/**
 * 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.ischema;

import java.io.IOException;
import java.util.List;
import java.util.Map;
import java.util.Set;

import com.google.common.collect.ImmutableSet;
import org.apache.calcite.schema.SchemaPlus;
import org.apache.calcite.schema.Table;

import static org.apache.drill.exec.store.ischema.InfoSchemaConstants.*;
import org.apache.drill.common.JSONOptions;
import org.apache.drill.common.expression.SchemaPath;
import org.apache.drill.common.logical.StoragePluginConfig;
import org.apache.drill.exec.ops.OptimizerRulesContext;
import org.apache.drill.exec.server.DrillbitContext;
import org.apache.drill.exec.store.AbstractSchema;
import org.apache.drill.exec.store.AbstractStoragePlugin;

import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Maps;
import org.apache.drill.exec.store.SchemaConfig;
import org.apache.drill.exec.store.StoragePluginOptimizerRule;

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

  private final InfoSchemaConfig config;
  private final DrillbitContext context;
  private final String name;

  public InfoSchemaStoragePlugin(InfoSchemaConfig config, DrillbitContext context, String name){
    this.config = config;
    this.context = context;
    this.name = name;
  }

  @Override
  public boolean supportsRead() {
    return true;
  }

  @Override
  public InfoSchemaGroupScan getPhysicalScan(String userName, JSONOptions selection, List<SchemaPath> columns)
      throws IOException {
    InfoSchemaTableType table = selection.getWith(context.getLpPersistence(),  InfoSchemaTableType.class);
    return new InfoSchemaGroupScan(table);
  }

  @Override
  public StoragePluginConfig getConfig() {
    return this.config;
  }

  @Override
  public void registerSchemas(SchemaConfig schemaConfig, SchemaPlus parent) throws IOException {
    ISchema s = new ISchema(parent, this);
    parent.add(s.getName(), s);
  }

  /**
   * Representation of the INFORMATION_SCHEMA schema.
   */
  private class ISchema extends AbstractSchema{
    private Map<String, InfoSchemaDrillTable> tables;
    public ISchema(SchemaPlus parent, InfoSchemaStoragePlugin plugin){
      super(ImmutableList.<String>of(), IS_SCHEMA_NAME);
      Map<String, InfoSchemaDrillTable> tbls = Maps.newHashMap();
      for(InfoSchemaTableType tbl : InfoSchemaTableType.values()){
        tbls.put(tbl.name(), new InfoSchemaDrillTable(plugin, IS_SCHEMA_NAME, tbl, config));
      }
      this.tables = ImmutableMap.copyOf(tbls);
    }

    @Override
    public Table getTable(String name) {
      return tables.get(name);
    }

    @Override
    public Set<String> getTableNames() {
      return tables.keySet();
    }

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

  @Override
  public Set<StoragePluginOptimizerRule> getPhysicalOptimizerRules(OptimizerRulesContext optimizerRulesContext) {
    return ImmutableSet.of(
        InfoSchemaPushFilterIntoRecordGenerator.IS_FILTER_ON_PROJECT,
        InfoSchemaPushFilterIntoRecordGenerator.IS_FILTER_ON_SCAN);
  }
}