"""
Custom structured JSON logging for filter outputs.
"""
import json
import logging
import sys
from datetime import datetime
from typing import Any, Dict


class JsonFormatter(logging.Formatter):
    def format(self, record: logging.LogRecord) -> str:
        log_obj: Dict[str, Any] = {
            "timestamp": datetime.utcnow().isoformat() + "Z",
            "level": record.levelname,
            "message": record.getMessage(),
            "module": record.module
        }
        if hasattr(record, 'metrics'):
            log_obj["metrics"] = record.metrics
        return json.dumps(log_obj)

def get_structured_logger(name: str) -> logging.Logger:
    """Instantiates a logger that outputs JSON structured text."""
    logger = logging.getLogger(name)
    logger.setLevel(logging.INFO)
    
    if not logger.handlers:
        handler = logging.StreamHandler(sys.stdout)
        handler.setFormatter(JsonFormatter())
        logger.addHandler(handler)
        
    return logger