#ifndef TREE_H
#define TREE_H

#include "lex.h"
#include "math_functions.h"

enum expr_type {
    EXPR_CONST,
    EXPR_NEG,
    EXPR_ADD,
    EXPR_SUB,
    EXPR_MULT,
    EXPR_DIV,
    EXPR_POW,
    EXPR_X,
    EXPR_FN
};

struct expr_node {
    enum expr_type type;
    union expr_vals {
        struct expr_binop_vals {
            struct expr_node *left;
            struct expr_node *right;
        } binop;
        struct expr_fn_vals {
            size_t fn_idx;
            struct expr_node *args[MAX_MATH_FUNCTION_ARGS];
        } fn;
        struct expr_node *unop;
        double num;
    } vals;
};

extern struct expr_node *node_create_const(double val);
extern struct expr_node *node_create_neg(struct expr_node *unop);
extern struct expr_node *node_create_add(struct expr_node *left, struct expr_node *right);
extern struct expr_node *node_create_sub(struct expr_node *left, struct expr_node *right);
extern struct expr_node *node_create_mult(struct expr_node *left, struct expr_node *right);
extern struct expr_node *node_create_div(struct expr_node *left, struct expr_node *right);
extern struct expr_node *node_create_pow(struct expr_node *base, struct expr_node *power);
extern struct expr_node *node_create_x(void);
extern struct expr_node *node_create_fn(size_t fn_idx, struct expr_node **args);

extern void node_debug_print(struct expr_node *node);
extern void node_debug_print_gv(const struct expr_node *node, FILE *output);

extern double node_eval(const struct expr_node *node, double x);

extern void node_free(struct expr_node *node);


#endif /* TREE_H */