"""Canonical filesystem locations for the SSR service, resolved from the repo
root. Stage-3-transitional: this package lives at `frontend_ssr/`, a sibling
of the static asset tree `frontend/` (not nested inside it -- nesting would
let StaticFiles serve this package's own source/templates as downloadable
files once app.py mounts frontend/). Still walks up to find `content/` as a
sibling too, same as backend/paths.py does today, since both still live in
one repo. Once frontend is its own repo (Stage 7), content/ is vendored at
build time instead and this goes back to a no-walk resolution, same as
backend's.
"""
import os

_HERE = os.path.dirname(os.path.abspath(__file__))


def _repo_root() -> str:
    d = _HERE
    while True:
        if os.path.isdir(os.path.join(d, "frontend")) and os.path.isdir(os.path.join(d, "content")):
            return d
        parent = os.path.dirname(d)
        if parent == d:
            raise RuntimeError(
                "cannot locate the repo root (no ancestor has sibling frontend/ and content/)"
            )
        d = parent


REPO_DIR = _repo_root()
STATIC_DIR = os.path.join(REPO_DIR, "frontend")
TEMPLATES_DIR = os.path.join(_HERE, "templates")
CONTENT_DIR = os.path.join(REPO_DIR, "content")