#ifndef TGRAMMAR_INCLUDED

#define TGRAMMAR_INCLUDED

#include <memory></memory>

// TnzCore includes

#include "tcommon.h"

// TnzBase includes

#include "ttokenizer.h"

#undef DVAPI

#undef DVVAR

#ifdef TNZBASE_EXPORTS

#define DVAPI DV_EXPORT_API

#define DVVAR DV_EXPORT_VAR

#else

#define DVAPI DV_IMPORT_API

#define DVVAR DV_IMPORT_VAR

#endif

//==============================================

//    Forward declarations

class TDoubleParam;

class TUnit;

namespace TSyntax

{

class Token;

class Calculator;

}

//==============================================

//-------------------------------------------------------------------

// Calculator & calculator nodes

//-------------------------------------------------------------------

namespace TSyntax

{

class DVAPI CalculatorNodeVisitor

{

public:

	CalculatorNodeVisitor() {}

	virtual ~CalculatorNodeVisitor() {}

};

//-------------------------------------------------------------------

class DVAPI CalculatorNode

{

	Calculator *m_calculator;

public:

	CalculatorNode(Calculator *calculator) : m_calculator(calculator) {}

	virtual ~CalculatorNode() {}

	Calculator *getCalculator() const { return m_calculator; }

	enum { T,

		   FRAME,

		   RFRAME };

	virtual double compute(double vars[3]) const = 0;

	virtual void accept(CalculatorNodeVisitor &visitor) = 0;

private:

	// Non-copyable

	CalculatorNode(const CalculatorNode &);

	CalculatorNode &operator=(const CalculatorNode &);

};

//-------------------------------------------------------------------

class DVAPI Calculator

{

	CalculatorNode *m_rootNode; //!< (owned) Root calculator node

	TDoubleParam *m_param; //!< (not owned) Owner of the calculator object

	const TUnit *m_unit;   //!< (not owned)

public:

	Calculator();

	virtual ~Calculator();

	void setRootNode(CalculatorNode *node);

	double compute(double t, double frame, double rframe)

	{

		double vars[3];

		vars[0] = t, vars[1] = frame, vars[2] = rframe;

		return m_rootNode->compute(vars);

	}

	void accept(CalculatorNodeVisitor &visitor) { m_rootNode->accept(visitor); }

	typedef double Calculator::*Variable;

	void setOwnerParameter(TDoubleParam *param) { m_param = param; }

	TDoubleParam *getOwnerParameter() const { return m_param; }

	const TUnit *getUnit() const { return m_unit; }

	void setUnit(const TUnit *unit) { m_unit = unit; }

private:

	// not copyable

	Calculator(const Calculator &);

	Calculator &operator=(const Calculator &);

};

//-------------------------------------------------------------------

class DVAPI NumberNode : public CalculatorNode

{

	double m_value;

public:

	NumberNode(Calculator *calc, double value) : CalculatorNode(calc), m_value(value) {}

	double compute(double vars[3]) const { return m_value; }

	void accept(CalculatorNodeVisitor &visitor) {}

};

//-------------------------------------------------------------------

class DVAPI VariableNode : public CalculatorNode

{

	int m_varIdx;

public:

	VariableNode(Calculator *calc, int varIdx)

		: CalculatorNode(calc), m_varIdx(varIdx) {}

	double compute(double vars[3]) const { return vars[m_varIdx]; }

	void accept(CalculatorNodeVisitor &visitor) {}

};

//-------------------------------------------------------------------

// Pattern

//-------------------------------------------------------------------

enum TokenType {

	Unknown = 0,

	Number,

	Constant,

	Variable,

	Operator,

	Parenthesis,

	Function,

	Comma,

	UnexpectedToken = -100,

	Eos,

	Mismatch,

	InternalError = -200

};

//-------------------------------------------------------------------

class DVAPI Pattern

{

	std::string m_description;

public:

	Pattern() {}

	virtual ~Pattern() {}

	virtual std::string getFirstKeyword() const { return ""; }

	virtual void getAcceptableKeywords(std::vector<std::string> &keywords) const {}</std::string>

	virtual int getPriority() const { return 0; }

	virtual bool expressionExpected(const std::vector<token> &previousTokens) const { return false; }</token>

	virtual bool matchToken(const std::vector<token> &previousTokens, const Token &token) const = 0;</token>

	virtual bool isFinished(const std::vector<token> &previousTokens, const Token &token) const = 0;</token>

	virtual bool isComplete(const std::vector<token> &previousTokens, const Token &token) const { return isFinished(previousTokens, token); }</token>

	virtual TokenType getTokenType(const std::vector<token> &previousTokens, const Token &token) const = 0; // see also SyntaxToken in tparser.h</token>

	virtual void createNode(

		Calculator *calc,

		std::vector<calculatornode *=""> &stack,</calculatornode>

		const std::vector<token> &tokens) const = 0;</token>

	std::string getDescription() const { return m_description; }

	void setDescription(std::string description) { m_description = description; }

	// helper methods

	CalculatorNode *popNode(std::vector<calculatornode *=""> &stack) const;</calculatornode>

};

//-------------------------------------------------------------------

class DVAPI Grammar

{

	class Imp;

	std::unique_ptr<imp> m_imp;</imp>

public:

	Grammar();

	~Grammar();

	void addPattern(Pattern *pattern); // take ownership

	enum Position { ExpressionStart,

					ExpressionEnd };

	// note: returns a matching pattern (or 0 if no pattern matches)

	const Pattern *getPattern(Position position, const Token &token) const;

	// returns matching <keywords, comment=""></keywords,>

	typedef std::vector<std::pair<std::string, std::string="">> Suggestions;</std::pair<std::string,>

	void getSuggestions(Suggestions &suggetsions, Position position) const;

private:

	// not implemented

	Grammar(const Grammar &);

	Grammar &operator=(const Grammar &);

};

} // namespace TSyntax

#endif // TGRAMMAR_INCLUDED