"""Skill registry with @skill decorator and loader."""

from __future__ import annotations

import importlib.util
import logging
from pathlib import Path
from typing import Callable

log = logging.getLogger(__name__)

_SKILLS: dict[str, "SkillDef"] = {}


class SkillDef:
    def __init__(self, name: str, description: str, func: Callable):
        self.name = name
        self.description = description
        self.func = func


def skill(name: str, description: str):
    """Decorator to register a skill."""
    def decorator(func: Callable) -> Callable:
        _SKILLS[name] = SkillDef(name, description, func)
        return func
    return decorator


def load_skill(path: Path):
    """Dynamically load a skill from a .py file."""
    spec = importlib.util.spec_from_file_location(path.stem, path)
    if spec and spec.loader:
        mod = importlib.util.module_from_spec(spec)
        spec.loader.exec_module(mod)
        log.info("Loaded skill from %s", path)


def discover_skills(skills_dir: Path):
    """Load all .py files from the skills directory."""
    if not skills_dir.exists():
        return
    for path in skills_dir.glob("*.py"):
        if path.name.startswith("_"):
            continue
        try:
            load_skill(path)
        except Exception as e:
            log.warning("Failed to load skill %s: %s", path.name, e)


def list_skills() -> list[SkillDef]:
    return list(_SKILLS.values())


def run_skill(name: str, **kwargs) -> str:
    if name not in _SKILLS:
        return f"Unknown skill: {name}"
    try:
        result = _SKILLS[name].func(**kwargs)
        return str(result) if result is not None else "Done."
    except Exception as e:
        return f"Skill error: {e}"