"""Dynamic plugin loader for strategy modules."""
import importlib.util
import sys
from pathlib import Path

from strategies.base import BaseStrategy


def load_strategies(strategies_dir: Path) -> list[BaseStrategy]:
    """Scan strategies_dir for *.py files and load all BaseStrategy subclasses."""
    loaded: list[BaseStrategy] = []

    for path in sorted(strategies_dir.glob("*.py")):
        # Skip dunder files and base
        if path.name.startswith("__") or path.name == "base.py":
            continue

        module_name = f"_strategy_plugin_{path.stem}"
        spec = importlib.util.spec_from_file_location(module_name, path)
        if spec is None or spec.loader is None:
            continue

        module = importlib.util.module_from_spec(spec)
        sys.modules[module_name] = module
        spec.loader.exec_module(module)

        for attr_name in dir(module):
            obj = getattr(module, attr_name)
            if (
                isinstance(obj, type)
                and issubclass(obj, BaseStrategy)
                and obj is not BaseStrategy
            ):
                loaded.append(obj())

    return loaded