apache.hadoop.hbase.protobuf.generated.ClientProtos.ResultOrException;
  import org.apache.hadoop.hbase.protobuf.generated.ClientProtos.ScanResponse;
  import org.apache.hadoop.hbase.protobuf.generated.ClientProtos.MultiResponse;
  import org.apache.hadoop.hbase.protobuf.generated.ClusterStatusProtos.RegionStoreSequenceIds;
  import org.apache.hadoop.hbase.protobuf.generated.HBaseProtos;
  import org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.NameBytesPair;
  import org.apache.hadoop.hbase.protobuf.generated.MasterProtos.EnableCatalogJanitorResponse;
  import org.apache.hadoop.hbase.protobuf.generated.MasterProtos.RunCatalogScanResponse;
  import org.apache.hadoop.hbase.protobuf.generated.RegionServerStatusProtos.GetLastFlushedSequenceIdResponse;
  import org.apache.hadoop.hbase.regionserver.RegionOpeningState;
  import org.apache.hadoop.hbase.security.access.UserPermission;
  import org.apache.hadoop.util.StringUtils;
  
  import com.google.protobuf.ByteString;
  import com.google.protobuf.RpcController;
  
  /**
   * Helper utility to build protocol buffer responses,
   * or retrieve data from protocol buffer responses.
   */
  @InterfaceAudience.Private
  public final class ResponseConverter {
    public static final Log LOG = LogFactory.getLog(ResponseConverter.class);
  
    private ResponseConverter() {
    }
  
  // Start utilities for Client
  
    /**
     * Get the results from a protocol buffer MultiResponse
     *
     * @param request the protocol buffer MultiResponse to convert
     * @param cells Cells to go with the passed in <code>proto</code>.  Can be null.
     * @return the results that were in the MultiResponse (a Result or an Exception).
     * @throws IOException
     */
    public static org.apache.hadoop.hbase.client.MultiResponse getResults(final MultiRequest request,
        final MultiResponse response, final CellScanner cells)
    throws IOException {
      int requestRegionActionCount = request.getRegionActionCount();
      int responseRegionActionResultCount = response.getRegionActionResultCount();
      if (requestRegionActionCount != responseRegionActionResultCount) {
        throw new IllegalStateException("Request mutation count=" + responseRegionActionResultCount +
            " does not match response mutation result count=" + responseRegionActionResultCount);
      }
  
      org.apache.hadoop.hbase.client.MultiResponse results =
        new org.apache.hadoop.hbase.client.MultiResponse();
  
      for (int i = 0; i < responseRegionActionResultCount; i++) {
        RegionAction actions = request.getRegionAction(i);
        RegionActionResult actionResult = response.getRegionActionResult(i);
        HBaseProtos.RegionSpecifier rs = actions.getRegion();
        if (rs.hasType() &&
           (rs.getType() != HBaseProtos.RegionSpecifier.RegionSpecifierType.REGION_NAME)){
         throw new IllegalArgumentException(
             "We support only encoded types for protobuf multi response.");
       }
       byte[] regionName = rs.getValue().toByteArray();
 
       if (actionResult.hasException()) {
         Throwable regionException =  ProtobufUtil.toException(actionResult.getException());
         results.addException(regionName, regionException);
         continue;
       }
 
       if (actions.getActionCount() != actionResult.getResultOrExceptionCount()) {
         throw new IllegalStateException("actions.getActionCount=" + actions.getActionCount() +
             ", actionResult.getResultOrExceptionCount=" +
             actionResult.getResultOrExceptionCount() + " for region " + actions.getRegion());
       }
 
       for (ResultOrException roe : actionResult.getResultOrExceptionList()) {
         Object responseValue;
         if (roe.hasException()) {
           responseValue = ProtobufUtil.toException(roe.getException());
         } else if (roe.hasResult()) {
           responseValue = ProtobufUtil.toResult(roe.getResult(), cells);
           // add the load stats, if we got any
           if (roe.hasLoadStats()) {
             ((Result) responseValue).addResults(roe.getLoadStats());
           }
         } else if (roe.hasServiceResult()) {
           responseValue = roe.getServiceResult();
         } else {
           // no result & no exception. Unexpected.
           throw new IllegalStateException("No result & no exception roe=" + roe +
               " for region " + actions.getRegion());
         }
         results.add(regionName, roe.getIndex(), responseValue);
       }
     }
 
     return results;
   }
 
   /**
    * Wrap a throwable to an action result.
    *
    * @param t
    * @return an action result builder
    */
   public static ResultOrException.Builder buildActionResult(final Throwable t) {
     ResultOrException.Builder builder = ResultOrException.newBuilder();
     if (t != null) builder.setException(buildException(t));
     return builder;
   }
 
   /**
    * Wrap a throwable to an action result.
    *
    * @param r
    * @return an action result builder
    */
   public static ResultOrException.Builder buildActionResult(final ClientProtos.Result r,
       ClientProtos.RegionLoadStats stats) {
     ResultOrException.Builder builder = ResultOrException.newBuilder();
     if (r != null) builder.setResult(r);
     if(stats != null) builder.setLoadStats(stats);
     return builder;
   }
 
   /**
    * @param t
    * @return NameValuePair of the exception name to stringified version os exception.
    */
   public static NameBytesPair buildException(final Throwable t) {
     NameBytesPair.Builder parameterBuilder = NameBytesPair.newBuilder();
     parameterBuilder.setName(t.getClass().getName());
     parameterBuilder.setValue(
       ByteString.copyFromUtf8(StringUtils.stringifyException(t)));
     return parameterBuilder.build();
   }
 
   /**
    * Converts the permissions list into a protocol buffer GetUserPermissionsResponse
    */
   public static GetUserPermissionsResponse buildGetUserPermissionsResponse(
       final List<UserPermission> permissions) {
     GetUserPermissionsResponse.Builder builder = GetUserPermissionsResponse.newBuilder();
     for (UserPermission perm : permissions) {
       builder.addUserPermission(ProtobufUtil.toUserPermission(perm));
     }
     return builder.build();
   }
 
 // End utilities for Client
 // Start utilities for Admin
 
   /**
    * Get the list of region info from a GetOnlineRegionResponse
    *
    * @param proto the GetOnlineRegionResponse
    * @return the list of region info
    */
   public static List<HRegionInfo> getRegionInfos(final GetOnlineRegionResponse proto) {
     if (proto == null || proto.getRegionInfoCount() == 0) return null;
     return ProtobufUtil.getRegionInfos(proto);
   }
 
   /**
    * Get the region opening state from a OpenRegionResponse
    *
    * @param proto the OpenRegionResponse
    * @return the region opening state
    */
   public static RegionOpeningState getRegionOpeningState
       (final OpenRegionResponse proto) {
     if (proto == null || proto.getOpeningStateCount() != 1) return null;
     return RegionOpeningState.valueOf(
       proto.getOpeningState(0).name());
   }
 
   /**
    * Get a list of region opening state from a OpenRegionResponse
    * 
    * @param proto the OpenRegionResponse
    * @return the list of region opening state
    */
   public static List<RegionOpeningState> getRegionOpeningStateList(
       final OpenRegionResponse proto) {
     if (proto == null) return null;
     List<RegionOpeningState> regionOpeningStates = new ArrayList<RegionOpeningState>();
     for (int i = 0; i < proto.getOpeningStateCount(); i++) {
       regionOpeningStates.add(RegionOpeningState.valueOf(
           proto.getOpeningState(i).name()));
     }
     return regionOpeningStates;
   }
 
   /**
    * Check if the region is closed from a CloseRegionResponse
    *
    * @param proto the CloseRegionResponse
    * @return the region close state
    */
   public static boolean isClosed
       (final CloseRegionResponse proto) {
     if (proto == null || !proto.hasClosed()) return false;
     return proto.getClosed();
   }
 
   /**
    * A utility to build a GetServerInfoResponse.
    *
    * @param serverName
    * @param webuiPort
    * @return the response
    */
   public static GetServerInfoResponse buildGetServerInfoResponse(
       final ServerName serverName, final int webuiPort) {
     GetServerInfoResponse.Builder builder = GetServerInfoResponse.newBuilder();
     ServerInfo.Builder serverInfoBuilder = ServerInfo.newBuilder();
     serverInfoBuilder.setServerName(ProtobufUtil.toServerName(serverName));
     if (webuiPort >= 0) {
       serverInfoBuilder.setWebuiPort(webuiPort);
     }
     builder.setServerInfo(serverInfoBuilder.build());
     return builder.build();
   }
 
   /**
    * A utility to build a GetOnlineRegionResponse.
    *
    * @param regions
    * @return the response
    */
   public static GetOnlineRegionResponse buildGetOnlineRegionResponse(
       final List<HRegionInfo> regions) {
     GetOnlineRegionResponse.Builder builder = GetOnlineRegionResponse.newBuilder();
     for (HRegionInfo region: regions) {
       builder.addRegionInfo(HRegionInfo.convert(region));
     }
     return builder.build();
   }
 
   /**
    * Creates a response for the catalog scan request
    * @return A RunCatalogScanResponse
    */
   public static RunCatalogScanResponse buildRunCatalogScanResponse(int numCleaned) {
     return RunCatalogScanResponse.newBuilder().setScanResult(numCleaned).build();
   }
 
   /**
    * Creates a response for the catalog scan request
    * @return A EnableCatalogJanitorResponse
    */
   public static EnableCatalogJanitorResponse buildEnableCatalogJanitorResponse(boolean prevValue) {
     return EnableCatalogJanitorResponse.newBuilder().setPrevValue(prevValue).build();
   }
 
 // End utilities for Admin
 
   /**
    * Creates a response for the last flushed sequence Id request
    * @return A GetLastFlushedSequenceIdResponse
    */
   public static GetLastFlushedSequenceIdResponse buildGetLastFlushedSequenceIdResponse(
       RegionStoreSequenceIds ids) {
     return GetLastFlushedSequenceIdResponse.newBuilder()
         .setLastFlushedSequenceId(ids.getLastFlushedSequenceId())
         .addAllStoreLastFlushedSequenceId(ids.getStoreSequenceIdList()).build();
   }
 
   /**
    * Stores an exception encountered during RPC invocation so it can be passed back
    * through to the client.
    * @param controller the controller instance provided by the client when calling the service
    * @param ioe the exception encountered
    */
   public static void setControllerException(RpcController controller, IOException ioe) {
     if (controller != null) {
       if (controller instanceof ServerRpcController) {
         ((ServerRpcController)controller).setFailedOn(ioe);
       } else {
         controller.setFailed(StringUtils.stringifyException(ioe));
       }
     }
   }
 
   /**
    * Create Results from the cells using the cells meta data. 
    * @param cellScanner
    * @param response
    * @return results
    */
   public static Result[] getResults(CellScanner cellScanner, ScanResponse response)
       throws IOException {
     if (response == null) return null;
     // If cellscanner, then the number of Results to return is the count of elements in the
     // cellsPerResult list.  Otherwise, it is how many results are embedded inside the response.
     int noOfResults = cellScanner != null?
       response.getCellsPerResultCount(): response.getResultsCount();
     Result[] results = new Result[noOfResults];
     for (int i = 0; i < noOfResults; i++) {
       if (cellScanner != null) {
         // Cells are out in cellblocks.  Group them up again as Results.  How many to read at a
         // time will be found in getCellsLength -- length here is how many Cells in the i'th Result
         int noOfCells = response.getCellsPerResult(i);
         boolean isPartial =
             response.getPartialFlagPerResultCount() > i ?
                 response.getPartialFlagPerResult(i) : false;
         List<Cell> cells = new ArrayList<Cell>(noOfCells);
         for (int j = 0; j < noOfCells; j++) {
           try {
             if (cellScanner.advance() == false) {
               // We are not able to retrieve the exact number of cells which ResultCellMeta says us.
               // We have to scan for the same results again. Throwing DNRIOE as a client retry on the
               // same scanner will result in OutOfOrderScannerNextException
               String msg = "Results sent from server=" + noOfResults + ". But only got " + i
                 + " results completely at client. Resetting the scanner to scan again.";
               LOG.error(msg);
               throw new DoNotRetryIOException(msg);
             }
           } catch (IOException ioe) {
             // We are getting IOE while retrieving the cells for Results.
             // We have to scan for the same results again. Throwing DNRIOE as a client retry on the
             // same scanner will result in OutOfOrderScannerNextException
             LOG.error("Exception while reading cells from result."
               + "Resetting the scanner to scan again.", ioe);
             throw new DoNotRetryIOException("Resetting the scanner.", ioe);
           }
           cells.add(cellScanner.current());
         }
         results[i] = Result.create(cells, null, response.getStale(), isPartial);
       } else {
         // Result is pure pb.
         results[i] = ProtobufUtil.toResult(response.getResults(i));
       }
     }
     return results;
   }
 }