#ifndef EXPR_HH
#define EXPR_HH

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

struct Expr;
struct Binary;
struct Grouping;
struct Literal;
struct Unary;

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

using ExprVariant = std::variant<
  std::shared_ptr<Binary>,
  std::shared_ptr<Grouping>,
  std::shared_ptr<Literal>,
  std::shared_ptr<Unary>
>;

struct Expr {
  // Copy constructor
  Expr(const Expr &other);

  // Move constructor
  Expr(const Expr &&other);

  // Binary expressoin
  Expr(Expr left, Token op, Expr right);

  // Literal expression
  Expr(Object value);

  // Unary expressoin
  Expr(Token op, Expr right);

  // Group expression
  // Has to take an extra parameter to avoid conflicting with copy constructor
  Expr(Expr expr, void *ptr);

  ExprType type;
  ExprVariant value;
};

struct Binary {
  Binary(Expr left, Token op, Expr right) : left{left}, op{op}, right{right} {}
  Expr left;
  Token op;
  Expr right;
};

struct Grouping {
  Grouping(Expr expr) : expr{expr} {}
  Expr expr;
};

struct Literal {
  Literal(Object value) : value{value} {}
  Object value;
};

struct Unary {
  Unary(Token op, Expr right) : op{op}, right{right} {}
  Token op;
  Expr right;
};

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

#endif