"""Where the job registry and its audit log live (Issue #15, Issue #57).

Standard library only, on purpose: create/resume's control-plane binding,
status.sh and lib.sh resolve these paths through ``_delegate_py_bin``, whose
last fallback is the PATH's ``python3``, which may not have paho-mqtt.
``mqtt_common`` re-exports every name here, so existing callers are unchanged.
"""
from __future__ import annotations

import os
from typing import Optional

DEFAULT_REGISTRY_DIR = ".mam/jobs"


def _workspace_mam_dir(leaf: str) -> Optional[str]:
    """`$WORKSPACE_ROOT/.mam/<leaf>` when lib.sh has told us which workspace we
    serve; None otherwise."""
    root = os.environ.get("WORKSPACE_ROOT")
    if root and root.strip() and os.path.isdir(root):
        return os.path.join(root, ".mam", leaf)
    return None


def default_registry_dir() -> str:
    """Registry root, resolved at call time (Issue #15).

    ``MAM_JOBS_DIR`` wins; otherwise the workspace lib.sh exported as
    ``WORKSPACE_ROOT``; otherwise the historical cwd-relative ``.mam/jobs``.
    Anchoring on the workspace is what keeps a test sandbox (or any caller
    whose cwd is not the workspace) from registering jobs into whichever
    ``.mam/jobs`` happens to sit under the current directory - the pytest
    suite used to leave hundreds of onboarding records in the real registry.
    """
    env = os.environ.get("MAM_JOBS_DIR")
    if env and env.strip():
        return env
    return _workspace_mam_dir("jobs") or DEFAULT_REGISTRY_DIR


def sibling_logs_dir(registry_dir: str) -> str:
    """The audit-log root that pairs with ``registry_dir``: the
    ``delegate_job_logs`` next to it. Pure; reads no environment. Issue #57.

    The registry is taken by its real path: a registry directory that is itself
    a symlink pairs with the audit log next to its target, which is what the
    wrapper (``pwd -P``) and the control-plane binding (``realpath``) already
    see, so submit and logs agree (Mac review R2). A relative registry resolves
    against the cwd, as registry.py opens it.
    """
    return os.path.join(os.path.dirname(os.path.realpath(registry_dir)), "delegate_job_logs")


def get_logs_dir(registry_dir: Optional[str] = None) -> str:
    """Audit-log root, resolved at call time (B-9).

    ``DELEGATE_JOB_LOGS_DIR`` when set: it means the audit log was moved to a
    place that cannot be derived from the registry. Otherwise the audit log
    follows the registry (Issue #57): the ``delegate_job_logs`` next to
    ``registry_dir``, or next to ``default_registry_dir()`` when the caller
    does not know its registry. The default registry is
    ``$WORKSPACE_ROOT/.mam/jobs`` (Issue #15), otherwise ``<cwd>/.mam/jobs``,
    so the usual roots are unchanged. Resolved per call rather than at import
    so a chdir after import cannot strand the audit trail in the old tree —
    the same reason ``DEFAULT_REGISTRY_DIR`` stays a relative string.
    """
    env = os.environ.get("DELEGATE_JOB_LOGS_DIR")
    if env and env.strip():
        return env
    return sibling_logs_dir(registry_dir or default_registry_dir())