from __future__ import annotations

import os
import logging
from pathlib import Path
from logging.handlers import RotatingFileHandler
from typing import Optional

_CONFIGURED = False


def _project_root() -> Path:
    # Resolve repo root from this file location: app/core/logger.py -> repo/app/core
    return Path(__file__).resolve().parents[2]


def configure_logging(level: Optional[str] = None, log_dir: Optional[str] = None) -> None:
    global _CONFIGURED
    if _CONFIGURED:
        return

    # Determine log level
    level_name = (level or os.getenv("LOG_LEVEL") or "INFO").upper()
    log_level = getattr(logging, level_name, logging.INFO)

    # Determine logs directory
    base_dir = Path(log_dir) if log_dir else _project_root() / "logs"
    base_dir.mkdir(parents=True, exist_ok=True)

    # Root logger configuration
    root = logging.getLogger()
    root.setLevel(log_level)

    fmt = logging.Formatter(
        fmt="%(asctime)s [%(levelname)s] %(name)s - %(message)s",
        datefmt="%Y-%m-%d %H:%M:%S",
    )

    file_handler = RotatingFileHandler(base_dir / "app.log", maxBytes=1_000_000, backupCount=3)
    file_handler.setFormatter(fmt)
    file_handler.setLevel(log_level)
    root.addHandler(file_handler)

    # Stream warnings+ to stderr for container visibility
    stream = logging.StreamHandler()
    stream.setLevel(logging.WARNING)
    stream.setFormatter(fmt)
    root.addHandler(stream)

    _CONFIGURED = True


def get_logger(name: Optional[str] = None) -> logging.Logger:
    if not _CONFIGURED:
        configure_logging()
    return logging.getLogger(name or "app")