from __future__ import annotations

import re
from pathlib import Path

from editor_app import config

DEFAULT_MAIN_PY = 'print("Hello, World!")\n'


def safe_workspace_leaf(username: str, user_id: int) -> str:
    base = re.sub(r"[^a-zA-Z0-9._-]+", "-", username.strip()).strip("-").lower() or "user"
    return f"{base}-{user_id}"


def user_workspace_root(user_id: int, username: str, workspace_root: Path | None = None) -> Path:
    root = (workspace_root or config.WORKSPACE_ROOT).resolve()
    return root / "users" / safe_workspace_leaf(username, user_id)


def ensure_default_code_main(user_root: Path) -> None:
    """Ensure code/ exists and add a starter main.py when missing."""
    code_dir = user_root / "code"
    code_dir.mkdir(parents=True, exist_ok=True)
    main_py = code_dir / "main.py"
    if not main_py.exists():
        main_py.write_text(DEFAULT_MAIN_PY, encoding="utf-8")