from __future__ import annotations

from typing import Callable

PUB_OP = "PUB"
HPUB_OP = "HPUB"
SUB_OP = "SUB"
UNSUB_OP = "UNSUB"
_CRLF_ = "\r\n"

Command = Callable[..., bytes]


def pub_cmd(subject, reply, payload) -> bytes:
    return f"{PUB_OP} {subject} {reply} {len(payload)}{_CRLF_}".encode() + payload + _CRLF_.encode()


def hpub_cmd(subject, reply, hdr, payload) -> bytes:
    hdr_len = len(hdr)
    total_size = len(payload) + hdr_len
    return f"{HPUB_OP} {subject} {reply} {hdr_len} {total_size}{_CRLF_}".encode() + hdr + payload + _CRLF_.encode()


def sub_cmd(subject, queue, sid) -> bytes:
    return f"{SUB_OP} {subject} {queue} {sid}{_CRLF_}".encode()


def unsub_cmd(sid, limit) -> bytes:
    limit_s = "" if limit == 0 else f"{limit}"
    return f"{UNSUB_OP} {sid} {limit_s}{_CRLF_}".encode()