"""Logging setup: stdout (always) plus a rotating file locally, with secret redaction."""
from __future__ import annotations

import logging
import logging.handlers
from pathlib import Path

FORMAT = "%(asctime)s %(levelname)-7s %(name)s: %(message)s"


class RedactSecrets(logging.Filter):
    """Replace known secret values in every log record."""

    def __init__(self, secrets: list[str]):
        super().__init__()
        self._secrets = sorted({s for s in secrets if s}, key=len, reverse=True)

    def filter(self, record: logging.LogRecord) -> bool:
        if not self._secrets:
            return True
        message = record.getMessage()
        redacted = message
        for secret in self._secrets:
            redacted = redacted.replace(secret, "***")
        if redacted != message:
            record.msg, record.args = redacted, None
        return True


def setup_logging(level: str = "INFO", *, log_dir: Path | None = None, secrets: list[str] | None = None) -> None:
    """``log_dir=None`` logs to stdout only (Heroku collects stdout via `heroku logs`)."""
    root = logging.getLogger()
    root.setLevel(level)
    for handler in list(root.handlers):
        root.removeHandler(handler)
    redact = RedactSecrets(secrets or [])
    handlers: list[logging.Handler] = [logging.StreamHandler()]
    if log_dir is not None:
        log_dir.mkdir(parents=True, exist_ok=True)
        handlers.append(
            logging.handlers.RotatingFileHandler(log_dir / "bot.log", maxBytes=10 * 1024 * 1024, backupCount=5, encoding="utf-8")
        )
    for handler in handlers:
        handler.setFormatter(logging.Formatter(FORMAT))
        handler.addFilter(redact)
        root.addHandler(handler)
    for noisy in ("telethon", "googleapiclient.discovery_cache", "urllib3", "google_auth_httplib2"):
        logging.getLogger(noisy).setLevel(logging.WARNING)