"""
Structured logging configuration for MTG Online backend.

Supports JSON and text log formats with container metadata.
Configured via MTG_LOG_LEVEL and MTG_LOG_FORMAT environment variables.
"""
import json
import logging
import os
import sys
from datetime import datetime, timezone


def _get_container_name() -> str:
    """Get container name from HOSTNAME env var or fallback."""
    return os.environ.get("HOSTNAME", "unknown")


class ContainerFormatter(logging.Formatter):
    """Formatter that adds container metadata to log records.

    Supports both text and JSON output formats.
    """

    SERVICE_NAME = "mtgonline-backend"

    def __init__(self, fmt_type: str = "text"):
        super().__init__()
        self.fmt_type = fmt_type
        self.container_name = _get_container_name()

    def format(self, record: logging.LogRecord) -> str:
        record.service = self.SERVICE_NAME
        record.container = self.container_name

        if self.fmt_type == "json":
            return self._format_json(record)
        return self._format_text(record)

    def _format_text(self, record: logging.LogRecord) -> str:
        return (
            f"{self.formatTime(record)} [{record.service}] "
            f"{record.levelname} - {record.getMessage()}"
        )

    def _format_json(self, record: logging.LogRecord) -> str:
        log_entry = {
            "timestamp": datetime.fromtimestamp(
                record.created, tz=timezone.utc
            ).isoformat(),
            "level": record.levelname,
            "service": record.service,
            "container": record.container,
            "logger": record.name,
            "message": record.getMessage(),
        }
        if record.exc_info and record.exc_info[0] is not None:
            log_entry["exception"] = self.formatException(record.exc_info)
        return json.dumps(log_entry, default=str)


def configure_logging() -> None:
    """Configure application logging based on environment variables.

    Reads:
        MTG_LOG_LEVEL  - Log level (DEBUG, INFO, WARNING, ERROR, CRITICAL)
        MTG_LOG_FORMAT - Output format ("text" or "json")
    """
    log_level = os.environ.get("MTG_LOG_LEVEL", "INFO").upper()
    log_format = os.environ.get("MTG_LOG_FORMAT", "text").lower()

    level = getattr(logging, log_level, logging.INFO)

    formatter = ContainerFormatter(fmt_type=log_format)

    handler = logging.StreamHandler(sys.stdout)
    handler.setFormatter(formatter)

    root_logger = logging.getLogger()
    root_logger.setLevel(level)
    root_logger.handlers.clear()
    root_logger.addHandler(handler)

    # Suppress noisy loggers unless DEBUG
    if level != logging.DEBUG:
        logging.getLogger("sqlalchemy.engine").setLevel(logging.WARNING)
        logging.getLogger("sqlalchemy.pool").setLevel(logging.WARNING)

    logger = logging.getLogger(__name__)
    logger.info(
        f"Logging configured: level={log_level}, "
        f"format={log_format}, container={_get_container_name()}"
    )


# Auto-configure on import
configure_logging()