"""
Structured logging configuration for CBPOA backend.

- LOG_LEVEL: DEBUG, INFO, WARNING, ERROR, CRITICAL (default INFO)
- LOG_FORMAT: "json" for production, "text" for human-readable dev output (default text)
"""
import logging
import json
import sys
import os
from datetime import datetime, timezone


class JSONFormatter(logging.Formatter):
    """Emit structured JSON log lines for production."""

    def format(self, record: logging.LogRecord) -> str:
        log_entry = {
            "timestamp": datetime.fromtimestamp(record.created, tz=timezone.utc).isoformat(),
            "level": record.levelname,
            "logger": record.name,
            "message": record.getMessage(),
        }
        if record.exc_info and record.exc_info[1]:
            log_entry["exception"] = self.formatException(record.exc_info)
        # Include extra fields (request_id, method, path, etc.)
        for key in ("request_id", "method", "path", "status_code", "duration_ms"):
            val = getattr(record, key, None)
            if val is not None:
                log_entry[key] = val
        return json.dumps(log_entry, ensure_ascii=False)


def setup_logging() -> None:
    """Configure root logger based on environment variables."""
    level_name = os.getenv("LOG_LEVEL", "INFO").upper()
    level = getattr(logging, level_name, logging.INFO)

    log_format = os.getenv("LOG_FORMAT", "text").lower()

    handler = logging.StreamHandler(sys.stdout)

    if log_format == "json":
        handler.setFormatter(JSONFormatter())
    else:
        handler.setFormatter(
            logging.Formatter(
                "%(asctime)s | %(levelname)-8s | %(name)s | %(message)s",
                datefmt="%Y-%m-%d %H:%M:%S",
            )
        )

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

    # Quiet noisy third-party loggers
    logging.getLogger("uvicorn.access").setLevel(logging.WARNING)