import importlib.util
from pathlib import Path
from typing import Any

from src.layout import Layout

REQUIRED_KEYS = ("arch", "triple", "container_image")


def _load_module(path: Path, name: str):
    spec = importlib.util.spec_from_file_location(name, path)
    if spec is None or spec.loader is None:
        raise RuntimeError(f"cannot load profile module {path}")
    mod = importlib.util.module_from_spec(spec)
    spec.loader.exec_module(mod)
    return mod


def load_profile(layout: Layout) -> dict[str, Any]:
    link = layout.profile_link
    if not link.exists():
        raise FileNotFoundError(f"{link} missing a profile")
    target = link.resolve()
    if not target.is_file():
        raise FileNotFoundError(f"profile {target.name}: missing config.py")
    mod = _load_module(target, f"orchid_profile_{target.name}")
    if not hasattr(mod, "profile"):
        raise AttributeError(f"profile {target.name}: config.py must define profile()")
    data = mod.profile()
    if not isinstance(data, dict):
        raise TypeError(f"profile {target.name}: profile() must return a dict")
    missing = [k for k in REQUIRED_KEYS if k not in data]
    if missing:
        raise ValueError(f"profile {target.name}: missing keys {missing}")
    data["__name__"] = target.name
    return data


def init_build_dir(build: Path, repo: Path, profile_name: str) -> None:
    profile_src = repo / "profiles" / (profile_name + ".py")
    if not (profile_src).is_file():
        raise FileNotFoundError(f"profile {profile_name!r} not found at {profile_src}")
    build.mkdir(parents=True, exist_ok=False)
    link = build / "profile"
    # Use relative symlink so the build dir can be moved with the repo.
    import os

    rel = Path(os.path.relpath(profile_src, build))
    link.symlink_to(rel)