/*
 * 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.spark.sql.hive.thriftserver

import java.util.regex.Pattern

import org.apache.hadoop.hive.ql.security.authorization.plugin.HiveOperationType
import org.apache.hive.service.cli._
import org.apache.hive.service.cli.operation.GetSchemasOperation
import org.apache.hive.service.cli.operation.MetadataOperation.DEFAULT_HIVE_CATALOG
import org.apache.hive.service.cli.session.HiveSession

import org.apache.spark.internal.{Logging, MDC}
import org.apache.spark.internal.LogKeys._
import org.apache.spark.sql.SparkSession

/**
 * Spark's own GetSchemasOperation
 *
 * @param session SparkSession to use
 * @param parentSession a HiveSession from SessionManager
 * @param catalogName catalog name. null if not applicable.
 * @param schemaName database name, null or a concrete database name
 */
private[hive] class SparkGetSchemasOperation(
    val session: SparkSession,
    parentSession: HiveSession,
    catalogName: String,
    schemaName: String)
  extends GetSchemasOperation(parentSession, catalogName, schemaName)
  with SparkOperation
  with Logging {

  override def runInternal(): Unit = {
    // Do not change cmdStr. It's used for Hive auditing and authorization.
    val cmdStr = s"catalog : $catalogName, schemaPattern : $schemaName"
    val logMsg = s"Listing databases '$cmdStr'"

    val catalogNameStr = if (catalogName == null) "null" else catalogName
    val schemaNameStr = if (schemaName == null) "null" else schemaName
    logInfo(log"Listing databases 'catalog : ${MDC(CATALOG_NAME, catalogNameStr)}, " +
      log"schemaPattern : ${MDC(DATABASE_NAME, schemaNameStr)}' " +
      log"with ${MDC(STATEMENT_ID, statementId)}")

    setState(OperationState.RUNNING)
    // Always use the latest class loader provided by executionHive's state.
    val executionHiveClassLoader = session.sharedState.jarClassLoader
    Thread.currentThread().setContextClassLoader(executionHiveClassLoader)

    if (isAuthV2Enabled) {
      authorizeMetaGets(HiveOperationType.GET_TABLES, null, cmdStr)
    }

    HiveThriftServer2.eventManager.onStatementStart(
      statementId,
      parentSession.getSessionHandle.getSessionId.toString,
      logMsg,
      statementId,
      parentSession.getUsername)

    try {
      val schemaPattern = convertSchemaPattern(schemaName)
      session.sessionState.catalog.listDatabases(schemaPattern).foreach { dbName =>
        rowSet.addRow(Array[AnyRef](dbName, DEFAULT_HIVE_CATALOG))
      }

      val globalTempViewDb = session.sessionState.catalog.globalTempDatabase
      val databasePattern = Pattern.compile(CLIServiceUtils.patternToRegex(schemaName))
      if (schemaName == null || schemaName.isEmpty ||
          databasePattern.matcher(globalTempViewDb).matches()) {
        rowSet.addRow(Array[AnyRef](globalTempViewDb, DEFAULT_HIVE_CATALOG))
      }
      setState(OperationState.FINISHED)
    } catch onError()

    HiveThriftServer2.eventManager.onStatementFinish(statementId)
  }
}
