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 * 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.kafka.streams.kstream.internals;

import org.apache.kafka.common.metrics.Sensor;
import org.apache.kafka.streams.kstream.KeyValueMapper;
import org.apache.kafka.streams.kstream.ValueJoiner;
import org.apache.kafka.streams.processor.To;
import org.apache.kafka.streams.processor.internals.metrics.StreamsMetricsImpl;
import org.apache.kafka.streams.state.ValueAndTimestamp;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import static org.apache.kafka.streams.processor.internals.metrics.TaskMetrics.droppedRecordsSensor;
import static org.apache.kafka.streams.state.ValueAndTimestamp.getValueOrNull;

@SuppressWarnings("deprecation") // Old PAPI. Needs to be migrated.
class KTableKTableInnerJoin extends KTableKTableAbstractJoin {
    private static final Logger LOG = LoggerFactory.getLogger(KTableKTableInnerJoin.class);

    private final KeyValueMapper keyValueMapper = (key, value) -> key;

    KTableKTableInnerJoin(final KTableImpl table1,
                          final KTableImpl table2,
                          final ValueJoiner joiner) {
        super(table1, table2, joiner);
    }

    @Override
    public org.apache.kafka.streams.processor.Processor> get() {
        return new KTableKTableJoinProcessor(valueGetterSupplier2.get());
    }

    @Override
    public KTableValueGetterSupplier view() {
        return new KTableKTableInnerJoinValueGetterSupplier(valueGetterSupplier1, valueGetterSupplier2);
    }

    private class KTableKTableInnerJoinValueGetterSupplier extends KTableKTableAbstractJoinValueGetterSupplier {

        KTableKTableInnerJoinValueGetterSupplier(final KTableValueGetterSupplier valueGetterSupplier1,
                                                 final KTableValueGetterSupplier valueGetterSupplier2) {
            super(valueGetterSupplier1, valueGetterSupplier2);
        }

        public KTableValueGetter get() {
            return new KTableKTableInnerJoinValueGetter(valueGetterSupplier1.get(), valueGetterSupplier2.get());
        }
    }

    private class KTableKTableJoinProcessor extends org.apache.kafka.streams.processor.AbstractProcessor> {

        private final KTableValueGetter valueGetter;
        private Sensor droppedRecordsSensor;

        KTableKTableJoinProcessor(final KTableValueGetter valueGetter) {
            this.valueGetter = valueGetter;
        }

        @Override
        public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
            super.init(context);
            droppedRecordsSensor = droppedRecordsSensor(
                Thread.currentThread().getName(),
                context.taskId().toString(),
                (StreamsMetricsImpl) context.metrics()
            );
            valueGetter.init(context);
        }

        @Override
        public void process(final K key, final Change change) {
            // we do join iff keys are equal, thus, if key is null we cannot join and just ignore the record
            if (key == null) {
                LOG.warn(
                    "Skipping record due to null key. change=[{}] topic=[{}] partition=[{}] offset=[{}]",
                    change, context().topic(), context().partition(), context().offset()
                );
                droppedRecordsSensor.record();
                return;
            }

            R newValue = null;
            final long resultTimestamp;
            R oldValue = null;

            final ValueAndTimestamp valueAndTimestampRight = valueGetter.get(key);
            final V2 valueRight = getValueOrNull(valueAndTimestampRight);
            if (valueRight == null) {
                return;
            }

            resultTimestamp = Math.max(context().timestamp(), valueAndTimestampRight.timestamp());

            if (change.newValue != null) {
                newValue = joiner.apply(change.newValue, valueRight);
            }

            if (sendOldValues && change.oldValue != null) {
                oldValue = joiner.apply(change.oldValue, valueRight);
            }

            context().forward(key, new Change<>(newValue, oldValue), To.all().withTimestamp(resultTimestamp));
        }

        @Override
        public void close() {
            valueGetter.close();
        }
    }

    private class KTableKTableInnerJoinValueGetter implements KTableValueGetter {

        private final KTableValueGetter valueGetter1;
        private final KTableValueGetter valueGetter2;

        KTableKTableInnerJoinValueGetter(final KTableValueGetter valueGetter1,
                                         final KTableValueGetter valueGetter2) {
            this.valueGetter1 = valueGetter1;
            this.valueGetter2 = valueGetter2;
        }

        @Override
        public void init(final org.apache.kafka.streams.processor.ProcessorContext context) {
            valueGetter1.init(context);
            valueGetter2.init(context);
        }

        @Override
        public ValueAndTimestamp get(final K key) {
            final ValueAndTimestamp valueAndTimestamp1 = valueGetter1.get(key);
            final V1 value1 = getValueOrNull(valueAndTimestamp1);

            if (value1 != null) {
                final ValueAndTimestamp valueAndTimestamp2 = valueGetter2.get(keyValueMapper.apply(key, value1));
                final V2 value2 = getValueOrNull(valueAndTimestamp2);

                if (value2 != null) {
                    return ValueAndTimestamp.make(
                        joiner.apply(value1, value2),
                        Math.max(valueAndTimestamp1.timestamp(), valueAndTimestamp2.timestamp()));
                } else {
                    return null;
                }
            } else {
                return null;
            }
        }

        @Override
        public void close() {
            valueGetter1.close();
            valueGetter2.close();
        }
    }
}