ClickHouse/src/Functions/FunctionCustomWeekToDateOrDate32.h

#pragma once
#include <Functions/IFunctionCustomWeek.h>

namespace DB
{

namespace ErrorCodes
{
    extern const int ILLEGAL_TYPE_OF_ARGUMENT;
    extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
}

template <typename Transform>
class FunctionCustomWeekToDateOrDate32 : public IFunctionCustomWeek<Transform>, WithContext
{
public:
    static constexpr auto name = Transform::name;
    String getName() const override { return name; }

    bool enable_date32_results = false;

    static FunctionPtr create(ContextPtr context_)
    {
        return std::make_shared<FunctionCustomWeekToDateOrDate32>(context_);
    }

    explicit FunctionCustomWeekToDateOrDate32(ContextPtr context_) : WithContext(context_)
    {
        enable_date32_results = context_->getSettingsRef().enable_date32_results;
    }

    DataTypePtr getReturnTypeImpl(const ColumnsWithTypeAndName & arguments) const override
    {
        if (arguments.size() == 1)
        {
            if (!isDate(arguments[0].type) && !isDate32(arguments[0].type) && !isDateTime(arguments[0].type)
                && !isDateTime64(arguments[0].type))
                throw Exception(
                    "Illegal type " + arguments[0].type->getName() + " of argument of function " + getName()
                        + ". Should be a date or a date with time",
                    ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
        }
        else if (arguments.size() == 2)
        {
            if (!isDate(arguments[0].type) && !isDate32(arguments[0].type) && !isDateTime(arguments[0].type)
                && !isDateTime64(arguments[0].type))
                throw Exception(
                    "Illegal type " + arguments[0].type->getName() + " of argument of function " + getName()
                        + ". Should be a date or a date with time",
                    ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
            if (!isUInt8(arguments[1].type))
                throw Exception(
                    "Function " + getName()
                        + " supports 1 or 2 or 3 arguments. The 1st argument "
                          "must be of type Date or DateTime. The 2nd argument (optional) must be "
                          "a constant UInt8 with week mode. The 3rd argument (optional) must be "
                          "a constant string with timezone name",
                    ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
        }
        else if (arguments.size() == 3)
        {
            if (!isDate(arguments[0].type) && !isDate32(arguments[0].type) && !isDateTime(arguments[0].type)
                && !isDateTime64(arguments[0].type))
                throw Exception(
                    "Illegal type " + arguments[0].type->getName() + " of argument of function " + getName()
                        + ". Should be a date or a date with time",
                    ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
            if (!isUInt8(arguments[1].type))
                throw Exception(
                    "Function " + getName()
                        + " supports 1 or 2 or 3 arguments. The 1st argument "
                          "must be of type Date or DateTime. The 2nd argument (optional) must be "
                          "a constant UInt8 with week mode. The 3rd argument (optional) must be "
                          "a constant string with timezone name",
                    ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
            if (!isString(arguments[2].type))
                throw Exception(
                    "Function " + getName()
                        + " supports 1 or 2 or 3 arguments. The 1st argument "
                          "must be of type Date or DateTime. The 2nd argument (optional) must be "
                          "a constant UInt8 with week mode. The 3rd argument (optional) must be "
                          "a constant string with timezone name",
                    ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
            if (isDate(arguments[0].type))
                throw Exception(
                    "The timezone argument of function " + getName() + " is allowed only when the 1st argument has the type DateTime",
                    ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
        }
        else
            throw Exception(
                "Number of arguments for function " + getName() + " doesn't match: passed " + toString(arguments.size())
                    + ", should be 1 or 2 or 3",
                ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);

        const IDataType * from_type = arguments[0].type.get();
        WhichDataType which(from_type);

        if ((which.isDate32() || which.isDateTime64()) && enable_date32_results)
            return std::make_shared<DataTypeDate32>();
        else
            return std::make_shared<DataTypeDate>();
    }

    ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr & result_type, size_t input_rows_count) const override
    {
        const IDataType * from_type = arguments[0].type.get();
        WhichDataType which(from_type);

        if (which.isDate())
            return CustomWeekTransformImpl<DataTypeDate, DataTypeDate>::execute(
                arguments, result_type, input_rows_count, Transform{});
        else if (which.isDate32())
            if (enable_date32_results)
                return CustomWeekTransformImpl<DataTypeDate32, DataTypeDate32>::execute(
                    arguments, result_type, input_rows_count, Transform{});
            else
                return CustomWeekTransformImpl<DataTypeDate, DataTypeDate32>::execute(
                    arguments, result_type, input_rows_count, Transform{});
        else if (which.isDateTime())
            return CustomWeekTransformImpl<DataTypeDateTime, DataTypeDate>::execute(
                arguments, result_type, input_rows_count, Transform{});
        else if (which.isDateTime64())
        {
            if (enable_date32_results)
                return CustomWeekTransformImpl<DataTypeDateTime64, DataTypeDate32>::execute(
                    arguments, result_type, input_rows_count,
                    TransformDateTime64<Transform>{assert_cast<const DataTypeDateTime64 *>(from_type)->getScale()});
            else
                return CustomWeekTransformImpl<DataTypeDateTime64, DataTypeDate>::execute(
                    arguments, result_type, input_rows_count,
                    TransformDateTime64<Transform>{assert_cast<const DataTypeDateTime64 *>(from_type)->getScale()});
        }
        else
            throw Exception(
                "Illegal type " + arguments[0].type->getName() + " of argument of function " + getName(),
                ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
    }

};

}