typedef struct os_date_t os_date_t;
struct os_date_t {
    u16 ms;
    u16 sec;
    u16 min;
    u16 hour;
    u16 day;
    u16 month;
    u16 year;
};

typedef struct os_iter_t os_iter_t;
struct os_iter_t {
    s8_t abs;
    s8_t rel;
    s8_t name;
    b8 is_directory;
    b8 is_valid;

    s8_t path;
    ma_arena_t *arena;

    union {
        struct w32_file_iter_t *w32;
        void *platform;
    };
};

typedef enum {
    os_mkdir_success,
    os_mkdir_file_exists,
    os_mkdir_path_not_found,
    os_mkdir_other_error,
} os_mkdir_t;

typedef enum {
    os_write_success,
    os_write_path_not_found,
    os_write_other_error,
} os_write_t;

fn os_date_t   os_local_time(void);
fn os_date_t   os_universal_time(void);
fn s8_t        os_format_date(ma_arena_t *arena, os_date_t date);
fn f64         os_seconds(void);
fn f64         os_milliseconds(void);

fn b32         os_copy(s8_t from, s8_t to, b32 overwrite);
fn b32         os_delete(s8_t path);
fn os_mkdir_t  os_mkdir(s8_t path);
fn os_write_t  os_write(s8_t path, s8_t content);

fn void        os_advance(os_iter_t *it);
fn os_iter_t  *os_iter(ma_arena_t *arena, s8_t path);

fn i64         os_mod_time(s8_t file);
fn s8_t        os_abs(ma_arena_t *arena, s8_t rel);
fn s8_t        os_exe(ma_arena_t *arena);
fn s8_t        os_exe_dir(ma_arena_t *arena);
fn b32         os_is_dir(s8_t path);
fn b32         os_is_file(s8_t path);
fn b32         os_is_abs(s8_t path);
fn b32         os_exists(s8_t path);

fn s8_t        os_cwd(ma_arena_t *arena);
fn void        os_set_cwd(s8_t new_cwd);


typedef i32 os_thread_fn_t(void *user_data);
typedef struct os_thread_t os_thread_t;
struct os_thread_t {
    b32 exited;
    i32 exit_code;
    union {
        struct w32_thread_t *w32;
        void                *ptr;
    };
};

fn os_thread_t os_thread_create(ma_arena_t *arena, os_thread_fn_t *func, void *user_data);
fn i32         os_thread_wait_for_exit(os_thread_t *thread);