// 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 <cctz/time_zone.h>

#include <cstddef>

#include <cstdint>

#include <memory>

#include <string>

#include <utility>

#include "common/status.h"

#include "core/assert_cast.h"

#include "core/binary_cast.hpp"

#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_const.h"

#include "core/column/column_nullable.h"

#include "core/column/column_string.h"

#include "core/column/column_vector.h"

#include "core/data_type/data_type.h"

#include "core/data_type/data_type_date.h"

#include "core/data_type/data_type_date_or_datetime_v2.h"

#include "core/data_type/data_type_date_time.h"

#include "core/data_type/data_type_nullable.h"

#include "core/data_type/data_type_string.h"

#include "core/data_type/define_primitive_type.h"

#include "core/data_type/primitive_type.h"

#include "core/string_ref.h"

#include "core/types.h"

#include "core/value/vdatetime_value.h"

#include "exec/common/util.hpp"

#include "exprs/aggregate/aggregate_function.h"

#include "exprs/function/datetime_errors.h"

#include "exprs/function/function.h"

#include "exprs/function/function_helpers.h"

#include "exprs/function/simple_function_factory.h"

#include "exprs/function_context.h"

#include "util/timezone_utils.h"

namespace doris {

struct ConvertTzState {

    bool use_state = false;

    bool is_valid = false;

    cctz::time_zone from_tz;

    cctz::time_zone to_tz;

};

class FunctionConvertTZ : public IFunction {

    constexpr static PrimitiveType PType = PrimitiveType::TYPE_DATETIMEV2;

    using DateValueType = PrimitiveTypeTraits<PType>::CppType;

    using ColumnType = PrimitiveTypeTraits<PType>::ColumnType;

public:

    static constexpr auto name = "convert_tz";

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

    String get_name() const override { return name; }

    size_t get_number_of_arguments() const override { return 3; }

    DataTypePtr get_return_type_impl(const DataTypes& arguments) const override {

        return have_nullable(arguments) ? make_nullable(std::make_shared<DataTypeDateTimeV2>())

                                        : std::make_shared<DataTypeDateTimeV2>();

    }

    // default value of timezone is invalid, should skip to avoid wrong exception

    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<ConvertTzState> state = std::make_shared<ConvertTzState>();

        context->set_function_state(scope, state);

        DCHECK_EQ(context->get_num_args(), 3);

        const auto* const_from_tz = context->get_constant_col(1);

        const auto* const_to_tz = context->get_constant_col(2);

        // ConvertTzState is used only when both the second and third parameters are constants

        if (const_from_tz != nullptr && const_to_tz != nullptr) {

            state->use_state = true;

            init_convert_tz_state(state, const_from_tz, const_to_tz);

        } else {

            state->use_state = false;

        }

        return IFunction::open(context, scope);

    }

    void init_convert_tz_state(std::shared_ptr<ConvertTzState> state,

                               const ColumnPtrWrapper* const_from_tz,

                               const ColumnPtrWrapper* const_to_tz) {

        auto const_data_from_tz = const_from_tz->column_ptr->get_data_at(0);

        auto const_data_to_tz = const_to_tz->column_ptr->get_data_at(0);

        // from_tz and to_tz must both be non-null.

        if (const_data_from_tz.data == nullptr || const_data_to_tz.data == nullptr) {

            state->is_valid = false;

            return;

        }

        auto from_tz_name = const_data_from_tz.to_string();

        auto to_tz_name = const_data_to_tz.to_string();

        if (!TimezoneUtils::find_cctz_time_zone(from_tz_name, state->from_tz)) [[unlikely]] {

            throw Exception(ErrorCode::INVALID_ARGUMENT, "Operation {} invalid timezone: {}", name,

                            from_tz_name);

        }

        if (!TimezoneUtils::find_cctz_time_zone(to_tz_name, state->to_tz)) [[unlikely]] {

            throw Exception(ErrorCode::INVALID_ARGUMENT, "Operation {} invalid timezone: {}", name,

                            to_tz_name);

        }

        state->is_valid = true;

    }

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

                        uint32_t result, size_t input_rows_count) const override {

        auto* convert_tz_state = reinterpret_cast<ConvertTzState*>(

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

        if (!convert_tz_state) {

            return Status::RuntimeError(

                    "funciton context for function '{}' must have ConvertTzState;", get_name());

        }

        auto result_null_map_column = ColumnUInt8::create(input_rows_count, 0);

        NullMap& result_null_map = result_null_map_column->get_data();

        ColumnPtr argument_columns[3];

        bool col_const[3];

        // calculate result null map and col_const

        for (int i = 0; i < 3; ++i) {

            ColumnPtr& col = block.get_by_position(arguments[i]).column;

            col_const[i] = is_column_const(*col);

            const NullMap* null_map = VectorizedUtils::get_null_map(col);

            if (null_map) {

                VectorizedUtils::update_null_map(result_null_map, *null_map, col_const[i]);

            }

        }

        // Extract nested columns from const(nullable) wrappers

        argument_columns[0] = col_const[0] ? static_cast<const ColumnConst&>(

                                                     *block.get_by_position(arguments[0]).column)

                                                     .convert_to_full_column()

                                           : block.get_by_position(arguments[0]).column;

        argument_columns[0] = remove_nullable(argument_columns[0]);

        default_preprocess_parameter_columns(argument_columns, col_const, {1, 2}, block, arguments);

        argument_columns[1] = remove_nullable(argument_columns[1]);

        argument_columns[2] = remove_nullable(argument_columns[2]);

        auto result_column = ColumnType::create();

        if (convert_tz_state->use_state) {

            // ignore argument columns, use cached timezone input in state

            execute_tz_const_with_state(convert_tz_state,

                                        assert_cast<const ColumnType*>(argument_columns[0].get()),

                                        result_column.get(), result_null_map, input_rows_count);

        } else if (col_const[1] && col_const[2]) {

            // arguments are const

            execute_tz_const(context, assert_cast<const ColumnType*>(argument_columns[0].get()),

                             assert_cast<const ColumnString*>(argument_columns[1].get()),

                             assert_cast<const ColumnString*>(argument_columns[2].get()),

                             result_column.get(), result_null_map, input_rows_count);

        } else {

            _execute(context, assert_cast<const ColumnType*>(argument_columns[0].get()),

                     assert_cast<const ColumnString*>(argument_columns[1].get()),

                     assert_cast<const ColumnString*>(argument_columns[2].get()),

                     result_column.get(), result_null_map, input_rows_count);

        } //if const

        if (block.get_data_type(result)->is_nullable()) {

            block.get_by_position(result).column = ColumnNullable::create(

                    std::move(result_column), std::move(result_null_map_column));

        } else {

            block.get_by_position(result).column = std::move(result_column);

        }

        return Status::OK();

    }

private:

    static void _execute(FunctionContext* context, const ColumnType* date_column,

                         const ColumnString* from_tz_column, const ColumnString* to_tz_column,

                         ColumnType* result_column, NullMap& result_null_map,

                         size_t input_rows_count) {

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

            if (result_null_map[i]) {

                result_column->insert_default();

                continue;

            }

            auto from_tz = from_tz_column->get_data_at(i).to_string();

            auto to_tz = to_tz_column->get_data_at(i).to_string();

            execute_inner_loop(date_column, from_tz, to_tz, result_column, result_null_map, i);

        }

    }

    static std::pair<int64_t, int64_t> unix_timestamp_for_convert_tz(

            const DateValueType& ts_value, const cctz::time_zone& from_tz) {

        cctz::civil_second civil_time(ts_value.year(), ts_value.month(), ts_value.day(),

                                      ts_value.hour(), ts_value.minute(), ts_value.second());

        const auto lookup = from_tz.lookup(civil_time);

        const bool skipped = lookup.kind == cctz::time_zone::civil_lookup::SKIPPED;

        const auto tp = skipped ? lookup.trans : lookup.pre;

        // Skipped civil times map to the transition instant. Do not keep the

        // input fractional part inside a local time interval that never existed.

        return {tp.time_since_epoch().count(), skipped ? 0 : ts_value.microsecond()};

    }

    static void execute_tz_const_with_state(ConvertTzState* convert_tz_state,

                                            const ColumnType* date_column,

                                            ColumnType* result_column, NullMap& result_null_map,

                                            size_t input_rows_count) {

        cctz::time_zone& from_tz = convert_tz_state->from_tz;

        cctz::time_zone& to_tz = convert_tz_state->to_tz;

        auto push_null = [&](size_t row) {

            result_null_map[row] = true;

            result_column->insert_default();

        };

        // state isn't valid means there's NULL in timezone input. so return null rather than exception

        if (!convert_tz_state->is_valid) [[unlikely]] {

            // If an invalid timezone is present, return null

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

                push_null(i);

            }

            return;

        }

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

            if (result_null_map[i]) {

                result_column->insert_default();

                continue;

            }

            DateValueType ts_value = date_column->get_element(i);

            DateValueType ts_value2;

            ts_value2.from_unixtime(unix_timestamp_for_convert_tz(ts_value, from_tz), to_tz);

            if (!ts_value2.is_valid_date()) [[unlikely]] {

                throw_out_of_bound_convert_tz<DateValueType>(date_column->get_element(i),

                                                             from_tz.name(), to_tz.name());

            }

            result_column->insert(Field::create_field<TYPE_DATETIMEV2>(ts_value2));

        }

    }

    static void execute_tz_const(FunctionContext* context, const ColumnType* date_column,

                                 const ColumnString* from_tz_column,

                                 const ColumnString* to_tz_column, ColumnType* result_column,

                                 NullMap& result_null_map, size_t input_rows_count) {

        auto from_tz = from_tz_column->get_data_at(0).to_string();

        auto to_tz = to_tz_column->get_data_at(0).to_string();

        cctz::time_zone from_zone, to_zone;

        if (!TimezoneUtils::find_cctz_time_zone(from_tz, from_zone)) [[unlikely]] {

            throw Exception(ErrorCode::INVALID_ARGUMENT, "Operation {} invalid timezone: {}", name,

                            from_tz);

        }

        if (!TimezoneUtils::find_cctz_time_zone(to_tz, to_zone)) [[unlikely]] {

            throw Exception(ErrorCode::INVALID_ARGUMENT, "Operation {} invalid timezone: {}", name,

                            to_tz);

        }

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

            if (result_null_map[i]) {

                result_column->insert_default();

                continue;

            }

            execute_inner_loop(date_column, from_tz, to_tz, result_column, result_null_map, i);

        }

    }

    static void execute_inner_loop(const ColumnType* date_column, const std::string& from_tz_name,

                                   const std::string& to_tz_name, ColumnType* result_column,

                                   NullMap& result_null_map, const size_t index_now) {

        DateValueType ts_value = date_column->get_element(index_now);

        cctz::time_zone from_tz {}, to_tz {};

        DateValueType ts_value2;

        if (!TimezoneUtils::find_cctz_time_zone(from_tz_name, from_tz)) [[unlikely]] {

            throw Exception(ErrorCode::INVALID_ARGUMENT, "Operation {} invalid timezone: {}", name,

                            from_tz_name);

        }

        if (!TimezoneUtils::find_cctz_time_zone(to_tz_name, to_tz)) [[unlikely]] {

            throw Exception(ErrorCode::INVALID_ARGUMENT, "Operation {} invalid timezone: {}", name,

                            to_tz_name);

        }

        ts_value2.from_unixtime(unix_timestamp_for_convert_tz(ts_value, from_tz), to_tz);

        if (!ts_value2.is_valid_date()) [[unlikely]] {

            throw_out_of_bound_convert_tz<DateValueType>(date_column->get_element(index_now),

                                                         from_tz.name(), to_tz.name());

        }

        result_column->insert(Field::create_field<TYPE_DATETIMEV2>(ts_value2));

    }

};

void register_function_convert_tz(SimpleFunctionFactory& factory) {

    factory.register_function<FunctionConvertTZ>();

}

} // namespace doris