"""AlphaLab session management - lazy import vnpy.alpha to avoid ImportError when alphalens missing."""
import sys
import os
_VNPY_SRC = os.path.abspath(os.path.join(os.path.dirname(__file__), "..", "vnpy_v4.4.0"))
if _VNPY_SRC not in sys.path:
    sys.path.insert(0, _VNPY_SRC)


class AlphaLabSession:
    """Session manager for vnpy.alpha AlphaLab operations."""
    
    def __init__(self, lab_path: str):
        """
        Initialize AlphaLab session.
        
        Args:
            lab_path: Path to AlphaLab directory
        """
        from vnpy.alpha.lab import AlphaLab
        
        self.lab_path = lab_path
        self.lab = AlphaLab(lab_path)
    
    def load_symbols(self, symbols: list[str], start: str, end: str, cfg) -> None:
        """
        Load symbol data from database and save to AlphaLab.
        
        Args:
            symbols: List of vt_symbols to load
            start: Start date (YYYY-MM-DD)
            end: End date (YYYY-MM-DD)
            cfg: Database configuration object
        """
        from sanguo_data.datareader import read_db_daily
        from .data_adapter import save_alpha_lab_data
        
        for symbol in symbols:
            bars = read_db_daily(symbol, start, end, cfg)
            if bars:
                save_alpha_lab_data(bars, self.lab_path)