/*
 * 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.source;

import org.apache.flink.api.common.eventtime.WatermarkGenerator;
import org.apache.flink.api.common.eventtime.WatermarkGeneratorSupplier;
import org.apache.flink.api.common.eventtime.WatermarkOutput;
import org.apache.flink.api.common.eventtime.WatermarkStrategy;
import org.apache.flink.table.data.RowData;

/** Paimon {@link WatermarkStrategy} to emit watermark on event. */
public class OnEventWatermarkStrategy implements WatermarkStrategy<RowData> {

    private static final long serialVersionUID = 1L;

    private final WatermarkStrategy<RowData> strategy;

    public OnEventWatermarkStrategy(WatermarkStrategy<RowData> strategy) {
        this.strategy = strategy;
    }

    @Override
    public WatermarkGenerator<RowData> createWatermarkGenerator(
            WatermarkGeneratorSupplier.Context context) {
        WatermarkGenerator<RowData> generator = strategy.createWatermarkGenerator(context);
        return new WatermarkGenerator<RowData>() {

            @Override
            public void onEvent(RowData event, long eventTimestamp, WatermarkOutput output) {
                generator.onEvent(event, eventTimestamp, output);
                generator.onPeriodicEmit(output);
            }

            @Override
            public void onPeriodicEmit(WatermarkOutput output) {
                // for idle watermark
                generator.onPeriodicEmit(output);
            }
        };
    }
}
