#ifndef LISP_H
#define LISP_H

#include "nob.h"

typedef enum e_TokenKind {
    TOKEN_KIND_PAR_LEFT,
    TOKEN_KIND_PAR_RIGHT,
    TOKEN_KIND_NUMBER,
    TOKEN_KIND_SYMBOL,
} TokenKind;

typedef struct s_Token {
    TokenKind kind;
    Nob_String_View data;
} Token;

typedef struct s_Tokens {
    Token *items;
    size_t count;
    size_t capacity;
} Tokens;

typedef enum e_NodeKind {
    NODE_KIND_SYMBOL,
    NODE_KIND_LIST,
    NODE_KIND_NUMBER,
    NODE_KIND_FUNCTION,
} NodeKind;

typedef struct s_Node Node;
typedef struct s_Nodes Nodes;
typedef struct s_Scopes Scopes;

// args is specifically not a pointer,
// functions shouldn't be able to mess with their arguments
typedef int (*LispFunction)(Nodes args, Scopes *scopes, Node *result);

struct s_Node {
    NodeKind kind;
    union {
        Nob_String_View as_symbol;
        Nodes *as_list;
        long long as_number;
        struct {
            Nob_String_View name;
            LispFunction apply;
        } as_function;
    };
};

struct s_Nodes {
    Node *items;
    size_t count;
    size_t capacity;
};

typedef struct s_ScopeObject {
    Nob_String_View name;
    Node node;
} ScopeObject;

// TODO: use hashtable
typedef struct s_Scope {
    ScopeObject *items;
    size_t count;
    size_t capacity;
} Scope;

struct s_Scopes {
    Scope **items;
    size_t count;
    size_t capacity;
};

const char *token_kind_name(TokenKind kind);
void node_print(Node node);

void build_scopes(Scopes *scopes);
void tokenize(Nob_String_View content, Tokens *tokens);

int parse_one(Tokens *tokens, Node *node);
int parse(Tokens *tokens, Nodes *nodes);

int eval_one(Node input, Scopes *scopes, Node *result);
int eval(Nodes inputs, Scopes *scopes, Nodes *results);

// builtins
int lisp_function_add(Nodes args, Scopes *scopes, Node *result);
int lisp_function_sub(Nodes args, Scopes *scope, Node *result);
int lisp_function_div(Nodes args, Scopes *scope, Node *result);
int lisp_function_mul(Nodes args, Scopes *scope, Node *result);
int lisp_function_mod(Nodes args, Scopes *scope, Node *result);

int lisp_function_eq(Nodes args, Scopes *scope, Node *result);
int lisp_function_lt(Nodes args, Scopes *scope, Node *result);
int lisp_function_gt(Nodes args, Scopes *scope, Node *result);
int lisp_function_lt_eq(Nodes args, Scopes *scope, Node *result);
int lisp_function_gt_eq(Nodes args, Scopes *scope, Node *result);

int lisp_function_println(Nodes args, Scopes *scopes, Node *result);
int lisp_function_list(Nodes args, Scopes *scopes, Node *result);
int lisp_function_append(Nodes args, Scopes *scope, Node *result);
int lisp_function_length(Nodes args, Scopes *scope, Node *result);
int lisp_function_isnull(Nodes args, Scopes *scope, Node *result);
int lisp_function_builtins(Nodes args, Scopes *scopes, Node *result);

#endif // LISP_H