#ifndef ALSK_ALSK_EDSL_OP_IMPL_OPERAND_H
#define ALSK_ALSK_EDSL_OP_IMPL_OPERAND_H

#include <type_traits>
#include <utility>

#include "../../../skeleton/muscle/muscle.h"

namespace alsk {
namespace edsl {

struct OperandTag;
struct LeafTag;

struct OperandBase {
	using IsOperand = OperandTag;

	constexpr OperandBase() noexcept = default;

	template<typename S, typename Operand, decltype(std::declval<Operand>().setup(std::declval<S&>()))* = nullptr>
	constexpr void setupFor(Operand& operand, S& skeleton) const noexcept {
		operand.setup(skeleton);
	}

	template<typename... Args>
	constexpr void setupFor(Args&&...) const noexcept {}
};

template<typename Function_, typename Signature_>
struct Operand: OperandBase {
	using IsLeaf    = LeafTag;

	using Function  = Function_;
	using Signature = Signature_;

	using Struct    = Function_;
	using Links     = Signature_;

	constexpr Operand() noexcept = default;

	template<typename Signature>
	constexpr auto link() const noexcept { return Operand<Function, Signature>{}; }
};

template<typename Function>
constexpr auto makeOperand() noexcept {
	return Operand<Function, void()>{};
}

template<typename Signature, typename Function>
constexpr auto makeOperand() noexcept {
	return Operand<Function, Signature>{};
}

template<typename Signature, Signature function>
constexpr auto makeOperand() noexcept {
	using Function = Fn<Signature, function>;
	return Operand<Function, typename Function::Signature>{};
}

}
}

// TODO C++17
#define alskMakeOperand(f) makeOperand<decltype(f)&, f>()

#endif