aiturk-hermes-ide/hermes_cli/backup.py

"""
Backup and import commands for hermes CLI.

`hermes backup` creates a zip archive of the entire ~/.hermes/ directory
(excluding the hermes-agent repo and transient files).

`hermes import` restores from a backup zip, overlaying onto the current
HERMES_HOME root.
"""

import json
import logging
import os
import shutil
import sqlite3
import stat
import sys
import tempfile
import threading
import time
import zipfile
from contextlib import contextmanager
from datetime import datetime, timezone
from pathlib import Path
from typing import Any, Dict, List, Optional, Tuple

from hermes_constants import (
    _get_platform_default_hermes_home,
    get_default_hermes_root,
    get_hermes_home,
    display_hermes_home,
)
from utils import (
    _preserve_file_mode,
    _preserve_file_owner,
    _restore_file_mode,
    _restore_file_owner,
    atomic_replace,
)

# Shared formatter; the private alias is kept because claw.py and the backup
# tests import ``_format_size`` from this module.
from hermes_cli.sizefmt import format_bytes as _format_size

logger = logging.getLogger(__name__)


# ---------------------------------------------------------------------------
# Exclusion rules
# ---------------------------------------------------------------------------

# Where ``hermes backup --quick`` / ``/snapshot`` / the pre-update safety net
# write their state snapshots (see ``create_quick_snapshot`` below). Defined up
# here because the exclusion set needs it.
_QUICK_SNAPSHOTS_DIR = "state-snapshots"

# Directory names to skip entirely (matched against each path component)
# ``hermes-agent`` is special-cased to root level only in ``_should_exclude``
# so that skill directories like ``skills/autonomous-ai-agents/hermes-agent/``
# are not accidentally excluded.
#
# The dependency/cache entries below matter for more than tidiness: without
# them a single plugin venv, MCP-server install, or pip/uv cache living under
# HERMES_HOME gets walked file-by-file, ballooning a backup to hundreds of
# thousands of entries that crawl for hours — the exact "backup stuck for
# days / 426543 files" symptom users hit. The dependency/test-env names mostly
# mirror ``agent.skill_utils.EXCLUDED_SKILL_DIRS`` (the project's canonical
# "regeneratable dir" set); ``.cache`` is an additional backup-only entry, as
# it names a broad regeneratable cache convention (pip/uv/etc.) that the skill
# scanner doesn't need to prune but a backup walk does. We deliberately do NOT
# exclude ``.archive`` here because the curator's ``skills/.archive/`` holds
# restorable user skills that must survive a backup.
_EXCLUDED_DIRS = {
    "hermes-agent",     # the codebase repo — re-clone instead
    "__pycache__",      # bytecode caches — regenerated on import
    ".git",             # nested git dirs (profiles shouldn't have these, but safety)
    "node_modules",     # js deps — reinstalled on demand
    "backups",          # prior auto-backups — don't nest backups exponentially
    _QUICK_SNAPSHOTS_DIR,  # quick/pre-update state snapshots — same reason as
                        # ``backups``: each holds a full copy of state.db, so
                        # zipping them re-ships the DB once per snapshot
    "checkpoints",      # session-local trajectory caches — regenerated per-session,
                        # session-hash-keyed so they don't port to another machine anyway
    # Live browser profiles (e.g. the CDP Brave profile under browser-profiles/).
    # Chromium holds its SQLite DBs with exclusive locks while running, and
    # sqlite3.Connection.backup() retries SQLITE_BUSY forever instead of honoring
    # the busy timeout — a full backup hangs mid-archive on the first locked DB.
    # Profiles are regenerable (cache + re-login) and unsafe to snapshot live.
    "browser-profiles",
    # Real-profile browsing snapshot (browser.use_real_profile). Holds copies of
    # the user's Cookies / Login Data / Web Data — a credential-bearing store
    # that must NOT enter a backup archive. It is regenerated from the user's
    # live profile on the next consented launch. Singular, distinct from the
    # ``browser-profiles`` CDP dir above; both are excluded.
    "browser-profile",
    # Python dependency trees (plugin / MCP-server venvs under HERMES_HOME) —
    # regenerated by reinstalling; never irreplaceable state.
    ".venv",
    "venv",
    "site-packages",
    # Tool / build caches — all regeneratable.
    ".cache",
    ".tox",
    ".nox",
    ".pytest_cache",
    ".mypy_cache",
    ".ruff_cache",
}

# Hermes-managed runtime downloads that only exist at the top of a profile
# home: local GGUF models, llama.cpp runtime binaries, and the managed Node
# installation. All of them are re-downloaded on demand (model catalog,
# runtime bootstrap, node installer) and routinely reach tens to hundreds of
# GB, so zipping them turns a backup into an hours-long compress of
# incompressible weights (the "backup stuck at N files" symptom). Matched
# ONLY at the root of HERMES_HOME and at ``profiles/<name>/`` — a deeper
# directory that happens to share one of these names (a skill's ``models/``,
# a user checkout) is user data and stays in the backup.
_EXCLUDED_ROOT_DIRS = {
    "models",
    "runtimes",
    "node",
}


def _in_excluded_root_dir(rel_path: Path) -> bool:
    """True when *rel_path* (relative to HERMES_HOME) is, or sits inside, a
    Hermes-managed runtime tree at the top of a profile home."""
    parts = rel_path.parts
    if not parts:
        return False
    if parts[0] in _EXCLUDED_ROOT_DIRS:
        return True
    # Named profiles are profile homes too: profiles/<name>/models etc.
    return len(parts) >= 3 and parts[0] == "profiles" and parts[2] in _EXCLUDED_ROOT_DIRS


# File-name suffixes to skip
_SQLITE_SIDECAR_SUFFIXES = (".db-wal", ".db-shm", ".db-journal")

_EXCLUDED_SUFFIXES = (
    ".pyc",
    ".pyo",
    # SQLite sidecar files — the backup takes a consistent snapshot of ``*.db``
    # via ``sqlite3.backup()``, so shipping the live WAL / shared-memory /
    # rollback-journal alongside would pair a fresh snapshot with stale sidecar
    # state and produce a torn restore on the next open. They're transient and
    # regenerated on first connection anyway.
    *_SQLITE_SIDECAR_SUFFIXES,
)

# File names to skip (runtime state that's meaningless on another machine)
_EXCLUDED_NAMES = {
    ".backup.lock",
    "gateway.pid",
    "cron.pid",
}

# File-name prefixes to skip. The desktop updater's pre-flight drops
# ``state.db.pre-update-emergency-<timestamp>.bak`` at the HERMES_HOME root
# (apps/desktop/electron/main.ts preflightStateDb) — a backup artifact in
# the same class as ``backups/`` and ``state-snapshots/``, so a full backup
# must not re-ship it. Matched by prefix because the name carries a
# timestamp; a plain ``.bak`` suffix rule would drop user files.
_EXCLUDED_PREFIXES = (
    "state.db.pre-update-emergency-",
)

# File names that ``hermes import`` must never overwrite, matched by basename so
# they're caught for the root profile (``gateway_state.json``) and for named
# profiles alike (``profiles/<name>/gateway_state.json``).
#
# These hold *volatile gateway/process runtime state that is namespaced to the
# machine or container the backup was taken on* — PIDs in a dead process
# namespace, a runtime lock, the process registry, and the gateway's last
# recorded run/desired state. Restoring them onto a different host (or a hosted
# container) is at best meaningless and at worst actively harmful:
#
#   - ``gateway_state.json`` drives the container-boot reconciler
#     (``container_boot._read_desired_state``), which only auto-starts a
#     gateway whose recorded state is ``running``. A backup taken from a
#     machine where the gateway was stopped (or carrying a stale/foreign
#     value) overwrites the container's own state and leaves the gateway
#     stuck "starting"/"cooking", disconnecting it from the Nous portal
#     (NS-508 / the second half of NS-501).
#   - ``gateway.pid`` / ``cron.pid`` / ``gateway.lock`` / ``processes.json``
#     reference PIDs and locks in the *source* machine's process namespace; a
#     numerically-equal PID in the new environment is a different process.
#     These mirror exactly what ``container_boot._STALE_RUNTIME_FILES`` already
#     sweeps on every container boot.
#
# Older backups predate the backup-side exclusions, so we filter on import too
# rather than trusting the archive's contents.
_IMPORT_SKIP_NAMES = {
    "gateway_state.json",
    "gateway.pid",
    "cron.pid",
    "gateway.lock",
    "processes.json",
}

# zipfile.open() drops Unix mode bits on extract; restore tightens these to 0600.
_SECRET_FILE_NAMES = {".env", "auth.json", "state.db"}

# Reserved archive subtree for provider state that lives OUTSIDE HERMES_HOME
# (e.g. ~/.honcho, ~/.hindsight). The active memory provider declares these via
# MemoryProvider.backup_paths(); they're stored under this prefix encoded
# relative to the user's home directory, and restored to their original
# home-relative location on import. Anything not under home is skipped.
_EXTERNAL_PREFIX = "_external/"


class BackupInProgressError(RuntimeError):
    """Raised when another process already owns the Hermes backup slot."""


class _SQLiteSnapshotError(RuntimeError):
    pass


class _SQLiteBackupTimeout(RuntimeError):
    """Raised when a SQLite snapshot remains busy past its deadline."""


@contextmanager
def _backup_operation_lock(hermes_home: Path, timeout_seconds: float = 0.25):
    """Acquire one cross-process backup slot for full and quick snapshots."""
    lock_path = hermes_home / ".backup.lock"
    lock_path.parent.mkdir(parents=True, exist_ok=True)
    handle = lock_path.open("a+b")
    acquired = False
    deadline = time.monotonic() + max(0.0, timeout_seconds)
    try:
        if os.name == "nt":
            import msvcrt

            if lock_path.stat().st_size == 0:
                handle.write(b" ")
                handle.flush()
            while True:
                try:
                    handle.seek(0)
                    msvcrt.locking(handle.fileno(), msvcrt.LK_NBLCK, 1)
                    acquired = True
                    break
                except (OSError, PermissionError):
                    if time.monotonic() >= deadline:
                        raise BackupInProgressError("another Hermes backup is already running")
                    time.sleep(0.05)
        else:
            import fcntl

            while True:
                try:
                    fcntl.flock(handle.fileno(), fcntl.LOCK_EX | fcntl.LOCK_NB)
                    acquired = True
                    break
                except (BlockingIOError, OSError):
                    if time.monotonic() >= deadline:
                        raise BackupInProgressError("another Hermes backup is already running")
                    time.sleep(0.05)

        yield
    finally:
        if acquired:
            try:
                if os.name == "nt":
                    import msvcrt

                    handle.seek(0)
                    msvcrt.locking(handle.fileno(), msvcrt.LK_UNLCK, 1)
                else:
                    import fcntl

                    fcntl.flock(handle.fileno(), fcntl.LOCK_UN)
            except (OSError, PermissionError):
                pass
        handle.close()


@contextmanager
def _atomic_output_path(final_path: Path):
    """Yield a hidden sibling path and publish it only after a clean close."""
    partial_path = final_path.with_name(
        f".{final_path.name}.{os.getpid()}-{threading.get_ident()}.partial"
    )
    partial_path.unlink(missing_ok=True)
    try:
        yield partial_path
        os.replace(partial_path, final_path)
    except BaseException:
        partial_path.unlink(missing_ok=True)
        raise


def _collect_memory_provider_external_paths() -> List[Path]:
    """Return existing absolute paths the active memory provider stores
    outside HERMES_HOME, resolved from config only (no network, no init).

    Reads ``memory.provider`` from config, loads just that provider, and asks
    it for ``backup_paths()``. Returns an empty list when no external provider
    is active or the provider can't be loaded — backup must never fail because
    of a flaky plugin.
    """
    try:
        from plugins.memory import _get_active_memory_provider, load_memory_provider
    except Exception:
        return []

    try:
        active = _get_active_memory_provider()
    except Exception:
        active = None
    if not active:
        return []

    try:
        provider = load_memory_provider(active)
    except Exception:
        provider = None
    if provider is None:
        return []

    try:
        declared = provider.backup_paths() or []
    except Exception as exc:
        logger.warning("backup_paths() failed for memory provider %r: %s", active, exc)
        return []

    out: List[Path] = []
    seen: set = set()
    for raw in declared:
        try:
            p = Path(raw).expanduser()
        except Exception:
            continue
        if not p.exists():
            continue
        try:
            resolved = p.resolve()
        except (OSError, ValueError):
            continue
        if resolved in seen:
            continue
        seen.add(resolved)
        out.append(p)
    return out


def _iter_external_files(base: Path) -> List[Path]:
    """Yield regular files under *base* (a file or a directory), skipping
    symlinks, caches, and pyc files. *base* itself may be a file."""
    files: List[Path] = []
    if base.is_file() and not base.is_symlink():
        files.append(base)
        return files
    if not base.is_dir():
        return files
    for dirpath, dirnames, filenames in os.walk(base, followlinks=False):
        dp = Path(dirpath)
        dirnames[:] = [d for d in dirnames if d not in _EXCLUDED_DIRS]
        for fname in filenames:
            fpath = dp / fname
            if fpath.is_symlink():
                continue
            if fpath.name in _EXCLUDED_NAMES or fpath.name.endswith(_EXCLUDED_SUFFIXES):
                continue
            files.append(fpath)
    return files


def _should_exclude(rel_path: Path) -> bool:
    """Return True if *rel_path* (relative to hermes root) should be skipped."""
    parts = rel_path.parts

    if _in_excluded_root_dir(rel_path):
        return True

    for part in parts:
        if part not in _EXCLUDED_DIRS:
            continue
        # ``hermes-agent`` only matches at the root level (first component).
        # Nested directories with the same name — e.g.
        # ``skills/autonomous-ai-agents/hermes-agent/`` — must be preserved.
        if part == "hermes-agent" and part != parts[0]:
            continue
        return True

    name = rel_path.name

    if name in _EXCLUDED_NAMES:
        return True

    if name.startswith(_EXCLUDED_PREFIXES):
        return True

    if name.endswith(_EXCLUDED_SUFFIXES):
        return True

    return False


def _should_skip_backup_file(abs_path: Path, rel_path: Path, out_path: Path) -> bool:
    """Return True when a candidate file should not be written to a backup zip."""
    if _should_exclude(rel_path):
        return True

    # zipfile.write() follows file symlinks, so skip links before any archive
    # write can copy data from outside HERMES_HOME.
    if abs_path.is_symlink():
        return True

    try:
        return abs_path.resolve() == out_path.resolve()
    except (OSError, ValueError):
        return False


def _iter_backup_files(
    hermes_root: Path,
    out_path: Path,
    skipped_dirs: Optional[set] = None,
):
    """Yield ``(abs_path, rel_path)`` for every file a full backup should hold.

    The one owner of the backup walk policy: directory pruning (so os.walk
    never descends a multi-GB excluded tree), the root-only ``hermes-agent``
    carve-out, profile-home-root runtime trees, and the per-file exclusion
    rules — shared by the manual ``hermes backup`` path and the automatic
    pre-update/pre-migration path so the two can never drift.

    ``skipped_dirs``, when given, collects pruned directories (root-relative,
    as strings) for the end-of-run summary.
    """
    for dirpath, dirnames, filenames in os.walk(hermes_root, followlinks=False):
        rel_dir = Path(dirpath).relative_to(hermes_root)

        # ``hermes-agent`` is only pruned at the root level; nested dirs
        # with the same name (e.g. in skills/) must be preserved. Managed
        # runtime trees (models/, runtimes/, node/) are pruned only at a
        # profile-home root — see _EXCLUDED_ROOT_DIRS.
        is_root = rel_dir == Path(".")
        orig_dirnames = dirnames[:]
        dirnames[:] = [
            d for d in dirnames
            if (d not in _EXCLUDED_DIRS or (d == "hermes-agent" and not is_root))
            and not _in_excluded_root_dir(rel_dir / d)
        ]
        if skipped_dirs is not None:
            for removed in set(orig_dirnames) - set(dirnames):
                skipped_dirs.add(str(rel_dir / removed))

        for fname in filenames:
            rel = rel_dir / fname
            fpath = hermes_root / rel
            if _should_skip_backup_file(fpath, rel, out_path):
                continue
            yield fpath, rel


# ---------------------------------------------------------------------------
# SQLite safe copy
# ---------------------------------------------------------------------------

def _safe_copy_db(
    src: Path,
    dst: Path,
    *,
    timeout_seconds: float = 10.0,
) -> bool:
    """Copy a SQLite database safely using the backup() API.

    Handles WAL mode — produces a consistent snapshot even while
    the DB is being written to. Fail closed if a consistent snapshot cannot
    be created: copying only the live main file can omit committed WAL data.
    """
    conn = None
    backup_conn = None
    try:
        # Disable sqlite3's implicit busy wait so backup() progress callbacks
        # control the full locked-source deadline instead of adding the
        # connection's default timeout before each callback.
        conn = sqlite3.connect(f"file:{src}?mode=ro", uri=True, timeout=0.0)
        backup_conn = sqlite3.connect(str(dst))
        busy_deadline = time.monotonic() + max(0.0, timeout_seconds)

        def _check_backup_progress(status: int, _remaining: int, _total: int) -> None:
            nonlocal busy_deadline
            now = time.monotonic()
            if status in (sqlite3.SQLITE_BUSY, sqlite3.SQLITE_LOCKED):
                if now >= busy_deadline:
                    raise _SQLiteBackupTimeout(
                        f"database remained locked for {timeout_seconds:g} seconds"
                    )
            else:
                busy_deadline = now + max(0.0, timeout_seconds)

        conn.backup(
            backup_conn,
            pages=256,
            progress=_check_backup_progress,
            sleep=0.1,
        )
        return True
    except Exception as exc:
        logger.warning("SQLite safe copy failed for %s: %s", src, exc)
        # Windows will not remove the partial destination while SQLite still
        # has it open. Close it before fail-closed cleanup; the finally block
        # still owns the source and any close failure.
        if backup_conn is not None:
            try:
                backup_conn.close()
            except Exception:
                pass
            backup_conn = None
        try:
            dst.unlink(missing_ok=True)
        except OSError:
            pass
        return False
    finally:
        for connection in (backup_conn, conn):
            if connection is not None:
                try:
                    connection.close()
                except Exception:
                    pass


def is_zeroed_sqlite_file(
    path: Path, *, probe_bytes: int = 100, force: bool = False
) -> bool:
    """True when *path* looks like the #68474 zeroed-state.db signature.

    Signature: no ``SQLite format 3`` header and no data — either empty
    (size 0, the total-loss case, #97568) or first *probe_bytes* all NUL.
    Used at SessionDB open and for snapshot diagnostics so a silent
    all-zero file becomes a guided recovery instead of a generic failure.

    Only regular files qualify: a special file at the path (FIFO, device,
    socket) is never "zeroed" — and probing one could block indefinitely
    (opening a FIFO for read waits for a writer), so refuse before any I/O.
    """
    try:
        if not path.is_file():
            return False
        size = path.stat().st_size
    except OSError:
        return False
    if size < 0:
        return False
    from hermes_cli.sqlite_safe_read import has_live_connection, read_header_bytes_preopen

    if not force and has_live_connection(path):
        return False

    head = read_header_bytes_preopen(
        path, length=max(16, probe_bytes), force=force
    )
    if head is None:
        return False
    if len(head) == 0:
        return True
    if head.startswith(b"SQLite format 3"):
        return False
    return all(byte == 0 for byte in head)



# ---------------------------------------------------------------------------
# SQLite integrity verification
# ---------------------------------------------------------------------------

_SQLITE_HEADER = b"SQLite format 3\0"

# Default ceiling above which ``PRAGMA integrity_check`` is skipped in favour
# of the (O(1)) header + structural probe. ``integrity_check`` walks every
# b-tree page in the file, so its cost scales with database size: on a 30 GB
# state.db it runs for many minutes of pegged CPU with no output, which reads
# to the user as a hung `hermes update` (#70553 follow-up). Sessions databases
# in the tens of GB are normal for heavy users, so the size-unbounded check is
# never an acceptable default on the update path.
DEFAULT_INTEGRITY_CHECK_MAX_BYTES = 2 << 30  # 2 GiB


def verify_sqlite_integrity(
    path: Path,
    *,
    check_header: bool = True,
    run_pragma: bool = True,
    max_bytes: int = DEFAULT_INTEGRITY_CHECK_MAX_BYTES,
) -> dict:
    """Verify that a SQLite database at *path* is intact.

    Checks, in order:
      1. File exists and has an expected minimum size.
      2. SQLite header magic bytes are present.
      3. For files at or under ``max_bytes``, a read-only
         ``PRAGMA integrity_check``. For larger files, a cheap structural
         probe (schema read) instead — see ``max_bytes``.

    Args:
        path: Path to the database file.
        check_header: When true (default), verify the SQLite header magic.
        run_pragma: When true (default), run ``PRAGMA integrity_check`` via
            a read-only connection and verify the result is ``"ok"``.
        max_bytes: Size ceiling for the full ``PRAGMA integrity_check``.
            Files larger than this fall back to the header check plus a
            cheap structural probe, because ``integrity_check`` pages
            through the ENTIRE file — minutes of silent pegged CPU on a
            multi-GB database. Defaults to
            :data:`DEFAULT_INTEGRITY_CHECK_MAX_BYTES` (2 GiB); pass ``0``
            to force the full check regardless of size.

    Returns:
        A dict with keys:
          - ``valid`` (bool): true when all requested checks passed.
          - ``message`` (str): human-readable outcome or error detail.
          - ``size`` (int | None): file size in bytes, or None if stat failed.
    """
    result: dict = {"valid": False, "message": "", "size": None}

    try:
        st = path.stat()
    except FileNotFoundError:
        result["message"] = f"not found: {path}"
        return result
    except OSError as exc:
        result["message"] = f"cannot stat: {exc}"
        return result

    result["size"] = st.st_size

    if st.st_size < 100:  # SQLite minimum viable size (header + 1 page)
        result["message"] = f"too small ({st.st_size} bytes) to be a valid SQLite database"
        return result

    oversized = max_bytes > 0 and st.st_size > max_bytes

    if check_header:
        # Byte-level read: refused when a live connection exists, because
        # close() would cancel this process's POSIX locks on the file (see
        # hermes_cli.sqlite_safe_read). Verification targets snapshots and
        # backup artifacts, which are offline by construction.
        from hermes_cli.sqlite_safe_read import read_header_bytes_preopen

        head = read_header_bytes_preopen(path, length=len(_SQLITE_HEADER))
        if head is None:
            result["valid"] = False
            result["message"] = "cannot read header"
            return result
        if head != _SQLITE_HEADER:
            result["valid"] = False
            result["message"] = (
                f"missing SQLite header magic (got {head[:16].hex()!r})"
            )
            return result

    if oversized:
        # Too large to page through PRAGMA integrity_check (which is O(file
        # size) and would peg a CPU for minutes on a multi-GB state.db).
        # Fall back to a cheap O(1) structural probe: the header check above
        # catches the #68474 zeroed signature, and opening the DB read-only
        # plus reading sqlite_master + the page geometry catches the
        # malformed-schema and truncated-header-page classes. Both are
        # constant-time — they parse the schema, they do not walk the data.
        run_pragma = False
        probe = None
        try:
            probe = sqlite3.connect(f"file:{path}?mode=ro", uri=True, timeout=1.0)
            probe.execute("PRAGMA schema_version").fetchone()
            probe.execute("SELECT count(*) FROM sqlite_master").fetchone()
            result["valid"] = True
            result["message"] = (
                f"size {st.st_size:,} bytes exceeds max_bytes {max_bytes:,}; "
                "skipped PRAGMA integrity_check (header + schema probe passed)"
            )
        except sqlite3.DatabaseError as exc:
            result["valid"] = False
            result["message"] = f"schema probe failed: {exc}"
            return result
        except Exception as exc:
            result["valid"] = False
            result["message"] = f"schema probe error: {exc}"
            return result
        finally:
            if probe is not None:
                try:
                    probe.close()
                except Exception:
                    pass

    if run_pragma:
        conn = None
        try:
            conn = sqlite3.connect(f"file:{path}?mode=ro", uri=True, timeout=1.0)
            cursor = conn.execute("PRAGMA integrity_check")
            rows = cursor.fetchall()
            if len(rows) == 1 and rows[0][0] == "ok":
                result["valid"] = True
                result["message"] = "integrity check passed"
                return result
            errors = [str(r[0]) for r in rows]
            result["message"] = f"integrity check failed: {'; '.join(errors[:5])}"
            return result
        except sqlite3.DatabaseError as exc:
            result["message"] = f"cannot open database: {exc}"
            return result
        except Exception as exc:
            result["message"] = f"integrity check error: {exc}"
            return result
        finally:
            if conn is not None:
                try:
                    conn.close()
                except Exception:
                    pass

    result["valid"] = True
    if not result["message"]:
        result["message"] = "header check passed"
    return result


def copy_db_and_verify(src: Path, dst: Path) -> bool:
    """Like :func:`_safe_copy_db` but verifies the destination after copy.

    Returns True only when the copy succeeded AND the destination is valid
    SQLite (header + integrity check). Verification honours the default
    size ceiling — a multi-GB destination gets the header + schema probe
    rather than a full ``PRAGMA integrity_check`` that would page through
    the whole file.
    """
    if not _safe_copy_db(src, dst):
        return False
    integrity = verify_sqlite_integrity(dst, run_pragma=True)
    if not integrity.get("valid"):
        try:
            dst.unlink(missing_ok=True)
        except OSError:
            pass
        logger.warning("Backup of %s failed integrity verification: %s", src, integrity.get("message"))
        return False
    return True


def _foreign_db_holder_pids(db_path: Path) -> Optional[List[int]]:
    """PIDs of OTHER processes holding *db_path* or its WAL/SHM open.

    Linux-only ``/proc/<pid>/fd`` scan (no psutil dependency), preserving the
    kernel's ``(deleted)`` suffix so an already-unlinked sidecar generation —
    the #90950 split-brain fingerprint — still counts as held. Returns
    ``None`` when the scan is unavailable (non-Linux, or /proc unreadable);
    callers must treat ``None`` as "unknown", not as "no holders".
    """
    if not sys.platform.startswith("linux"):
        return None

    def _canonical(path: str) -> str:
        return os.path.normcase(
            os.path.abspath(path.removesuffix(" (deleted)"))
        )

    canonical_db = _canonical(os.fspath(db_path))
    watched = {canonical_db, canonical_db + "-wal", canonical_db + "-shm"}
    pids: List[int] = []
    try:
        own_pid = os.getpid()
        for pid_str in os.listdir("/proc"):
            if not pid_str.isdigit():
                continue
            pid = int(pid_str)
            if pid == own_pid:
                continue
            fd_dir = f"/proc/{pid}/fd"
            try:
                fds = os.listdir(fd_dir)
            except OSError:
                continue
            for fd in fds:
                try:
                    target = os.readlink(f"{fd_dir}/{fd}")
                except OSError:
                    continue
                if _canonical(target) in watched:
                    pids.append(pid)
                    break
    except OSError:
        return None
    return pids


def _safe_restore_db(src: Path, dst: Path) -> bool:
    """Restore a SQLite database from snapshot *src* into live *dst*.

    Uses SQLite's backup() API to write snapshot pages into the live
    database file, preserving the file's inode and WAL state so that
    any other process still holding the DB open (gateway, dashboard,
    another CLI session) sees the restored data on the next read —
    instead of continuing to serve stale cached pages from a replaced
    inode.

    The old approach was ``unlink() + move()``, which replaced the file
    under any live connection.  SQLite connections cache pages in
    per-connection page caches keyed by inode; after an unlink+move the
    old inode still existed (the live connection held a reference), so
    that connection continued serving the pre-restore data while new
    connections saw the restored snapshot — a partial/inconsistent
    state (issue #65942).

    By writing pages through the backup API the file inode is preserved,
    the WAL journal is updated correctly, and all connections (old and
    new) converge on the restored data.

    Falls back to the unlink+move approach on failure ONLY when no other
    process or in-process connection holds the file: replacing the inode
    under a live holder is the #90950 split-brain, so that branch fails
    closed (returns ``False``) and the caller reports the file as skipped.
    """
    try:
        dst_conn = sqlite3.connect(str(dst))
        try:
            # Force a WAL checkpoint so the backup starts from a clean
            # state rather than writing on top of a deep WAL.
            dst_conn.execute("PRAGMA wal_checkpoint(TRUNCATE)")
        except Exception:
            pass
        src_conn = sqlite3.connect(f"file:{src}?mode=ro", uri=True)
        try:
            src_conn.backup(dst_conn)
        finally:
            src_conn.close()
        dst_conn.close()
        # Restore original file permissions from the snapshot
        try:
            mode = src.stat().st_mode
            dst.chmod(mode)
        except Exception:
            pass
        return True
    except Exception as exc:
        logger.warning("SQLite safe restore failed for %s -> %s: %s", src, dst, exc)
        # Fallback: unlink+move (the old approach).  This still works for
        # the common case where no other process holds the DB open.
        from hermes_cli.sqlite_safe_read import (
            LiveConnectionError,
            offline_file_access,
        )

        try:
            holders = _foreign_db_holder_pids(dst)
            if holders:
                # Replacing the inode under a live holder is the #90950
                # corruption class: the holder keeps writing through a
                # deleted-inode fd (split brain), and removing its sidecars
                # detaches the WAL index it is checkpointing through. The
                # backup-API path above is the live-safe route; if it failed,
                # fail closed rather than corrupt.
                logger.error(
                    "Refusing unlink+move restore of %s: process(es) %s still "
                    "hold the database or its WAL open. Stop them and retry.",
                    dst, holders,
                )
                return False
            # The foreign-pid scan above deliberately excludes THIS process,
            # but an in-process SessionDB (the agent's own handle during
            # /snapshot restore, a second SessionDB instance, a read pool)
            # is exactly as much of a live holder: unlinking the DB and its
            # sidecars under it leaves this process on deleted-inode fds —
            # the same #90950 split brain, produced first-party (proven live
            # on main: `/proc/self/fd` shows `state.db-wal (deleted)` right
            # after this fallback ran under a tracked connection).
            # ``offline_file_access`` fails CLOSED when any tracked
            # connection to *dst* is live and holds the connection-lifecycle
            # lock across the whole swap so no new connection can appear
            # mid-replace.
            with offline_file_access(dst, what="unlink+move restore of"):
                tmp = dst.parent / f".{dst.name}.snap_restore"
                shutil.copy2(src, tmp)
                dst.unlink(missing_ok=True)
                # Drop the destination's sidecars before installing the
                # snapshot. The snapshot is a checkpointed ``sqlite3.backup()``
                # image (see ``_safe_copy_db``) that owns no WAL, so any
                # ``-wal``/``-shm`` still sitting here describes the database we
                # just unlinked — an ungracefully killed gateway leaves them
                # behind, which is exactly when a restore gets run. SQLite
                # replays that foreign WAL over the restored file on the next
                # open and the database comes up "malformed" (or silently
                # resurrects post-snapshot rows). Same reasoning as
                # ``_EXCLUDED_SUFFIXES``, applied to the restore destination.
                for _sidecar_suffix in ("-wal", "-shm", "-journal"):
                    dst.with_name(dst.name + _sidecar_suffix).unlink(missing_ok=True)
                shutil.move(str(tmp), str(dst))
            return True
        except LiveConnectionError as exc2:
            logger.error(
                "Refusing unlink+move restore of %s: %s Close the in-process "
                "database handles (or restart Hermes) and retry.",
                dst, exc2,
            )
            return False
        except Exception as exc2:
            logger.error("Fallback restore also failed for %s -> %s: %s", src, dst, exc2)
            return False


# ---------------------------------------------------------------------------
# Backup
# ---------------------------------------------------------------------------

def run_backup(args) -> None:
    """Create a zip backup of the Hermes home directory."""
    hermes_root = get_default_hermes_root()

    if not hermes_root.is_dir():
        print(f"Error: Hermes home directory not found at {hermes_root}")
        sys.exit(1)

    try:
        with _backup_operation_lock(hermes_root):
            _run_backup_locked(args, hermes_root)
    except BackupInProgressError as exc:
        print(f"Error: {exc}")
        raise SystemExit(2) from exc


def _run_backup_locked(args, hermes_root: Path) -> None:
    """Write a full backup while the cross-process backup slot is held."""

    # Determine output path
    out_path = None
    try:
        if args.output:
            out_path = Path(args.output).expanduser().resolve()
            # If user gave a directory, put the zip inside it
            if out_path.is_dir():
                stamp = datetime.now().strftime("%Y-%m-%d-%H%M%S")
                out_path = out_path / f"hermes-backup-{stamp}.zip"
        else:
            stamp = datetime.now().strftime("%Y-%m-%d-%H%M%S")
            out_path = Path.home() / f"hermes-backup-{stamp}.zip"

        # Ensure the suffix is .zip
        if out_path.suffix.lower() != ".zip":
            out_path = out_path.with_suffix(out_path.suffix + ".zip")

        # Ensure parent directory exists
        out_path.parent.mkdir(parents=True, exist_ok=True)
    except OSError as exc:
        # A bad/unwritable output path (permission denied, unreadable parent,
        # etc.) should give a clean one-line error, not a raw traceback
        # (round-3 QA SUB-01). is_dir() and mkdir() both hit the filesystem.
        print(f"Error: cannot write backup to {args.output or out_path}: {exc}")
        raise SystemExit(1) from exc

    # Collect files
    scan_started = time.monotonic()
    logger.info("backup phase=scan status=started")
    print(f"Scanning {display_hermes_home()} ...")
    skipped_dirs: set = set()
    files_to_add: list[tuple[Path, Path]] = list(
        _iter_backup_files(hermes_root, out_path, skipped_dirs)
    )

    # External memory-provider state (e.g. ~/.honcho, ~/.hindsight) lives
    # outside HERMES_HOME, so the walk above never sees it. Ask the active
    # provider for its declared paths and stage them under the reserved
    # ``_external/`` arc prefix, encoded relative to the user's home dir.
    # Only paths under home are captured (security + portability); anything
    # else is skipped with a note.
    home_dir = Path.home().resolve()
    external_to_add: list[tuple[Path, str]] = []  # (absolute, arcname)
    skipped_external: list[str] = []
    for base in _collect_memory_provider_external_paths():
        try:
            base_resolved = base.resolve()
            base_resolved.relative_to(home_dir)
        except (ValueError, OSError):
            skipped_external.append(str(base))
            continue
        for fpath in _iter_external_files(base):
            try:
                rel_to_home = fpath.resolve().relative_to(home_dir)
            except (ValueError, OSError):
                continue
            arcname = _EXTERNAL_PREFIX + rel_to_home.as_posix()
            external_to_add.append((fpath, arcname))

    if not files_to_add and not external_to_add:
        logger.info(
            "backup phase=scan status=empty duration_ms=%.1f",
            (time.monotonic() - scan_started) * 1000,
        )
        print("No files to back up.")
        return

    # Create the zip
    file_count = len(files_to_add) + len(external_to_add)
    logger.info(
        "backup phase=scan status=complete duration_ms=%.1f files=%d",
        (time.monotonic() - scan_started) * 1000,
        file_count,
    )
    logger.info("backup phase=archive status=started files=%d", file_count)
    print(f"Backing up {file_count} files ...")

    total_bytes = 0
    errors = []
    t0 = time.monotonic()

    with _atomic_output_path(out_path) as archive_path, zipfile.ZipFile(
        archive_path, "w", zipfile.ZIP_DEFLATED, compresslevel=6
    ) as zf:
        for i, (abs_path, rel_path) in enumerate(files_to_add, 1):
            try:
                # Safe copy for SQLite databases (handles WAL mode)
                if abs_path.suffix == ".db":
                    # Stage the snapshot alongside the output zip so that the
                    # temp file lives on the same filesystem.  The system
                    # default (/tmp) may be a small tmpfs that cannot hold
                    # large databases, causing silent backup incompleteness.
                    with tempfile.NamedTemporaryFile(
                        suffix=".db", delete=False, dir=str(out_path.parent)
                    ) as tmp:
                        tmp_db = Path(tmp.name)
                    if _safe_copy_db(abs_path, tmp_db):
                        zf.write(tmp_db, arcname=str(rel_path))
                        total_bytes += tmp_db.stat().st_size
                        tmp_db.unlink(missing_ok=True)
                    else:
                        tmp_db.unlink(missing_ok=True)
                        errors.append(f"  {rel_path}: SQLite safe copy failed")
                        continue
                else:
                    zf.write(abs_path, arcname=str(rel_path))
                    total_bytes += abs_path.stat().st_size
            except (PermissionError, OSError, ValueError) as exc:
                errors.append(f"  {rel_path}: {exc}")
                continue

            # Progress every 500 files
            if i % 500 == 0:
                print(f"  {i}/{file_count} files ...")
                logger.info(
                    "backup phase=archive status=progress completed=%d total=%d",
                    i,
                    file_count,
                )

        # External memory-provider state, stored under the ``_external/`` arc
        # prefix. These never include ``.db`` files in practice (config/env
        # blobs), so a straight zf.write is fine.
        for abs_path, arcname in external_to_add:
            try:
                zf.write(abs_path, arcname=arcname)
                total_bytes += abs_path.stat().st_size
            except (PermissionError, OSError, ValueError) as exc:
                errors.append(f"  {arcname}: {exc}")
                continue

    elapsed = time.monotonic() - t0
    zip_size = out_path.stat().st_size
    logger.info(
        "backup phase=archive status=complete duration_ms=%.1f files=%d errors=%d bytes=%d",
        elapsed * 1000,
        file_count,
        len(errors),
        zip_size,
    )

    # Summary
    print()
    if errors:
        print(f"Backup incomplete: {out_path}")
    else:
        print(f"Backup complete: {out_path}")
    print(f"  Files:       {file_count}")
    print(f"  Original:    {_format_size(total_bytes)}")
    print(f"  Compressed:  {_format_size(zip_size)}")
    print(f"  Time:        {elapsed:.1f}s")

    if external_to_add:
        print(
            f"\n  Included {len(external_to_add)} memory-provider file(s) "
            f"stored outside {display_hermes_home()}."
        )

    if skipped_external:
        print(
            f"\n  Skipped {len(skipped_external)} memory-provider path(s) "
            f"outside your home directory (not portable):"
        )
        for p in sorted(skipped_external)[:10]:
            print(f"    {p}")

    if skipped_dirs:
        print("\n  Excluded directories:")
        for d in sorted(skipped_dirs):
            print(f"    {d}/")

    if errors:
        print(f"\n  Warnings ({len(errors)} files skipped):")
        for e in errors[:10]:
            print(e)
        if len(errors) > 10:
            print(f"  ... and {len(errors) - 10} more")

    if not errors:
        print(f"\nRestore with: hermes import {out_path.name}")


# ---------------------------------------------------------------------------
# Import
# ---------------------------------------------------------------------------

def _validate_backup_zip(zf: zipfile.ZipFile) -> tuple[bool, str]:
    """Check that a zip looks like a Hermes backup.

    Returns (ok, reason).
    """
    names = zf.namelist()
    if not names:
        return False, "zip archive is empty"

    # Look for telltale files that a hermes home would have
    markers = {"config.yaml", ".env", "state.db"}
    found = set()
    for n in names:
        # Could be at the root or one level deep (if someone zipped the directory)
        basename = Path(n).name
        if basename in markers:
            found.add(basename)

    if not found:
        return False, (
            "zip does not appear to be a Hermes backup "
            "(no config.yaml, .env, or state databases found)"
        )

    return True, ""


def _detect_prefix(zf: zipfile.ZipFile) -> str:
    """Detect if the zip has a common directory prefix wrapping all entries.

    Some tools zip as `.hermes/config.yaml` instead of `config.yaml`.
    Returns the prefix to strip (empty string if none).
    """
    names = [n for n in zf.namelist() if not n.endswith("/")]
    if not names:
        return ""

    # Find common prefix
    parts_list = [Path(n).parts for n in names]

    # Check if all entries share a common first directory
    first_parts = {p[0] for p in parts_list if len(p) > 1}
    if len(first_parts) == 1:
        prefix = first_parts.pop()
        # Only strip if it looks like a hermes dir name
        if prefix in {".hermes", "hermes"}:
            return prefix + "/"

    return ""


def _default_new_file_mode() -> Optional[int]:
    """Return the mode ``open(path, "wb")`` gives a file it has to create.

    ``tempfile.mkstemp`` always creates at 0600, so staging an import through a
    temp file would tighten every *newly created* file to owner-only — the same
    hazard ``utils._restore_file_mode`` documents for Docker/NAS volume mounts
    that rely on broader permissions.  The umask can only be read by setting it,
    so this is resolved once per import rather than once per member.  The probe
    installs a *restrictive* mask rather than 0 so that anything another thread
    creates inside the two-syscall window is owner-only, never world-writable.
    Returns ``None`` if the umask cannot be read, in which case the caller
    leaves mkstemp's mode alone.
    """
    try:
        current = os.umask(0o077)
        os.umask(current)
    except OSError:
        return None
    return 0o666 & ~current


def _extract_member_atomically(
    zf: zipfile.ZipFile,
    member: str,
    target: Path,
    new_file_mode: Optional[int] = None,
) -> None:
    """Restore one zip member onto *target* with no truncation window.

    ``open(target, "wb")`` truncates the user's existing file to zero *before*
    any replacement bytes exist.  A Ctrl-C, an ENOSPC, a corrupt member, or a
    crash between the truncate and the write therefore leaves that file empty
    with nothing behind it — during ``hermes import``, which is the
    disaster-recovery path a user reaches for *because* they already lost
    something.  Staging into the target's own directory and publishing with a
    rename means the target only ever moves from its old contents to the
    complete new contents.

    ``atomic_replace`` rather than a bare ``os.replace``: it resolves a
    symlinked target first, so a deployment that links ``config.yaml`` into a
    dotfiles repo keeps the link instead of having it silently swapped for a
    regular file (GitHub #16743), and it falls back to copy/fsync/unlink on
    ``EXDEV``/``EBUSY`` for cross-device and bind-mount installs.  That
    fallback uses ``shutil.copyfile``, which does truncate in place, so on the
    cross-device path the guarantee above degrades to today's behaviour rather
    than improving on it; closing that belongs in ``utils.atomic_replace``,
    where every atomic writer in the repo would benefit, not here.

    Permission bits *and* ownership are carried across the replace so routing
    through mkstemp does not change the file the caller would otherwise have
    produced.  ``os.replace`` swaps in a temp file owned by the *writing* user,
    so without the chown a ``sudo hermes import`` would silently re-own every
    restored file to root — on the disaster-recovery path, and on exactly the
    Docker/NAS installs ``utils._restore_file_owner`` documents.  Both concerns
    delegate to the shared ``utils`` helpers rather than being re-derived here.
    The temp file is removed on any failure so a partial import leaves no
    residue.

    The one bit of the old file *not* carried across is setuid/setgid.  The
    replacement bytes come out of the zip, so preserving those would let an
    archive take over the identity an existing privileged file executes as —
    and unlike the other ``utils`` writers, which re-serialize content this
    process produced, the trust boundary here is an untrusted archive.  The
    mask is applied once, before the temp file is chmod'd, so neither the
    pre-replace ``fchmod`` nor the post-replace restore can re-elevate the
    target.
    """
    # ``_preserve_file_mode`` returns None when the target does not exist (or
    # cannot be stat'd), in which case the umask-derived create-mode applies —
    # the same shape as ``atomic_yaml_write``'s ``create_mode`` fallback.
    mode = _preserve_file_mode(target)
    owner = _preserve_file_owner(target)
    if mode is None:
        mode = new_file_mode
    else:
        # Deliberately NOT a faithful mode copy: setuid/setgid are dropped.
        # ``_preserve_file_mode`` returns ``stat.S_IMODE``, i.e. all twelve
        # bits, and the content replacing this file comes from the archive.
        # Carrying the elevated bits across would let archive-controlled bytes
        # take over an existing setuid/setgid file, so ``hermes import`` would
        # hand whoever produced the zip the identity that file runs as.  Nothing
        # constrains that to Hermes' own state either: the ``_external/`` branch
        # of ``run_import`` publishes members anywhere under ``$HOME``.  The
        # sticky bit is kept — it is inert on a regular file.
        mode &= ~(stat.S_ISUID | stat.S_ISGID)

    # Truncate the stem: mkstemp adds ~16 characters, and a member already near
    # NAME_MAX would otherwise fail here on a write that used to succeed.
    fd, tmp_name = tempfile.mkstemp(
        dir=str(target.parent), prefix=f".{target.name[:80]}.", suffix=".partial"
    )
    try:
        with os.fdopen(fd, "wb") as dst:
            if mode is not None:
                # Apply the mode to the temp file BEFORE the replace so the
                # target never transits through mkstemp's 0600, and so
                # ``atomic_replace``'s EXDEV/EBUSY ``shutil.copystat`` fallback
                # copies the intended bits rather than 0600.  fchmod is
                # Unix-only; Windows takes the path-based chmod.
                if hasattr(os, "fchmod"):
                    os.fchmod(dst.fileno(), mode)
                else:
                    os.chmod(tmp_name, mode)
            # Stream instead of ``src.read()``: a multi-gigabyte state.db member
            # must not be held in memory in one piece.
            with zf.open(member) as src:
                shutil.copyfileobj(src, dst)
            dst.flush()
            os.fsync(dst.fileno())
        real_path = Path(atomic_replace(tmp_name, target))
        # Owner first, mode second — the ordering ``atomic_yaml_write`` uses,
        # because chown drops setuid/setgid and a mode restore that ran first
        # would be partly undone.  Here ``mode`` no longer carries those bits,
        # so the two agree: neither step can re-elevate the restored file.
        _restore_file_owner(real_path, owner)
        _restore_file_mode(real_path, mode)
    except BaseException:
        try:
            os.unlink(tmp_name)
        except OSError:
            pass
        raise


def _count_session_rows(path: Path) -> Optional[Tuple[int, int]]:
    """Return ``(sessions, messages)`` stored in the session database *path*.

    Read-only and best effort.  ``None`` means "unknown" — a missing file, a
    database that is not a Hermes session store, or one that cannot be read.
    Callers must never read ``None`` as "zero rows": acting on an unreadable
    database would mask the very loss this count exists to surface.  Same
    contract as :func:`_count_cron_jobs`.
    """
    if not path.is_file():
        return None
    try:
        conn = sqlite3.connect(f"file:{path}?mode=ro", uri=True)
    except sqlite3.Error:
        return None
    try:
        sessions = conn.execute("SELECT COUNT(*) FROM sessions").fetchone()[0]
        messages = conn.execute("SELECT COUNT(*) FROM messages").fetchone()[0]
        return int(sessions), int(messages)
    except (sqlite3.Error, TypeError, ValueError):
        return None
    finally:
        conn.close()


def _import_db_member(
    zf: zipfile.ZipFile,
    member: str,
    target: Path,
    new_file_mode: Optional[int] = None,
) -> None:
    """Publish a SQLite ``.db`` member onto *target* without replacing its inode.

    ``_extract_member_atomically`` publishes with a rename.  For an ordinary
    file that is the safest write available; for a live SQLite database it is
    the #65942 / #90950 corruption class.  A gateway, dashboard, or WebUI
    process holding the database open keeps its descriptor on the now-unlinked
    inode: it goes on serving pre-import pages and writing sessions that no
    other process will ever see, and any sidecar WAL left beside the new file
    describes the database that was just unlinked.  Nothing fails, so nothing
    is reported — the sessions simply are not there afterwards (issue #100960).

    ``hermes import`` is the disaster-recovery path, so that failure mode lands
    on users who have already lost something once.  Route the member through
    the same ``_safe_restore_db`` page copy that ``/snapshot restore`` has used
    since #65942: the live inode is preserved, every open connection converges
    on the imported data, and the sidecars are handled there.  A target that
    does not exist yet has no holders and no inode worth preserving, so it
    takes the ordinary atomic publish.

    Raises ``OSError`` when the database could not be replaced safely, so the
    caller reports a skipped file instead of counting a silent success.
    """
    if not target.exists():
        _extract_member_atomically(zf, member, target, new_file_mode)
        return

    # The database keeps its own mode/ownership: the bytes come from the
    # archive but the file does not, so the archive has no say in either.
    mode = _preserve_file_mode(target)
    owner = _preserve_file_owner(target)

    fd, tmp_name = tempfile.mkstemp(
        dir=str(target.parent), prefix=f".{target.name[:80]}.", suffix=".dbimport"
    )
    try:
        with os.fdopen(fd, "wb") as dst:
            # Stream: a multi-gigabyte state.db member must not be held in
            # memory in one piece.
            with zf.open(member) as src:
                shutil.copyfileobj(src, dst)
            dst.flush()
            os.fsync(dst.fileno())
        if not _safe_restore_db(Path(tmp_name), target):
            raise OSError(
                "live-safe restore refused or failed; the existing database was "
                "left untouched. Stop the gateway/dashboard processes holding it "
                "open and re-run the import."
            )
        _restore_file_owner(target, owner)
        _restore_file_mode(target, mode)
    finally:
        try:
            os.unlink(tmp_name)
        except OSError:
            pass


def run_import(args) -> None:
    """Restore a Hermes backup from a zip file."""
    zip_path = Path(args.zipfile).expanduser().resolve()

    if not zip_path.is_file():
        print(f"Error: File not found: {zip_path}")
        sys.exit(1)

    if not zipfile.is_zipfile(zip_path):
        print(f"Error: Not a valid zip file: {zip_path}")
        sys.exit(1)

    # The restore target must be the home the command operates under — the
    # same path printed as "Target:" via display_hermes_home(). Resolving
    # through get_default_hermes_root() instead maps a profile home
    # (<root>/profiles/<name>) back to <root>, silently retargeting the
    # restore at the live root while the profile directory stays empty.
    hermes_root = get_hermes_home()

    with zipfile.ZipFile(zip_path, "r") as zf:
        # Validate
        ok, reason = _validate_backup_zip(zf)
        if not ok:
            print(f"Error: {reason}")
            sys.exit(1)

        prefix = _detect_prefix(zf)
        members = [n for n in zf.namelist() if not n.endswith("/")]
        file_count = len(members)

        print(f"Backup contains {file_count} files")
        print(f"Target: {display_hermes_home()}")

        if prefix:
            print(f"Detected archive prefix: {prefix!r} (will be stripped)")

        # Check for existing installation
        has_config = (hermes_root / "config.yaml").exists()
        has_env = (hermes_root / ".env").exists()

        if (has_config or has_env) and not args.force:
            print()
            print("Warning: Target directory already has Hermes configuration.")
            print("Importing will overwrite existing files with backup contents.")
            print()
            try:
                answer = input("Continue? [y/N] ").strip().lower()
            except (EOFError, KeyboardInterrupt):
                print("\nAborted.")
                sys.exit(1)
            if answer not in {"y", "yes"}:
                print("Aborted.")
                return

        # Extract
        print(f"\nImporting {file_count} files ...")
        hermes_root.mkdir(parents=True, exist_ok=True)

        errors = []
        restored = 0
        restored_external = 0
        skipped_runtime: list[str] = []
        # (rel, live_counts, imported_counts) for every session database the
        # import replaced with one holding fewer rows. A restore is allowed to
        # do that — it just must not do it silently (issue #100960).
        db_shrunk: list[tuple[str, tuple[int, int], tuple[int, int]]] = []
        home_dir = Path.home().resolve()
        # Resolved once: every member is published via a temp file, and mkstemp
        # would otherwise create newly restored files as 0600.
        new_file_mode = _default_new_file_mode()
        t0 = time.monotonic()

        for member in members:
            # External memory-provider state captured under the reserved
            # ``_external/`` arc prefix restores to its original home-relative
            # location (e.g. ~/.honcho/config.json), NOT under HERMES_HOME.
            if member.startswith(_EXTERNAL_PREFIX):
                ext_rel = member[len(_EXTERNAL_PREFIX):]
                if not ext_rel:
                    continue
                target = home_dir / ext_rel
                # Security: the resolved target must stay under the home dir.
                try:
                    target.resolve().relative_to(home_dir)
                except ValueError:
                    errors.append(f"  {member}: path traversal blocked")
                    continue
                try:
                    target.parent.mkdir(parents=True, exist_ok=True)
                    _extract_member_atomically(zf, member, target, new_file_mode)
                    # External provider configs commonly hold credentials.
                    if target.suffix in {".json", ".env", ".conf"} or target.name in _SECRET_FILE_NAMES:
                        try:
                            os.chmod(target, 0o600)
                        except OSError:
                            pass
                    restored += 1
                    restored_external += 1
                except (PermissionError, OSError) as exc:
                    errors.append(f"  {member}: {exc}")
                if restored % 500 == 0:
                    print(f"  {restored}/{file_count} files ...")
                continue

            # Strip prefix if detected
            if prefix and member.startswith(prefix):
                rel = member[len(prefix):]
            else:
                rel = member

            if not rel:
                continue

            # Never overwrite volatile gateway/process runtime state. These are
            # namespaced to the machine/container the backup was taken on;
            # clobbering them (especially gateway_state.json) breaks the gateway
            # reconciler on the target and disconnects hosted instances from the
            # Nous portal. Matched by basename so both the root profile and
            # named profiles (profiles/<name>/gateway_state.json) are covered.
            if Path(rel).name in _IMPORT_SKIP_NAMES:
                skipped_runtime.append(rel)
                continue

            # A ``.db`` member is page-restored into the live file below; a
            # WAL/SHM/journal member from the archive describes a different
            # database image, and installing it beside the restored file (over
            # a live sidecar, via os.replace) would replay a foreign WAL on
            # the next open. Current backups never ship these
            # (_EXCLUDED_SUFFIXES); older or hand-built archives might.
            if rel.endswith(_SQLITE_SIDECAR_SUFFIXES):
                skipped_runtime.append(rel)
                continue

            target = hermes_root / rel

            # Security: reject absolute paths and traversals
            try:
                target.resolve().relative_to(hermes_root.resolve())
            except ValueError:
                errors.append(f"  {rel}: path traversal blocked")
                continue

            try:
                target.parent.mkdir(parents=True, exist_ok=True)
                if target.suffix == ".db":
                    # Count before the write: afterwards the rows this import
                    # drops are gone and there is nothing left to compare.
                    before = _count_session_rows(target)
                    _import_db_member(zf, member, target, new_file_mode)
                    after = _count_session_rows(target)
                    if before and after and after[1] < before[1]:
                        db_shrunk.append((rel, before, after))
                else:
                    _extract_member_atomically(zf, member, target, new_file_mode)
                if target.name in _SECRET_FILE_NAMES:
                    os.chmod(target, 0o600)
                restored += 1
            except (PermissionError, OSError) as exc:
                errors.append(f"  {rel}: {exc}")

            if restored % 500 == 0:
                print(f"  {restored}/{file_count} files ...")

        elapsed = time.monotonic() - t0

        # Summary
        print()
        print(f"Import complete: {restored} files restored in {elapsed:.1f}s")
        print(f"  Target: {display_hermes_home()}")

        if restored_external:
            print(
                f"\n  Restored {restored_external} memory-provider file(s) to "
                f"their original location(s) outside {display_hermes_home()}."
            )

        if errors:
            print(f"\n  Warnings ({len(errors)} files skipped):")
            for e in errors[:10]:
                print(e)
            if len(errors) > 10:
                print(f"  ... and {len(errors) - 10} more")

        if db_shrunk:
            # The backup predates work that is now overwritten. Say so: the
            # reported incident was twelve sessions disappearing with nothing
            # logged anywhere (issue #100960).
            print("\n  ⚠ Session data replaced by older backup contents:")
            for rel, before, after in db_shrunk:
                print(
                    f"    {rel}: {before[0]} session(s) / {before[1]} message(s)"
                    f" -> {after[0]} / {after[1]}"
                )
            print(
                "    Anything recorded after the backup was taken is not in it. "
                "Recover from a newer backup or snapshot: hermes snapshot list"
            )

        if skipped_runtime:
            print(
                f"\n  Preserved {len(skipped_runtime)} runtime state "
                f"file(s) (kept this machine's, not the backup's):"
            )
            for rel in sorted(skipped_runtime)[:10]:
                print(f"    {rel}")
            if len(skipped_runtime) > 10:
                print(f"    ... and {len(skipped_runtime) - 10} more")

        # Post-import: restore profile wrapper scripts
        profiles_dir = hermes_root / "profiles"
        restored_profiles = []
        if profiles_dir.is_dir():
            try:
                from hermes_cli.profiles import (
                    create_wrapper_script, check_alias_collision,
                    _is_wrapper_dir_in_path, _get_wrapper_dir,
                )
                for entry in sorted(profiles_dir.iterdir()):
                    if not entry.is_dir():
                        continue
                    profile_name = entry.name
                    # Only create wrappers for directories with config
                    if not (entry / "config.yaml").exists() and not (entry / ".env").exists():
                        continue
                    collision = check_alias_collision(profile_name)
                    if collision:
                        print(f"  Skipped alias '{profile_name}': {collision}")
                        restored_profiles.append((profile_name, False))
                    else:
                        wrapper = create_wrapper_script(profile_name)
                        restored_profiles.append((profile_name, wrapper is not None))

                if restored_profiles:
                    created = [n for n, ok in restored_profiles if ok]
                    skipped = [n for n, ok in restored_profiles if not ok]
                    if created:
                        print(f"\n  Profile aliases restored: {', '.join(created)}")
                    if skipped:
                        print(f"  Profile aliases skipped:  {', '.join(skipped)}")
                    if not _is_wrapper_dir_in_path():
                        print(f"\n  Note: {_get_wrapper_dir()} is not in your PATH.")
                        print('  Add to your shell config (~/.bashrc or ~/.zshrc):')
                        print('    export PATH="$HOME/.local/bin:$PATH"')
            except ImportError:
                # hermes_cli.profiles might not be available (fresh install)
                if any(profiles_dir.iterdir()):
                    print("\n  Profiles detected but aliases could not be created.")
                    print("  Run: hermes profile list  (after installing hermes)")

        # Guidance
        print()
        if not (hermes_root / "hermes-agent").is_dir():
            print("Note: The hermes-agent codebase was not included in the backup.")
            print("  If this is a fresh install, run: hermes update")

        if restored_profiles:
            gw_profiles = [n for n, _ in restored_profiles]
            print("\nTo re-enable gateway services for profiles:")
            for pname in gw_profiles:
                print(f"  hermes -p {pname} gateway install")

        # Bring the restored install to life: the backup may contain bot
        # tokens and registered cron jobs, but they're inert without a
        # gateway process. Install/start the service automatically (a
        # platform-less gateway is a supported mode, so this is safe even
        # for backups with no messaging config). Best-effort and prompt-free;
        # failures print a manual fallback and never fail the import.
        native_default = _get_platform_default_hermes_home()
        default_has_install = any(
            (native_default / marker).exists()
            for marker in ("config.yaml", ".env", "state.db")
        )
        # A restore into a sandbox or profile home must not silently install
        # a second gateway pointed at it — on the default service name that
        # would shadow or hijack the machine's primary install. Only revive
        # the service automatically when the restore landed in the default
        # home, or when no other install exists on this machine.
        if hermes_root != native_default and default_has_install:
            print(
                "\nRestored into a non-default home; leaving the gateway service "
                "alone to avoid clashing with the install at "
                f"{native_default}."
            )
            print("To start a gateway for this home, run:  hermes gateway install")
        else:
            try:
                from hermes_cli.gateway import ensure_gateway_service, _is_service_running

                if not _is_service_running():
                    print()
                    ensure_gateway_service(context="import")
            except Exception:
                print("\nStart the gateway to activate cron jobs and messaging:")
                print("  hermes gateway install")

        print("Done. Your Hermes configuration has been restored.")


# ---------------------------------------------------------------------------
# Quick state snapshots (used by /snapshot slash command and hermes backup --quick)
# ---------------------------------------------------------------------------

# Critical state files to include in quick snapshots (relative to HERMES_HOME).
# Everything else is either regeneratable (logs, cache) or managed separately
# (skills, repo, sessions/).
#
# Entries may be individual files OR directories.  Directories are captured
# recursively; missing entries are silently skipped.  Pairing data lives in
# platform-specific JSON blobs outside state.db, so it's listed here explicitly
# — `hermes update` snapshots this set before pulling so approved-user lists
# are recoverable if anything goes wrong (issue #15733).
_QUICK_STATE_FILES = (
    "state.db",
    "config.yaml",
    ".env",
    "auth.json",
    "cron/jobs.json",
    "cron/executions.db",
    "gateway_state.json",
    "channel_directory.json",
    "channel_aliases.json",
    "processes.json",
    "gateway/discord_message_recovery.db",  # Discord reconnect replay ledger
    # Per-profile user-created stores that live outside the git checkout and
    # are therefore destroyed if the update flow removes/replaces the file and
    # the post-update schema-init re-creates an empty one (issue #52889). All
    # are at $HERMES_HOME/<name> for the default/root profile; on non-root
    # profiles the real path is outside HERMES_HOME and the entry is silently
    # skipped (best-effort, same as the pairing stores). SQLite DBs are copied
    # WAL-safely via _safe_copy_db.
    "projects.db",                      # per-profile project store
    "response_store.db",                # gateway conversation history / tool payloads
    "memory_store.db",                  # holographic memory facts/entities
    "verification_evidence.db",         # agent verification audit trail
    "kanban.db",                        # default board (back-compat <root>/kanban.db)
    "kanban/boards",                    # non-default boards: each <slug>/kanban.db + board metadata (workspaces/ + attachments/ are skipped as regenerable)
    # Pairing stores (generic + per-platform JSONs outside state.db)
    "pairing",                          # legacy location (gateway/pairing.py)
    "platforms/pairing",                # new location (gateway/pairing.py)
    "feishu_comment_pairing.json",      # Feishu comment subscription pairings
)

# ``_QUICK_SNAPSHOTS_DIR`` lives with the exclusion rules at the top of the module.
_QUICK_DEFAULT_KEEP = 20


def _quick_snapshot_root(hermes_home: Optional[Path] = None) -> Path:
    home = hermes_home or get_hermes_home()
    return home / _QUICK_SNAPSHOTS_DIR


def create_quick_snapshot(
    label: Optional[str] = None,
    hermes_home: Optional[Path] = None,
    keep: Optional[int] = None,
    max_file_size: Optional[int] = None,
) -> Optional[str]:
    """Create one atomic quick snapshot while holding the shared backup slot."""
    home = hermes_home or get_hermes_home()
    with _backup_operation_lock(home):
        return _create_quick_snapshot_locked(
            label=label,
            hermes_home=home,
            keep=keep,
            max_file_size=max_file_size,
        )


def _create_quick_snapshot_locked(
    label: Optional[str] = None,
    hermes_home: Optional[Path] = None,
    keep: Optional[int] = None,
    max_file_size: Optional[int] = None,
) -> Optional[str]:
    """Create a quick state snapshot of critical files.

    Copies STATE_FILES to a timestamped directory under state-snapshots/.
    Auto-prunes old snapshots beyond the keep limit.

    Args:
        max_file_size: When set, individual files larger than this many bytes
            are skipped (with a printed warning) instead of copied. Used by
            the pre-update safety snapshot so a multi-GB ``state.db`` can
            never stall ``hermes update`` or silently eat disk — the small
            pairing/cron/config files the snapshot exists to protect are
            always captured. ``None`` (default) copies everything, which
            preserves manual ``/snapshot`` and ``hermes backup --quick``
            behavior.

    Returns:
        Snapshot ID (timestamp-based), or None if no files found.
    """
    home = hermes_home or get_hermes_home()
    root = _quick_snapshot_root(home)

    def _too_large(path: Path, rel_name: str) -> bool:
        """True (and warn) when ``path`` exceeds the max_file_size cap."""
        if max_file_size is None:
            return False
        try:
            size = path.stat().st_size
        except OSError:
            return False
        if size <= max_file_size:
            return False
        print(
            f"  ⚠ Snapshot: skipping {rel_name} "
            f"({_format_size(size)} exceeds {_format_size(max_file_size)} limit)"
        )
        logger.warning(
            "Quick snapshot skipped %s: %d bytes exceeds %d byte limit",
            rel_name,
            size,
            max_file_size,
        )
        return True

    ts = datetime.now(timezone.utc).strftime("%Y%m%d-%H%M%S")
    base_snap_id = f"{ts}-{label}" if label else ts
    snap_id = base_snap_id
    suffix = 2
    while (root / snap_id).exists():
        snap_id = f"{base_snap_id}-{suffix}"
        suffix += 1
    snap_dir = root / snap_id
    staging_dir = root / f".{snap_id}.{os.getpid()}.partial"
    shutil.rmtree(staging_dir, ignore_errors=True)
    staging_dir.mkdir(parents=True, exist_ok=False)
    logger.info("quick snapshot phase=copy status=started id=%s", snap_id)

    manifest: Dict[str, int] = {}  # rel_path -> file size
    failed_dbs: list[str] = []  # present *.db that could not be snapshotted
    # #68805: track protected DB files skipped for size — they are snapshot
    # incompleteness just like a failed copy, so pruning must be suppressed
    # to preserve the older complete snapshot that may contain the only
    # recoverable database.
    oversized_skipped: list[str] = []

    for rel in _QUICK_STATE_FILES:
        src = home / rel
        if not src.exists():
            continue

        if src.is_dir():
            # Walk the directory and record each file individually in the
            # manifest so restore can treat them uniformly.  Empty dirs are
            # skipped (nothing to snapshot).
            for sub in src.rglob("*"):
                if not sub.is_file():
                    continue
                sub_rel = sub.relative_to(home).as_posix()
                # Skip heavy, regenerable per-board subtrees (scratch
                # workspaces and task attachments can be large); we only need
                # the board databases + their metadata to restore a board.
                if "/workspaces/" in f"/{sub_rel}/" or "/attachments/" in f"/{sub_rel}/":
                    continue
                if _too_large(sub, sub_rel):
                    if sub.suffix == ".db":
                        oversized_skipped.append(sub_rel)
                    continue
                dst = staging_dir / sub_rel
                dst.parent.mkdir(parents=True, exist_ok=True)
                try:
                    # Route SQLite DBs through the WAL-safe backup() path so a
                    # board DB with an open WAL (the gateway may hold it at
                    # snapshot time) is captured consistently.
                    if sub.suffix == ".db":
                        if not _safe_copy_db(sub, dst):
                            failed_dbs.append(sub_rel)
                            print(
                                f"  ⚠ Snapshot: SQLite safe copy FAILED for {sub_rel} "
                                f"— file may be locked or corrupted"
                            )
                            if is_zeroed_sqlite_file(sub):
                                print(
                                    f"  ⚠ Snapshot: {sub_rel} looks ZEROED "
                                    f"(no SQLite header; {sub.stat().st_size} bytes of NULs?)"
                                )
                            continue
                    else:
                        shutil.copy2(sub, dst)
                    manifest[sub_rel] = dst.stat().st_size
                except (OSError, PermissionError) as exc:
                    logger.warning("Could not snapshot %s: %s", sub_rel, exc)
            continue

        if not src.is_file():
            continue

        if _too_large(src, rel):
            if src.suffix == ".db":
                oversized_skipped.append(rel)
            continue

        dst = staging_dir / rel
        dst.parent.mkdir(parents=True, exist_ok=True)

        try:
            if src.suffix == ".db":
                if not _safe_copy_db(src, dst):
                    failed_dbs.append(rel)
                    print(
                        f"  ⚠ Snapshot: SQLite safe copy FAILED for {rel} "
                        f"— file may be locked or corrupted"
                    )
                    if is_zeroed_sqlite_file(src):
                        print(
                            f"  ⚠ Snapshot: {rel} looks ZEROED "
                            f"(no SQLite header; {src.stat().st_size} bytes)"
                        )
                    continue
            else:
                shutil.copy2(src, dst)
            manifest[rel] = dst.stat().st_size
        except (OSError, PermissionError) as exc:
            logger.warning("Could not snapshot %s: %s", rel, exc)

    if failed_dbs:
        # Critical: update path used to log-and-continue with exit 0, so a
        # missing state.db backup looked like a successful pre-update snapshot
        # (#68474). Surface this on stdout where operators actually look.
        print(
            "  ⚠ CRITICAL: could not snapshot DB file(s): "
            + ", ".join(failed_dbs)
        )
        print(
            "  ⚠ If sessions disappear after update, check "
            f"{root} and run: hermes snapshot list"
        )
        logger.error(
            "Quick snapshot failed to capture DB file(s): %s",
            ", ".join(failed_dbs),
        )

    if not manifest:
        shutil.rmtree(staging_dir, ignore_errors=True)
        if failed_dbs:
            # Distinguish "nothing to snapshot" from "state.db present but unreadable"
            print(
                "  ⚠ Snapshot aborted: no files captured "
                f"(failed DBs: {', '.join(failed_dbs)})"
            )
        return None

    # Write manifest
    meta = {
        "id": snap_id,
        "timestamp": ts,
        "label": label,
        "file_count": len(manifest),
        "total_size": sum(manifest.values()),
        "files": manifest,
        "failed_dbs": failed_dbs,
        "oversized_skipped": oversized_skipped,
    }
    with open(staging_dir / "manifest.json", "w", encoding="utf-8") as f:
        json.dump(meta, f, indent=2)

    os.replace(staging_dir, snap_dir)

    # Auto-prune. Defaults preserve historical manual /snapshot behavior; callers
    # with known high-churn safety snapshots (for example pre-update) can pass a
    # smaller keep value so large state.db copies do not accumulate indefinitely.
    # #68805 review: skip pruning when a present DB failed to capture OR was
    # skipped for size — either way the snapshot is incomplete and the older
    # snapshot may contain the only recoverable database.
    incomplete = failed_dbs or oversized_skipped
    if not incomplete:
        _prune_quick_snapshots(root, keep=_QUICK_DEFAULT_KEEP if keep is None else keep)
    else:
        if oversized_skipped:
            print(
                "  ⚠ Skipping snapshot prune: DB file(s) skipped for size: "
                + ", ".join(oversized_skipped)
            )
            logger.warning(
                "Quick snapshot skipped oversized DB file(s): %s",
                ", ".join(oversized_skipped),
            )
        logger.warning(
            "Skipping snapshot prune because %d DB(s) failed to capture "
            "and/or %d were oversized — preserving older snapshots as "
            "recovery source",
            len(failed_dbs), len(oversized_skipped),
        )

    logger.info(
        "quick snapshot phase=copy status=complete id=%s files=%d bytes=%d",
        snap_id,
        len(manifest),
        sum(manifest.values()),
    )
    return snap_id


def list_quick_snapshots(
    limit: int = 20,
    hermes_home: Optional[Path] = None,
) -> List[Dict[str, Any]]:
    """List existing quick state snapshots, most recent first."""
    root = _quick_snapshot_root(hermes_home)
    if not root.exists():
        return []

    results = []
    for d in sorted(root.iterdir(), reverse=True):
        if not d.is_dir() or d.name.startswith(".") or d.name.endswith(".partial"):
            continue
        manifest_path = d / "manifest.json"
        if manifest_path.exists():
            try:
                with open(manifest_path, encoding="utf-8") as f:
                    results.append(json.load(f))
            except (json.JSONDecodeError, OSError):
                results.append({"id": d.name, "file_count": 0, "total_size": 0})
        if len(results) >= limit:
            break

    return results


def restore_quick_snapshot(
    snapshot_id: str,
    hermes_home: Optional[Path] = None,
) -> bool:
    """Restore state from a quick snapshot.

    Overwrites current state files with the snapshot's copies.
    Returns True if at least one file was restored.
    """
    home = hermes_home or get_hermes_home()
    root = _quick_snapshot_root(home)

    # Security: reject snapshot_id values that contain path separators or
    # traversal sequences so that `root / snapshot_id` stays inside root.
    if not snapshot_id or "/" in snapshot_id or "\\" in snapshot_id or snapshot_id in (".", ".."):
        logger.error("Invalid snapshot_id: %s", snapshot_id)
        return False

    snap_dir = root / snapshot_id

    # Confirm the resolved path is still inside root (handles symlinks etc.)
    try:
        snap_dir.resolve().relative_to(root.resolve())
    except ValueError:
        logger.error("Snapshot path traversal blocked for id: %s", snapshot_id)
        return False

    if not snap_dir.is_dir():
        return False

    manifest_path = snap_dir / "manifest.json"
    if not manifest_path.exists():
        return False

    with open(manifest_path, encoding="utf-8") as f:
        meta = json.load(f)

    restored = 0
    for rel in meta.get("files", {}):
        # Security: reject absolute paths and traversals in manifest entries
        src = snap_dir / rel
        try:
            src.resolve().relative_to(snap_dir.resolve())
        except ValueError:
            logger.error("Manifest path traversal blocked: %s", rel)
            continue

        dst = home / rel
        try:
            dst.resolve().relative_to(home.resolve())
        except ValueError:
            logger.error("Manifest path traversal blocked: %s", rel)
            continue

        if not src.exists():
            continue

        dst.parent.mkdir(parents=True, exist_ok=True)

        try:
            if dst.suffix == ".db":
                # Restore through SQLite backup API so live connections
                # (gateway, dashboard, another CLI session) see the
                # restored data instead of continuing to serve stale
                # cached pages from a replaced inode (issue #65942).
                if not _safe_restore_db(src, dst):
                    # Refused (live holder) or failed: the destination was
                    # left as it was. Count it as a failure, not a restore.
                    logger.error("Failed to restore %s: live-safe restore refused", rel)
                    continue
            else:
                shutil.copy2(src, dst)
            restored += 1
        except (OSError, PermissionError) as exc:
            logger.error("Failed to restore %s: %s", rel, exc)

    logger.info("Restored %d files from snapshot %s", restored, snapshot_id)
    return restored > 0


# Relative path of the cron job database inside HERMES_HOME. Kept in sync with
# the entry in ``_QUICK_STATE_FILES`` and with ``cron/jobs.py``'s ``JOBS_FILE``.
_CRON_JOBS_REL = "cron/jobs.json"


def _count_cron_jobs(path: Path) -> Optional[int]:
    """Return the number of cron jobs stored in ``path``.

    The canonical on-disk shape is ``{"jobs": [...]}`` (see ``cron/jobs.py``).
    A legacy bare-list shape (``[...]``) is also honoured.

    Returns:
        The job count for any *valid, readable* JSON document, or ``None`` if
        the file is missing or cannot be parsed. ``None`` means "unknown" —
        callers must not treat it as "zero jobs", because acting on an
        unreadable file could mask a real corruption the user needs to see.
    """
    if not path.is_file():
        return None
    try:
        # utf-8-sig: same dialect as cron/jobs.load_jobs — Windows editors
        # may leave a UTF-8 BOM that plain utf-8 json.load rejects. Without
        # it a BOM'd jobs.json counts as "unreadable" (None) and the
        # post-update cron-loss auto-restore safety net silently disables.
        with open(path, "r", encoding="utf-8-sig") as f:
            data = json.load(f)
    except (OSError, json.JSONDecodeError):
        return None
    if isinstance(data, dict):
        jobs = data.get("jobs", [])
        return len(jobs) if isinstance(jobs, list) else None
    if isinstance(data, list):
        return len(data)
    return None


def restore_cron_jobs_if_emptied(
    snapshot_id: str,
    hermes_home: Optional[Path] = None,
) -> Optional[Dict[str, Any]]:
    """Safety net for silent cron-job loss across ``hermes update``.

    Config-version migrations have been observed to leave ``cron/jobs.json``
    valid-but-empty after an update, silently dropping every scheduled job
    (issue #34600). The desktop scheduler can also overwrite the file with its
    own small set of internally-tracked crons, causing partial loss (issue
    #52144).

    This compares the *current* job count against the pre-update snapshot. If
    the live file now has **fewer** jobs than the snapshot, the snapshot copy
    of ``cron/jobs.json`` is restored in place.

    The check is deliberately conservative — it only ever restores when there
    is unambiguous evidence of loss (snapshot had more jobs than live file),
    so a user who genuinely deleted jobs during/after the update is never
    second-guessed, and an unreadable live file (count ``None``) is left
    untouched so real corruption still surfaces.

    Args:
        snapshot_id: The pre-update quick-snapshot id (from
            :func:`create_quick_snapshot`).
        hermes_home: Override for the Hermes home directory (tests).

    Returns:
        ``None`` when no action was taken (the common, healthy path). On a
        successful restore, a dict ``{"restored": True, "job_count": N,
        "snapshot_id": ...}`` so the caller can warn the user.
    """
    if not snapshot_id:
        return None

    home = hermes_home or get_hermes_home()
    live_path = home / _CRON_JOBS_REL

    live_count = _count_cron_jobs(live_path)
    # ``None`` (missing or unparseable) is intentionally left alone — that's a
    # different failure mode the user should see rather than have papered over.
    if live_count is None:
        return None

    snap_path = _quick_snapshot_root(home) / snapshot_id / _CRON_JOBS_REL
    snap_count = _count_cron_jobs(snap_path)
    if not snap_count:  # None or 0 — nothing worth restoring
        return None

    # Restore when live has FEWER jobs than the pre-update snapshot.
    # Catches both total loss (0 vs N) and partial loss (1 vs 19) — the
    # desktop scheduler can overwrite jobs.json with its own small set of
    # internally-tracked crons after an update/restart.
    if live_count >= snap_count:
        return None

    try:
        live_path.parent.mkdir(parents=True, exist_ok=True)
        shutil.copy2(snap_path, live_path)
    except (OSError, PermissionError) as exc:
        logger.error(
            "Cron jobs were emptied during update but auto-restore failed: %s", exc
        )
        return None

    logger.warning(
        "Restored %d cron job(s) from pre-update snapshot %s "
        "(live file had %d job(s), snapshot had %d — jobs were lost during migration)",
        snap_count,
        snapshot_id,
        live_count,
        snap_count,
    )
    return {"restored": True, "job_count": snap_count, "snapshot_id": snapshot_id}


def _sibling_profile_homes(invoking_home: Path) -> list[tuple[str, Path]]:
    """(name, home) for every OTHER profile on this install. Never raises.

    The update's code swap and gateway fleet restart touch every profile,
    so the pre-update snapshot must too (#66140). The invoking profile is
    excluded — its snapshot is taken by the existing call.
    """
    homes: list[tuple[str, Path]] = []
    try:
        from hermes_cli.profiles import (
            _get_default_hermes_home,
            _get_profiles_root,
            _PROFILE_ID_RE,
        )

        invoking = invoking_home.resolve()
        default_home = _get_default_hermes_home()
        if default_home.is_dir() and default_home.resolve() != invoking:
            homes.append(("default", default_home))
        root = _get_profiles_root()
        if root.is_dir():
            for entry in sorted(root.iterdir()):
                if (
                    entry.is_dir()
                    and entry.name != "default"
                    and _PROFILE_ID_RE.match(entry.name)
                    and entry.resolve() != invoking
                ):
                    homes.append((entry.name, entry))
    except Exception as exc:
        logger.debug("Sibling profile enumeration failed: %s", exc)
    return homes


def create_pre_update_snapshots_all_profiles(
    invoking_home: Optional[Path] = None,
    keep: Optional[int] = None,
    max_file_size: Optional[int] = None,
) -> Dict[str, str]:
    """Pre-update quick snapshots for every SIBLING profile (#66140).

    Same snapshot set, same per-file size cap, same keep policy as the
    invoking profile's snapshot — identical semantics per profile, no
    partial-tier coherence class. Each sibling's snapshot lands under its
    OWN ``<home>/state-snapshots/`` so per-profile restore tooling finds
    it where it expects. Returns ``{profile_name: snapshot_id}`` for the
    siblings that snapshotted successfully. Never raises.
    """
    results: Dict[str, str] = {}
    home = invoking_home or get_hermes_home()
    for name, profile_home in _sibling_profile_homes(home):
        try:
            snap_id = create_quick_snapshot(
                label="pre-update",
                hermes_home=profile_home,
                keep=keep,
                max_file_size=max_file_size,
            )
            if snap_id:
                results[name] = snap_id
        except Exception as exc:
            logger.debug("Pre-update snapshot for profile %s failed: %s", name, exc)
    return results


# Config paths that the update flow must never change (#64160): the model
# routing keys and the Mixture-of-Agents section are consumed machine-wide
# (gateway, cron, desktop), so an update/repair cycle that rewrites them
# silently redirects paid inference. Each entry is a dotted path into the raw
# config.yaml document; a single-element tuple protects the whole section.
_PROTECTED_CONFIG_PATHS: Tuple[Tuple[str, ...], ...] = (
    ("model", "provider"),
    ("model", "default"),
    ("model", "base_url"),
    ("model", "api_key"),
    ("moa",),
)


def _read_raw_yaml_dict(path: Path) -> Optional[Dict[str, Any]]:
    """Parse ``path`` as a YAML mapping. ``None`` = missing/unreadable/non-dict."""
    if not path.is_file():
        return None
    try:
        import yaml

        with open(path, "r", encoding="utf-8") as f:
            data = yaml.safe_load(f)
    except Exception:
        return None
    return data if isinstance(data, dict) else None


def _get_config_path_value(data: Dict[str, Any], dotted: Tuple[str, ...]) -> Any:
    node: Any = data
    for key in dotted:
        if not isinstance(node, dict):
            return None
        node = node.get(key)
    return node


def _set_config_path_value(data: Dict[str, Any], dotted: Tuple[str, ...], value: Any) -> None:
    node = data
    for key in dotted[:-1]:
        child = node.get(key)
        if not isinstance(child, dict):
            child = {}
            node[key] = child
        node = child
    node[dotted[-1]] = value


def restore_config_model_settings_if_rewritten(
    snapshot_id: str,
    hermes_home: Optional[Path] = None,
) -> Optional[Dict[str, Any]]:
    """Safety net for silent config.yaml model/MoA loss across ``hermes update``.

    Desktop update/repair cycles have been observed to rewrite user-set
    ``model.provider``/``model.default`` and drop the ``moa:`` section
    entirely (issue #64160; the macOS repair/relaunch variant rewrote a
    pinned ``model.default`` to a transient composer pick). These keys are
    consumed by the gateway and unattended cron jobs too, so a rewrite
    silently changes paid inference behavior machine-wide.

    Mirrors :func:`restore_cron_jobs_if_emptied`: compare the *current*
    config against the pre-update snapshot taken minutes earlier by this
    same update run, and restore only the protected keys — never the whole
    file — when a value the user had set was changed or dropped. Everything
    the update legitimately wrote (version stamps, new sections) is left in
    place.

    Args:
        snapshot_id: The pre-update quick-snapshot id (from
            :func:`create_quick_snapshot`).
        hermes_home: Override for the Hermes home directory (tests/siblings).

    Returns:
        ``None`` when no action was taken (the common, healthy path). On a
        successful restore, ``{"restored": True, "keys": [...],
        "snapshot_id": ...}`` so the caller can warn the user.
    """
    if not snapshot_id:
        return None

    home = hermes_home or get_hermes_home()
    live_path = home / "config.yaml"
    snap_path = _quick_snapshot_root(home) / snapshot_id / "config.yaml"

    snap = _read_raw_yaml_dict(snap_path)
    if not snap:
        return None  # no snapshot copy — nothing to compare against
    live = _read_raw_yaml_dict(live_path)
    if live is None:
        # Missing or unparseable live config is a different failure mode the
        # user should see rather than have papered over (matches the cron net).
        return None

    restored_keys: list[str] = []
    for dotted in _PROTECTED_CONFIG_PATHS:
        snap_val = _get_config_path_value(snap, dotted)
        if snap_val in (None, "", {}, []):
            continue  # user never set it — nothing to protect
        live_val = _get_config_path_value(live, dotted)
        if live_val == snap_val:
            continue
        _set_config_path_value(live, dotted, snap_val)
        restored_keys.append(".".join(dotted))

    if not restored_keys:
        return None

    try:
        from utils import atomic_yaml_write

        atomic_yaml_write(live_path, live)
    except (OSError, PermissionError) as exc:
        logger.error(
            "config.yaml model settings were rewritten during update but "
            "auto-restore failed: %s",
            exc,
        )
        return None

    logger.warning(
        "Restored user config value(s) %s from pre-update snapshot %s — "
        "the update flow rewrote them (#64160)",
        ", ".join(restored_keys),
        snapshot_id,
    )
    return {"restored": True, "keys": restored_keys, "snapshot_id": snapshot_id}


def restore_config_model_settings_all_profiles(
    profile_snapshots: Dict[str, str],
    invoking_home: Optional[Path] = None,
) -> list[Dict[str, Any]]:
    """Run the config model-settings safety net for every sibling profile.

    Same contract as :func:`restore_cron_jobs_all_profiles`: each profile's
    live ``config.yaml`` is compared against ITS OWN same-generation
    pre-update snapshot. Returns one result dict per restored profile, each
    with a ``profile`` key added. Never raises.
    """
    restored: list[Dict[str, Any]] = []
    if not profile_snapshots:
        return restored
    home = invoking_home or get_hermes_home()
    by_name = dict(_sibling_profile_homes(home))
    for name, snap_id in profile_snapshots.items():
        profile_home = by_name.get(name)
        if profile_home is None:
            continue
        try:
            result = restore_config_model_settings_if_rewritten(
                snap_id, hermes_home=profile_home
            )
        except Exception as exc:
            logger.debug(
                "Config model-settings restore check for profile %s failed: %s",
                name,
                exc,
            )
            continue
        if result:
            result["profile"] = name
            restored.append(result)
    return restored


def restore_cron_jobs_all_profiles(
    profile_snapshots: Dict[str, str],
    invoking_home: Optional[Path] = None,
) -> list[Dict[str, Any]]:
    """Run the cron-jobs safety net for every sibling profile (#66140).

    ``profile_snapshots`` is the map returned by
    :func:`create_pre_update_snapshots_all_profiles`. Each profile's live
    ``cron/jobs.json`` is compared against ITS OWN snapshot — restores are
    same-generation by construction (the snapshot was taken minutes ago by
    this update run). Returns one result dict per restored profile, each
    with a ``profile`` key added. Never raises.
    """
    restored: list[Dict[str, Any]] = []
    if not profile_snapshots:
        return restored
    home = invoking_home or get_hermes_home()
    by_name = dict(_sibling_profile_homes(home))
    for name, snap_id in profile_snapshots.items():
        profile_home = by_name.get(name)
        if profile_home is None:
            continue
        try:
            result = restore_cron_jobs_if_emptied(snap_id, hermes_home=profile_home)
        except Exception as exc:
            logger.debug("Cron restore check for profile %s failed: %s", name, exc)
            continue
        if result:
            result["profile"] = name
            restored.append(result)
    return restored


def _prune_quick_snapshots(root: Path, keep: int = _QUICK_DEFAULT_KEEP) -> int:
    """Remove oldest quick snapshots beyond the keep limit. Returns count deleted."""
    if not root.exists():
        return 0

    dirs = sorted(
        (
            d
            for d in root.iterdir()
            if d.is_dir() and not d.name.startswith(".") and not d.name.endswith(".partial")
        ),
        key=lambda d: d.name,
        reverse=True,
    )

    deleted = 0
    for d in dirs[keep:]:
        try:
            shutil.rmtree(d)
            deleted += 1
        except OSError as exc:
            logger.warning("Failed to prune snapshot %s: %s", d.name, exc)

    return deleted


def prune_quick_snapshots(
    keep: int = _QUICK_DEFAULT_KEEP,
    hermes_home: Optional[Path] = None,
) -> int:
    """Manually prune quick snapshots. Returns count deleted."""
    return _prune_quick_snapshots(_quick_snapshot_root(hermes_home), keep=keep)


def run_quick_backup(args) -> None:
    """CLI entry point for hermes backup --quick."""
    label = getattr(args, "label", None)
    snap_id = create_quick_snapshot(label=label)
    if snap_id:
        print(f"State snapshot created: {snap_id}")
        snaps = list_quick_snapshots()
        print(f"  {len(snaps)} snapshot(s) stored in {display_hermes_home()}/state-snapshots/")
        print(f"  Restore with: /snapshot restore {snap_id}")
    else:
        print("No state files found to snapshot.")


# ---------------------------------------------------------------------------
# Shared full-zip backup helper
# ---------------------------------------------------------------------------

def _write_full_zip_backup(out_path: Path, hermes_root: Path) -> Optional[Path]:
    """Single-flight wrapper for automatic full zip backups."""
    try:
        with _backup_operation_lock(hermes_root):
            return _write_full_zip_backup_locked(out_path, hermes_root)
    except BackupInProgressError as exc:
        logger.warning("Full-zip backup skipped: %s", exc)
        return None


def _write_full_zip_backup_locked(out_path: Path, hermes_root: Path) -> Optional[Path]:
    """Write a full zip snapshot of ``hermes_root`` to ``out_path``.

    Uses the same exclusion rules and SQLite safe-copy as :func:`run_backup`.
    Returns the output path on success, None on failure (nothing to back up,
    or write error — caller should surface the outcome but not raise).
    """
    scan_started = time.monotonic()
    logger.info("automatic backup phase=scan status=started")
    try:
        files_to_add = list(_iter_backup_files(hermes_root, out_path))
    except OSError as exc:
        logger.warning("Full-zip backup: walk failed: %s", exc)
        return None

    if not files_to_add:
        return None

    logger.info(
        "automatic backup phase=scan status=complete duration_ms=%.1f files=%d",
        (time.monotonic() - scan_started) * 1000,
        len(files_to_add),
    )

    archive_started = time.monotonic()
    try:
        with _atomic_output_path(out_path) as archive_path, zipfile.ZipFile(
            archive_path, "w", zipfile.ZIP_DEFLATED, compresslevel=6
        ) as zf:
            for index, (abs_path, rel_path) in enumerate(files_to_add, 1):
                try:
                    if abs_path.suffix == ".db":
                        # Stage the snapshot alongside the output zip so that the
                        # temp file lives on the same filesystem.  The system
                        # default (/tmp) may be a small tmpfs that cannot hold
                        # large databases, causing silent backup incompleteness.
                        with tempfile.NamedTemporaryFile(
                            suffix=".db", delete=False, dir=str(out_path.parent)
                        ) as tmp:
                            tmp_db = Path(tmp.name)
                        try:
                            if not _safe_copy_db(abs_path, tmp_db):
                                logger.warning(
                                    "Full-zip backup aborted: SQLite snapshot failed for %s",
                                    rel_path,
                                )
                                raise _SQLiteSnapshotError(str(rel_path))
                            zf.write(tmp_db, arcname=str(rel_path))
                        finally:
                            tmp_db.unlink(missing_ok=True)
                    else:
                        zf.write(abs_path, arcname=str(rel_path))
                except (PermissionError, OSError, ValueError) as exc:
                    logger.debug("Skipping %s in zip backup: %s", rel_path, exc)
                    continue
                if index % 500 == 0:
                    logger.info(
                        "automatic backup phase=archive status=progress completed=%d total=%d",
                        index,
                        len(files_to_add),
                    )
    except (OSError, _SQLiteSnapshotError) as exc:
        logger.warning("Full-zip backup: zip write failed: %s", exc)
        # ``_atomic_output_path`` already removed the hidden partial.  Do not
        # unlink ``out_path`` here: it may be a previous valid backup that the
        # atomic publisher deliberately preserved.
        return None

    logger.info(
        "automatic backup phase=archive status=complete duration_ms=%.1f files=%d bytes=%d",
        (time.monotonic() - archive_started) * 1000,
        len(files_to_add),
        out_path.stat().st_size,
    )

    return out_path


# ---------------------------------------------------------------------------
# Pre-update auto-backup
# ---------------------------------------------------------------------------

_PRE_UPDATE_BACKUPS_DIR = "backups"
_PRE_UPDATE_PREFIX = "pre-update-"
_PRE_UPDATE_DEFAULT_KEEP = 5


def _pre_update_backup_dir(hermes_home: Optional[Path] = None) -> Path:
    home = hermes_home or get_hermes_home()
    return home / _PRE_UPDATE_BACKUPS_DIR


def _prune_pre_update_backups(backup_dir: Path, keep: int) -> int:
    """Remove oldest pre-update backups beyond the keep limit.

    Returns the number of files deleted.  Only touches files matching
    ``pre-update-*.zip`` so hand-made zips dropped in the same directory
    are never touched.

    ``keep`` is floored to 1 because this helper is only called immediately
    after a fresh backup is written: deleting that backup right after the
    user paid the disk/CPU cost to create it would leave them worse off
    than no backup at all (and the wrapper in ``main.py`` would still print
    a misleading ``Saved: <path>`` line for a file that no longer exists).
    Operators who genuinely don't want a backup should set
    ``updates.pre_update_backup: off`` in config — that gates creation.
    """
    keep = max(keep, 1)
    if not backup_dir.exists():
        return 0

    backups = sorted(
        (p for p in backup_dir.iterdir()
         if p.is_file() and p.name.startswith(_PRE_UPDATE_PREFIX) and p.suffix.lower() == ".zip"),
        key=lambda p: p.name,
        reverse=True,
    )

    deleted = 0
    for p in backups[keep:]:
        try:
            p.unlink()
            deleted += 1
        except OSError as exc:
            logger.warning("Failed to prune backup %s: %s", p.name, exc)

    return deleted


def create_pre_update_backup(
    hermes_home: Optional[Path] = None,
    keep: int = _PRE_UPDATE_DEFAULT_KEEP,
) -> Optional[Path]:
    """Create a full zip backup of HERMES_HOME under ``backups/``.

    Mirrors :func:`run_backup` (same exclusion rules, same SQLite safe-copy)
    but writes to ``<HERMES_HOME>/backups/pre-update-<timestamp>.zip`` and
    auto-prunes old pre-update backups.

    Returns the path to the created zip, or ``None`` if no files were
    found or the backup could not be created.  Never raises — the caller
    (``hermes update``) should continue even if the backup fails.
    """
    hermes_root = hermes_home or get_default_hermes_root()
    if not hermes_root.is_dir():
        return None

    backup_dir = _pre_update_backup_dir(hermes_root)
    try:
        backup_dir.mkdir(parents=True, exist_ok=True)
    except OSError as exc:
        logger.warning("Could not create pre-update backup dir %s: %s", backup_dir, exc)
        return None

    stamp = datetime.now().strftime("%Y-%m-%d-%H%M%S")
    out_path = backup_dir / f"{_PRE_UPDATE_PREFIX}{stamp}.zip"

    result = _write_full_zip_backup(out_path, hermes_root)
    if result is None:
        return None

    _prune_pre_update_backups(backup_dir, keep=keep)
    return out_path


# ---------------------------------------------------------------------------
# Pre-migration auto-backup (used by `hermes claw migrate`)
# ---------------------------------------------------------------------------

_PRE_MIGRATION_PREFIX = "pre-migration-"
_PRE_MIGRATION_DEFAULT_KEEP = 5


def _prune_pre_migration_backups(backup_dir: Path, keep: int) -> int:
    """Remove oldest pre-migration backups beyond the keep limit.

    Only touches files matching ``pre-migration-*.zip`` so other backups in
    the same directory are never touched.
    """
    keep = max(keep, 0)
    if not backup_dir.exists():
        return 0

    backups = sorted(
        (p for p in backup_dir.iterdir()
         if p.is_file() and p.name.startswith(_PRE_MIGRATION_PREFIX) and p.suffix.lower() == ".zip"),
        key=lambda p: p.name,
        reverse=True,
    )

    deleted = 0
    for p in backups[keep:]:
        try:
            p.unlink()
            deleted += 1
        except OSError as exc:
            logger.warning("Failed to prune pre-migration backup %s: %s", p.name, exc)

    return deleted


def create_pre_migration_backup(
    hermes_home: Optional[Path] = None,
    keep: int = _PRE_MIGRATION_DEFAULT_KEEP,
) -> Optional[Path]:
    """Create a full zip backup of HERMES_HOME under ``backups/`` before a
    ``hermes claw migrate`` apply.

    Shares implementation with :func:`create_pre_update_backup` via
    ``_write_full_zip_backup`` — same exclusions, same SQLite safe-copy,
    restorable with ``hermes import <archive>``.  Writes to
    ``<HERMES_HOME>/backups/pre-migration-<timestamp>.zip`` and auto-prunes
    old pre-migration backups.

    Returns the path to the created zip, or ``None`` if nothing was found
    to back up (fresh install) or the write failed.  Never raises — the
    caller decides whether to abort or proceed.
    """
    hermes_root = hermes_home or get_default_hermes_root()
    if not hermes_root.is_dir():
        return None

    # Reuses the shared backups/ directory so `hermes import` and the
    # update-backup listing pick up pre-migration archives too.
    backup_dir = _pre_update_backup_dir(hermes_root)
    try:
        backup_dir.mkdir(parents=True, exist_ok=True)
    except OSError as exc:
        logger.warning("Could not create pre-migration backup dir %s: %s", backup_dir, exc)
        return None

    stamp = datetime.now().strftime("%Y-%m-%d-%H%M%S")
    out_path = backup_dir / f"{_PRE_MIGRATION_PREFIX}{stamp}.zip"

    result = _write_full_zip_backup(out_path, hermes_root)
    if result is None:
        return None

    _prune_pre_migration_backups(backup_dir, keep=keep)
    return out_path