/*
 * 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.cassandra.cql3.statements;

import org.apache.cassandra.auth.Permission;
import org.apache.cassandra.cql3.CFName;
import org.apache.cassandra.exceptions.ConfigurationException;
import org.apache.cassandra.exceptions.InvalidRequestException;
import org.apache.cassandra.exceptions.UnauthorizedException;
import org.apache.cassandra.schema.KeyspaceMetadata;
import org.apache.cassandra.schema.MigrationManager;
import org.apache.cassandra.schema.Schema;
import org.apache.cassandra.schema.TableMetadata;
import org.apache.cassandra.schema.ViewMetadata;
import org.apache.cassandra.service.ClientState;
import org.apache.cassandra.service.QueryState;
import org.apache.cassandra.transport.Event;

public class DropTableStatement extends SchemaAlteringStatement
{
    private final boolean ifExists;

    public DropTableStatement(CFName name, boolean ifExists)
    {
        super(name);
        this.ifExists = ifExists;
    }

    public void checkAccess(ClientState state) throws UnauthorizedException, InvalidRequestException
    {
        try
        {
            state.hasColumnFamilyAccess(keyspace(), columnFamily(), Permission.DROP);
        }
        catch (InvalidRequestException e)
        {
            if (!ifExists)
                throw e;
        }
    }

    public void validate(ClientState state)
    {
        // validated in announceMigration()
    }

    public Event.SchemaChange announceMigration(QueryState queryState, boolean isLocalOnly) throws ConfigurationException
    {
        try
        {
            KeyspaceMetadata ksm = Schema.instance.getKeyspaceMetadata(keyspace());
            if (ksm == null)
                throw new ConfigurationException(String.format("Cannot drop table in unknown keyspace '%s'", keyspace()));
            TableMetadata metadata = ksm.getTableOrViewNullable(columnFamily());
            if (metadata != null)
            {
                if (metadata.isView())
                    throw new InvalidRequestException("Cannot use DROP TABLE on Materialized View");

                boolean rejectDrop = false;
                StringBuilder messageBuilder = new StringBuilder();
                for (ViewMetadata def : ksm.views)
                {
                    if (def.baseTableId.equals(metadata.id))
                    {
                        if (rejectDrop)
                            messageBuilder.append(',');
                        rejectDrop = true;
                        messageBuilder.append(def.name);
                    }
                }
                if (rejectDrop)
                {
                    throw new InvalidRequestException(String.format("Cannot drop table when materialized views still depend on it (%s.{%s})",
                                                                    keyspace(),
                                                                    messageBuilder.toString()));
                }
            }
            MigrationManager.announceTableDrop(keyspace(), columnFamily(), isLocalOnly);
            return new Event.SchemaChange(Event.SchemaChange.Change.DROPPED, Event.SchemaChange.Target.TABLE, keyspace(), columnFamily());
        }
        catch (ConfigurationException e)
        {
            if (ifExists)
                return null;
            throw e;
        }
    }
}