#ifndef EXPR_HH
#define EXPR_HH

#include "../tokenizer.hh"
#include <memory>
#include <string>
#include <variant>

struct Expr;

using ExprPtr = std::shared_ptr<Expr>;

struct _Binary {
  ExprPtr left;
  Token op;
  ExprPtr right;
};

struct _Grouping {
  ExprPtr expression;
};

struct _Literal {
  Object value;
};

struct _Unary {
  Token op;
  ExprPtr right;
};

enum class ExprType {
  BINARY,
  GROUPING,
  LITERAL,
  UNARY,
};

using ExprVariant = std::variant<_Binary, _Grouping, _Literal, _Unary>;

struct Expr {
  ExprType type;
  ExprVariant value;

  ExprPtr to_expr_ptr() { return std::make_shared<Expr>(*this); }
};

inline Expr Binary(ExprPtr left, Token op, ExprPtr right) {
  return Expr{ExprType::BINARY, _Binary{left, op, right}};
}

inline Expr Grouping(ExprPtr expr) {
  return Expr{ExprType::GROUPING, _Grouping{expr}};
}

inline Expr Literal(Object value) {
  return Expr{ExprType::LITERAL, _Literal{value}};
}

inline Expr Unary(Token op, ExprPtr right) {
  return Expr{ExprType::UNARY, _Unary{op, right}};
}

class AstPrinter {
public:
  std::string print(const Expr &expr);
private:
  std::string parenthesize(const std::string &name, std::vector<Expr> exprs);
};

#endif