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/*
 * Copyright (c) 2010-2017, KolibriFX AS. Licensed under the Apache License, version 2.0.
 */

package com.kolibrifx.plovercrest.server.internal.streams;

import java.nio.ByteBuffer;
import java.util.Collection;
import java.util.stream.Collectors;
import com.kolibrifx.common.Disposable;
import com.kolibrifx.plovercrest.client.AbstractTableSerializer;
import com.kolibrifx.plovercrest.client.TableMetadata;
import com.kolibrifx.plovercrest.client.TableSerializer;
import com.kolibrifx.plovercrest.client.TableSerializerFactory;
import com.kolibrifx.plovercrest.server.PlovercrestEngine;
import com.kolibrifx.plovercrest.server.Table;
import com.kolibrifx.plovercrest.server.TableInfo;
import com.kolibrifx.plovercrest.server.internal.TableNamesListenerHandler;
import com.kolibrifx.plovercrest.server.streams.Stream;
import com.kolibrifx.plovercrest.server.streams.StreamEngine;
import com.kolibrifx.plovercrest.server.streams.StreamInfo;
import com.kolibrifx.plovercrest.server.streams.StreamNamesListener;
import com.kolibrifx.plovercrest.server.streams.StreamProvider;

public class TableStreamProvider implements StreamProvider {
    private static class ByteBufferReadSerializer extends AbstractTableSerializer {
        @Override
        public void serialize(final ByteBuffer out, final ByteBuffer m) {
            throw new UnsupportedOperationException();
        }

        @Override
        public ByteBuffer unserialize(final long timestamp, final ByteBuffer in) {
            return in;
        }

        @Override
        public Class elementClass() {
            return ByteBuffer.class;
        }

        @Override
        public long getTimestampForMessage(final ByteBuffer message) {
            throw new UnsupportedOperationException();
        }
    }

    private static final ByteBufferReadSerializer NOOP_READER = new ByteBufferReadSerializer();

    private final PlovercrestEngine engine;
    private final TableSerializerFactory serializerFactory;

    public TableStreamProvider(final PlovercrestEngine engine, final TableSerializerFactory serializerFactory) {
        this.engine = engine;
        this.serializerFactory = serializerFactory;
    }

    @SuppressWarnings("unchecked")
    private  TableSerializer getSerializer(final Class elementClass, final TableMetadata metadata) {
        if (elementClass == ByteBuffer.class) {
            // hackish: rethink this
            return (TableSerializer) NOOP_READER;
        }
        return serializerFactory.createSerializer(metadata, elementClass);
    }

    @Override
    public  Stream tryOpen(final StreamEngine tools, final String name, final Class elementClass) {
        final Table table = engine.open(name);
        if (table == null) {
            return null;
        }
        return new TableStream<>(engine, table, getSerializer(elementClass, table.getInfo().getMetadata()));
    }

    @Override
    public Collection list() {
        return engine.getTableNames().stream().map(x -> new StreamInfo(x, true)).collect(Collectors.toList());
    }

    @Override
    public boolean tryCreate(final TableInfo info) {
        engine.create(info); // can throw
        return true;
    }

    @Override
    public Disposable addAvailableStreamsListener(final StreamNamesListener listener) {
        return new TableNamesListenerHandler(engine, listener);
    }
}