// 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.

#pragma once

#include <fmt/format.h>

#include <glog/logging.h>

#include <stddef.h>

#include <memory>

#include <ostream>

#include <string>

#include <utility>

#include "common/status.h"

#include "core/assert_cast.h"

#include "core/block/block.h"

#include "core/block/column_numbers.h"

#include "core/block/column_with_type_and_name.h"

#include "core/column/column.h"

#include "core/column/column_array.h"

#include "core/data_type/data_type.h"

#include "core/data_type/data_type_array.h"

#include "core/pod_array_fwd.h"

#include "core/types.h"

#include "exprs/function/function.h"

namespace doris {

class FunctionContext;

} // namespace doris

namespace doris {

class FunctionArrayCompact : public IFunction {

public:

static constexpr auto name = "array_compact";

static FunctionPtr create() { return std::make_shared<FunctionArrayCompact>(); }

using NullMapType = PaddedPODArray<UInt8>;

/// Get function name.

String get_name() const override { return name; }

bool is_variadic() const override { return false; }

size_t get_number_of_arguments() const override { return 1; }

DataTypePtr get_return_type_impl(const DataTypes& arguments) const override {

DCHECK(arguments[0]->get_primitive_type() == TYPE_ARRAY)

<< "first argument for function: " << name << " should be DataTypeArray"

<< " and arguments[0] is " << arguments[0]->get_name();

return arguments[0];

}

Status execute_impl(FunctionContext* context, Block& block, const ColumnNumbers& arguments,

uint32_t result, size_t input_rows_count) const override {

ColumnPtr src_column =

block.get_by_position(arguments[0]).column->convert_to_full_column_if_const();

const auto& src_column_array = check_and_get_column<ColumnArray>(*src_column);

if (!src_column_array) {

return Status::RuntimeError(

fmt::format("unsupported types for function {}({})", get_name(),

block.get_by_position(arguments[0]).type->get_name()));

}

const auto& src_offsets = src_column_array->get_offsets();

const auto* src_nested_column = &src_column_array->get_data();

DCHECK(src_nested_column != nullptr);

DataTypePtr src_column_type = block.get_by_position(arguments[0]).type;

auto nested_type = assert_cast<const DataTypeArray&>(*src_column_type).get_nested_type();

auto dest_column_ptr = ColumnArray::create(nested_type->create_column(),

ColumnArray::ColumnOffsets::create());

IColumn* dest_nested_column = &dest_column_ptr->get_data();

auto& dest_offsets = dest_column_ptr->get_offsets();

DCHECK(dest_nested_column != nullptr);

auto res_val = _execute(*src_nested_column, src_offsets, *dest_nested_column, dest_offsets);

if (!res_val) {

return Status::RuntimeError(

fmt::format("execute failed or unsupported types for function {}({})",

get_name(), block.get_by_position(arguments[0]).type->get_name()));

}

block.replace_by_position(result, std::move(dest_column_ptr));

return Status::OK();

}

private:

bool _execute(const IColumn& src_column, const ColumnArray::Offsets64& src_offsets,

IColumn& dest_column, ColumnArray::Offsets64& dest_offsets) const {

ColumnArray::Offset64 src_offsets_size = src_offsets.size();

ColumnArray::Offset64 src_pos = 0;

ColumnArray::Offset64 dest_pos = 0;

for (size_t i = 0; i < src_offsets_size; ++i) {

auto src_offset = src_offsets[i];

if (src_pos < src_offset) {

// Insert first element

dest_column.insert_from(src_column, src_pos);

++src_pos;

++dest_pos;

// For the rest of elements, insert if the element is different from the previous.

for (; src_pos < src_offset; ++src_pos) {

if (0 != (src_column.compare_at(src_pos - 1, src_pos, src_column, 1))) {

dest_column.insert_from(src_column, src_pos);

++dest_pos;

}

}

}

dest_offsets.push_back(dest_pos);

}

return true;

}

};

} // namespace doris