// 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.

// This file is copied from

// https://github.com/ClickHouse/ClickHouse/blob/master/src/Functions/IFunction.h

// and modified by Doris

#pragma once

#include <fmt/format.h>

#include <glog/logging.h>

#include <cstddef>

#include <memory>

#include <string>

#include <utility>

#include "common/exception.h"

#include "common/logging.h"

#include "common/status.h"

#include "olap/rowset/segment_v2/inverted_index_iterator.h" // IWYU pragma: keep

#include "udf/udf.h"

#include "vec/core/block.h"

#include "vec/core/column_numbers.h"

#include "vec/core/column_with_type_and_name.h"

#include "vec/core/columns_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_struct.h"

namespace doris::vectorized {

struct FunctionAttr {

    bool enable_decimal256 {false};

    bool new_version_unix_timestamp {false};

};

#define RETURN_REAL_TYPE_FOR_DATEV2_FUNCTION(TYPE)                                             \

    bool is_nullable = false;                                                                  \

    bool is_datev2 = false;                                                                    \

    for (auto it : arguments) {                                                                \

        is_nullable = is_nullable || it.type->is_nullable();                                   \

        is_datev2 = is_datev2 || it.type->get_primitive_type() == TYPE_DATEV2 ||               \

                    it.type->get_primitive_type() == TYPE_DATETIMEV2;                          \

    }                                                                                          \

    return is_nullable || !is_datev2                                                           \

                   ? make_nullable(                                                            \

                             std::make_shared<typename PrimitiveTypeTraits<TYPE>::DataType>()) \

                   : std::make_shared<typename PrimitiveTypeTraits<TYPE>::DataType>();

#define SET_NULLMAP_IF_FALSE(EXPR) \

    if (!EXPR) [[unlikely]] {      \

        null_map[i] = true;        \

    }

class Field;

class VExpr;

// Only use dispose the variadic argument

template <typename T>

auto has_variadic_argument_types(T&& arg) -> decltype(T::get_variadic_argument_types()) {};

void has_variadic_argument_types(...);

template <typename T>

concept HasGetVariadicArgumentTypesImpl = requires(T t) {

    { t.get_variadic_argument_types_impl() } -> std::same_as<DataTypes>;

};

bool have_null_column(const Block& block, const ColumnNumbers& args);

bool have_null_column(const ColumnsWithTypeAndName& args);

/// The simplest executable object.

/// Motivation:

///  * Prepare something heavy once before main execution loop instead of doing it for each block.

///  * Provide const interface for IFunctionBase (later).

class IPreparedFunction {

public:

    virtual ~IPreparedFunction() = default;

    /// Get the main function name.

    virtual String get_name() const = 0;

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

                           uint32_t result, size_t input_rows_count, bool dry_run) const = 0;

};

using PreparedFunctionPtr = std::shared_ptr<IPreparedFunction>;

class PreparedFunctionImpl : public IPreparedFunction {

public:

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

                   uint32_t result, size_t input_rows_count, bool dry_run = false) const final;

    /** If the function have non-zero number of arguments,

      *  and if all arguments are constant, that we could automatically provide default implementation:

      *  arguments are converted to ordinary columns with single value which is not const, then function is executed as usual,

      *  and then the result is converted to constant column.

      */

    virtual bool use_default_implementation_for_constants() const { return true; }

    /** If use_default_implementation_for_nulls() is true, after execute the function,

      * whether need to replace the nested data of null data to the default value.

      * E.g. for binary arithmetic exprs, need return true to avoid false overflow.

      */

    virtual bool need_replace_null_data_to_default() const { return false; }

protected:

    virtual Status execute_impl_dry_run(FunctionContext* context, Block& block,

                                        const ColumnNumbers& arguments, uint32_t result,

                                        size_t input_rows_count) const {

        return execute_impl(context, block, arguments, result, input_rows_count);

    }

    virtual Status execute_impl(FunctionContext* context, Block& block,

                                const ColumnNumbers& arguments, uint32_t result,

                                size_t input_rows_count) const = 0;

    /** Default implementation in presence of Nullable arguments or NULL constants as arguments is the following:

      *  if some of arguments are NULL constants then return NULL constant,

      *  if some of arguments are Nullable, then execute function as usual for block,

      *   where Nullable columns are substituted with nested columns (they have arbitrary values in rows corresponding to NULL value)

      *   and wrap result in Nullable column where NULLs are in all rows where any of arguments are NULL.

      */

    virtual bool use_default_implementation_for_nulls() const { return true; }

    virtual bool skip_return_type_check() const { return false; }

    /** Some arguments could remain constant during this implementation.

      * Every argument required const must write here and no checks elsewhere.

      */

    virtual ColumnNumbers get_arguments_that_are_always_constant() const { return {}; }

private:

    Status default_implementation_for_nulls(FunctionContext* context, Block& block,

                                            const ColumnNumbers& args, uint32_t result,

                                            size_t input_rows_count, bool dry_run,

                                            bool* executed) const;

    Status default_implementation_for_constant_arguments(FunctionContext* context, Block& block,

                                                         const ColumnNumbers& args, uint32_t result,

                                                         size_t input_rows_count, bool dry_run,

                                                         bool* executed) const;

    Status execute_without_low_cardinality_columns(FunctionContext* context, Block& block,

                                                   const ColumnNumbers& arguments, uint32_t result,

                                                   size_t input_rows_count, bool dry_run) const;

    Status _execute_skipped_constant_deal(FunctionContext* context, Block& block,

                                          const ColumnNumbers& args, uint32_t result,

                                          size_t input_rows_count, bool dry_run) const;

};

/// Function with known arguments and return type.

class IFunctionBase {

public:

    virtual ~IFunctionBase() = default;

    /// Get the main function name.

    virtual String get_name() const = 0;

    virtual const DataTypes& get_argument_types() const = 0;

    virtual const DataTypePtr& get_return_type() const = 0;

    /// Do preparations and return executable.

    /// sample_block should contain data types of arguments and values of constants, if relevant.

    virtual PreparedFunctionPtr prepare(FunctionContext* context, const Block& sample_block,

                                        const ColumnNumbers& arguments, uint32_t result) const = 0;

    /// Override this when function need to store state in the `FunctionContext`, or do some

    /// preparation work according to information from `FunctionContext`.

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

        return Status::OK();

    }

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

                   uint32_t result, size_t input_rows_count, bool dry_run = false) const {

        try {

            return prepare(context, block, arguments, result)

                    ->execute(context, block, arguments, result, input_rows_count, dry_run);

        } catch (const Exception& e) {

            return e.to_status();

        }

    }

    virtual Status evaluate_inverted_index(

            const ColumnsWithTypeAndName& arguments,

            const std::vector<vectorized::IndexFieldNameAndTypePair>& data_type_with_names,

            std::vector<segment_v2::IndexIterator*> iterators, uint32_t num_rows,

            segment_v2::InvertedIndexResultBitmap& bitmap_result) const {

        return Status::OK();

    }

    /// Do cleaning work when function is finished, i.e., release state variables in the

    /// `FunctionContext` which are registered in `prepare` phase.

    virtual Status close(FunctionContext* context, FunctionContext::FunctionStateScope scope) {

        return Status::OK();

    }

    virtual bool is_use_default_implementation_for_constants() const = 0;

    virtual bool is_udf_function() const { return false; }

    virtual bool can_push_down_to_index() const { return false; }

    virtual bool is_blockable() const { return false; }

};

using FunctionBasePtr = std::shared_ptr<IFunctionBase>;

/// Creates IFunctionBase from argument types list.

class IFunctionBuilder {

public:

    virtual ~IFunctionBuilder() = default;

    /// Get the main function name.

    virtual String get_name() const = 0;

    /// Override and return true if function could take different number of arguments.

    ///TODO: this function is not actually used now. but in check_number_of_arguments we still need it because for many

    /// functions we didn't set the correct number of arguments.

    virtual bool is_variadic() const = 0;

    /// For non-variadic functions, return number of arguments; otherwise return zero (that should be ignored).

    virtual size_t get_number_of_arguments() const = 0;

    /// Throw if number of arguments is incorrect. Default implementation will check only in non-variadic case.

    virtual void check_number_of_arguments(size_t number_of_arguments) const = 0;

    /// Check arguments and return IFunctionBase.

    virtual FunctionBasePtr build(const ColumnsWithTypeAndName& arguments,

                                  const DataTypePtr& return_type) const = 0;

    /// For higher-order functions (functions, that have lambda expression as at least one argument).

    /// You pass data types with empty DataTypeFunction for lambda arguments.

    /// This function will replace it with DataTypeFunction containing actual types.

    virtual DataTypes get_variadic_argument_types() const = 0;

    /// Returns indexes of arguments, that must be ColumnConst

    virtual ColumnNumbers get_arguments_that_are_always_constant() const = 0;

};

using FunctionBuilderPtr = std::shared_ptr<IFunctionBuilder>;

inline std::string get_types_string(const ColumnsWithTypeAndName& arguments) {

    std::string types;

    for (const auto& argument : arguments) {

        if (!types.empty()) {

            types += ", ";

        }

        types += argument.type->get_name();

    }

    return types;

}

/// used in function_factory. when we register a function, save a builder. to get a function, to get a builder.

/// will use DefaultFunctionBuilder as the default builder in function's registration if we didn't explicitly specify.

class FunctionBuilderImpl : public IFunctionBuilder {

public:

    FunctionBasePtr build(const ColumnsWithTypeAndName& arguments,

                          const DataTypePtr& return_type) const final {

        if (skip_return_type_check()) {

            return build_impl(arguments, return_type);

        }

        const DataTypePtr& func_return_type = get_return_type(arguments);

        if (func_return_type == nullptr) {

            throw doris::Exception(

                    ErrorCode::INTERNAL_ERROR,

                    "function return type check failed, function_name={}, "

                    "expect_return_type={}, real_return_type is nullptr, input_arguments={}",

                    get_name(), return_type->get_name(), get_types_string(arguments));

        }

        // check return types equal.

        if (!(return_type->equals(*func_return_type) ||

              // For null constant argument, `get_return_type` would return

              // Nullable<DataTypeNothing> when `use_default_implementation_for_nulls` is true.

              (return_type->is_nullable() && func_return_type->is_nullable() &&

               ((DataTypeNullable*)func_return_type.get())

                               ->get_nested_type()

                               ->get_primitive_type() == INVALID_TYPE) ||

              is_date_or_datetime_or_decimal(return_type, func_return_type) ||

              is_nested_type_date_or_datetime_or_decimal(return_type, func_return_type))) {

            throw doris::Exception(

                    ErrorCode::INTERNAL_ERROR,

                    "function return type check failed, function_name={}, "

                    "fe plan return type={},  be real return type={}, input_arguments={}",

                    get_name(), return_type->get_name(), func_return_type->get_name(),

                    get_types_string(arguments));

        }

        return build_impl(arguments, return_type);

    }

    bool is_variadic() const override { return false; }

    // Default implementation. Will check only in non-variadic case.

    void check_number_of_arguments(size_t number_of_arguments) const override;

    // the return type should be same with what FE plans.

    // it returns: `get_return_type_impl` if `use_default_implementation_for_nulls` = false

    //  `get_return_type_impl` warpped in NULL if `use_default_implementation_for_nulls` = true and input has NULL

    DataTypePtr get_return_type(const ColumnsWithTypeAndName& arguments) const;

    DataTypes get_variadic_argument_types() const override {

        return get_variadic_argument_types_impl();

    }

    ColumnNumbers get_arguments_that_are_always_constant() const override { return {}; }

protected:

    // Get the result type by argument type. If the function does not apply to these arguments, throw an exception.

    // the get_return_type_impl and its overrides should only return the nested type if `use_default_implementation_for_nulls` is true.

    // whether to wrap in nullable type will be automatically decided.

    virtual DataTypePtr get_return_type_impl(const ColumnsWithTypeAndName& arguments) const {

        DataTypes data_types(arguments.size());

        for (size_t i = 0; i < arguments.size(); ++i) {

            data_types[i] = arguments[i].type;

        }

        return get_return_type_impl(data_types);

    }

    virtual DataTypePtr get_return_type_impl(const DataTypes& /*arguments*/) const {

        throw doris::Exception(ErrorCode::NOT_IMPLEMENTED_ERROR,

                               "get_return_type is not implemented for {}", get_name());

        return nullptr;

    }

    /** If use_default_implementation_for_nulls() is true, than change arguments for get_return_type() and build_impl():

      *  if some of arguments are Nullable(Nothing) then don't call get_return_type(), call build_impl() with return_type = Nullable(Nothing),

      *  if some of arguments are Nullable, then:

      *   - Nullable types are substituted with nested types for get_return_type() function

      *   - WRAP get_return_type() RESULT IN NULLABLE type and pass to build_impl

      *

      * Otherwise build returns build_impl(arguments, get_return_type(arguments));

      */

    virtual bool use_default_implementation_for_nulls() const { return true; }

    virtual bool skip_return_type_check() const { return false; }

    virtual bool need_replace_null_data_to_default() const { return false; }

    /// return a real function object to execute. called in build(...).

    virtual FunctionBasePtr build_impl(const ColumnsWithTypeAndName& arguments,

                                       const DataTypePtr& return_type) const = 0;

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

private:

    bool is_date_or_datetime_or_decimal(const DataTypePtr& return_type,

                                        const DataTypePtr& func_return_type) const;

    bool is_nested_type_date_or_datetime_or_decimal(const DataTypePtr& return_type,

                                                    const DataTypePtr& func_return_type) const;

};

/// Previous function interface.

class IFunction : public std::enable_shared_from_this<IFunction>,

                  public FunctionBuilderImpl,

                  public IFunctionBase,

                  public PreparedFunctionImpl {

public:

    String get_name() const override = 0;

    /// Notice: We should not change the column in the block, because the column may be shared by multiple expressions or exec nodes.

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

                        uint32_t result, size_t input_rows_count) const override = 0;

    /// Override this functions to change default implementation behavior. See details in IMyFunction.

    bool use_default_implementation_for_nulls() const override { return true; }

    bool skip_return_type_check() const override { return false; }

    bool need_replace_null_data_to_default() const override { return false; }

    /// all constancy check should use this function to do automatically

    ColumnNumbers get_arguments_that_are_always_constant() const override { return {}; }

    bool is_use_default_implementation_for_constants() const override {

        return use_default_implementation_for_constants();

    }

    using PreparedFunctionImpl::execute;

    using PreparedFunctionImpl::execute_impl_dry_run;

    using FunctionBuilderImpl::get_return_type_impl;

    using FunctionBuilderImpl::get_variadic_argument_types_impl;

    using FunctionBuilderImpl::get_return_type;

    [[noreturn]] PreparedFunctionPtr prepare(FunctionContext* context,

                                             const Block& /*sample_block*/,

                                             const ColumnNumbers& /*arguments*/,

                                             uint32_t /*result*/) const final {

        throw doris::Exception(ErrorCode::NOT_IMPLEMENTED_ERROR,

                               "prepare is not implemented for IFunction {}", get_name());

        __builtin_unreachable();

    }

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

        return Status::OK();

    }

    [[noreturn]] const DataTypes& get_argument_types() const final {

        throw doris::Exception(ErrorCode::NOT_IMPLEMENTED_ERROR,

                               "get_argument_types is not implemented for IFunction {}",

                               get_name());

        __builtin_unreachable();

    }

    [[noreturn]] const DataTypePtr& get_return_type() const final {

        throw doris::Exception(ErrorCode::NOT_IMPLEMENTED_ERROR,

                               "get_return_type is not implemented for IFunction {}", get_name());

        __builtin_unreachable();

    }

protected:

    FunctionBasePtr build_impl(const ColumnsWithTypeAndName& /*arguments*/,

                               const DataTypePtr& /*return_type*/) const final {

        throw doris::Exception(ErrorCode::NOT_IMPLEMENTED_ERROR,

                               "build_impl is not implemented for IFunction {}", get_name());

        __builtin_unreachable();

        return {};

    }

};

/*

 * when we register a function which didn't specify its base(i.e. inherited from IFunction), actually we use this as a wrapper.

 * it saves real implementation as `function`. 

*/

class DefaultFunction final : public IFunctionBase {

public:

    DefaultFunction(std::shared_ptr<IFunction> function_, DataTypes arguments_,

                    DataTypePtr return_type_)

            : function(std::move(function_)),

              arguments(std::move(arguments_)),

              return_type(std::move(return_type_)) {}

    String get_name() const override { return function->get_name(); }

    const DataTypes& get_argument_types() const override { return arguments; }

    const DataTypePtr& get_return_type() const override { return return_type; }

    // return a default wrapper for IFunction.

    PreparedFunctionPtr prepare(FunctionContext* context, const Block& /*sample_block*/,

                                const ColumnNumbers& /*arguments*/,

                                uint32_t /*result*/) const override {

        return function;

    }

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

        return function->open(context, scope);

    }

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

        return function->close(context, scope);

    }

    Status evaluate_inverted_index(

            const ColumnsWithTypeAndName& args,

            const std::vector<vectorized::IndexFieldNameAndTypePair>& data_type_with_names,

            std::vector<segment_v2::IndexIterator*> iterators, uint32_t num_rows,

            segment_v2::InvertedIndexResultBitmap& bitmap_result) const override {

        return function->evaluate_inverted_index(args, data_type_with_names, iterators, num_rows,

                                                 bitmap_result);

    }

    bool is_use_default_implementation_for_constants() const override {

        return function->is_use_default_implementation_for_constants();

    }

    bool can_push_down_to_index() const override { return function->can_push_down_to_index(); }

    bool is_blockable() const override { return function->is_blockable(); }

private:

    std::shared_ptr<IFunction> function;

    DataTypes arguments;

    DataTypePtr return_type;

};

class DefaultFunctionBuilder : public FunctionBuilderImpl {

public:

    explicit DefaultFunctionBuilder(std::shared_ptr<IFunction> function_)

            : function(std::move(function_)) {}

    void check_number_of_arguments(size_t number_of_arguments) const override {

        function->check_number_of_arguments(number_of_arguments);

    }

    String get_name() const override { return function->get_name(); }

    bool is_variadic() const override { return function->is_variadic(); }

    size_t get_number_of_arguments() const override { return function->get_number_of_arguments(); }

    ColumnNumbers get_arguments_that_are_always_constant() const override {

        return function->get_arguments_that_are_always_constant();

    }

protected:

    DataTypePtr get_return_type_impl(const DataTypes& arguments) const override {

        return function->get_return_type_impl(arguments);

    }

    DataTypePtr get_return_type_impl(const ColumnsWithTypeAndName& arguments) const override {

        return function->get_return_type_impl(arguments);

    }

    bool use_default_implementation_for_nulls() const override {

        return function->use_default_implementation_for_nulls();

    }

    bool skip_return_type_check() const override { return function->skip_return_type_check(); }

    bool need_replace_null_data_to_default() const override {

        return function->need_replace_null_data_to_default();

    }

    FunctionBasePtr build_impl(const ColumnsWithTypeAndName& arguments,

                               const DataTypePtr& return_type) const override {

        DataTypes data_types(arguments.size());

        for (size_t i = 0; i < arguments.size(); ++i) {

            data_types[i] = arguments[i].type;

        }

        return std::make_shared<DefaultFunction>(function, data_types, return_type);

    }

    DataTypes get_variadic_argument_types_impl() const override {

        return function->get_variadic_argument_types_impl();

    }

private:

    std::shared_ptr<IFunction> function;

};

using FunctionPtr = std::shared_ptr<IFunction>;

/** Return ColumnNullable of src, with null map as OR-ed null maps of args columns in blocks.

  * Or ColumnConst(ColumnNullable) if the result is always NULL or if the result is constant and always not NULL.

  */

ColumnPtr wrap_in_nullable(const ColumnPtr& src, const Block& block, const ColumnNumbers& args,

                           uint32_t result, size_t input_rows_count);

} // namespace doris::vectorized