/*
 * Licensed 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 io.prestosql.operator.scalar;

import com.google.common.collect.ImmutableList;
import io.airlift.slice.Slices;
import io.prestosql.metadata.Metadata;
import io.prestosql.operator.DriverYieldSignal;
import io.prestosql.operator.project.PageProcessor;
import io.prestosql.spi.Page;
import io.prestosql.spi.block.Block;
import io.prestosql.spi.block.BlockBuilder;
import io.prestosql.spi.function.FunctionKind;
import io.prestosql.spi.function.Signature;
import io.prestosql.spi.type.ArrayType;
import io.prestosql.spi.type.Type;
import io.prestosql.sql.gen.ExpressionCompiler;
import io.prestosql.sql.gen.PageFunctionCompiler;
import io.prestosql.sql.relational.CallExpression;
import io.prestosql.sql.relational.RowExpression;
import org.openjdk.jmh.annotations.Benchmark;
import org.openjdk.jmh.annotations.BenchmarkMode;
import org.openjdk.jmh.annotations.Fork;
import org.openjdk.jmh.annotations.Measurement;
import org.openjdk.jmh.annotations.Mode;
import org.openjdk.jmh.annotations.OperationsPerInvocation;
import org.openjdk.jmh.annotations.OutputTimeUnit;
import org.openjdk.jmh.annotations.Param;
import org.openjdk.jmh.annotations.Scope;
import org.openjdk.jmh.annotations.Setup;
import org.openjdk.jmh.annotations.State;
import org.openjdk.jmh.annotations.Warmup;
import org.openjdk.jmh.runner.Runner;
import org.openjdk.jmh.runner.options.Options;
import org.openjdk.jmh.runner.options.OptionsBuilder;
import org.openjdk.jmh.runner.options.VerboseMode;
import org.testng.annotations.Test;

import java.util.List;
import java.util.Optional;
import java.util.concurrent.ThreadLocalRandom;
import java.util.concurrent.TimeUnit;

import static io.prestosql.memory.context.AggregatedMemoryContext.newSimpleAggregatedMemoryContext;
import static io.prestosql.metadata.MetadataManager.createTestMetadataManager;
import static io.prestosql.spi.type.BigintType.BIGINT;
import static io.prestosql.spi.type.BooleanType.BOOLEAN;
import static io.prestosql.spi.type.DoubleType.DOUBLE;
import static io.prestosql.spi.type.VarcharType.VARCHAR;
import static io.prestosql.sql.relational.Expressions.field;
import static io.prestosql.testing.TestingConnectorSession.SESSION;

@SuppressWarnings("MethodMayBeStatic")
@State(Scope.Thread)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
@Fork(2)
@Warmup(iterations = 10, time = 500, timeUnit = TimeUnit.MILLISECONDS)
@Measurement(iterations = 10, time = 500, timeUnit = TimeUnit.MILLISECONDS)
@BenchmarkMode(Mode.AverageTime)
public class BenchmarkArrayIntersect
{
    private static final int POSITIONS = 1_000;

    @Benchmark
    @OperationsPerInvocation(POSITIONS)
    public List<Optional<Page>> arrayIntersect(BenchmarkData data)
    {
        return ImmutableList.copyOf(data.getPageProcessor().process(
                SESSION,
                new DriverYieldSignal(),
                newSimpleAggregatedMemoryContext().newLocalMemoryContext(PageProcessor.class.getSimpleName()),
                data.getPage()));
    }

    @SuppressWarnings("FieldMayBeFinal")
    @State(Scope.Thread)
    public static class BenchmarkData
    {
        private String name = "array_intersect";

        @Param({"BIGINT", "VARCHAR", "DOUBLE", "BOOLEAN"})
        private String type = "BIGINT";

        @Param({"10", "100", "1000"})
        private int arraySize = 10;

        private Page page;
        private PageProcessor pageProcessor;

        @Setup
        public void setup()
        {
            Type elementType;
            switch (type) {
                case "BIGINT":
                    elementType = BIGINT;
                    break;
                case "VARCHAR":
                    elementType = VARCHAR;
                    break;
                case "DOUBLE":
                    elementType = DOUBLE;
                    break;
                case "BOOLEAN":
                    elementType = BOOLEAN;
                    break;
                default:
                    throw new UnsupportedOperationException();
            }

            ArrayType arrayType = new ArrayType(elementType);
            Signature signature = new Signature(name, FunctionKind.SCALAR, arrayType.getTypeSignature(), arrayType.getTypeSignature(), arrayType.getTypeSignature());
            ImmutableList<RowExpression> projections = ImmutableList.of(
                    new CallExpression(signature, arrayType, ImmutableList.of(field(0, arrayType), field(1, arrayType))));

            Metadata metadata = createTestMetadataManager();
            ExpressionCompiler compiler = new ExpressionCompiler(metadata, new PageFunctionCompiler(metadata, 0));
            pageProcessor = compiler.compilePageProcessor(Optional.empty(), projections).get();

            page = new Page(createChannel(POSITIONS, arraySize, elementType), createChannel(POSITIONS, arraySize, elementType));
        }

        private static Block createChannel(int positionCount, int arraySize, Type elementType)
        {
            ArrayType arrayType = new ArrayType(elementType);
            BlockBuilder blockBuilder = arrayType.createBlockBuilder(null, positionCount);
            for (int position = 0; position < positionCount; position++) {
                BlockBuilder entryBuilder = blockBuilder.beginBlockEntry();
                for (int i = 0; i < arraySize; i++) {
                    if (elementType.getJavaType() == long.class) {
                        elementType.writeLong(entryBuilder, ThreadLocalRandom.current().nextLong() % arraySize);
                    }
                    else if (elementType.getJavaType() == double.class) {
                        elementType.writeDouble(entryBuilder, ThreadLocalRandom.current().nextDouble() % arraySize);
                    }
                    else if (elementType.getJavaType() == boolean.class) {
                        elementType.writeBoolean(entryBuilder, ThreadLocalRandom.current().nextBoolean());
                    }
                    else if (elementType.equals(VARCHAR)) {
                        // make sure the size of a varchar is rather small; otherwise the aggregated slice may overflow
                        elementType.writeSlice(entryBuilder, Slices.utf8Slice(Long.toString(ThreadLocalRandom.current().nextLong() % arraySize)));
                    }
                    else {
                        throw new UnsupportedOperationException();
                    }
                }
                blockBuilder.closeEntry();
            }
            return blockBuilder.build();
        }

        public PageProcessor getPageProcessor()
        {
            return pageProcessor;
        }

        public Page getPage()
        {
            return page;
        }
    }

    @Test
    public void verify()
    {
        BenchmarkData data = new BenchmarkData();
        data.setup();
        new BenchmarkArrayIntersect().arrayIntersect(data);
    }

    public static void main(String[] args)
            throws Throwable
    {
        // assure the benchmarks are valid before running
        BenchmarkData data = new BenchmarkData();
        data.setup();
        new BenchmarkArrayIntersect().arrayIntersect(data);

        Options options = new OptionsBuilder()
                .verbosity(VerboseMode.NORMAL)
                .include(".*" + BenchmarkArrayIntersect.class.getSimpleName() + ".*")
                .build();
        new Runner(options).run();
    }
}
