// Licensed to the Apache Software Foundation (ASF) under one

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// 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 <memory>

#include <vector>

#include "common/logging.h"

#include "common/status.h"

#include "core/column/column.h"

#include "core/column/column_array.h"

#include "core/column/column_struct.h"

#include "core/data_type/data_type_decimal.h"

#include "core/data_type/data_type_number.h" // IWYU pragma: keep

#include "core/data_type/data_type_struct.h"

#include "core/field.h"

#include "core/types.h"

#include "exprs/function/dictionary.h"

#include "exprs/function/dictionary_factory.h"

#include "exprs/function/function.h"

#include "exprs/function/simple_function_factory.h"

namespace doris {

struct DictGetState {

    std::shared_ptr<const IDictionary> dict;

    ///TODO:

    // 1. we do not need to check dict every time(shoud only check in open)

    // 2. for some dict, will init some struct each time, we should cache it

};

class FunctionDictGetMany : public IFunction {

public:

    static constexpr auto name = "dict_get_many";

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

    String get_name() const override { return name; }

    bool is_variadic() const override { return false; }

    size_t get_number_of_arguments() const override { return 3; }

    DataTypes get_variadic_argument_types_impl() const override { return {}; }

    DataTypePtr get_return_type_impl(const ColumnsWithTypeAndName& arguments) const override {

        return std::make_shared<DataTypeDecimal128>();

    }

    bool skip_return_type_check() const override { return true; }

    bool use_default_implementation_for_nulls() const override { return false; }

    Status open(FunctionContext* context, FunctionContext::FunctionStateScope scope) override {

        if (scope == FunctionContext::THREAD_LOCAL) {

            return Status::OK();

        }

        std::shared_ptr<DictGetState> state = std::make_shared<DictGetState>();

        context->set_function_state(scope, state);

        DCHECK(context->get_num_args() == 3);

        auto dict_fn = context->dict_function();

        if (!dict_fn) {

            throw doris::Exception(ErrorCode::INVALID_ARGUMENT, "not set dict_function");

        }

        auto dict = ExecEnv::GetInstance()->dict_factory()->get(dict_fn->dictionary_id,

                                                                dict_fn->version_id);

        if (!dict) {

            std::string dict_name =

                    context->get_constant_col(0)->column_ptr->get_data_at(0).to_string();

            throw doris::Exception(ErrorCode::INVALID_ARGUMENT,

                                   "can not find dict name : {} , dict_id : {} , version_id : {}  ",

                                   dict_name, dict_fn->dictionary_id, dict_fn->version_id);

        }

        state->dict = dict;

        return Status::OK();

    }

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

                        uint32_t result, size_t input_rows_count) const override {

        auto* dict_state = reinterpret_cast<DictGetState*>(

                context->get_function_state(FunctionContext::FRAGMENT_LOCAL));

        if (!dict_state) {

            return Status::RuntimeError("funciton context for function '{}' must have dict_state;",

                                        get_name());

        }

        // dict get many(name, array<value names>, struct<key columns>) -> struct <value columns>

        // get value names

        const Array array_names =

                (*block.get_by_position(arguments[1]).column)[0].get<TYPE_ARRAY>();

        std::vector<std::string> attribute_names;

        for (auto field : array_names) {

            attribute_names.push_back(field.template get<TYPE_STRING>());

        }

        const auto dict = dict_state->dict;

        DataTypes attribute_types;

        for (auto attribute_name : attribute_names) {

            attribute_types.push_back(dict->get_attribute_type(attribute_name));

        }

        // get key columns (struct<key columns>)

        const ColumnPtr key_struct_column =

                block.get_by_position(arguments[2]).column->convert_to_full_column_if_const();

        // columns_copy is just copy ptr , not column

        auto key_columns = assert_cast<const ColumnStruct&>(*key_struct_column).get_columns_copy();

        DataTypes key_types = remove_nullable(

                assert_cast<const DataTypeStruct&>(*block.get_by_position(arguments[2]).type)

                        .get_elements());

        auto result_columns =

                dict->get_tuple_columns(attribute_names, attribute_types, key_columns, key_types);

        block.replace_by_position(result, ColumnStruct::create(result_columns));

        return Status::OK();

    }

};

void register_function_dict_get_many(SimpleFunctionFactory& factory) {

    factory.register_function<FunctionDictGetMany>();

}

} // namespace doris