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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_json_object.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_struct.h"

#include "core/string_ref.h"

#include "exprs/vexpr.h"

#include "exprs/vexpr_context.h"

#include "util/jsonb_document.h"

#include "util/jsonb_writer.h"

namespace doris {

VExplodeJsonObjectTableFunction::VExplodeJsonObjectTableFunction() {

    _fn_name = "vexplode_json_object";

}

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

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

            << "VExplodeJsonObjectTableFunction only support 1 child but has "

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

    RETURN_IF_ERROR(_expr_context->root()->children()[0]->execute_column(

            _expr_context.get(), block, nullptr, block->rows(), _json_object_column));

    return Status::OK();

}

void VExplodeJsonObjectTableFunction::process_row(size_t row_idx) {

    TableFunction::process_row(row_idx);

    StringRef text = _json_object_column->get_data_at(row_idx);

    if (text.data != nullptr) {

        const JsonbDocument* doc = nullptr;

        auto st = JsonbDocument::checkAndCreateDocument(text.data, text.size, &doc);

        if (!st.ok() || !doc || !doc->getValue()) [[unlikely]] {

            // error jsonb, put null into output, cur_size = 0 , we will insert_default

            return;

        }

        // value is NOT necessary to be deleted since JsonbValue will not allocate memory

        const JsonbValue* value = doc->getValue();

        auto writer = std::make_unique<JsonbWriter>();

        if (value->isObject()) {

            _cur_size = value->numElements();

            const auto* obj = value->unpack<ObjectVal>();

            _object_pairs.first =

                    ColumnNullable::create(ColumnString::create(), ColumnUInt8::create());

            _object_pairs.second =

                    ColumnNullable::create(ColumnString::create(), ColumnUInt8::create());

            _object_pairs.first->reserve(_cur_size);

            _object_pairs.second->reserve(_cur_size);

            for (const auto& it : *obj) {

                _object_pairs.first->insert_data(it.getKeyStr(), it.klen());

                writer->reset();

                writer->writeValue(it.value());

                if (it.value()->isNull()) {

                    _object_pairs.second->insert_default();

                } else {

                    const std::string_view& jsonb_value = std::string_view(

                            writer->getOutput()->getBuffer(), writer->getOutput()->getSize());

                    _object_pairs.second->insert_data(jsonb_value.data(), jsonb_value.size());

                }

            }

        }

        // we do not support other json type except object

    }

}

void VExplodeJsonObjectTableFunction::process_close() {

    _json_object_column = nullptr;

    _object_pairs.first = nullptr;

    _object_pairs.second = nullptr;

}

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

    // if current is empty map row, also append a default value

    if (current_empty()) {

        column->insert_many_defaults(length);

        return;

    }

    ColumnStruct* ret = nullptr;

    // this _is_nullable is whole output column's nullable

    if (_is_nullable) {

        // make map kv value into struct

        ret = assert_cast<ColumnStruct*>(

                assert_cast<ColumnNullable*>(column.get())->get_nested_column_ptr().get());

        assert_cast<ColumnUInt8*>(

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

                ->insert_many_defaults(length);

    } else if (is_column<ColumnStruct>(column.get())) {

        ret = assert_cast<ColumnStruct*>(column.get());

    } else {

        throw Exception(ErrorCode::INTERNAL_ERROR,

                        "only support expand json object int to struct(kv pair), but given: ",

                        column->get_name());

    }

    if (!ret || ret->tuple_size() != 2) {

        throw Exception(ErrorCode::INTERNAL_ERROR,

                        "only support expand json object int to kv pair column, but given: ",

                        ret->tuple_size());

    }

    ret->get_column(0).insert_many_from(*_object_pairs.first, _cur_offset, length);

    ret->get_column(1).insert_many_from(*_object_pairs.second, _cur_offset, length);

}

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

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

    if (current_empty()) {

        column->insert_default();

        max_step = 1;

    } else {

        ColumnStruct* struct_column = nullptr;

        if (_is_nullable) {

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

            struct_column =

                    assert_cast<ColumnStruct*>(nullable_column->get_nested_column_ptr().get());

            auto* nullmap_column =

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

            // here nullmap_column insert max_step many defaults as if MAP[row_idx] is NULL

            // will be not update value, _cur_size = 0, means current_empty;

            // so here could insert directly

            nullmap_column->insert_many_defaults(max_step);

        } else {

            struct_column = assert_cast<ColumnStruct*>(column.get());

        }

        if (!struct_column || struct_column->tuple_size() != 2) {

            throw Exception(ErrorCode::INTERNAL_ERROR,

                            "only support expand json object int to kv pair column, but given:  ",

                            struct_column->tuple_size());

        }

        struct_column->get_column(0).insert_range_from(*_object_pairs.first, _cur_offset, max_step);

        struct_column->get_column(1).insert_range_from(*_object_pairs.second, _cur_offset,

                                                       max_step);

    }

    forward(max_step);

    return max_step;

}

} // namespace doris