/**
 * 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.master.procedure;

import java.io.IOException;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

import org.apache.hadoop.hbase.ConcurrentTableModificationException;
import org.apache.hadoop.hbase.DoNotRetryIOException;
import org.apache.hadoop.hbase.HBaseIOException;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.MetaTableAccessor;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.TableNotDisabledException;
import org.apache.hadoop.hbase.TableNotFoundException;
import org.apache.hadoop.hbase.client.Connection;
import org.apache.hadoop.hbase.client.RegionInfo;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.client.ResultScanner;
import org.apache.hadoop.hbase.client.Scan;
import org.apache.hadoop.hbase.client.Table;
import org.apache.hadoop.hbase.client.TableDescriptor;
import org.apache.hadoop.hbase.client.TableState;
import org.apache.hadoop.hbase.master.MasterCoprocessorHost;
import org.apache.hadoop.hbase.procedure2.ProcedureStateSerializer;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.hadoop.hbase.util.ServerRegionReplicaUtil;
import org.apache.yetus.audience.InterfaceAudience;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import org.apache.hadoop.hbase.shaded.protobuf.ProtobufUtil;
import org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProcedureProtos;
import org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProcedureProtos.ModifyTableState;

@InterfaceAudience.Private
public class ModifyTableProcedure
    extends AbstractStateMachineTableProcedure<ModifyTableState> {
  private static final Logger LOG = LoggerFactory.getLogger(ModifyTableProcedure.class);

  private TableDescriptor unmodifiedTableDescriptor = null;
  private TableDescriptor modifiedTableDescriptor;
  private boolean deleteColumnFamilyInModify;
  private boolean shouldCheckDescriptor;
  /**
   * List of column families that cannot be deleted from the hbase:meta table.
   * They are critical to cluster operation. This is a bit of an odd place to
   * keep this list but then this is the tooling that does add/remove. Keeping
   * it local!
   */
  private static final List<byte []> UNDELETABLE_META_COLUMNFAMILIES =
    Collections.unmodifiableList(Arrays.asList(
      HConstants.CATALOG_FAMILY, HConstants.TABLE_FAMILY, HConstants.REPLICATION_BARRIER_FAMILY));

  public ModifyTableProcedure() {
    super();
    initialize(null, false);
  }

  public ModifyTableProcedure(final MasterProcedureEnv env, final TableDescriptor htd)
  throws HBaseIOException {
    this(env, htd, null);
  }

  public ModifyTableProcedure(final MasterProcedureEnv env, final TableDescriptor htd,
      final ProcedurePrepareLatch latch)
  throws HBaseIOException {
    this(env, htd, latch, null, false);
  }

  public ModifyTableProcedure(final MasterProcedureEnv env,
      final TableDescriptor newTableDescriptor, final ProcedurePrepareLatch latch,
      final TableDescriptor oldTableDescriptor, final boolean shouldCheckDescriptor)
          throws HBaseIOException {
    super(env, latch);
    initialize(oldTableDescriptor, shouldCheckDescriptor);
    this.modifiedTableDescriptor = newTableDescriptor;
    preflightChecks(env, null/*No table checks; if changing peers, table can be online*/);
  }

  @Override
  protected void preflightChecks(MasterProcedureEnv env, Boolean enabled) throws HBaseIOException {
    super.preflightChecks(env, enabled);
    if (this.modifiedTableDescriptor.isMetaTable()) {
      // If we are modifying the hbase:meta table, make sure we are not deleting critical
      // column families else we'll damage the cluster.
      Set<byte []> cfs = this.modifiedTableDescriptor.getColumnFamilyNames();
      for (byte[] family : UNDELETABLE_META_COLUMNFAMILIES) {
        if (!cfs.contains(family)) {
          throw new HBaseIOException("Delete of hbase:meta column family " +
            Bytes.toString(family));
        }
      }
    }
  }

  private void initialize(final TableDescriptor unmodifiedTableDescriptor,
      final boolean shouldCheckDescriptor) {
    this.unmodifiedTableDescriptor = unmodifiedTableDescriptor;
    this.shouldCheckDescriptor = shouldCheckDescriptor;
    this.deleteColumnFamilyInModify = false;
  }

  @Override
  protected Flow executeFromState(final MasterProcedureEnv env, final ModifyTableState state)
      throws InterruptedException {
    LOG.trace("{} execute state={}", this, state);
    try {
      switch (state) {
        case MODIFY_TABLE_PREPARE:
          prepareModify(env);
          setNextState(ModifyTableState.MODIFY_TABLE_PRE_OPERATION);
          break;
        case MODIFY_TABLE_PRE_OPERATION:
          preModify(env, state);
          setNextState(ModifyTableState.MODIFY_TABLE_UPDATE_TABLE_DESCRIPTOR);
          break;
        case MODIFY_TABLE_UPDATE_TABLE_DESCRIPTOR:
          updateTableDescriptor(env);
          setNextState(ModifyTableState.MODIFY_TABLE_REMOVE_REPLICA_COLUMN);
          break;
        case MODIFY_TABLE_REMOVE_REPLICA_COLUMN:
          updateReplicaColumnsIfNeeded(env, unmodifiedTableDescriptor, modifiedTableDescriptor);
          setNextState(ModifyTableState.MODIFY_TABLE_POST_OPERATION);
          break;
        case MODIFY_TABLE_POST_OPERATION:
          postModify(env, state);
          setNextState(ModifyTableState.MODIFY_TABLE_REOPEN_ALL_REGIONS);
          break;
        case MODIFY_TABLE_REOPEN_ALL_REGIONS:
          if (env.getAssignmentManager().isTableEnabled(getTableName())) {
            addChildProcedure(new ReopenTableRegionsProcedure(getTableName()));
          }
          if (deleteColumnFamilyInModify) {
            setNextState(ModifyTableState.MODIFY_TABLE_DELETE_FS_LAYOUT);
          } else {
            return Flow.NO_MORE_STATE;
          }
          break;
        case MODIFY_TABLE_DELETE_FS_LAYOUT:
          deleteFromFs(env, unmodifiedTableDescriptor, modifiedTableDescriptor);
          return Flow.NO_MORE_STATE;
        default:
          throw new UnsupportedOperationException("unhandled state=" + state);
      }
    } catch (IOException e) {
      if (isRollbackSupported(state)) {
        setFailure("master-modify-table", e);
      } else {
        LOG.warn("Retriable error trying to modify table={} (in state={})", getTableName(), state,
          e);
      }
    }
    return Flow.HAS_MORE_STATE;
  }

  @Override
  protected void rollbackState(final MasterProcedureEnv env, final ModifyTableState state)
      throws IOException {
    if (state == ModifyTableState.MODIFY_TABLE_PREPARE ||
        state == ModifyTableState.MODIFY_TABLE_PRE_OPERATION) {
      // nothing to rollback, pre-modify is just checks.
      // TODO: coprocessor rollback semantic is still undefined.
      return;
    }

    // The delete doesn't have a rollback. The execution will succeed, at some point.
    throw new UnsupportedOperationException("unhandled state=" + state);
  }

  @Override
  protected boolean isRollbackSupported(final ModifyTableState state) {
    switch (state) {
      case MODIFY_TABLE_PRE_OPERATION:
      case MODIFY_TABLE_PREPARE:
        return true;
      default:
        return false;
    }
  }

  @Override
  protected void completionCleanup(final MasterProcedureEnv env) {
    releaseSyncLatch();
  }

  @Override
  protected ModifyTableState getState(final int stateId) {
    return ModifyTableState.forNumber(stateId);
  }

  @Override
  protected int getStateId(final ModifyTableState state) {
    return state.getNumber();
  }

  @Override
  protected ModifyTableState getInitialState() {
    return ModifyTableState.MODIFY_TABLE_PREPARE;
  }

  @Override
  protected void serializeStateData(ProcedureStateSerializer serializer)
      throws IOException {
    super.serializeStateData(serializer);

    MasterProcedureProtos.ModifyTableStateData.Builder modifyTableMsg =
        MasterProcedureProtos.ModifyTableStateData.newBuilder()
            .setUserInfo(MasterProcedureUtil.toProtoUserInfo(getUser()))
            .setModifiedTableSchema(ProtobufUtil.toTableSchema(modifiedTableDescriptor))
            .setDeleteColumnFamilyInModify(deleteColumnFamilyInModify)
            .setShouldCheckDescriptor(shouldCheckDescriptor);

    if (unmodifiedTableDescriptor != null) {
      modifyTableMsg
          .setUnmodifiedTableSchema(ProtobufUtil.toTableSchema(unmodifiedTableDescriptor));
    }

    serializer.serialize(modifyTableMsg.build());
  }

  @Override
  protected void deserializeStateData(ProcedureStateSerializer serializer)
      throws IOException {
    super.deserializeStateData(serializer);

    MasterProcedureProtos.ModifyTableStateData modifyTableMsg =
        serializer.deserialize(MasterProcedureProtos.ModifyTableStateData.class);
    setUser(MasterProcedureUtil.toUserInfo(modifyTableMsg.getUserInfo()));
    modifiedTableDescriptor = ProtobufUtil.toTableDescriptor(modifyTableMsg.getModifiedTableSchema());
    deleteColumnFamilyInModify = modifyTableMsg.getDeleteColumnFamilyInModify();
    shouldCheckDescriptor = modifyTableMsg.hasShouldCheckDescriptor()
        ? modifyTableMsg.getShouldCheckDescriptor() : false;

    if (modifyTableMsg.hasUnmodifiedTableSchema()) {
      unmodifiedTableDescriptor =
          ProtobufUtil.toTableDescriptor(modifyTableMsg.getUnmodifiedTableSchema());
    }
  }

  @Override
  public TableName getTableName() {
    return modifiedTableDescriptor.getTableName();
  }

  @Override
  public TableOperationType getTableOperationType() {
    return TableOperationType.EDIT;
  }

  /**
   * Check conditions before any real action of modifying a table.
   * @param env MasterProcedureEnv
   * @throws IOException
   */
  private void prepareModify(final MasterProcedureEnv env) throws IOException {
    // Checks whether the table exists
    if (!MetaTableAccessor.tableExists(env.getMasterServices().getConnection(), getTableName())) {
      throw new TableNotFoundException(getTableName());
    }

    // check that we have at least 1 CF
    if (modifiedTableDescriptor.getColumnFamilyCount() == 0) {
      throw new DoNotRetryIOException("Table " + getTableName().toString() +
        " should have at least one column family.");
    }

    // If descriptor check is enabled, check whether the table descriptor when procedure was
    // submitted matches with the current
    // table descriptor of the table, else retrieve the old descriptor
    // for comparison in order to update the descriptor.
    if (shouldCheckDescriptor) {
      if (TableDescriptor.COMPARATOR.compare(unmodifiedTableDescriptor,
        env.getMasterServices().getTableDescriptors().get(getTableName())) != 0) {
        LOG.error("Error while modifying table '" + getTableName().toString()
            + "' Skipping procedure : " + this);
        throw new ConcurrentTableModificationException(
            "Skipping modify table operation on table '" + getTableName().toString()
                + "' as it has already been modified by some other concurrent operation, "
                + "Please retry.");
      }
    } else {
      this.unmodifiedTableDescriptor =
          env.getMasterServices().getTableDescriptors().get(getTableName());
    }

    if (env.getMasterServices().getTableStateManager()
        .isTableState(getTableName(), TableState.State.ENABLED)) {
      if (modifiedTableDescriptor.getRegionReplication() != unmodifiedTableDescriptor
          .getRegionReplication()) {
        throw new TableNotDisabledException(
            "REGION_REPLICATION change is not supported for enabled tables");
      }
    }
    this.deleteColumnFamilyInModify = isDeleteColumnFamily(unmodifiedTableDescriptor,
      modifiedTableDescriptor);
  }

  /**
   * Find out whether all column families in unmodifiedTableDescriptor also exists in
   * the modifiedTableDescriptor.
   * @return True if we are deleting a column family.
   */
  private static boolean isDeleteColumnFamily(TableDescriptor originalDescriptor,
      TableDescriptor newDescriptor) {
    boolean result = false;
    final Set<byte[]> originalFamilies = originalDescriptor.getColumnFamilyNames();
    final Set<byte[]> newFamilies = newDescriptor.getColumnFamilyNames();
    for (byte[] familyName : originalFamilies) {
      if (!newFamilies.contains(familyName)) {
        result = true;
        break;
      }
    }
    return result;
  }

  /**
   * Action before modifying table.
   * @param env MasterProcedureEnv
   * @param state the procedure state
   * @throws IOException
   * @throws InterruptedException
   */
  private void preModify(final MasterProcedureEnv env, final ModifyTableState state)
      throws IOException, InterruptedException {
    runCoprocessorAction(env, state);
  }

  /**
   * Update descriptor
   * @param env MasterProcedureEnv
   * @throws IOException
   **/
  private void updateTableDescriptor(final MasterProcedureEnv env) throws IOException {
    env.getMasterServices().getTableDescriptors().update(modifiedTableDescriptor);
  }

  /**
   * Removes from hdfs the families that are not longer present in the new table descriptor.
   * @param env MasterProcedureEnv
   * @throws IOException
   */
  private void deleteFromFs(final MasterProcedureEnv env,
      final TableDescriptor oldTableDescriptor, final TableDescriptor newTableDescriptor)
      throws IOException {
    final Set<byte[]> oldFamilies = oldTableDescriptor.getColumnFamilyNames();
    final Set<byte[]> newFamilies = newTableDescriptor.getColumnFamilyNames();
    for (byte[] familyName : oldFamilies) {
      if (!newFamilies.contains(familyName)) {
        MasterDDLOperationHelper.deleteColumnFamilyFromFileSystem(
          env,
          getTableName(),
          getRegionInfoList(env),
          familyName, oldTableDescriptor.getColumnFamily(familyName).isMobEnabled());
      }
    }
  }

  /**
   * update replica column families if necessary.
   * @param env MasterProcedureEnv
   * @throws IOException
   */
  private void updateReplicaColumnsIfNeeded(
    final MasterProcedureEnv env,
    final TableDescriptor oldTableDescriptor,
    final TableDescriptor newTableDescriptor) throws IOException {
    final int oldReplicaCount = oldTableDescriptor.getRegionReplication();
    final int newReplicaCount = newTableDescriptor.getRegionReplication();

    if (newReplicaCount < oldReplicaCount) {
      Set<byte[]> tableRows = new HashSet<>();
      Connection connection = env.getMasterServices().getConnection();
      Scan scan = MetaTableAccessor.getScanForTableName(connection, getTableName());
      scan.addColumn(HConstants.CATALOG_FAMILY, HConstants.REGIONINFO_QUALIFIER);

      try (Table metaTable = connection.getTable(TableName.META_TABLE_NAME)) {
        ResultScanner resScanner = metaTable.getScanner(scan);
        for (Result result : resScanner) {
          tableRows.add(result.getRow());
        }
        MetaTableAccessor.removeRegionReplicasFromMeta(
          tableRows,
          newReplicaCount,
          oldReplicaCount - newReplicaCount,
          connection);
      }
    }
    if (newReplicaCount > oldReplicaCount) {
      Connection connection = env.getMasterServices().getConnection();
      // Get the existing table regions
      List<RegionInfo> existingTableRegions =
          MetaTableAccessor.getTableRegions(connection, getTableName());
      // add all the new entries to the meta table
      addRegionsToMeta(env, newTableDescriptor, existingTableRegions);
      if (oldReplicaCount <= 1) {
        // The table has been newly enabled for replica. So check if we need to setup
        // region replication
        ServerRegionReplicaUtil.setupRegionReplicaReplication(env.getMasterConfiguration());
      }
    }
  }

  private static void addRegionsToMeta(final MasterProcedureEnv env,
      final TableDescriptor tableDescriptor, final List<RegionInfo> regionInfos)
      throws IOException {
    MetaTableAccessor.addRegionsToMeta(env.getMasterServices().getConnection(), regionInfos,
      tableDescriptor.getRegionReplication());
  }
  /**
   * Action after modifying table.
   * @param env MasterProcedureEnv
   * @param state the procedure state
   * @throws IOException
   * @throws InterruptedException
   */
  private void postModify(final MasterProcedureEnv env, final ModifyTableState state)
      throws IOException, InterruptedException {
    runCoprocessorAction(env, state);
  }

  /**
   * Coprocessor Action.
   * @param env MasterProcedureEnv
   * @param state the procedure state
   * @throws IOException
   * @throws InterruptedException
   */
  private void runCoprocessorAction(final MasterProcedureEnv env, final ModifyTableState state)
      throws IOException, InterruptedException {
    final MasterCoprocessorHost cpHost = env.getMasterCoprocessorHost();
    if (cpHost != null) {
      switch (state) {
        case MODIFY_TABLE_PRE_OPERATION:
          cpHost.preModifyTableAction(getTableName(), unmodifiedTableDescriptor,
            modifiedTableDescriptor, getUser());
          break;
        case MODIFY_TABLE_POST_OPERATION:
          cpHost.postCompletedModifyTableAction(getTableName(), unmodifiedTableDescriptor,
            modifiedTableDescriptor,getUser());
          break;
        default:
          throw new UnsupportedOperationException(this + " unhandled state=" + state);
      }
    }
  }

  /**
   * Fetches all Regions for a table. Cache the result of this method if you need to use it multiple
   * times. Be aware that it may change over in between calls to this procedure.
   */
  private List<RegionInfo> getRegionInfoList(final MasterProcedureEnv env) throws IOException {
    return env.getAssignmentManager().getRegionStates().getRegionsOfTable(getTableName());
  }
}