#!/usr/bin/env python3
"""shared_scripts.py — where the felhom.eu sibling clone's scripts/ directory is (R-1114).

Four of this repo's gates use a script that lives ONCE in felhom.eu/scripts/ and is never copied
(reuse_refs_check, instructions_gate, observations_gate; customer_copy_vocab for the retrieval-promise
gate; golden_currency_gate for the golden notice). They used to look only at `<repo>/../felhom.eu`. In a
git worktree outside `git/` (e.g. /mnt/5_hdd/felhom.eu/wt/<name>) that directory does not exist, the
gates reported MISSING and the runner failed — measured 2026-10-16 night by two helper sessions.

The order, one place for all of them:
  1. FELHOM_SHARED_SCRIPTS, when set (the decoy suite points it at a fixture; nothing else should).
  2. The MAIN clone's sibling: `git worktree list --porcelain` names the main working tree first. Used only
     when repo_root IS a git top level, so a fixture directory inside the real repo never resolves to the
     real felhom.eu.
  3. `<repo_root>/../felhom.eu/scripts` — the normal clone and CI (which clones felhom.eu beside the repo).
An absent directory is returned as-is: each caller already reports a missing shared script as a
failure or INCONCLUSIVE, never a pass. Pinned by test_shared_scripts.py.
"""
import os
import subprocess


def _git(repo_root, *args):
    try:
        p = subprocess.run(["git", "-C", repo_root] + list(args), capture_output=True, text=True, timeout=20)
    except (OSError, subprocess.SubprocessError):
        return None
    return p.stdout if p.returncode == 0 else None


def main_clone(repo_root):
    """The main working tree of the git repository repo_root is the top level of, or None."""
    top = _git(repo_root, "rev-parse", "--show-toplevel")
    if top is None or os.path.realpath(top.strip()) != os.path.realpath(repo_root):
        return None
    out = _git(repo_root, "worktree", "list", "--porcelain")
    if not out:
        return None
    for line in out.splitlines():
        if line.startswith("worktree "):
            return line[len("worktree "):].strip()
    return None


def shared_scripts_dir(repo_root):
    """felhom.eu/scripts for this repo root: env override, else the main clone's sibling, else ../felhom.eu."""
    env = os.environ.get("FELHOM_SHARED_SCRIPTS")
    if env:
        return env
    main = main_clone(repo_root)
    if main:
        cand = os.path.join(os.path.dirname(main), "felhom.eu", "scripts")
        if os.path.isdir(cand):
            return cand
    return os.path.join(os.path.dirname(os.path.abspath(repo_root)), "felhom.eu", "scripts")


def workspace_dir(repo_root):
    """The directory the sibling repos live in: the main clone's parent (for a worktree outside git/), else
    repo_root's parent. The runner hands it to the shared gates as FELHOM_WORKSPACE."""
    main = main_clone(repo_root)
    if main and os.path.isdir(os.path.join(os.path.dirname(main), "felhom.eu")):
        return os.path.dirname(main)
    return os.path.dirname(os.path.abspath(repo_root))