#ifndef AST_H
#define AST_H

struct stmt_node;
struct expr_node;

struct type_node {
    bool _unsigned;
    bool _short;
    bool _long;
    unsigned char ptr_level;
    char* name;
};

struct int_lit_node {
    long long val;
};

struct float_lit_node {
    double val;
};

struct char_lit_node {
    char val;
};

struct str_lit_node {
    char* val;
};

struct var_ref_node {
    char* ident;
};

struct var_decl_node {
    struct type_node type;
    char* ident;

    struct var_decl_node* next;
};

struct lval_node {
    enum {
        LVAL_VAR_DECL,
        LVAL_VAR_REF,
    } type;
    union {
        struct var_ref_node _var_ref;
        struct var_decl_node _var_decl;
    } as;
};

/* TODO: add to expression, parse */
struct assign_node {
    struct lval_node lval;
    struct expr_node* rval;
};

struct expr_node {
    enum {
        EXPR_INT_LIT,
        EXPR_FLOAT_LIT,
        EXPR_CHAR_LIT,
        EXPR_STR_LIT,
        EXPR_VAR_REF,
        EXPR_ASSIGN,
    } type;
    union {
        struct int_lit_node _int_lit;
        struct float_lit_node _float_lit;
        struct char_lit_node _char_lit;
        struct str_lit_node _str_lit;
        struct var_ref_node _var_ref;
        struct assign_node _assign;
    } as;
};

struct group_node {
    struct stmt_node* body_head;
};

struct fn_decl_node {
    struct type_node return_type;
    char* name;
    struct var_decl_node* args_head;
    struct group_node body;
};

struct return_node {
    struct expr_node* ret_val; /* null to return void */
};

struct stmt_node {
    enum {
        STMT_EMPTY,
        STMT_EXPR,
        STMT_VAR_DECL,
        STMT_RETURN,
        STMT_GROUP,
    } type;
    union {
        struct expr_node _expr;
        struct var_decl_node _var_decl;
        struct return_node _return;
        struct group_node _group;
    } as;

    struct stmt_node* next;
};

struct root_node {
    enum {
        ROOT_FN_DECL,
    } type;
    union {
        struct fn_decl_node _fn_decl;
    } as;

    struct root_node* next;
};

void ast_destroy(struct root_node* head);

#endif