import logging
import json
import sys
from datetime import datetime
from typing import Optional


class StructuredFormatter(logging.Formatter):
    """JSON structured log formatter for production."""
    
    def format(self, record):
        log_entry = {
            "timestamp": datetime.utcnow().isoformat() + "Z",
            "level": record.levelname,
            "logger": record.name,
            "message": record.getMessage(),
        }
        
        if record.exc_info and record.exc_info[0]:
            log_entry["exception"] = self.formatException(record.exc_info)
        
        if hasattr(record, "extra_data"):
            log_entry["data"] = record.extra_data
        
        return json.dumps(log_entry, ensure_ascii=False)


class HumanFormatter(logging.Formatter):
    """Human-readable log formatter for development."""
    
    def format(self, record):
        return f"{datetime.now().strftime('%H:%M:%S')} [{record.levelname}] {record.name}: {record.getMessage()}"


def setup_logging(level: str = "INFO", structured: bool = False):
    """
    Setup logging cho toàn bộ ứng dụng.
    
    Args:
        level: Log level (DEBUG, INFO, WARNING, ERROR)
        structured: True = JSON format (production), False = human readable (development)
    """
    root_logger = logging.getLogger()
    root_logger.setLevel(getattr(logging, level.upper(), logging.INFO))
    
    # Xóa existing handlers
    root_logger.handlers.clear()
    
    handler = logging.StreamHandler(sys.stdout)
    handler.setFormatter(StructuredFormatter() if structured else HumanFormatter())
    root_logger.addHandler(handler)


def log_event(logger: logging.Logger, level: str, message: str, **kwargs):
    """
    Ghi log với structured data.
    
    Usage:
        log_event(logger, "info", "File processed", file_name="test.pdf", pages=5)
    """
    extra = {"extra_data": kwargs} if kwargs else {}
    getattr(logger, level.lower(), logger.info)(message, extra=extra)