//===----------------------------------------------------------------------===//
//                         DuckDB
//
// duckdb/function/scalar_function.hpp
//
//
//===----------------------------------------------------------------------===//

#pragma once

#include "duckdb/common/vector_operations/binary_executor.hpp"
#include "duckdb/common/vector_operations/ternary_executor.hpp"
#include "duckdb/common/vector_operations/unary_executor.hpp"
#include "duckdb/common/vector_operations/vector_operations.hpp"
#include "duckdb/execution/expression_executor_state.hpp"
#include "duckdb/function/function.hpp"
#include "duckdb/planner/plan_serialization.hpp"
#include "duckdb/storage/statistics/base_statistics.hpp"
#include "duckdb/common/optional_ptr.hpp"

namespace duckdb {

struct FunctionLocalState {
	DUCKDB_API virtual ~FunctionLocalState();

	template <class TARGET>
	TARGET &Cast() {
		D_ASSERT(dynamic_cast<TARGET *>(this));
		return reinterpret_cast<TARGET &>(*this);
	}
	template <class TARGET>
	const TARGET &Cast() const {
		D_ASSERT(dynamic_cast<const TARGET *>(this));
		return reinterpret_cast<const TARGET &>(*this);
	}
};

class Binder;
class BoundFunctionExpression;
class DependencyList;
class ScalarFunctionCatalogEntry;

struct FunctionStatisticsInput {
	FunctionStatisticsInput(BoundFunctionExpression &expr_p, optional_ptr<FunctionData> bind_data_p,
	                        vector<BaseStatistics> &child_stats_p, unique_ptr<Expression> *expr_ptr_p)
	    : expr(expr_p), bind_data(bind_data_p), child_stats(child_stats_p), expr_ptr(expr_ptr_p) {
	}

	BoundFunctionExpression &expr;
	optional_ptr<FunctionData> bind_data;
	vector<BaseStatistics> &child_stats;
	unique_ptr<Expression> *expr_ptr;
};

//! The type used for scalar functions
typedef std::function<void(DataChunk &, ExpressionState &, Vector &)> scalar_function_t;
//! Binds the scalar function and creates the function data
typedef unique_ptr<FunctionData> (*bind_scalar_function_t)(ClientContext &context, ScalarFunction &bound_function,
                                                           vector<unique_ptr<Expression>> &arguments);
typedef unique_ptr<FunctionLocalState> (*init_local_state_t)(ExpressionState &state,
                                                             const BoundFunctionExpression &expr,
                                                             FunctionData *bind_data);
typedef unique_ptr<BaseStatistics> (*function_statistics_t)(ClientContext &context, FunctionStatisticsInput &input);
//! Adds the dependencies of this BoundFunctionExpression to the set of dependencies
typedef void (*dependency_function_t)(BoundFunctionExpression &expr, DependencyList &dependencies);

typedef void (*function_serialize_t)(FieldWriter &writer, const FunctionData *bind_data,
                                     const ScalarFunction &function);
typedef unique_ptr<FunctionData> (*function_deserialize_t)(PlanDeserializationState &state, FieldReader &reader,
                                                           ScalarFunction &function);

class ScalarFunction : public BaseScalarFunction {
public:
	DUCKDB_API ScalarFunction(string name, vector<LogicalType> arguments, LogicalType return_type,
	                          scalar_function_t function, bind_scalar_function_t bind = nullptr,
	                          dependency_function_t dependency = nullptr, function_statistics_t statistics = nullptr,
	                          init_local_state_t init_local_state = nullptr,
	                          LogicalType varargs = LogicalType(LogicalTypeId::INVALID),
	                          FunctionSideEffects side_effects = FunctionSideEffects::NO_SIDE_EFFECTS,
	                          FunctionNullHandling null_handling = FunctionNullHandling::DEFAULT_NULL_HANDLING);

	DUCKDB_API ScalarFunction(vector<LogicalType> arguments, LogicalType return_type, scalar_function_t function,
	                          bind_scalar_function_t bind = nullptr, dependency_function_t dependency = nullptr,
	                          function_statistics_t statistics = nullptr, init_local_state_t init_local_state = nullptr,
	                          LogicalType varargs = LogicalType(LogicalTypeId::INVALID),
	                          FunctionSideEffects side_effects = FunctionSideEffects::NO_SIDE_EFFECTS,
	                          FunctionNullHandling null_handling = FunctionNullHandling::DEFAULT_NULL_HANDLING);

	//! The main scalar function to execute
	scalar_function_t function;
	//! The bind function (if any)
	bind_scalar_function_t bind;
	//! Init thread local state for the function (if any)
	init_local_state_t init_local_state;
	//! The dependency function (if any)
	dependency_function_t dependency;
	//! The statistics propagation function (if any)
	function_statistics_t statistics;

	function_serialize_t serialize;
	function_deserialize_t deserialize;

	DUCKDB_API bool operator==(const ScalarFunction &rhs) const;
	DUCKDB_API bool operator!=(const ScalarFunction &rhs) const;

	DUCKDB_API bool Equal(const ScalarFunction &rhs) const;

private:
	bool CompareScalarFunctionT(const scalar_function_t &other) const;

public:
	DUCKDB_API static void NopFunction(DataChunk &input, ExpressionState &state, Vector &result);

	template <class TA, class TR, class OP>
	static void UnaryFunction(DataChunk &input, ExpressionState &state, Vector &result) {
		D_ASSERT(input.ColumnCount() >= 1);
		UnaryExecutor::Execute<TA, TR, OP>(input.data[0], result, input.size());
	}

	template <class TA, class TB, class TR, class OP>
	static void BinaryFunction(DataChunk &input, ExpressionState &state, Vector &result) {
		D_ASSERT(input.ColumnCount() == 2);
		BinaryExecutor::ExecuteStandard<TA, TB, TR, OP>(input.data[0], input.data[1], result, input.size());
	}

	template <class TA, class TB, class TC, class TR, class OP>
	static void TernaryFunction(DataChunk &input, ExpressionState &state, Vector &result) {
		D_ASSERT(input.ColumnCount() == 3);
		TernaryExecutor::ExecuteStandard<TA, TB, TC, TR, OP>(input.data[0], input.data[1], input.data[2], result,
		                                                     input.size());
	}

public:
	template <class OP>
	static scalar_function_t GetScalarUnaryFunction(LogicalType type) {
		scalar_function_t function;
		switch (type.id()) {
		case LogicalTypeId::TINYINT:
			function = &ScalarFunction::UnaryFunction<int8_t, int8_t, OP>;
			break;
		case LogicalTypeId::SMALLINT:
			function = &ScalarFunction::UnaryFunction<int16_t, int16_t, OP>;
			break;
		case LogicalTypeId::INTEGER:
			function = &ScalarFunction::UnaryFunction<int32_t, int32_t, OP>;
			break;
		case LogicalTypeId::BIGINT:
			function = &ScalarFunction::UnaryFunction<int64_t, int64_t, OP>;
			break;
		case LogicalTypeId::UTINYINT:
			function = &ScalarFunction::UnaryFunction<uint8_t, uint8_t, OP>;
			break;
		case LogicalTypeId::USMALLINT:
			function = &ScalarFunction::UnaryFunction<uint16_t, uint16_t, OP>;
			break;
		case LogicalTypeId::UINTEGER:
			function = &ScalarFunction::UnaryFunction<uint32_t, uint32_t, OP>;
			break;
		case LogicalTypeId::UBIGINT:
			function = &ScalarFunction::UnaryFunction<uint64_t, uint64_t, OP>;
			break;
		case LogicalTypeId::HUGEINT:
			function = &ScalarFunction::UnaryFunction<hugeint_t, hugeint_t, OP>;
			break;
		case LogicalTypeId::FLOAT:
			function = &ScalarFunction::UnaryFunction<float, float, OP>;
			break;
		case LogicalTypeId::DOUBLE:
			function = &ScalarFunction::UnaryFunction<double, double, OP>;
			break;
		default:
			throw InternalException("Unimplemented type for GetScalarUnaryFunction");
		}
		return function;
	}

	template <class TR, class OP>
	static scalar_function_t GetScalarUnaryFunctionFixedReturn(LogicalType type) {
		scalar_function_t function;
		switch (type.id()) {
		case LogicalTypeId::TINYINT:
			function = &ScalarFunction::UnaryFunction<int8_t, TR, OP>;
			break;
		case LogicalTypeId::SMALLINT:
			function = &ScalarFunction::UnaryFunction<int16_t, TR, OP>;
			break;
		case LogicalTypeId::INTEGER:
			function = &ScalarFunction::UnaryFunction<int32_t, TR, OP>;
			break;
		case LogicalTypeId::BIGINT:
			function = &ScalarFunction::UnaryFunction<int64_t, TR, OP>;
			break;
		case LogicalTypeId::UTINYINT:
			function = &ScalarFunction::UnaryFunction<uint8_t, TR, OP>;
			break;
		case LogicalTypeId::USMALLINT:
			function = &ScalarFunction::UnaryFunction<uint16_t, TR, OP>;
			break;
		case LogicalTypeId::UINTEGER:
			function = &ScalarFunction::UnaryFunction<uint32_t, TR, OP>;
			break;
		case LogicalTypeId::UBIGINT:
			function = &ScalarFunction::UnaryFunction<uint64_t, TR, OP>;
			break;
		case LogicalTypeId::HUGEINT:
			function = &ScalarFunction::UnaryFunction<hugeint_t, TR, OP>;
			break;
		case LogicalTypeId::FLOAT:
			function = &ScalarFunction::UnaryFunction<float, TR, OP>;
			break;
		case LogicalTypeId::DOUBLE:
			function = &ScalarFunction::UnaryFunction<double, TR, OP>;
			break;
		default:
			throw InternalException("Unimplemented type for GetScalarUnaryFunctionFixedReturn");
		}
		return function;
	}
};

} // namespace duckdb