#ifndef __PDDL_PARSE__AST_FORWARD_H
#define __PDDL_PARSE__AST_FORWARD_H

#include <iosfwd>
#include <memory>
#include <experimental/optional>
#include <set>
#include <vector>

#include <pddlparse/Variant.h>

namespace pddl
{

////////////////////////////////////////////////////////////////////////////////////////////////////
//
// AST Forward Declarations
//
////////////////////////////////////////////////////////////////////////////////////////////////////

namespace ast
{

////////////////////////////////////////////////////////////////////////////////////////////////////
// Primitives
////////////////////////////////////////////////////////////////////////////////////////////////////

struct Constant;
using ConstantPointer = std::unique_ptr<Constant>;
struct ConstantDeclaration;
using ConstantDeclarationPointer = std::unique_ptr<ConstantDeclaration>;
using ConstantDeclarations = std::vector<ConstantDeclarationPointer>;
struct Dummy;
using DummyPointer = std::unique_ptr<Dummy>;
struct PrimitiveType;
using PrimitiveTypePointer = std::unique_ptr<PrimitiveType>;
using PrimitiveTypes = std::vector<PrimitiveTypePointer>;
struct PrimitiveTypeDeclaration;
using PrimitiveTypeDeclarationPointer = std::unique_ptr<PrimitiveTypeDeclaration>;
using PrimitiveTypeDeclarations = std::vector<PrimitiveTypeDeclarationPointer>;
struct Unsupported;
using UnsupportedPointer = std::unique_ptr<Unsupported>;
struct Variable;
using VariablePointer = std::unique_ptr<Variable>;
using Variables = std::vector<VariablePointer>;
struct VariableDeclaration;
using VariableDeclarationPointer = std::unique_ptr<VariableDeclaration>;
using VariableDeclarations = std::vector<VariableDeclarationPointer>;

////////////////////////////////////////////////////////////////////////////////////////////////////
// Compounds
////////////////////////////////////////////////////////////////////////////////////////////////////

struct Predicate;
using PredicatePointer = std::unique_ptr<Predicate>;
using Predicates = std::vector<PredicatePointer>;
struct PredicateDeclaration;
using PredicateDeclarationPointer = std::unique_ptr<PredicateDeclaration>;
using PredicateDeclarations = std::vector<PredicateDeclarationPointer>;

////////////////////////////////////////////////////////////////////////////////////////////////////
// Expressions
////////////////////////////////////////////////////////////////////////////////////////////////////

template<class Argument>
struct And;
template<class Argument>
using AndPointer = std::unique_ptr<And<Argument>>;
template<class Argument>
struct At;
template<class Argument>
using AtPointer = std::unique_ptr<At<Argument>>;
template<class Argument>
struct Either;
template<class Argument>
using EitherPointer = std::unique_ptr<Either<Argument>>;
template<class Argument>
struct Exists;
template<class Argument>
using ExistsPointer = std::unique_ptr<Exists<Argument>>;
template<class Argument>
struct ForAll;
template<class Argument>
using ForAllPointer = std::unique_ptr<ForAll<Argument>>;
template<class Argument>
struct Imply;
template<class Argument>
using ImplyPointer = std::unique_ptr<Imply<Argument>>;
template<class Argument>
struct Not;
template<class Argument>
using NotPointer = std::unique_ptr<Not<Argument>>;
template<class Argument>
struct Or;
template<class Argument>
using OrPointer = std::unique_ptr<Or<Argument>>;
template<class ArgumentLeft, class ArgumentRight>
struct When;
template<class ArgumentLeft, class ArgumentRight>
using WhenPointer = std::unique_ptr<When<ArgumentLeft, ArgumentRight>>;

////////////////////////////////////////////////////////////////////////////////////////////////////
// PDDL Structure
////////////////////////////////////////////////////////////////////////////////////////////////////

struct Action;
using ActionPointer = std::unique_ptr<Action>;
using Actions = std::vector<ActionPointer>;
struct Description;
using DescriptionPointer = std::unique_ptr<Description>;
struct Domain;
using DomainPointer = std::unique_ptr<Domain>;
struct Problem;
using ProblemPointer = std::unique_ptr<Problem>;
enum class Requirement;
using Requirements = std::vector<Requirement>;

////////////////////////////////////////////////////////////////////////////////////////////////////
// Variants
////////////////////////////////////////////////////////////////////////////////////////////////////

namespace detail
{
using TermT = Variant<
	ConstantPointer,
	VariablePointer>;
}

class Term : public detail::TermT
{
	using detail::TermT::TermT;
};

using Terms = std::vector<Term>;

////////////////////////////////////////////////////////////////////////////////////////////////////

namespace detail
{
using AtomicFormulaT = Variant<
	PredicatePointer,
	UnsupportedPointer>;
}

class AtomicFormula : public detail::AtomicFormulaT
{
	using detail::AtomicFormulaT::AtomicFormulaT;
};

////////////////////////////////////////////////////////////////////////////////////////////////////

class Precondition;

namespace detail
{
using PreconditionT = Variant<
	AtomicFormula,
	AndPointer<Precondition>,
	ExistsPointer<Precondition>,
	ForAllPointer<Precondition>,
	ImplyPointer<Precondition>,
	NotPointer<Precondition>,
	OrPointer<Precondition>,
	UnsupportedPointer>;
}

class Precondition : public detail::PreconditionT
{
	using detail::PreconditionT::PreconditionT;
};

using Preconditions = std::vector<Precondition>;

////////////////////////////////////////////////////////////////////////////////////////////////////

class ConditionalEffect;

namespace detail
{
using ConditionalEffectT = Variant<
	AtomicFormula,
	AndPointer<ConditionalEffect>,
	NotPointer<ConditionalEffect>,
	UnsupportedPointer>;
}

class ConditionalEffect : public detail::ConditionalEffectT
{
	using detail::ConditionalEffectT::ConditionalEffectT;
};

////////////////////////////////////////////////////////////////////////////////////////////////////

class Effect;

namespace detail
{
using EffectT = Variant<
	AtomicFormula,
	AndPointer<Effect>,
	ForAllPointer<Effect>,
	NotPointer<Effect>,
	WhenPointer<Precondition, ConditionalEffect>,
	UnsupportedPointer>;
}

class Effect : public detail::EffectT
{
	using detail::EffectT::EffectT;
};

////////////////////////////////////////////////////////////////////////////////////////////////////

namespace detail
{
using TypeT = Variant<
	EitherPointer<PrimitiveTypePointer>,
	PrimitiveTypePointer>;
}

class Type : public detail::TypeT
{
	using detail::TypeT::TypeT;
};

////////////////////////////////////////////////////////////////////////////////////////////////////

namespace detail
{
using LiteralT = Variant<
	AtomicFormula,
	NotPointer<AtomicFormula>>;
}

class Literal : public detail::LiteralT
{
	using detail::LiteralT::LiteralT;
};

using Literals = std::vector<Literal>;

////////////////////////////////////////////////////////////////////////////////////////////////////

class Fact;

namespace detail
{
using FactT = Variant<
	AtomicFormula,
	AtPointer<Literal>,
	NotPointer<Fact>>;
}

class Fact : public detail::FactT
{
	using detail::FactT::FactT;
};

using Facts = std::vector<Fact>;

////////////////////////////////////////////////////////////////////////////////////////////////////

using Goal = Precondition;

////////////////////////////////////////////////////////////////////////////////////////////////////

}
}

#endif