import logging
import os
from collections import deque
from datetime import datetime, timedelta, timezone
from logging.handlers import TimedRotatingFileHandler
from typing import Any


def _get_path(cfg: dict[str, Any]) -> str:
    return cfg.get("incidents", {}).get("path", "/var/server-bot/incidents.log")


def incidents_path(cfg: dict[str, Any]) -> str:
    return _get_path(cfg)


def _get_logger(cfg: dict[str, Any]) -> logging.Logger:
    logger = logging.getLogger("incidents")
    if logger.handlers:
        return logger

    path = _get_path(cfg)
    os.makedirs(os.path.dirname(path), exist_ok=True)

    rotate_when = cfg.get("incidents", {}).get("rotate_when", "W0")
    backup_count = int(cfg.get("incidents", {}).get("backup_count", 8))
    handler = TimedRotatingFileHandler(
        path,
        when=rotate_when,
        interval=1,
        backupCount=backup_count,
        encoding="utf-8",
        utc=True,
    )
    formatter = logging.Formatter(
        "%(asctime)s\t%(message)s",
        datefmt="%Y-%m-%dT%H:%M:%SZ",
    )
    handler.setFormatter(formatter)

    logger.setLevel(logging.INFO)
    logger.addHandler(handler)
    logger.propagate = False
    return logger


def log_incident(cfg: dict[str, Any], text: str) -> None:
    if not cfg.get("incidents", {}).get("enabled", True):
        return
    logger = _get_logger(cfg)
    logger.info(text)


def _parse_line(line: str) -> tuple[datetime | None, str]:
    if "\t" not in line:
        return None, line.strip()
    ts, msg = line.split("\t", 1)
    try:
        dt = datetime.strptime(ts.strip(), "%Y-%m-%dT%H:%M:%SZ").replace(tzinfo=timezone.utc)
    except ValueError:
        dt = None
    return dt, msg.strip()


def read_recent(cfg: dict[str, Any], hours: int, limit: int = 200) -> list[str]:
    path = _get_path(cfg)
    if not os.path.exists(path):
        return []

    since = datetime.now(timezone.utc) - timedelta(hours=hours)
    lines = deque(maxlen=limit)
    with open(path, "r", encoding="utf-8", errors="replace") as f:
        for line in f:
            dt, msg = _parse_line(line.rstrip())
            if dt is None or dt < since:
                continue
            lines.append(f"{dt:%Y-%m-%d %H:%M}  {msg}")
    return list(lines)