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// 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.

#include "exprs/table_function/vexplode.h"

#include <glog/logging.h>

#include <ostream>

#include "common/status.h"

#include "core/block/block.h"

#include "core/block/column_with_type_and_name.h"

#include "core/column/column.h"

#include "core/column/column_array.h"

#include "core/column/column_nothing.h"

#include "core/column/column_variant.h"

#include "core/data_type/data_type.h"

#include "core/data_type/data_type_array.h"

#include "core/data_type/data_type_nothing.h"

#include "exprs/function/function_helpers.h"

#include "exprs/vexpr.h"

#include "exprs/vexpr_context.h"

namespace doris {

#include "common/compile_check_begin.h"

VExplodeTableFunction::VExplodeTableFunction() {

    _fn_name = "vexplode";

}

Status VExplodeTableFunction::_process_init_variant(Block* block, int value_column_idx) {

    // explode variant array

    auto column_without_nullable = remove_nullable(block->get_by_position(value_column_idx).column);

    auto column = column_without_nullable->convert_to_full_column_if_const();

    auto& variant_column = assert_cast<ColumnVariant&>(*(column->assume_mutable()));

    variant_column.finalize();

    _detail.output_as_variant = true;

    _detail.variant_enable_doc_mode = variant_column.enable_doc_mode();

    if (!variant_column.is_null_root()) {

        _array_column = variant_column.get_root();

        // We need to wrap the output nested column within a variant column.

        // Otherwise the type is missmatched

        const auto* array_type = check_and_get_data_type<DataTypeArray>(

                remove_nullable(variant_column.get_root_type()).get());

        if (array_type == nullptr) {

            return Status::NotSupported("explode not support none array type {}",

                                        variant_column.get_root_type()->get_name());

        }

        _detail.nested_type = array_type->get_nested_type();

    } else {

        // null root, use nothing type

        _array_column = ColumnNullable::create(ColumnArray::create(ColumnNothing::create(0)),

                                               ColumnUInt8::create(0));

        _array_column->assume_mutable()->insert_many_defaults(variant_column.size());

        _detail.nested_type = std::make_shared<DataTypeNothing>();

    }

    return Status::OK();

}

Status VExplodeTableFunction::process_init(Block* block, RuntimeState* state) {

    CHECK(_expr_context->root()->children().size() == 1)

            << "VExplodeTableFunction only support 1 child but has "

            << _expr_context->root()->children().size();

    int value_column_idx = -1;

    RETURN_IF_ERROR(_expr_context->root()->children()[0]->execute(_expr_context.get(), block,

                                                                  &value_column_idx));

    if (block->get_by_position(value_column_idx).type->get_primitive_type() == TYPE_VARIANT) {

        RETURN_IF_ERROR(_process_init_variant(block, value_column_idx));

    } else {

        _array_column =

                block->get_by_position(value_column_idx).column->convert_to_full_column_if_const();

    }

    if (!extract_column_array_info(*_array_column, _detail)) {

        return Status::NotSupported("column type {} not supported now",

                                    block->get_by_position(value_column_idx).column->get_name());

    }

    return Status::OK();

}

bool VExplodeTableFunction::support_block_fast_path() const {

    return !_is_outer;

}

Status VExplodeTableFunction::prepare_block_fast_path(Block* /*block*/, RuntimeState* /*state*/,

                                                      BlockFastPathContext* ctx) {

    if (!support_block_fast_path()) {

        return Status::NotSupported("vexplode doesn't support block fast path in current mode");

    }

    if (_detail.offsets_ptr == nullptr || _detail.nested_col.get() == nullptr) {

        return Status::InternalError("vexplode block fast path not initialized");

    }

    ctx->array_nullmap_data = _detail.array_nullmap_data;

    ctx->offsets_ptr = _detail.offsets_ptr;

    ctx->nested_col = _detail.nested_col;

    ctx->nested_nullmap_data = _detail.nested_nullmap_data;

    return Status::OK();

}

void VExplodeTableFunction::process_row(size_t row_idx) {

    DCHECK(row_idx < _array_column->size());

    TableFunction::process_row(row_idx);

    if (!_detail.array_nullmap_data || !_detail.array_nullmap_data[row_idx]) {

        _array_offset = (*_detail.offsets_ptr)[row_idx - 1];

        _cur_size = (*_detail.offsets_ptr)[row_idx] - _array_offset;

    }

}

void VExplodeTableFunction::process_close() {

    _array_column = nullptr;

    _detail.reset();

    _array_offset = 0;

}

void VExplodeTableFunction::get_same_many_values(MutableColumnPtr& column, int length) {

    size_t pos = _array_offset + _cur_offset;

    if (current_empty() || (_detail.nested_nullmap_data && _detail.nested_nullmap_data[pos])) {

        column->insert_many_defaults(length);

    } else {

        if (_is_nullable) {

            assert_cast<ColumnNullable*>(column.get())

                    ->get_nested_column_ptr()

                    ->insert_many_from(*_detail.nested_col, pos, length);

            assert_cast<ColumnUInt8*>(

                    assert_cast<ColumnNullable*>(column.get())->get_null_map_column_ptr().get())

                    ->insert_many_defaults(length);

        } else {

            column->insert_many_from(*_detail.nested_col, pos, length);

        }

    }

}

int VExplodeTableFunction::get_value(MutableColumnPtr& column, int max_step) {

    max_step = std::min(max_step, (int)(_cur_size - _cur_offset));

    size_t pos = _array_offset + _cur_offset;

    if (current_empty()) {

        column->insert_default();

        max_step = 1;

    } else {

        if (_is_nullable) {

            auto* nullable_column = assert_cast<ColumnNullable*>(column.get());

            auto nested_column = nullable_column->get_nested_column_ptr();

            auto* nullmap_column =

                    assert_cast<ColumnUInt8*>(nullable_column->get_null_map_column_ptr().get());

            nested_column->insert_range_from(*_detail.nested_col, pos, max_step);

            size_t old_size = nullmap_column->size();

            nullmap_column->resize(old_size + max_step);

            memcpy(nullmap_column->get_data().data() + old_size,

                   _detail.nested_nullmap_data + pos * sizeof(UInt8), max_step * sizeof(UInt8));

        } else {

            column->insert_range_from(*_detail.nested_col, pos, max_step);

        }

    }

    forward(max_step);

    return max_step;

}

#include "common/compile_check_end.h"

} // namespace doris