// 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.

#include <glog/logging.h>
#include <stddef.h>

#include <algorithm>
#include <boost/iterator/iterator_facade.hpp>
#include <memory>
#include <ostream>
#include <string>
#include <tuple>
#include <utility>

#include "common/status.h"
#include "vec/aggregate_functions/aggregate_function.h"
#include "vec/columns/column.h"
#include "vec/columns/column_array.h"
#include "vec/columns/column_const.h"
#include "vec/columns/column_map.h"
#include "vec/columns/column_nullable.h"
#include "vec/columns/column_vector.h"
#include "vec/columns/columns_number.h"
#include "vec/common/assert_cast.h"
#include "vec/common/typeid_cast.h"
#include "vec/core/block.h"
#include "vec/core/column_numbers.h"
#include "vec/core/column_with_type_and_name.h"
#include "vec/core/types.h"
#include "vec/data_types/data_type.h"
#include "vec/data_types/data_type_array.h"
#include "vec/data_types/data_type_map.h"
#include "vec/data_types/data_type_nullable.h"
#include "vec/data_types/data_type_number.h"
#include "vec/data_types/get_least_supertype.h"
#include "vec/functions/array/function_array_index.h"
#include "vec/functions/function.h"
#include "vec/functions/simple_function_factory.h"

namespace doris {
class FunctionContext;
} // namespace doris

namespace doris::vectorized {

// construct a map
// map(key1, value2, key2, value2) -> {key1: value2, key2: value2}
class FunctionMap : public IFunction {
public:
    static constexpr auto name = "map";
    static FunctionPtr create() { return std::make_shared<FunctionMap>(); }

    /// Get function name.
    String get_name() const override { return name; }

    bool is_variadic() const override { return true; }

    bool use_default_implementation_for_nulls() const override { return false; }

    size_t get_number_of_arguments() const override { return 0; }

    DataTypePtr get_return_type_impl(const DataTypes& arguments) const override {
        DCHECK(arguments.size() % 2 == 0)
                << "function: " << get_name() << ", arguments should not be even number";

        DataTypes key_types;
        DataTypes val_types;
        for (size_t i = 0; i < arguments.size(); i += 2) {
            key_types.push_back(arguments[i]);
            val_types.push_back(arguments[i + 1]);
        }

        DataTypePtr key_type;
        DataTypePtr val_type;
        get_least_supertype(key_types, &key_type);
        get_least_supertype(val_types, &val_type);

        return std::make_shared<DataTypeMap>(make_nullable(key_type), make_nullable(val_type));
    }

    Status execute_impl(FunctionContext* context, Block& block, const ColumnNumbers& arguments,
                        size_t result, size_t input_rows_count) const override {
        DCHECK(arguments.size() % 2 == 0)
                << "function: " << get_name() << ", arguments should not be even number";

        size_t num_element = arguments.size();

        auto result_col = block.get_by_position(result).type->create_column();
        auto map_column = typeid_cast<ColumnMap*>(result_col.get());
        if (!map_column) {
            return Status::RuntimeError("unsupported types for function {} return {}", get_name(),
                                        block.get_by_position(result).type->get_name());
        }

        // map keys column
        auto& result_col_map_keys_data = map_column->get_keys();
        result_col_map_keys_data.reserve(input_rows_count * num_element / 2);
        // map values column
        auto& result_col_map_vals_data = map_column->get_values();
        result_col_map_vals_data.reserve(input_rows_count * num_element / 2);
        // map offsets column
        auto& result_col_map_offsets = map_column->get_offsets();
        result_col_map_offsets.resize(input_rows_count);

        std::unique_ptr<bool[]> col_const = std::make_unique<bool[]>(num_element);
        for (size_t i = 0; i < num_element; ++i) {
            auto& col = block.get_by_position(arguments[i]).column;
            std::tie(col, col_const[i]) = unpack_if_const(col);
            bool is_nullable = i % 2 == 0 ? result_col_map_keys_data.is_nullable()
                                          : result_col_map_vals_data.is_nullable();
            // convert to nullable column
            if (is_nullable && !col->is_nullable()) {
                col = ColumnNullable::create(col, ColumnUInt8::create(col->size(), 0));
            }
        }

        // insert value into map
        ColumnArray::Offset64 offset = 0;
        for (size_t row = 0; row < input_rows_count; ++row) {
            for (size_t i = 0; i < num_element; i += 2) {
                result_col_map_keys_data.insert_from(*block.get_by_position(arguments[i]).column,
                                                     index_check_const(row, col_const[i]));
                result_col_map_vals_data.insert_from(
                        *block.get_by_position(arguments[i + 1]).column,
                        index_check_const(row, col_const[i + 1]));
            }
            offset += num_element / 2;
            result_col_map_offsets[row] = offset;
        }
        block.replace_by_position(result, std::move(result_col));
        return Status::OK();
    }
};

template <bool is_key, bool OldVersion = false>
class FunctionMapContains : public IFunction {
public:
    static constexpr auto name = is_key ? "map_contains_key" : "map_contains_value";
    static FunctionPtr create() { return std::make_shared<FunctionMapContains>(); }

    /// 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 2; }

    bool use_default_implementation_for_nulls() const override {
        return array_contains.use_default_implementation_for_nulls();
    }

    DataTypePtr get_return_type_impl(const DataTypes& arguments) const override {
        DataTypePtr datatype = arguments[0];
        if (datatype->is_nullable()) {
            datatype = assert_cast<const DataTypeNullable*>(datatype.get())->get_nested_type();
        }
        DCHECK(is_map(datatype)) << "first argument for function: " << name
                                 << " should be DataTypeMap";

        if constexpr (OldVersion) {
            return make_nullable(std::make_shared<DataTypeNumber<UInt8>>());
        } else {
            if (arguments[0]->is_nullable()) {
                return make_nullable(std::make_shared<DataTypeNumber<UInt8>>());
            } else {
                return std::make_shared<DataTypeNumber<UInt8>>();
            }
        }
    }

    Status execute_impl(FunctionContext* context, Block& block, const ColumnNumbers& arguments,
                        size_t result, size_t input_rows_count) const override {
        // backup original argument 0
        auto orig_arg0 = block.get_by_position(arguments[0]);
        auto left_column =
                block.get_by_position(arguments[0]).column->convert_to_full_column_if_const();
        const ColumnMap* map_column = nullptr;
        ColumnPtr nullmap_column = nullptr;
        if (left_column->is_nullable()) {
            auto nullable_column = reinterpret_cast<const ColumnNullable*>(left_column.get());
            map_column = check_and_get_column<ColumnMap>(nullable_column->get_nested_column());
            nullmap_column = nullable_column->get_null_map_column_ptr();
        } else {
            map_column = check_and_get_column<ColumnMap>(*left_column.get());
        }
        if (!map_column) {
            return Status::RuntimeError("unsupported types for function {}({})", get_name(),
                                        block.get_by_position(arguments[0]).type->get_name());
        }

        DataTypePtr datatype = block.get_by_position(arguments[0]).type;
        if (datatype->is_nullable()) {
            datatype = assert_cast<const DataTypeNullable*>(datatype.get())->get_nested_type();
        }
        const auto datatype_map = static_cast<const DataTypeMap*>(datatype.get());
        if constexpr (is_key) {
            const auto& array_column = map_column->get_keys_array_ptr();
            const auto datatype_array =
                    std::make_shared<DataTypeArray>(datatype_map->get_key_type());
            if (nullmap_column) {
                block.get_by_position(arguments[0]) = {
                        ColumnNullable::create(array_column, nullmap_column),
                        make_nullable(datatype_array),
                        block.get_by_position(arguments[0]).name + ".keys"};
            } else {
                block.get_by_position(arguments[0]) = {
                        array_column, datatype_array,
                        block.get_by_position(arguments[0]).name + ".keys"};
            }
        } else {
            const auto& array_column = map_column->get_values_array_ptr();
            const auto datatype_array =
                    std::make_shared<DataTypeArray>(datatype_map->get_value_type());
            if (nullmap_column) {
                block.get_by_position(arguments[0]) = {
                        ColumnNullable::create(array_column, nullmap_column),
                        make_nullable(datatype_array),
                        block.get_by_position(arguments[0]).name + ".values"};
            } else {
                block.get_by_position(arguments[0]) = {
                        array_column, datatype_array,
                        block.get_by_position(arguments[0]).name + ".values"};
            }
        }

        RETURN_IF_ERROR(
                array_contains.execute_impl(context, block, arguments, result, input_rows_count));

        // restore original argument 0
        block.get_by_position(arguments[0]) = orig_arg0;
        return Status::OK();
    }

private:
    FunctionArrayIndex<ArrayContainsAction> array_contains;
};

template <bool is_key>
class FunctionMapEntries : public IFunction {
public:
    static constexpr auto name = is_key ? "map_keys" : "map_values";
    static FunctionPtr create() { return std::make_shared<FunctionMapEntries>(); }

    /// 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 {
        DataTypePtr datatype = arguments[0];
        if (datatype->is_nullable()) {
            datatype = assert_cast<const DataTypeNullable*>(datatype.get())->get_nested_type();
        }
        DCHECK(is_map(datatype)) << "first argument for function: " << name
                                 << " should be DataTypeMap";
        const auto datatype_map = static_cast<const DataTypeMap*>(datatype.get());
        if (is_key) {
            return std::make_shared<DataTypeArray>(datatype_map->get_key_type());
        } else {
            return std::make_shared<DataTypeArray>(datatype_map->get_value_type());
        }
    }

    Status execute_impl(FunctionContext* context, Block& block, const ColumnNumbers& arguments,
                        size_t result, size_t input_rows_count) const override {
        auto left_column =
                block.get_by_position(arguments[0]).column->convert_to_full_column_if_const();
        const ColumnMap* map_column = nullptr;
        if (left_column->is_nullable()) {
            auto nullable_column = reinterpret_cast<const ColumnNullable*>(left_column.get());
            map_column = check_and_get_column<ColumnMap>(nullable_column->get_nested_column());
        } else {
            map_column = check_and_get_column<ColumnMap>(*left_column.get());
        }
        if (!map_column) {
            return Status::RuntimeError("unsupported types for function {}({})", get_name(),
                                        block.get_by_position(arguments[0]).type->get_name());
        }

        if constexpr (is_key) {
            block.replace_by_position(result, map_column->get_keys_array_ptr());
        } else {
            block.replace_by_position(result, map_column->get_values_array_ptr());
        }

        return Status::OK();
    }
};

void register_function_map(SimpleFunctionFactory& factory) {
    factory.register_function<FunctionMap>();
    factory.register_function<FunctionMapContains<true>>();
    factory.register_function<FunctionMapContains<false>>();
    factory.register_function<FunctionMapEntries<true>>();
    factory.register_function<FunctionMapEntries<false>>();
}

} // namespace doris::vectorized