"""Bundled-skill maintenance ops: reset, diff, list-modified, opt-out, remove-pristine.

Extracted from ``tools.skills_sync``. Profile-scoped paths and patchable helpers
(``_get_bundled_dir``, ``sync_skills``, ...) are resolved through ``_ss()`` at
call time so monkeypatching ``tools.skills_sync`` keeps working.
"""

from pathlib import Path
from typing import List, Optional, Tuple


def _ss():
    from tools import skills_sync

    return skills_sync


def _is_tracked_user_modification(origin_hash: str, user_hash: str) -> bool:
    """Whether an on-disk skill is a user modification ``hermes update`` keeps. Shared by
    the sync loop and ``list_user_modified_bundled_skills`` so they never drift: needs a
    recorded origin hash (un-baselined v1 entries don't count) AND differing content."""
    return bool(origin_hash) and user_hash != origin_hash


def _bundled_by_name(bundled_dir: Path) -> dict:
    return dict(_ss()._discover_bundled_skills(bundled_dir))


def reset_bundled_skill(name: str, restore: bool = False) -> dict:
    """Reset a bundled skill's manifest tracking so future syncs work normally.

    An edited bundled skill stays ``user_modified`` forever — even after copying the
    bundled version back — because the manifest holds the OLD origin hash; clearing
    the entry breaks that loop. ``restore`` also deletes the user's copy so the next
    sync re-copies bundled. Returns ``{ok, action, message, synced}``; action is
    manifest_cleared / restored / not_in_manifest / bundled_missing / not_reset.
    """
    ss = _ss()
    manifest = ss._read_manifest()
    bundled_dir = ss._get_bundled_dir()
    bundled_by_name = _bundled_by_name(bundled_dir)
    in_manifest = name in manifest
    is_bundled = name in bundled_by_name

    def _fail(action: str, message: str) -> dict:
        return {"ok": False, "action": action, "message": message, "synced": None}

    if not in_manifest and not is_bundled:
        return _fail("not_in_manifest", f"'{name}' is not a tracked bundled skill. Nothing to reset. "
                     f"(Hub-installed skills use `hermes skills uninstall`.)")

    # Delete the user's copy BEFORE touching the manifest so a failed rmtree
    # cannot leave the skill in a manifest-less limbo state.
    deleted_user_copy = False
    if restore:
        if not is_bundled:
            return _fail("bundled_missing", f"'{name}' has no bundled source — manifest entry preserved "
                         f"but cannot restore from bundled (skill was removed upstream).")
        dest = ss._compute_relative_dest(bundled_by_name[name], bundled_dir)
        if dest.exists():
            try:
                ss._rmtree_writable(dest)
            except (OSError, IOError) as e:
                return _fail("not_reset", f"Could not delete user copy at {dest}: {e}. "
                             f"Manifest entry preserved — nothing was changed.")
            deleted_user_copy = True

    if in_manifest:
        del manifest[name]
        ss._write_manifest(manifest)
    synced = ss.sync_skills(quiet=True)

    if not restore:
        action, message = "manifest_cleared", (f"Cleared manifest entry for '{name}'. Future `hermes update` runs "
                                               f"will re-baseline against your current copy and accept upstream changes.")
    elif deleted_user_copy:
        action, message = "restored", f"Restored '{name}' from bundled source."
    else:
        action, message = "restored", f"Restored '{name}' (no prior user copy, re-copied from bundled)."
    return {"ok": True, "action": action, "message": message, "synced": synced}


def list_user_modified_bundled_skills() -> List[dict]:
    """Bundled skills ``hermes update`` keeps because the user edited them (same test
    the sync loop uses). Name-sorted ``{"name", "dest", "bundled_src"}`` dicts."""
    ss = _ss()
    manifest = ss._read_manifest()
    if not manifest:
        return []
    bundled_dir = ss._get_bundled_dir()
    modified: List[dict] = []
    for skill_name, skill_dir in ss._discover_bundled_skills(bundled_dir):
        origin_hash = manifest.get(skill_name, "")  # empty = untracked/un-baselined v1: next sync handles it
        dest = ss._compute_relative_dest(skill_dir, bundled_dir)
        if origin_hash and dest.exists() and _is_tracked_user_modification(origin_hash, ss._dir_hash(dest)):
            modified.append({"name": skill_name, "dest": dest, "bundled_src": skill_dir})
    return sorted(modified, key=lambda e: e["name"])


def _read_for_diff(path: Path) -> Tuple[Optional[bytes], Optional[str]]:
    """Read a file once for diffing: ``(raw_bytes, text)`` with ``text=None`` for
    binary content, ``(None, None)`` if unreadable."""
    try:
        data = path.read_bytes()
        return data, (None if b"\x00" in data else data.decode("utf-8"))
    except OSError:
        return None, None
    except UnicodeDecodeError:
        return data, None


def diff_bundled_skill(name: str) -> dict:
    """Diff a user's copy of a bundled skill against stock. Returns ``{ok, name, found,
    modified, message, diffs}``; each diff is ``{"path", "status", "diff"}`` with status
    modified / added (only in user copy) / removed (only in bundled) / binary."""
    import difflib

    from tools.skills_sync_optional import _skill_file_list

    ss = _ss()

    def _fail(found: bool, message: str) -> dict:
        return {"ok": False, "name": name, "found": found, "modified": False, "diffs": [], "message": message}

    bundled_dir = ss._get_bundled_dir()
    bundled_src = _bundled_by_name(bundled_dir).get(name)
    if bundled_src is None:
        return _fail(False, f"'{name}' is not a tracked bundled skill (no stock version to "
                     f"diff against). Hub-installed skills use `hermes skills inspect`.")
    dest = ss._compute_relative_dest(bundled_src, bundled_dir)
    if not dest.exists():
        return _fail(True, f"No local copy of '{name}' found at {dest}.")

    user_files = set(_skill_file_list(dest))
    stock_files = set(_skill_file_list(bundled_src))
    diffs: List[dict] = []
    for rel in sorted(user_files | stock_files):
        if rel not in stock_files:
            diffs.append({"path": rel, "status": "added", "diff": f"+ only in your copy: {rel}"})
        elif rel not in user_files:
            diffs.append({"path": rel, "status": "removed", "diff": f"- only in stock: {rel}"})
        else:
            user_bytes, user_text = _read_for_diff(dest / rel)
            stock_bytes, stock_text = _read_for_diff(bundled_src / rel)
            if user_text is None or stock_text is None:
                # At least one side is binary — report only if the bytes differ.
                if user_bytes != stock_bytes:
                    diffs.append({"path": rel, "status": "binary", "diff": "<binary file differs>"})
            elif user_text != stock_text:
                text = "".join(difflib.unified_diff(
                    stock_text.splitlines(keepends=True), user_text.splitlines(keepends=True),
                    fromfile=f"stock/{rel}", tofile=f"yours/{rel}",
                ))
                diffs.append({"path": rel, "status": "modified", "diff": text})

    message = (f"'{name}' differs from the stock version in {len(diffs)} file(s)." if diffs
               else f"'{name}' matches the stock version.")
    return {"ok": True, "name": name, "found": True, "modified": bool(diffs), "diffs": diffs, "message": message}


_OPT_OUT_MESSAGES = {  # (enabled, changed) -> message
    (True, True): "Opted out of bundled skills. Future install / update / sync runs will not seed bundled skills into this profile.",
    (True, False): "Already opted out — marker was already present.",
    (False, True): "Opted back in. The next `hermes update` (or `hermes skills opt-in --sync`) will re-seed bundled skills.",
    (False, False): "Not opted out — no marker to remove.",
}


def set_bundled_skills_opt_out(enabled: bool) -> dict:
    """Toggle the .no-bundled-skills marker: the on-disk half of ``hermes skills
    opt-out`` / ``opt-in`` that stops installer/update/sync seeding. Removing
    already-present skills is a separate step (``remove_pristine_bundled_skills``).
    Returns ``{ok, changed, marker, message}``."""
    ss = _ss()
    marker = ss._hermes_home() / ss.NO_BUNDLED_SKILLS_MARKER
    existed = marker.exists()
    try:
        if enabled:
            ss._hermes_home().mkdir(parents=True, exist_ok=True)
            marker.write_text(
                "This profile opted out of bundled-skill seeding (`hermes skills opt-out`).\n"
                "Delete this file to re-enable sync on the next `hermes update`.\n",
                encoding="utf-8",
            )
        elif existed:
            marker.unlink()
    except OSError as e:
        return {"ok": False, "changed": False, "marker": str(marker),
                "message": f"Could not update opt-out marker at {marker}: {e}"}
    changed = enabled != existed
    return {"ok": True, "changed": changed, "marker": str(marker), "message": _OPT_OUT_MESSAGES[(enabled, changed)]}


def remove_pristine_bundled_skills(dry_run: bool = False) -> dict:
    """Delete bundled skills that are present, manifest-tracked, AND unmodified.

    Removed ONLY when in the sync manifest (genuinely bundled, not hub/hand-written),
    still in the bundled source (hash-comparable), and byte-identical to the origin
    hash; everything else lands in ``skipped``. Removed skills lose their manifest
    entry so a later opt-in re-seed treats them as new.
    Returns ``{ok, removed, skipped: [{name, reason}], dry_run, message}``.
    """
    ss = _ss()
    manifest = ss._read_manifest()
    bundled_dir = ss._get_bundled_dir()
    bundled_by_name = _bundled_by_name(bundled_dir)

    removed: List[str] = []
    skipped: List[dict] = []
    for name, origin_hash in sorted(manifest.items()):
        src = bundled_by_name.get(name)
        if src is None:
            skipped.append({"name": name, "reason": "no bundled source (removed upstream)"})
            continue
        dest = ss._compute_relative_dest(src, bundled_dir)
        if not dest.exists():
            # Already gone from disk; just forget the stale manifest entry.
            if not dry_run:
                manifest.pop(name, None)
            continue
        if ss._dir_hash(dest) != origin_hash:
            skipped.append({"name": name, "reason": "user-modified (kept)"})
            continue
        if not dry_run:
            try:
                ss._rmtree_writable(dest)
            except (OSError, IOError) as e:
                skipped.append({"name": name, "reason": f"delete failed: {e}"})
                continue
            manifest.pop(name, None)
        removed.append(name)

    if not dry_run and removed:
        ss._write_manifest(manifest)

    verb = "Would remove" if dry_run else "Removed"
    return {
        "ok": True, "removed": removed, "skipped": skipped, "dry_run": dry_run,
        "message": f"{verb} {len(removed)} pristine bundled skill(s); kept {len(skipped)}.",
    }