"""Paths and process helpers shared by UE, Blender launchers and plain Python."""
import os
from pathlib import Path
import re
import shutil

PROJECT = Path(__file__).resolve().parents[3]
GENERATED = "/Game/Workshop/Generated"


def slug(value):
    if not re.fullmatch(r"[A-Za-z][A-Za-z0-9_]*", value):
        raise ValueError("Nazwa musi zaczynac sie litera i zawierac tylko litery ASCII, cyfry lub _.")
    return value


def executable(name, explicit=None):
    candidate = explicit or os.environ.get("WORKSHOP_" + name.upper()) or shutil.which(name)
    if not candidate and name == "blender" and os.name == "nt":
        # Standard Windows installs do not necessarily add Blender to PATH.
        root = Path(os.environ.get("PROGRAMFILES", r"C:\Program Files")) / "Blender Foundation"
        installed = [path for path in root.glob("Blender */blender.exe") if path.is_file()]
        if installed:
            candidate = max(installed, key=lambda path: tuple(int(part) for part in re.findall(r"\d+", path.parent.name)))
    if candidate and Path(candidate).is_file():
        return str(Path(candidate).resolve())
    raise FileNotFoundError(
        f"Nie znaleziono {name}. Dodaj program do PATH lub ustaw WORKSHOP_{name.upper()} "
        "na pelna sciezke do pliku wykonywalnego.")