/*
 * 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.paimon.flink.sink.cdc;

import org.apache.paimon.schema.TableSchema;
import org.apache.paimon.table.sink.ChannelComputer;
import org.apache.paimon.table.sink.KeyAndBucketExtractor;

/**
 * {@link ChannelComputer} for writing {@link CdcRecord}s into postpone bucket tables. Records with
 * same primary keys are distributed to the same subtask.
 */
public class CdcPostponeBucketChannelComputer implements ChannelComputer<CdcRecord> {

    private final TableSchema schema;

    private transient int numChannels;
    private transient KeyAndBucketExtractor<CdcRecord> extractor;

    public CdcPostponeBucketChannelComputer(TableSchema schema) {
        this.schema = schema;
    }

    @Override
    public void setup(int numChannels) {
        this.numChannels = numChannels;
        this.extractor = new CdcRecordKeyAndBucketExtractor(schema);
    }

    @Override
    public int channel(CdcRecord record) {
        extractor.setRecord(record);
        return Math.abs(
                (extractor.partition().hashCode() + extractor.trimmedPrimaryKey().hashCode())
                        % numChannels);
    }
}
