/*
 * 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 com.facebook.presto.operator.scalar;

import com.facebook.presto.common.block.Block;
import com.facebook.presto.common.block.BlockBuilder;
import com.facebook.presto.common.type.Type;
import com.facebook.presto.operator.aggregation.TypedSet;
import com.facebook.presto.spi.function.Description;
import com.facebook.presto.spi.function.ScalarFunction;
import com.facebook.presto.spi.function.SqlType;
import com.facebook.presto.spi.function.TypeParameter;
import it.unimi.dsi.fastutil.longs.LongOpenHashSet;
import it.unimi.dsi.fastutil.longs.LongSet;

import java.util.concurrent.atomic.AtomicBoolean;

import static com.facebook.presto.common.type.BigintType.BIGINT;

@ScalarFunction("array_union")
@Description("Union elements of the two given arrays")
public final class ArrayUnionFunction
{
    private ArrayUnionFunction() {}

    @TypeParameter("E")
    @SqlType("array(E)")
    public static Block union(
            @TypeParameter("E") Type type,
            @SqlType("array(E)") Block leftArray,
            @SqlType("array(E)") Block rightArray)
    {
        int leftArrayCount = leftArray.getPositionCount();
        int rightArrayCount = rightArray.getPositionCount();
        TypedSet typedSet = new TypedSet(type, leftArrayCount + rightArrayCount, "array_union");
        BlockBuilder distinctElementBlockBuilder = type.createBlockBuilder(null, leftArrayCount + rightArrayCount);
        appendTypedArray(leftArray, type, typedSet, distinctElementBlockBuilder);
        appendTypedArray(rightArray, type, typedSet, distinctElementBlockBuilder);

        return distinctElementBlockBuilder.build();
    }

    private static void appendTypedArray(Block array, Type type, TypedSet typedSet, BlockBuilder blockBuilder)
    {
        for (int i = 0; i < array.getPositionCount(); i++) {
            if (!typedSet.contains(array, i)) {
                typedSet.add(array, i);
                type.appendTo(array, i, blockBuilder);
            }
        }
    }

    @SqlType("array(bigint)")
    public static Block bigintUnion(@SqlType("array(bigint)") Block leftArray, @SqlType("array(bigint)") Block rightArray)
    {
        int leftArrayCount = leftArray.getPositionCount();
        int rightArrayCount = rightArray.getPositionCount();
        LongSet set = new LongOpenHashSet(leftArrayCount + rightArrayCount);
        BlockBuilder distinctElementBlockBuilder = BIGINT.createBlockBuilder(null, leftArrayCount + rightArrayCount);
        AtomicBoolean containsNull = new AtomicBoolean(false);
        appendBigintArray(leftArray, containsNull, set, distinctElementBlockBuilder);
        appendBigintArray(rightArray, containsNull, set, distinctElementBlockBuilder);

        return distinctElementBlockBuilder.build();
    }

    private static void appendBigintArray(Block array, AtomicBoolean containsNull, LongSet set, BlockBuilder blockBuilder)
    {
        for (int i = 0; i < array.getPositionCount(); i++) {
            if (array.isNull(i)) {
                if (!containsNull.get()) {
                    containsNull.set(true);
                    blockBuilder.appendNull();
                }
                continue;
            }
            long value = BIGINT.getLong(array, i);
            if (set.add(value)) {
                BIGINT.writeLong(blockBuilder, value);
            }
        }
    }
}

@@ -652,62 +652,8 @@
 ck;%0A
-import com.facebook.presto.common.block.BlockBuilder;%0A
 impo
@@ -737,24 +737,33 @@
 aggregation.
+Optimized
 TypedSet;%0Aim
@@ -976,221 +976,8 @@
 ter;
-%0Aimport it.unimi.dsi.fastutil.longs.LongOpenHashSet;%0Aimport it.unimi.dsi.fastutil.longs.LongSet;%0A%0Aimport java.util.concurrent.atomic.AtomicBoolean;%0A%0Aimport static com.facebook.presto.common.type.BigintType.BIGINT;
 %0A%0A@S
@@ -1495,16 +1495,25 @@
         
+Optimized
 TypedSet
@@ -1528,16 +1528,25 @@
 t = new 
+Optimized
 TypedSet
@@ -1588,2074 +1588,182 @@
 ount
-, %22array_union%22);%0A        BlockBuilder distinctElementBlockBuilder = type.createBlockBuilder(null, leftArrayCount + rightArrayCount);%0A        appendTypedArray(leftArray, type, typedSet, distinctElementBlockBuilder);%0A        appendTypedArray(rightArray, type, typedSet, distinctElementBlockBuilder);%0A%0A        return distinctElementBlockBuilder.build();%0A    %7D%0A%0A    private static void appendTypedArray(Block array, Type type, TypedSet typedSet, BlockBuilder blockBuilder)%0A    %7B%0A        for (int i = 0; i %3C array.getPositionCount(); i++) %7B%0A            if (!typedSet.contains(array, i)) %7B%0A                typedSet.add(array, i);%0A                type.appendTo(array, i, blockBuilder);%0A            %7D%0A        %7D%0A    %7D%0A%0A    @SqlType(%22array(bigint)%22)%0A    public static Block bigintUnion(@SqlType(%22array(bigint)%22) Block leftArray, @SqlType(%22array(bigint)%22) Block rightArray)%0A    %7B%0A        int leftArrayCount = leftArray.getPositionCount();%0A        int rightArrayCount = rightArray.getPositionCount();%0A        LongSet set = new LongOpenHashSet(leftArrayCount + rightArrayCount);%0A        BlockBuilder distinctElementBlockBuilder = BIGINT.createBlockBuilder(null, leftArrayCount + rightArrayCount);%0A        AtomicBoolean containsNull = new AtomicBoolean(false);%0A        appendBigintArray(leftArray, containsNull, set, distinctElementBlockBuilder);%0A        appendBigintArray(rightArray, containsNull, set, distinctElementBlockBuilder);%0A%0A        return distinctElementBlockBuilder.build();%0A    %7D%0A%0A    private static void appendBigintArray(Block array, AtomicBoolean containsNull, LongSet set, BlockBuilder blockBuilder)%0A    %7B%0A        for (int i = 0; i %3C array.getPositionCount(); i++) %7B%0A            if (array.isNull(i)) %7B%0A                if (!containsNull.get()) %7B%0A                    containsNull.set(true);%0A                    blockBuilder.appendNull();%0A                %7D%0A                continue;%0A            %7D%0A            long value = BIGINT.getLong(array, i);%0A            if (set.add(value)) %7B%0A                BIGINT.writeLong(blockBuilder, value);%0A            %7D%0A        %7D%0A    %7D
+);%0A%0A        typedSet.union(leftArray);%0A        typedSet.union(rightArray);%0A%0A        return typedSet.getBlock();%0A    %7D%0A%0A    // TODO: Specialize for bigint using LongOpenHashSet
 %0A%7D%0A

Optimize array_union using OptimizedTypedSet