import logging
import logging.handlers
import os
import sys
from pathlib import Path

import coloredlogs

from bot.constants import Logging


def setup() -> None:
    """Set up loggers."""
    # Configure the "TRACE" logging level (e.g. "log.trace(message)")
    logging.TRACE = 5
    logging.addLevelName(logging.TRACE, "TRACE")
    logging.Logger.trace = _monkeypatch_trace

    format_string = "%(asctime)s | %(name)s | %(levelname)s | %(message)s"
    log_format = logging.Formatter(format_string)
    root_logger = logging.getLogger()

    if Logging.file_logs:
        # Set up file logging
        log_file = Path("logs/sir-lancebot.log")
        log_file.parent.mkdir(exist_ok=True)

        # File handler rotates logs every 5 MB
        file_handler = logging.handlers.RotatingFileHandler(
            log_file, maxBytes=5 * (2 ** 20), backupCount=10, encoding="utf-8",
        )
        file_handler.setFormatter(log_format)
        root_logger.addHandler(file_handler)

    if "COLOREDLOGS_LEVEL_STYLES" not in os.environ:
        coloredlogs.DEFAULT_LEVEL_STYLES = {
            **coloredlogs.DEFAULT_LEVEL_STYLES,
            "trace": {"color": 246},
            "critical": {"background": "red"},
            "debug": coloredlogs.DEFAULT_LEVEL_STYLES["info"],
        }

    if "COLOREDLOGS_LOG_FORMAT" not in os.environ:
        coloredlogs.DEFAULT_LOG_FORMAT = format_string

    coloredlogs.install(level=logging.TRACE, stream=sys.stdout)

    root_logger.setLevel(logging.DEBUG if Logging.debug else logging.INFO)
    # Silence irrelevant loggers
    logging.getLogger("discord").setLevel(logging.ERROR)
    logging.getLogger("websockets").setLevel(logging.ERROR)
    logging.getLogger("PIL").setLevel(logging.ERROR)
    logging.getLogger("matplotlib").setLevel(logging.ERROR)
    logging.getLogger("async_rediscache").setLevel(logging.WARNING)

    _set_trace_loggers()

    root_logger.info("Logging initialization complete")


def _monkeypatch_trace(self: logging.Logger, msg: str, *args, **kwargs) -> None:
    """
    Log 'msg % args' with severity 'TRACE'.

    To pass exception information, use the keyword argument exc_info with a true value, e.g.
    logger.trace("Houston, we have an %s", "interesting problem", exc_info=1)
    """
    if self.isEnabledFor(logging.TRACE):
        self._log(logging.TRACE, msg, args, **kwargs)


def _set_trace_loggers() -> None:
    """
    Set loggers to the trace level according to the value from the BOT_TRACE_LOGGERS env var.

    When the env var is a list of logger names delimited by a comma,
    each of the listed loggers will be set to the trace level.

    If this list is prefixed with a "!", all of the loggers except the listed ones will be set to the trace level.

    Otherwise if the env var begins with a "*",
    the root logger is set to the trace level and other contents are ignored.
    """
    level_filter = Logging.trace_loggers
    if level_filter:
        if level_filter.startswith("*"):
            logging.getLogger().setLevel(logging.TRACE)

        elif level_filter.startswith("!"):
            logging.getLogger().setLevel(logging.TRACE)
            for logger_name in level_filter.strip("!,").split(","):
                logging.getLogger(logger_name).setLevel(logging.DEBUG)

        else:
            for logger_name in level_filter.strip(",").split(","):
                logging.getLogger(logger_name).setLevel(logging.TRACE)