/*
 * 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.config.DatabaseDescriptor;
import org.apache.cassandra.exceptions.*;
import org.apache.cassandra.locator.AbstractReplicationStrategy;
import org.apache.cassandra.locator.LocalStrategy;
import org.apache.cassandra.schema.KeyspaceMetadata;
import org.apache.cassandra.schema.KeyspaceParams;
import org.apache.cassandra.schema.MigrationManager;
import org.apache.cassandra.schema.Schema;
import org.apache.cassandra.schema.SchemaConstants;
import org.apache.cassandra.service.ClientState;
import org.apache.cassandra.service.ClientWarn;
import org.apache.cassandra.service.QueryState;
import org.apache.cassandra.service.StorageService;
import org.apache.cassandra.transport.Event;

public class AlterKeyspaceStatement extends SchemaAlteringStatement
{
    private final String name;
    private final KeyspaceAttributes attrs;

    public AlterKeyspaceStatement(String name, KeyspaceAttributes attrs)
    {
        super();
        this.name = name;
        this.attrs = attrs;
    }

    @Override
    public String keyspace()
    {
        return name;
    }

    public void checkAccess(ClientState state) throws UnauthorizedException, InvalidRequestException
    {
        state.hasKeyspaceAccess(name, Permission.ALTER);
    }

    public void validate(ClientState state) throws RequestValidationException
    {
        KeyspaceMetadata ksm = Schema.instance.getKeyspaceMetadata(name);
        if (ksm == null)
            throw new InvalidRequestException("Unknown keyspace " + name);
        if (SchemaConstants.isSystemKeyspace(ksm.name))
            throw new InvalidRequestException("Cannot alter system keyspace");

        attrs.validate();

        if (attrs.getReplicationStrategyClass() == null && !attrs.getReplicationOptions().isEmpty())
            throw new ConfigurationException("Missing replication strategy class");

        if (attrs.getReplicationStrategyClass() != null)
        {
            // The strategy is validated through KSMetaData.validate() in announceKeyspaceUpdate below.
            // However, for backward compatibility with thrift, this doesn't validate unexpected options yet,
            // so doing proper validation here.
            KeyspaceParams params = attrs.asAlteredKeyspaceParams(ksm.params);
            params.validate(name);
            if (params.replication.klass.equals(LocalStrategy.class))
                throw new ConfigurationException("Unable to use given strategy class: LocalStrategy is reserved for internal use.");
            warnIfIncreasingRF(ksm, params);
        }
    }

    private void warnIfIncreasingRF(KeyspaceMetadata ksm, KeyspaceParams params)
    {
        AbstractReplicationStrategy oldStrategy = AbstractReplicationStrategy.createReplicationStrategy(ksm.name,
                                                                                                        ksm.params.replication.klass,
                                                                                                        StorageService.instance.getTokenMetadata(),
                                                                                                        DatabaseDescriptor.getEndpointSnitch(),
                                                                                                        ksm.params.replication.options);
        AbstractReplicationStrategy newStrategy = AbstractReplicationStrategy.createReplicationStrategy(keyspace(),
                                                                                                        params.replication.klass,
                                                                                                        StorageService.instance.getTokenMetadata(),
                                                                                                        DatabaseDescriptor.getEndpointSnitch(),
                                                                                                        params.replication.options);
        if (newStrategy.getReplicationFactor() > oldStrategy.getReplicationFactor())
            ClientWarn.instance.warn("When increasing replication factor you need to run a full (-full) repair to distribute the data.");
    }

    public Event.SchemaChange announceMigration(QueryState queryState, boolean isLocalOnly) throws RequestValidationException
    {
        KeyspaceMetadata oldKsm = Schema.instance.getKeyspaceMetadata(name);
        // In the (very) unlikely case the keyspace was dropped since validate()
        if (oldKsm == null)
            throw new InvalidRequestException("Unknown keyspace " + name);

        KeyspaceMetadata newKsm = oldKsm.withSwapped(attrs.asAlteredKeyspaceParams(oldKsm.params));
        MigrationManager.announceKeyspaceUpdate(newKsm, isLocalOnly);
        return new Event.SchemaChange(Event.SchemaChange.Change.UPDATED, keyspace());
    }
}