import base64
import hashlib
import hmac
import json
import time
import zlib


def gen_user_sig(
    sdk_appid: int,
    secret_key: str,
    userid: str,
    expire: int = 180 * 86400,
) -> str:
    curr_time = int(time.time())

    sig_doc = {
        "TLS.ver": "2.0",
        "TLS.identifier": str(userid),
        "TLS.sdkappid": sdk_appid,
        "TLS.expire": expire,
        "TLS.time": curr_time,
    }

    sig_bytes = json.dumps(sig_doc, separators=(",", ":")).encode("utf-8")
    compressed = zlib.compress(sig_bytes)
    base64_userbuf = base64.urlsafe_b64encode(compressed).rstrip(b"=").decode("utf-8")

    signature = hmac.new(
        secret_key.encode("utf-8"),
        base64_userbuf.encode("utf-8"),
        hashlib.sha256,
    ).digest()
    base64_sig = base64.urlsafe_b64encode(signature).rstrip(b"=").decode("utf-8")

    return f"{base64_sig}{base64_userbuf}"