#!/usr/bin/env python3
"""Skill Manager Tool — agent-managed skill creation & editing.

Skills are the agent's procedural memory (narrow "how to do X"; MEMORY.md/USER.md are
broad, declarative). New skills land in ~/.hermes/skills/ (or ``skills.create_dir``);
existing skills (bundled, hub, user) are modified in place. Layout:
``<skills>/[category/]<skill>/SKILL.md`` + optional ``references/ templates/ scripts/ assets/``.
"""

import contextvars as _ctxvars
import hashlib
import json
from contextlib import ExitStack, suppress
import logging
import re
import shutil
from pathlib import Path
from typing import Any, Dict, List, Optional, Tuple

import hermes_yaml as yaml

from hermes_constants import get_hermes_home
from utils import atomic_write_text, is_truthy_value
from hermes_cli.config import cfg_get
from agent.skill_utils import (
    extract_skill_description,
    is_skill_description_truncated_for_prompt,
    parse_frontmatter as _parse_frontmatter,
    SKILL_PROMPT_DESC_LIMIT)
from tools.skill_manager_guards import (
    _background_review_delete_guard, _background_review_preflight, _background_review_read_before_write_guard,
    _containing_skills_root, _curator_consolidation_delete_guard, _is_path_redirect, _pinned_guard,
    _validate_delete_target, _is_background_review, _refusal as _err)
from tools.skill_manager_batch import (
    _PATCH_EITHER_OR, _PATCH_NEEDS_NEW_STRING, _PATCH_NEEDS_OLD_STRING, _op_shape_error, _skill_manage_batch)
from tools.skills_guard import scan_skill, should_allow_install, format_scan_report

logger = logging.getLogger(__name__)


def _guard_agent_created_enabled() -> bool:
    """skills.guard_agent_created (default False): opt-in — terminal() runs the same code ungated."""
    try:
        from hermes_cli.config import load_config
        return is_truthy_value(cfg_get(load_config(), "skills", "guard_agent_created"), default=False)
    except Exception:
        return False


def _security_scan_skill(skill_dir: Path) -> Optional[str]:
    """Post-write scan (opt-in); error string if blocked, else None. An "ask" verdict
    (dangerous findings) is surfaced as an error so the agent can retry without them."""
    if not _guard_agent_created_enabled():
        return None
    try:
        result = scan_skill(skill_dir, source="agent-created")
        allowed, reason = should_allow_install(result)
        if allowed is None:
            logger.warning("Agent-created skill blocked (dangerous findings): %s", reason)
        if allowed is not True:
            return f"Security scan blocked this skill ({reason}):\n{format_scan_report(result)}"
    except Exception as e:
        logger.warning("Security scan failed for %s: %s", skill_dir, e, exc_info=True)
    return None


# All skills live in ~/.hermes/skills/ (single source of truth)
HERMES_HOME = get_hermes_home()
SKILLS_DIR = HERMES_HOME / "skills"
_SKILLS_DIR_AT_IMPORT = SKILLS_DIR


def _skills_dir() -> Path:
    """Active profile's skills dir at call time (multi-profile runtimes rebind per session).
    An explicitly patched module-level ``SKILLS_DIR`` (tests) wins over the live HERMES_HOME.

    Long-lived multi-profile runtimes (Dashboard/TUI/Desktop backend, cron, kanban workers) import this
    module once under the launch HERMES_HOME and later bind a different profile per session (#40677).
    """
    configured = Path(SKILLS_DIR)
    return configured if configured != _SKILLS_DIR_AT_IMPORT else get_hermes_home() / "skills"


def _skill_lock_path(name: str) -> Path:
    """Per-skill lock file under ``<skills>/.locks/`` (same idiom as the usage ledger's
    ``.usage.json.lock``), never inside the skill dir so delete/recreate cannot unlink it under a
    waiting writer. Keyed by a digest of the basename so ``foo`` and ``category/foo`` share one
    lock and no name can hit a filesystem limit (callers validate the basename first)."""
    digest = hashlib.sha256(Path(name).name.encode("utf-8", "surrogatepass")).hexdigest()
    return _skills_dir() / ".locks" / f"{digest}.lock"


def _skill_mutation_lock(name: str):
    """Exclusive lock held across one skill's whole read-modify-write; thread-re-entrant."""
    from tools.skill_usage import skill_file_lock
    return skill_file_lock(_skill_lock_path(name))


def _skill_mutation_locks(names):
    """Every lock of an atomic batch, acquired in one stable path order (deadlock-free across batches)."""
    from tools.skill_usage import skill_file_lock
    stack = ExitStack()
    for lock_path in sorted({_skill_lock_path(n) for n in names}):
        stack.enter_context(skill_file_lock(lock_path))
    return stack


MAX_NAME_LENGTH = 64
MAX_DESCRIPTION_LENGTH = 1024
MAX_SKILL_CONTENT_CHARS = 100_000   # ~36k tokens at 2.75 chars/token
MAX_SKILL_FILE_BYTES = 1_048_576    # 1 MiB per supporting file
VALID_NAME_RE = re.compile(r'^[a-z0-9][a-z0-9._-]*$')  # filesystem-safe, URL-friendly
ALLOWED_SUBDIRS = {"references", "templates", "scripts", "assets"}  # for write_file/remove_file
_FRONTMATTER_END_RE = re.compile(r'\n---\s*\n')
_NAME_RULE = "Use lowercase letters, numbers, hyphens, dots, and underscores."


# --- Validation helpers -------------------------------------------------------

def _check_identifier(value: str, label: str, invalid: str) -> Optional[str]:
    if len(value) > MAX_NAME_LENGTH:
        return f"{label} exceeds {MAX_NAME_LENGTH} characters."
    return None if VALID_NAME_RE.match(value) else invalid


def _validate_name(name: str) -> Optional[str]:
    if not name:
        return "Skill name is required."
    return _check_identifier(
        name, "Skill name", f"Invalid skill name '{name}'. {_NAME_RULE} Must start with a letter or digit.")


def _validate_category(category: Optional[str]) -> Optional[str]:
    if category is None or (isinstance(category, str) and not category.strip()):
        return None
    if not isinstance(category, str):
        return "Category must be a string."
    category = category.strip()
    invalid = (f"Invalid category '{category}'. {_NAME_RULE} "
               "Categories must be a single directory name.")
    if "/" in category or "\\" in category:
        return invalid
    return _check_identifier(category, "Category", invalid)


def _validate_frontmatter(content: str, *, new_skill: bool = False) -> Optional[str]:
    """Validate frontmatter (name + description) and a non-empty body. ``new_skill`` (create
    only) also enforces SKILL_PROMPT_DESC_LIMIT so new skills never lose routing signal to
    index truncation; edit/patch skip it so existing over-limit skills stay maintainable."""
    if not content.strip():
        return "Content cannot be empty."
    content = content.lstrip("\ufeff")  # tolerate a Windows UTF-8 BOM
    if not content.startswith("---"):
        return "SKILL.md must start with YAML frontmatter (---). See existing skills for format."
    end_match = _FRONTMATTER_END_RE.search(content[3:])
    if not end_match:
        return "SKILL.md frontmatter is not closed. Ensure you have a closing '---' line."
    try:
        parsed = yaml.safe_load(content[3:end_match.start() + 3])
    except yaml.YAMLError as e:
        return f"YAML frontmatter parse error: {e}"
    if not isinstance(parsed, dict):
        return "Frontmatter must be a YAML mapping (key: value pairs)."
    for field in ("name", "description"):
        if field not in parsed:
            return f"Frontmatter must include '{field}' field."
    desc = str(parsed["description"])
    if len(desc) > MAX_DESCRIPTION_LENGTH:
        return f"Description exceeds {MAX_DESCRIPTION_LENGTH} characters."
    if new_skill and len(desc.strip().strip("'\"")) > SKILL_PROMPT_DESC_LIMIT:
        return (
            f"Description is {len(desc.strip())} chars — new skills must fit the "
            f"{SKILL_PROMPT_DESC_LIMIT}-char system-prompt budget (one sentence, trigger first, "
            f"ends with a period). The skill index truncates longer descriptions to "
            f"{SKILL_PROMPT_DESC_LIMIT - 3} chars + '...', destroying the routing signal. "
            f"Move detail into the skill body.")
    if not content[end_match.end() + 3:].strip():
        return "SKILL.md must have content after the frontmatter (instructions, procedures, etc.)."
    return None


def _validate_content_size(content: str, label: str = "SKILL.md") -> Optional[str]:
    if len(content) > MAX_SKILL_CONTENT_CHARS:
        return (
            f"{label} content is {len(content):,} characters (limit: {MAX_SKILL_CONTENT_CHARS:,}). "
            f"Consider splitting into a smaller SKILL.md with supporting files in references/ "
            f"or templates/.")
    return None


def _description_preview(content: str) -> str:
    """First 120 chars of the frontmatter description; '' on any failure."""
    with suppress(Exception):
        fm_end = _FRONTMATTER_END_RE.search(content[3:])
        if fm_end:
            return str(yaml.safe_load(content[3:fm_end.start() + 3]).get("description", ""))[:120]
    return ""


def _resolve_skill_dir(name: str, category: str | None = None) -> Path:
    """New-skill dir; honors ``skills.create_dir`` (e.g. a shared fleet dir)."""
    base = _skills_dir()
    try:
        from agent.skill_utils import get_skill_create_dir
        base = get_skill_create_dir() or base
    except Exception:
        logger.debug("skills.create_dir lookup failed", exc_info=True)
    return base / (category or "") / name


def _iter_skill_dirs(root: Path):
    from agent.skill_utils import is_excluded_skill_path
    for skill_md in root.rglob("SKILL.md"):
        if not is_excluded_skill_path(skill_md):
            yield skill_md.parent


def _read_frontmatter_name(skill_md: Path) -> Optional[str]:
    """Read a SKILL.md's frontmatter ``name:`` — the name skills_list displays.

    Fail-quiet on unreadable files: the fallback lookup in ``_find_skill``
    must never break the directory-name match, and an unreadable SKILL.md
    simply has no second name to offer. The value is truncated with the
    same ``MAX_NAME_LENGTH`` budget skills_list applies when displaying it.
    """
    try:
        from agent.skill_utils import parse_frontmatter

        content = skill_md.read_text(encoding="utf-8-sig", errors="replace")[:4000]
        frontmatter, _ = parse_frontmatter(content)
    except OSError:
        logger.debug("frontmatter read failed for %s", skill_md, exc_info=True)
        return None
    name = frontmatter.get("name")
    if isinstance(name, str):
        return name[:MAX_NAME_LENGTH]
    return None


def _find_skill(name: str) -> Optional[dict[str, Any]]:
    """Find a skill (local skills dir, then skills.external_dirs) -> ``{"path": Path}`` | None.

    Accepts the bare dir name (``axolotl``; matches category-nested skills too) and the
    categorized relative path (``mlops/axolotl``) — the two forms skill_view resolves. The
    categorized form matches RELATIVE to the local root only (relative_to raises for external dirs).

    As a last resort the frontmatter ``name:`` is matched too, so the name ``skills list``
    and the dashboard display (frontmatter name wins over the directory name there)
    resolves everywhere instead of failing with a misleading "not found in active
    profile" error when the two names diverge. Directory-name matches keep priority —
    a frontmatter match is only considered after the whole scan found no
    directory/categorized match, so one skill's frontmatter cannot shadow another
    skill's directory. A display name held by two or more distinct skills resolves to
    nothing: like skill_view's same-tier collision refusal, refusing to guess beats
    silently mutating the wrong skill; the directory name still resolves."""
    from agent.skill_utils import get_all_skills_dirs
    local_root = None
    if "/" in name or "\\" in name:
        try:
            local_root = _skills_dir().resolve()
        except OSError:
            logger.debug(
                "skills dir resolve failed; categorized lookups fall back to the unresolved path",
                exc_info=True)
            local_root = _skills_dir()
    display_matches: list[Path] = []
    seen_display: set = set()
    for skills_dir in get_all_skills_dirs():
        if not skills_dir.exists():
            continue
        for skill_dir in _iter_skill_dirs(skills_dir):
            if skill_dir.name == name:
                return {"path": skill_dir}
            if local_root is not None:
                resolved = skill_dir.resolve()
                if (resolved.is_relative_to(local_root)
                        and resolved.relative_to(local_root).as_posix() == name):  # POSIX form
                    return {"path": skill_dir}
            if _read_frontmatter_name(skill_dir / "SKILL.md") == name:
                key = skill_dir / "SKILL.md"
                with suppress(Exception):
                    key = key.resolve()
                if key not in seen_display:
                    seen_display.add(key)
                    display_matches.append(skill_dir)
    if len(display_matches) == 1:
        return {"path": display_matches[0]}
    if display_matches:
        logger.warning(
            "Skill display name '%s' is ambiguous (%d skills claim it: %s) — refusing to guess; "
            "resolve it by directory name instead",
            name, len(display_matches), "; ".join(str(p) for p in display_matches))
    return None


def _find_skill_in_other_profiles(name: str) -> list[tuple[str, Path]]:
    """``(profile, skill_dir)`` pairs for OTHER profiles holding ``name`` (so the not-found
    error can explain a wrong-profile mistake). Fail-quiet."""
    matches: list[tuple[str, Path]] = []
    try:
        from hermes_constants import get_default_hermes_root
        root = get_default_hermes_root()
    except Exception:
        return matches
    _active = _skills_dir()
    active_dir = _active.resolve() if _active.exists() else _active
    # Every profile's skills dir EXCEPT the active one (already searched). A candidate whose
    # path cannot be resolved is skipped (not a fatal error); is_dir() checks stay unguarded.
    candidates: list[tuple[str, Path]] = []
    with suppress(OSError, RuntimeError):
        if (root / "skills").resolve() != active_dir:
            candidates.append(("default", root / "skills"))
    if (root / "profiles").is_dir():
        with suppress(OSError):
            for entry in (root / "profiles").iterdir():
                if not entry.is_dir():
                    continue
                try:
                    if (entry / "skills").resolve() == active_dir:
                        continue
                except (OSError, RuntimeError):
                    continue
                candidates.append((entry.name, entry / "skills"))
    for profile_name, skills_dir in candidates:
        if not skills_dir.is_dir():
            continue
        with suppress(OSError):
            hit = next((d for d in _iter_skill_dirs(skills_dir) if d.name == name), None)
            if hit is not None:
                matches.append((profile_name, hit))  # one match per profile is enough
    return matches


def _skill_not_found_error(name: str, suffix: str = "") -> str:
    """Not-found error naming other profiles that hold the skill, plus ``suffix``."""
    from agent.file_safety import _resolve_active_profile_name
    base = f"Skill '{name}' not found in active profile '{_resolve_active_profile_name()}'."
    others = _find_skill_in_other_profiles(name)
    if len(others) == 1:
        other_profile, other_path = others[0]
        base += (
            f" A skill by that name exists in profile '{other_profile}' ({other_path}). To edit "
            f"it, switch profiles (`hermes -p {other_profile}`) or edit the file directly "
            f"(file tools / terminal).")
    elif others:
        names = ", ".join(f"'{p}'" for p, _ in others)
        base += (
            f" Skills by that name exist in other profiles: {names}. Switch profiles (`hermes -p "
            f"<name>`) to edit there, or edit the files directly (file tools / terminal).")
    else:
        base += " Use skills_list() to see available skills."
    return base + suffix


def _validate_file_path(file_path: str) -> Optional[str]:
    """Validate a write_file/remove_file path: under an allowed subdir, no escape."""
    from tools.path_security import has_traversal_component
    if not file_path:
        return "file_path is required."
    parts = Path(file_path).parts
    # Traversal first, so the SKILL.md exception is unreachable by a traversal-laden path.
    if has_traversal_component(file_path):
        return "Path traversal ('..') is not allowed."
    # SKILL.md lives at the skill root; accept 'SKILL.md' and '<skill>/SKILL.md'.
    if parts and parts[-1] == "SKILL.md" and len(parts) in (1, 2):
        return None
    if not parts or parts[0] not in ALLOWED_SUBDIRS:
        allowed = ", ".join(sorted(ALLOWED_SUBDIRS))
        return f"File must be under one of: {allowed}. Got: '{file_path}'"
    if len(parts) < 2:
        return f"Provide a file path, not just a directory. Example: '{parts[0]}/myfile.md'"
    return None


def _resolve_supporting_file(skill_dir: Path, file_path: str):
    """Validate ``file_path`` and resolve it inside ``skill_dir``
    -> ``(target, None)`` | ``(None, error_dict)``."""
    from tools.path_security import validate_within_dir
    target = skill_dir / (file_path or "")
    err = _validate_file_path(file_path) or validate_within_dir(target, skill_dir)
    return (None, _err(err)) if err else (target, None)


def _locate_for_write(name: str, action: str, not_found_suffix: str = ""):
    """Find the skill; a delete also runs the background-review delete guard -> ``(skill_dir, None)``
    | ``(None, error_dict)``."""
    existing = _find_skill(name)
    if not existing:
        return None, _err(_skill_not_found_error(name, not_found_suffix))
    skill_dir = existing["path"]
    guard = _background_review_delete_guard(name, skill_dir) if action == "delete" else None
    return (None, guard) if guard else (skill_dir, None)


def _guarded_write(name: str, skill_dir: Path, target: Path, action: str, label: str,
                   content: str) -> Optional[dict[str, Any]]:
    """Read-before-write guard (existing targets only), atomic write, then the security scan;
    a blocked scan restores the original (or unlinks a new file). Error dict or None."""
    original = None
    if target.exists():
        if read_guard := _background_review_read_before_write_guard(name, target, action, label):
            return read_guard
        original = target.read_text(encoding="utf-8-sig")
    from hermes_constants import mkdir_under_hermes_home
    mkdir_under_hermes_home(target.parent)
    atomic_write_text(target, content, preserve_mode=True, create_mode=0o644)
    scan_error = _security_scan_skill(skill_dir)
    if not scan_error:
        return None
    if original is not None:
        atomic_write_text(target, original, preserve_mode=True)
    else:
        target.unlink(missing_ok=True)
    return _err(scan_error)


def _add_description_prompt_preview(result: dict[str, Any], content: str) -> dict[str, Any]:
    fm, _ = _parse_frontmatter(content)
    if is_skill_description_truncated_for_prompt(fm):
        result["system_prompt_preview"] = (
            f"System prompt will show: \"{extract_skill_description(fm)}\" — keep the trigger "
            f"self-contained in the first {SKILL_PROMPT_DESC_LIMIT - 3} chars.")
    return result


def _attach_lint_findings(result: dict[str, Any], skill_md: Path, before: Optional[str] = None) -> None:
    """Attach ADVISORY authoring findings (hard rejects already ran in _validate_frontmatter).
    With ``before`` (the pre-write content) only rules the write INTRODUCED are attached, so a
    patch reports the line it crossed rather than re-listing the skill's standing findings."""
    try:
        from tools.skill_linter import lint_content, lint_skill  # local import: optional path
        findings = lint_skill(skill_md)
        if before is not None:
            standing = {f.rule for f in lint_content(before, skill_dir=skill_md.parent)}
            findings = [f for f in findings if f.rule not in standing]
    except Exception:
        findings = None
    if not findings:
        return
    result["lint_warnings"] = [
        {"severity": f.severity, "rule": f.rule, "message": f.message} for f in findings]
    result["lint_hint"] = (
        "The write succeeded. These are advisory authoring-convention findings (not blockers) "
        "— fix them with skill_manage(action='patch') to match Hermes skill standards.")


def _clip(text: str, n: int, ellipsis: str) -> str:
    return text[:n] + (ellipsis if len(text) > n else "")


# --- Core actions -------------------------------------------------------------

def _create_skill(name: str, content: str, category: str | None = None) -> dict[str, Any]:
    if err := (_validate_name(name) or _validate_category(category)
               or _validate_frontmatter(content, new_skill=True) or _validate_content_size(content)):
        return _err(err)
    if existing := _find_skill(name):
        return _err(f"A skill named '{name}' already exists at {existing['path']}.")
    skill_dir = _resolve_skill_dir(name, category)
    from hermes_constants import mkdir_under_hermes_home
    mkdir_under_hermes_home(skill_dir.parent)
    try:
        skill_dir.mkdir(exist_ok=False)
    except FileExistsError:
        # mkdir raised EEXIST for a file, symlink (live or dangling) or dir alike; only an EMPTY
        # real directory (leftover of an earlier create whose SKILL.md write failed) may be used.
        # Anything else — or anything unstat-able/unlistable — is someone else's: never adopt.
        try:
            usable = (not _is_path_redirect(skill_dir) and skill_dir.is_dir()
                      and not any(skill_dir.iterdir()))
        except OSError:  # permissions / ACL
            usable = False
        if not usable:
            return _err(f"Cannot create skill '{name}': {skill_dir} already exists (not an empty "
                        "directory, or unreadable). Choose another name, or move/remove that path and retry.")
    skill_md = skill_dir / "SKILL.md"
    if guard := _guarded_write(name, skill_dir, skill_md, "create", "SKILL.md", content):
        with suppress(OSError):  # rmdir, not rmtree: only an empty dir goes, anything foreign stays
            skill_dir.rmdir()
        return guard
    root = _skills_dir()  # display relative under the profile dir; absolute under skills.create_dir
    display = skill_dir.relative_to(root) if skill_dir.is_relative_to(root) else skill_dir
    result = {
        "success": True, "message": f"Skill '{name}' created.", "path": str(display),
        "skill_md": str(skill_md), "_change": {"description": _description_preview(content)},
        **({"category": category} if category else {}),
        "hint": "To add reference files, templates, or scripts, use "
                f"skill_manage(action='write_file', name='{name}', file_path='references/example.md', "
                "file_content='...')"}
    _attach_lint_findings(_add_description_prompt_preview(result, content), skill_md)
    return result


def _edit_skill(name: str, content: str) -> dict[str, Any]:
    """Replace the SKILL.md of any existing skill (full rewrite)."""
    if err := _validate_frontmatter(content) or _validate_content_size(content):
        return _err(err)
    skill_dir, guard = _locate_for_write(name, "edit")
    # SKILL.md always exists here (_find_skill requires it), so a blocked scan restores it.
    if guard := guard or _guarded_write(name, skill_dir, skill_dir / "SKILL.md", "edit", "SKILL.md", content):
        return guard
    result = {
        "success": True, "message": f"Skill '{name}' updated (full rewrite).",
        "path": str(skill_dir), "_change": {"description": _description_preview(content)}}
    return _add_description_prompt_preview(result, content)


def _patch_skill(name: str, old_string: str, new_string: str, file_path: str | None = None,
                 replace_all: bool = False) -> dict[str, Any]:
    """Targeted find-and-replace in SKILL.md (default) or a supporting file; unique match unless replace_all."""
    if not old_string:
        return _err(_PATCH_NEEDS_OLD_STRING)
    if new_string is None:
        return _err(_PATCH_NEEDS_NEW_STRING)
    # No old_string == new_string guard here: fuzzy_find_and_replace rejects that with a
    # richer error (file_preview) this layer cannot produce.
    skill_dir, guard = _locate_for_write(name, "patch")
    if guard:
        return guard
    target_label = file_path or "SKILL.md"
    if file_path:
        target, err = _resolve_supporting_file(skill_dir, file_path)
        if err:
            return err
    else:
        target = skill_dir / "SKILL.md"
    if not target.exists():
        return _err(f"File not found: {target.relative_to(skill_dir)}")
    if read_guard := _background_review_read_before_write_guard(name, target, "patch", target_label):
        return read_guard
    content = target.read_text(encoding="utf-8-sig")

    # Use the same fuzzy matching engine as the file patch tool.
    from tools.fuzzy_match import fuzzy_find_and_replace
    correction_notes = []
    new_content, match_count, _strategy, match_error = fuzzy_find_and_replace(
        content, old_string, new_string, replace_all, correction_notes=correction_notes)
    if match_error:
        with suppress(Exception):
            from tools.fuzzy_match import format_no_match_hint
            match_error += format_no_match_hint(match_error, match_count, old_string, content)
        return _err(match_error) | {"file_preview": _clip(content, 500, "...")}
    if err := _validate_content_size(new_content, label=target_label):
        return _err(err)
    if not file_path and (err := _validate_frontmatter(new_content)):
        return _err(f"Patch would break SKILL.md structure: {err}")
    if guard := _guarded_write(name, skill_dir, target, "patch", target_label, new_content):
        return guard
    result = {
        "success": True,
        "message": f"Patched {target_label} in skill '{name}' ({match_count} replacement{'s' if match_count > 1 else ''}).",
        "_change": {"old": _clip(old_string, 200, "…"), "new": _clip(new_string, 200, "…")}}
    if correction_notes:
        result["note"] = "\n".join(correction_notes)
    # SKILL.md grows by patches, not by creates: surface findings on the patch that crosses a line
    # (oversized-body, incident-log-shape) — a clean patch attaches nothing and stays quiet.
    if not file_path:
        _attach_lint_findings(result, target, before=content)
    return result


def _delete_skill(name: str, absorbed_into: Optional[str] = None) -> dict[str, Any]:
    """Delete a skill. ``absorbed_into``: None = undeclared (legacy, accepted); "" = explicit prune;
    "<skill>" = absorbed into that umbrella, which must exist (so the model can't claim one)."""
    skill_dir, guard = _locate_for_write(name, "delete")
    if guard := guard or _curator_consolidation_delete_guard(name, absorbed_into):
        return guard
    if pinned_err := _pinned_guard(name):
        return _err(pinned_err)
    absorbed_target = absorbed_into.strip() if isinstance(absorbed_into, str) else ""
    if absorbed_target:
        if absorbed_target == name:
            return _err(f"absorbed_into='{absorbed_target}' cannot equal the skill being deleted.")
        if not _find_skill(absorbed_target):
            return _err(f"absorbed_into='{absorbed_target}' does not exist. "
                        f"Create or patch the umbrella skill first, then retry the delete.")
    skills_root = _containing_skills_root(skill_dir)
    if unsafe := _validate_delete_target(skill_dir):  # defense-in-depth before rmtree
        return _err(unsafe)
    # Curator consolidations must be RECOVERABLE (`hermes curator restore`): archive instead
    # of rmtree. Foreground deletes keep hard-delete semantics.
    absorbed_note = f" Content absorbed into '{absorbed_target}'." if absorbed_target else ""
    if _is_background_review():
        try:
            from tools.skill_usage import archive_skill
            ok, archive_msg = archive_skill(name)
        except Exception as e:
            return _err(f"failed to archive '{name}': {e}")
        if not ok:
            return _err(archive_msg)
        return {"success": True,
                "message": f"Skill '{name}' archived ({archive_msg}).{absorbed_note}",
                "_archived": True}
    shutil.rmtree(skill_dir)
    _rmdir_if_empty(skill_dir.parent, skills_root)  # empty category dir, never the root
    return {"success": True, "message": f"Skill '{name}' deleted.{absorbed_note}"}


def _rmdir_if_empty(parent: Path, stop: Path) -> None:
    if parent != stop and parent.exists() and not any(parent.iterdir()):
        parent.rmdir()


def _write_file(name: str, file_path: str, file_content: str) -> dict[str, Any]:
    """Add or overwrite a supporting file within any skill directory."""
    if err := _validate_file_path(file_path):
        return _err(err)
    if not file_content and file_content != "":
        return _err("file_content is required.")
    if (content_bytes := len(file_content.encode("utf-8"))) > MAX_SKILL_FILE_BYTES:
        return _err(f"File content is {content_bytes:,} bytes (limit: {MAX_SKILL_FILE_BYTES:,} "
                    f"bytes / 1 MiB). Consider splitting into smaller files.")
    if err := _validate_content_size(file_content, label=file_path):
        return _err(err)
    skill_dir, guard = _locate_for_write(name, "write_file", " Create it first with action='create'.")
    if guard:
        return guard
    target, err = _resolve_supporting_file(skill_dir, file_path)
    if guard := err or _guarded_write(name, skill_dir, target, "write_file", file_path, file_content):
        return guard
    result = {"success": True, "message": f"File '{file_path}' written to skill '{name}'.", "path": str(target)}
    # references/ is where per-session hoarding shows up; surface the sprawl finding on the write
    # that crosses the line so the review fork sees it in the same turn.
    if file_path.startswith("references/") and (skill_dir / "SKILL.md").exists():
        _attach_lint_findings(result, skill_dir / "SKILL.md")
    return result


def _remove_file(name: str, file_path: str) -> dict[str, Any]:
    """Remove a supporting file from any skill directory."""
    if err := _validate_file_path(file_path):
        return _err(err)
    skill_dir, guard = _locate_for_write(name, "remove_file")
    if guard:
        return guard
    target, err = _resolve_supporting_file(skill_dir, file_path)
    if err:
        return err
    if not target.exists():  # list what IS there so the model can pick the right path
        available = [str(f.relative_to(skill_dir)) for subdir in ALLOWED_SUBDIRS
                     if (skill_dir / subdir).exists() for f in (skill_dir / subdir).rglob("*") if f.is_file()]
        return _err(f"File '{file_path}' not found in skill '{name}'.", available_files=available or None)
    if read_guard := _background_review_read_before_write_guard(name, target, "remove_file", file_path):
        return read_guard
    target.unlink()
    _rmdir_if_empty(target.parent, skill_dir)
    return {"success": True, "message": f"File '{file_path}' removed from skill '{name}'."}


# --- Main entry point ---------------------------------------------------------

# Set while replaying an approved staged skill write so skill_manage() does not re-gate it.
_skill_gate_bypass: _ctxvars.ContextVar[bool] = _ctxvars.ContextVar(
    "skill_gate_bypass", default=False)


def _run_write_gate(build_staging):
    """Shared write gate: None to proceed, else a JSON tool result (blocked/staged).
    ``build_staging(wa) -> (payload, gist)`` runs only when staging. Fails open if
    write_approval cannot be imported."""
    try:
        from tools import write_approval as wa
    except Exception:
        return None  # fail open
    decision = wa.evaluate_gate(wa.SKILLS)
    if decision.allow:
        return None
    if decision.blocked:
        return tool_error(decision.message, success=False)
    payload, gist = build_staging(wa)
    record = wa.stage_write(wa.SKILLS, payload, summary=gist, origin=wa.current_origin())
    return json.dumps({"success": True, "staged": True, "pending_id": record["id"],
                       "gist": gist, "message": decision.message}, ensure_ascii=False)


def _apply_skill_write_gate(action, name, **payload_kwargs):
    """Flat-shape gate: stage the full kwargs so approval can replay them; bypassed during replay."""
    if action not in _ACTION_HANDLERS or _skill_gate_bypass.get():
        return None
    def _staging(wa):
        payload = {"action": action, "name": name,
                   **{k: v for k, v in payload_kwargs.items() if v is not None}}
        gist_kw = {k: payload_kwargs.get(k) or ""
                   for k in ("content", "file_path", "old_string", "new_string")}
        return payload, wa.skill_gist(action, name, **gist_kw)
    return _run_write_gate(_staging)


_FLAT_OP_KEYS = ("content", "category", "file_path", "file_content", "old_string", "new_string",
                 "absorbed_into", "operations")


def _skill_manage_from(payload: dict[str, Any], **extra) -> str:
    """Call ``skill_manage`` with the flat-shape fields (and absorbed_into/operations) of ``payload``."""
    return skill_manage(
        action=payload.get("action", ""), name=payload.get("name", ""),
        replace_all=payload.get("replace_all", False),
        **{k: payload.get(k) for k in _FLAT_OP_KEYS}, **extra)


def apply_skill_pending(payload: dict[str, Any]) -> str:
    """Replay a staged skill write, bypassing the gate (the /skills approve handler)."""
    token = _skill_gate_bypass.set(True)
    try:
        return _skill_manage_from(payload)
    finally:
        _skill_gate_bypass.reset(token)


def _act_patch(a):
    """Two shapes: old_string/new_string = targeted replacement (validated in _patch_skill so the
    tool and the helper give the same guidance); content alone = full rewrite (the old 'edit')."""
    if a["content"] and (a["old_string"] or a["new_string"] is not None):
        return tool_error(_PATCH_EITHER_OR, success=False)
    if a["content"]:
        return _edit_skill(a["name"], a["content"])
    return _patch_skill(a["name"], a["old_string"], a["new_string"], a["file_path"], a["replace_all"])


# action -> handler(args dict) returning a result dict, or a tool_error JSON string for
# argument-shape errors. "edit" is a legacy alias for a full rewrite (not in the schema).
_ACTION_HANDLERS = {
    "create": lambda a: _create_skill(a["name"], a["content"], a["category"]),
    "edit": lambda a: _edit_skill(a["name"], a["content"]),
    "patch": _act_patch,
    "delete": lambda a: _delete_skill(a["name"], absorbed_into=a["absorbed_into"]),
    "write_file": lambda a: _write_file(a["name"], a["file_path"], a["file_content"]),
    "remove_file": lambda a: _remove_file(a["name"], a["file_path"])}


def _record_success(action, name, result, *, file_path, absorbed_into, task_id,
                    session_id, ledger_before) -> None:
    """Best-effort post-mutation side effects (never break the tool): ledger, prompt-cache
    clear, curator telemetry (which fires ``on_skill_lifecycle`` for plugins)."""
    with suppress(Exception):
        from tools import skill_ledger as _ledger
        _post = _find_skill(name)
        # delete: consolidation vs prune, and whether the recoverable archive handled it
        _evidence = ({"absorbed_into": absorbed_into, "archived": bool(result.get("_archived"))}
                     if action == "delete" else {})
        _evidence.update({k: v for k, v in (("session_id", session_id), ("file_path", file_path)) if v})
        _ledger.record_mutation(
            action, name, before=ledger_before if ledger_before is not None else [],
            after_root=_post["path"] if _post else None, evidence=_evidence)
    with suppress(Exception):
        from agent.prompt_builder import clear_skills_system_prompt_cache
        clear_skills_system_prompt_cache(clear_snapshot=True)
    # Curator telemetry: only the background review fork marks a skill agent-created
    # (foreground creates belong to the user). A recoverable curator archive keeps its
    # record as STATE_ARCHIVED (`hermes curator status`/`restore`); only a hard delete forgets.
    with suppress(Exception):
        from tools.skill_usage import bump_patch, forget, record_created
        # During the curator consolidation pass, a verified consolidation must be RECOVERABLE: archival into
        # ~/.hermes/skills/.archive/ is documented as the maximum destructive action the curator may take,
        # and `hermes curator restore` promises the skill can be brought back. Route through the recoverable
        # archive primitive instead of permanent rmtree so a misjudged consolidation can be undone (#29912).
        # Foreground, user-directed deletes keep their existing hard-delete semantics.
        from tools.skill_provenance import is_background_review
        if action == "create":
            record_created(name, agent_created=is_background_review(),
                           task_id=task_id, session_id=session_id)
        elif action in {"patch", "edit", "write_file", "remove_file"}:
            bump_patch(name, action=action, task_id=task_id, session_id=session_id)
        elif action == "delete" and not result.get("_archived"):
            forget(name)


def skill_manage(
    action: str, name: str, content: str | None = None, category: str | None = None, file_path: str | None = None,
    file_content: str | None = None, old_string: str | None = None, new_string: str | None = None,
    replace_all: bool = False, absorbed_into: str | None = None, task_id: str | None = None,
    session_id: str | None = None, operations=None) -> str:
    """Dispatch to the action handler -> JSON string. ``operations`` (atomic batch shape,
    see _skill_manage_batch) overrides the flat fields."""
    if operations is not None:
        return _skill_manage_batch(
            operations, default_name=name or None, task_id=task_id, session_id=session_id)
    if (preflight := _background_review_preflight(action, name)) is not None:
        return json.dumps(preflight, ensure_ascii=False)
    # Approval gate: skills are too large to review inline, so they always stage regardless
    # of origin; bypassed when replaying an approved staged write.
    args = dict(content=content, category=category, file_path=file_path, file_content=file_content,
                old_string=old_string, new_string=new_string, replace_all=replace_all,
                absorbed_into=absorbed_into)
    if (gate_result := _apply_skill_write_gate(action, name, **args)) is not None:
        return gate_result
    if (shape_err := _op_shape_error(action, args)) is not None:
        return tool_error(shape_err, success=False)
    # Validate before the lock is keyed on the name, so a rejected name never touches .locks/
    # (create takes a bare name; the other actions also accept ``category/name``).
    if (name_err := _validate_name(name if action == "create" or not name else Path(name).name)) is not None:
        return json.dumps(_err(name_err), ensure_ascii=False)
    # A mutation is read-modify-write even when its action eventually delegates
    # to a helper: guards, ledger capture, patch matching, validation, rollback,
    # and the atomic replacement all belong to the same ownership window.
    with _skill_mutation_lock(name):
        # Ledger pre-capture: telemetry, not a gate — failures must NEVER block the mutation. delete
        # destroys the whole package (consolidation may have re-homed support files first), so
        # complete it from the newest curator backup or a restore is hollow.
        # Audit ledger (tracker #79686 P3): capture the pre-mutation state of the skill directory so every
        # mutation — any actor — lands in the append-only JSONL ledger with before/after blobs.
        _ledger_before = None
        with suppress(Exception):
            from tools import skill_ledger as _ledger
            _pre = _find_skill(name)
            _ledger_before = _ledger.capture_before(
                _pre["path"] if _pre else None, complete_package=(action == "delete"), skill=name)
        handler = _ACTION_HANDLERS.get(action, lambda a: _err(
            f"Unknown action '{action}'. Use: create, edit, patch, delete, write_file, remove_file"))
        result = handler({"name": name, **args})
        if isinstance(result, str):
            return result  # tool_error JSON for argument-shape problems (patch)
        if result.get("success"):
            _record_success(
                action, name, result, file_path=file_path, absorbed_into=absorbed_into,
                task_id=task_id, session_id=session_id, ledger_before=_ledger_before)
    return json.dumps(result, ensure_ascii=False)


# --- OpenAI Function-Calling Schema -------------------------------------------

def _skill_manage_description() -> str:
    return (
        "Create, update, or delete skills — your procedural memory for "
        "recurring task types. The call is an operations array (a single "
        "edit is a list of one); it applies atomically — any failure rolls "
        "every touched skill back. Ops: create (full SKILL.md; lands in "
        "the profile's skills directory or configured skills.create_dir; must precede that skill's other "
        "ops), patch (targeted old_string/new_string fix — preferred; "
        "content alone REPLACES the whole file, read it via skill_view() "
        "first), write_file/remove_file (supporting files), delete (sole "
        "op only). Existing skills are modified wherever they live. Keep "
        "the description's first 57 chars a self-contained trigger: 'Use "
        "when <trigger>. <one-line behavior>.' Write lessons, not logs: "
        "imperative rule + why, no PR numbers/dates/incident narration, one "
        "rule per lesson, references/ named by topic (extend before adding). "
        "skill_view() shows format conventions."
    )


_NAME = {"type": "string"}
_OLD_STRING = {"type": "string",
               "description": "Text to find (same matching semantics as the patch tool)."}
_NEW_STRING = {"type": "string", "description": "Replacement; empty string deletes the match."}
_FILE_PATH = {
    "type": "string",
    "description": (
        "Path RELATIVE to the skill's own directory, e.g. 'references/api.md' — no leading "
        "slash, never absolute; first segment references/, templates/, scripts/, or assets/."
    ),
}  # stated once (write_file); patch/remove_file point at it


def _op_schema(action: str, props: dict, required: tuple) -> dict:
    """One self-contained per-action op shape. ``additionalProperties: false`` is what lets a
    grammar-constrained backend refuse another action's text slot outright."""
    return {"type": "object", "additionalProperties": False,
            "properties": {"name": _NAME, "action": {"type": "string", "enum": [action]}, **props},
            "required": ["name", "action", *required]}


SKILL_MANAGE_SCHEMA = {
    "name": "skill_manage",
    # ONE advertised call shape (memory-tool pattern): the call IS an operations
    # array. The legacy flat shape (top-level action/name/content/...) is still
    # ACCEPTED for old transcripts and staged-write replay, but not advertised.
    "description": _skill_manage_description(),
    "parameters": {
        "type": "object",
        "properties": {
            "operations": {
                "type": "array",
                "description": (
                    "Ordered ops; each names its target skill (lowercase, hyphens/underscores, "
                    "max 64 chars). Each action is its own shape; another action's text slot is invalid."
                ),
                # Per-action branches, not one flat union: with one object holding content /
                # new_string / file_content side by side, a 27B model that just used write_file
                # kept emitting file_content on create and the whole batch rolled back (#112677).
                "items": {"anyOf": [
                    _op_schema("create", {
                        "content": {"type": "string",
                                    "description": "Full SKILL.md text (YAML frontmatter + markdown body)."},
                        "category": {"type": "string",
                                     "description": "Optional category subdir (e.g. 'devops')."},
                    }, ("content",)),
                    _op_schema("patch", {
                        "old_string": _OLD_STRING, "new_string": _NEW_STRING,
                        "replace_all": {"type": "boolean",
                                        "description": "Replace all occurrences (default false)."},
                        "file_path": {"type": "string",
                                      "description": "Optional supporting file (write_file's shape); default SKILL.md."},
                    }, ("old_string", "new_string")),
                    _op_schema("patch", {
                        "content": {"type": "string",
                                    "description": "Full SKILL.md rewrite (REPLACES the whole file; last resort)."},
                    }, ("content",)),
                    _op_schema("write_file", {
                        "file_path": _FILE_PATH,
                        "file_content": {"type": "string", "description": "Full text of the supporting file."},
                    }, ("file_path", "file_content")),
                    _op_schema("remove_file", {
                        "file_path": {"type": "string", "description": "Supporting file (write_file's shape)."},
                    }, ("file_path",)),
                    # `absorbed_into` stays in the delete shape: with additionalProperties:false a
                    # grammar-constrained backend would otherwise strip it and the curator's
                    # consolidation delete guard would fail-close every consolidation.
                    _op_schema("delete", {
                        "absorbed_into": {"type": "string",
                                          "description": "Curator consolidation only: umbrella skill "
                                                         "that absorbed this one (must exist)."},
                    }, ()),
                ]},
            },
            # Also accepted, never advertised: the legacy flat single-op fields.
        },
        "required": ["operations"],
    },
}


# --- Registry ---
from tools.registry import registry, tool_error

registry.register(
    name="skill_manage", toolset="skills", schema=SKILL_MANAGE_SCHEMA, emoji="📝",
    handler=lambda args, **kw: _skill_manage_from(
        args, task_id=kw.get("task_id"), session_id=kw.get("session_id")))