import logging
from datetime import datetime

def setup_logger(name: str, log_file: str = None, level: str = 'INFO') -> logging.Logger:
    logger = logging.getLogger(name)
    logger.setLevel(getattr(logging, level.upper()))
    
    if not logger.handlers:
        formatter = logging.Formatter(
            '%(asctime)s - %(name)s - %(levelname)s - %(message)s'
        )
        
        console_handler = logging.StreamHandler()
        console_handler.setFormatter(formatter)
        logger.addHandler(console_handler)
        
        if log_file:
            file_handler = logging.FileHandler(log_file)
            file_handler.setFormatter(formatter)
            logger.addHandler(file_handler)
    
    return logger

def safe_divide(a: float, b: float, default: float = 0) -> float:
    try:
        return a / b if b != 0 else default
    except (TypeError, ZeroDivisionError):
        return default

def format_number(num: float, decimals: int = 2) -> str:
    try:
        if num == float('inf'):
            return '∞'
        elif num == float('-inf'):
            return '-∞'
        else:
            return f"{num:.{decimals}f}"
    except:
        return "N/A"

def get_current_date() -> str:
    return datetime.now().strftime('%Y%m%d')

def validate_ts_code(ts_code: str) -> bool:
    if not ts_code or not isinstance(ts_code, str):
        return False
    
    parts = ts_code.split('.')
    if len(parts) != 2:
        return False
    
    stock_code, exchange = parts
    return (len(stock_code) == 6 and stock_code.isdigit() and 
            exchange in ['SH', 'SZ'])