#ifndef _CALC_AST_HPP_
#define _CALC_AST_HPP_
extern "C" {
#include "syntax_tree.h"
extern syntax_tree *parse(const char *input);
}
#include <vector>
#include <memory>

enum AddOp {
    // +
    OP_PLUS,
    // -
    OP_MINUS
};

enum MulOp {
    // *
    OP_MUL,
    // /
    OP_DIV
};

class CalcAST;

struct CalcASTNode;
struct CalcASTInput;
struct CalcASTExpression;
struct CalcASTNum;
struct CalcASTTerm;
struct CalcASTFactor;

class CalcASTVisitor;

class CalcAST
{
  public:
    CalcAST() = delete;
    CalcAST(syntax_tree *);
    CalcAST(CalcAST &&tree)
    {
        root      = tree.root;
        tree.root = nullptr;
    };
    CalcASTInput *get_root() { return root.get(); }
    void          run_visitor(CalcASTVisitor &visitor);

  private:
    CalcASTNode                  *transform_node_iter(syntax_tree_node *);
    std::shared_ptr<CalcASTInput> root = nullptr;
};

struct CalcASTNode
{
    virtual void accept(CalcASTVisitor &) = 0;
};

struct CalcASTInput : CalcASTNode
{
    virtual void                       accept(CalcASTVisitor &) override final;
    std::shared_ptr<CalcASTExpression> expression;
};

struct CalcASTFactor : CalcASTNode
{
    virtual void accept(CalcASTVisitor &) override;
};

struct CalcASTNum : CalcASTFactor
{
    virtual void accept(CalcASTVisitor &) override final;
    int          val;
};

struct CalcASTExpression : CalcASTFactor
{
    virtual void                       accept(CalcASTVisitor &) override final;
    std::shared_ptr<CalcASTExpression> expression;
    AddOp                              op;
    std::shared_ptr<CalcASTTerm>       term;
};

struct CalcASTTerm : CalcASTNode
{
    virtual void                   accept(CalcASTVisitor &) override final;
    std::shared_ptr<CalcASTTerm>   term;
    MulOp                          op;
    std::shared_ptr<CalcASTFactor> factor;
};

class CalcASTVisitor
{
  public:
    virtual void visit(CalcASTInput &)      = 0;
    virtual void visit(CalcASTNum &)        = 0;
    virtual void visit(CalcASTExpression &) = 0;
    virtual void visit(CalcASTTerm &)       = 0;
};
#endif