/**
 * 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.drill.exec.store.hive.schema;

import com.google.common.collect.ImmutableList;
import com.google.common.collect.Lists;
import com.google.common.collect.Sets;
import org.apache.calcite.rel.type.RelDataType;
import org.apache.calcite.rel.type.RelDataTypeFactory;
import org.apache.calcite.schema.Schema;
import org.apache.calcite.schema.Statistic;
import org.apache.calcite.schema.Table;
import org.apache.commons.lang3.tuple.Pair;
import org.apache.drill.exec.store.AbstractSchema;
import org.apache.drill.exec.store.SchemaConfig;
import org.apache.drill.exec.store.hive.DrillHiveMetaStoreClient;
import org.apache.drill.exec.store.hive.HiveStoragePluginConfig;
import org.apache.drill.exec.store.hive.schema.HiveSchemaFactory.HiveSchema;
import org.apache.thrift.TException;

import java.util.List;
import java.util.Set;

public class HiveDatabaseSchema extends AbstractSchema{
  static final org.slf4j.Logger logger = org.slf4j.LoggerFactory.getLogger(HiveDatabaseSchema.class);

  private final HiveSchema hiveSchema;
  private Set<String> tables;
  private final DrillHiveMetaStoreClient mClient;
  private final SchemaConfig schemaConfig;

  public HiveDatabaseSchema( //
      HiveSchema hiveSchema, //
      String name,
      DrillHiveMetaStoreClient mClient,
      SchemaConfig schemaConfig) {
    super(hiveSchema.getSchemaPath(), name);
    this.hiveSchema = hiveSchema;
    this.mClient = mClient;
    this.schemaConfig = schemaConfig;
  }

  @Override
  public Table getTable(String tableName) {
    return hiveSchema.getDrillTable(this.name, tableName);
  }

  @Override
  public Set<String> getTableNames() {
    if (tables == null) {
      try {
        tables = Sets.newHashSet(mClient.getTableNames(this.name, schemaConfig.getIgnoreAuthErrors()));
      } catch (final TException e) {
        logger.warn("Failure while attempting to access HiveDatabase '{}'.", this.name, e.getCause());
        tables = Sets.newHashSet(); // empty set.
      }
    }
    return tables;
  }

  @Override
  public String getTypeName() {
    return HiveStoragePluginConfig.NAME;
  }

  @Override
  public List<Pair<String, ? extends Table>> getTablesByNamesByBulkLoad(final List<String> tableNames,
      final int bulkSize) {
    final String schemaName = getName();
    final List<org.apache.hadoop.hive.metastore.api.Table> tables = DrillHiveMetaStoreClient
        .getTablesByNamesByBulkLoadHelper(mClient, tableNames, schemaName, bulkSize);

    final List<Pair<String, ? extends Table>> tableNameToTable = Lists.newArrayList();
    for (final org.apache.hadoop.hive.metastore.api.Table table : tables) {
      if (table == null) {
        continue;
      }

      final String tableName = table.getTableName();
      final TableType tableType;
      if (table.getTableType().equals(org.apache.hadoop.hive.metastore.TableType.VIRTUAL_VIEW.toString())) {
        tableType = TableType.VIEW;
      } else {
        tableType = TableType.TABLE;
      }
      tableNameToTable.add(Pair.of(tableName, new HiveTableWithoutStatisticAndRowType(tableType)));
    }
    return tableNameToTable;
  }

  private static class HiveTableWithoutStatisticAndRowType implements Table {
    private final TableType tableType;

    public HiveTableWithoutStatisticAndRowType(final TableType tableType) {
      this.tableType = tableType;
    }

    @Override
    public RelDataType getRowType(RelDataTypeFactory typeFactory) {
      throw new UnsupportedOperationException(
          "RowType was not retrieved when this table had been being requested");
    }

    @Override
    public Statistic getStatistic() {
      throw new UnsupportedOperationException(
          "Statistic was not retrieved when this table had been being requested");
    }

    @Override
    public Schema.TableType getJdbcTableType() {
      return tableType;
    }
  }

}