from __future__ import annotations

import logging
import os
import sys
from logging.handlers import RotatingFileHandler
from pathlib import Path
from typing import Optional, Union


def create_logger(
    name: str = "factuges-sync",
    *,
    level: int = logging.INFO,
    log_path: Optional[Union[str, Path]] = None,
    max_bytes: int = 5_000_000,  # rotación opcional
    backup_count: int = 3,
) -> logging.Logger:
    """
    Crea un logger consistente para FactuGES Sync.

    Reglas:
    - SIEMPRE envia logs a stdout (Docker-friendly).
    - SOLO en producción escribe también a fichero si `log_path` está definido.
    - `log_path` puede ser `str` o `Path`.
    - Evita duplicar handlers.
    """

    logger = logging.getLogger(name)
    logger.setLevel(level)

    # Si ya está configurado, no duplicamos handlers
    if logger.handlers:
        return logger

    formatter = logging.Formatter(
        "%(asctime)s - %(levelname)s - %(message)s"
    )

    # ------------------------------
    # 1) Handler de consola (siempre)
    # ------------------------------
    h_console = logging.StreamHandler(sys.stdout)
    h_console.setFormatter(formatter)
    logger.addHandler(h_console)

    # ------------------------------
    # 2) Handler de fichero (solo prod)
    # ------------------------------
    is_production = os.getenv("ENV") == "production"

    if log_path and is_production:
        p = Path(log_path)

        # Aseguramos directorios
        p.parent.mkdir(parents=True, exist_ok=True)

        # Puedes usar FileHandler simple, pero Rotating es más seguro.
        h_file = RotatingFileHandler(
            filename=str(p),
            maxBytes=max_bytes,
            backupCount=backup_count,
            encoding="utf-8",
        )
        h_file.setFormatter(formatter)
        logger.addHandler(h_file)

        # Verificación explícita
        try:
            test_msg = f"Log file active at: {p}"
            h_file.acquire()
            h_file.stream.write(f"{test_msg}\n")
            h_file.flush()
            h_file.release()

            logger.info(test_msg)
        except Exception as e:
            logger.error(f"ERROR: cannot write to log file {p}: {e}")
            raise

    return logger


# logger "global" ya creado
logger = create_logger()