import os
import importlib.util
import sys
from typing import Any, Callable, Dict

PLUGINS_DIR = "plugins"
os.makedirs(PLUGINS_DIR, exist_ok=True)


class PluginManager:
    """
    Dynamically loads Python modules from plugins/ and
    exposes their functions in a registry.
    """

    def __init__(self):
        self.registry: Dict[str, Callable[..., Any]] = {}
        self._load_all()

    def _load_all(self):
        """Scan plugins/ and import every .py as a module."""
        for fname in os.listdir(PLUGINS_DIR):
            if not fname.endswith(".py"):
                continue
            path = os.path.join(PLUGINS_DIR, fname)
            name = os.path.splitext(fname)[0]
            self._load_module(name, path)

    def _load_module(self, name: str, path: str):
        """Load a single plugin module and register its callables."""
        spec = importlib.util.spec_from_file_location(name, path)
        if spec and spec.loader:
            mod = importlib.util.module_from_spec(spec)
            sys.modules[name] = mod
            spec.loader.exec_module(mod)  # type: ignore
            for attr in dir(mod):
                if attr.startswith("_"):
                    continue
                obj = getattr(mod, attr)
                if callable(obj):
                    key = f"{name}.{attr}"
                    self.registry[key] = obj

    def register_plugin(self, code: str, name: str):
        """
        Persist a new plugin file (name.py), load it immediately,
        and add its functions to the registry.
        """
        path = os.path.join(PLUGINS_DIR, f"{name}.py")
        with open(path, "w", encoding="utf-8") as f:
            f.write(code)
        # replace any existing module
        if name in sys.modules:
            del sys.modules[name]
        self._load_module(name, path)