"""Unit: the RAG view's drill-down catalog tree (phase 97, task 04).

The RAG (Knowledge base) view lists the catalog the way the agent's
``ls`` sees it (the phase-94 concept, ONE end to end): sources at the
top, then per level the subfolders (recursive count + the STORED
description) and the level's files (the ``#docs-table`` — phase 106,
task 08, D8, added the Created column BEFORE Indexed, making it the
6-column contract). The view's catalog load is now
``loadTree()``: ONE fetch of ``GET /api/docs/tree`` (the full recursive
tree in a single payload — task 02), then client-side drill navigation
(no per-level fetch, no URL change).

This module pins the source-level contract (the house pattern of
``tests/unit/test_sync_button.py`` — read the frontend files as text,
no browser; the behavior is E2E-covered by the phase's dedicated
suite, task 06):

* the shell's RAG view ships the static tree skeleton (``#kb-crumb``,
  ``#kb-level`` + ``#kb-level-title``/``#kb-level-summary``,
  ``#folders-wrap`` + ``#folders-table`` — ONE table for every level,
  the Folder | Documents | Updated | Description head — phase 106
  (task 08, D8) added the Updated column (the subtree's MAX document
  created_at, D9) BETWEEN Documents and Description) in order after
  ``#stat-cards`` and BEFORE the file table (now the 6-column
  Source | Path | Title | Chunks | Created | Indexed head — phase 106
  (task 08, D8) added the Created column BEFORE Indexed);
* the exact ``/api/docs/tree`` fetch (and the flat ``/api/docs`` fetch
  is gone from the view module);
* the drill state (``current`` / ``kbTree``), the state transitions
  (source row click, folder row click, breadcrumb up, top reset), and
  the aria-current last segment;
* the textContent contract (no ``innerHTML`` with document-derived
  data — the module's standing rule);
* the top-level semantics (the rows ARE the sources — the ``ls()``
  equivalence — and the file table is hidden at the top);
* the level block's ls rule (hidden when no description is stored);
* the stat cards' whole-tree walk;
* the empty-state semantic (``#sources-empty`` ONLY on zero sources —
  the deliberate phase-97 change: a registered 0-document source
  renders its row instead);
* the never-stale reset-to-top fallback (PLAN §7.4 — a vanished
  location resets ``current`` to the top BEFORE rendering);
* ``loadTree`` wired at exactly the three refresh points (view-refresh,
  sync success, upload success) plus the boot load — and the
  anonymous branch still never fetches the catalog.

Phase 97 (task 05) adds the FOLDER-DESCRIPTION EDITOR (the phase-57
affordance, mirrored) — the source pins this module gains for it:

* the static ``#kb-level-edit`` button in the level block (type=button,
  the .kb-summary-edit class, the "Edit" label, after the description
  ``<p>`` — in the .kb-level-body the editor swaps inside);
* the Description cell of EVERY source/folder row (``makeDescCell``,
  called from both row builders) — the stored description as a text
  node + the ALWAYS-present Edit button (a description can be CREATED
  where none is stored: no gate on the stored value);
* the shared editor (``wireDescriptionEdit``): the swap builds a
  textarea prefilled via ``.value`` (never innerHTML — the XSS
  contract), Save / Cancel, and the ``role="status"``
  ``aria-live="polite"`` live region;
* the exact PATCH — ``/api/folders/summary``, method PATCH, body
  ``{ source, folder_path, summary }`` with ``folder_path ""`` for the
  source root (exactly one call site in the module);
* the outcomes — success updates the in-memory ``kbTree`` node IN
  PLACE (no re-fetch) + re-renders the text via textContent + "
  Description updated."; a cleared echo (summary null) empties the
  text (row cell) / hides the level block (the phase-57 announcement
  beat, guarded) + "Description cleared."; a failure (non-ok OR
  network) keeps the editor open with neutral retry copy (phase-55);
  Cancel restores the text node without a fetch;
* the double-click guard (disabled before the fetch, re-enabled in the
  ``finally``); the level editor's ``getTarget()`` getter + the
  ``reset()`` handle called on every re-render (PLAN §7.4);
* the five ``.kb-summary-*`` classes in styles.css (house palette, no
  new hue in the phase-97 block).

Phase 98 (task 04) adds the "SUMMARY PENDING" markers — the pins this
module gains for them:

* the row Description cell's THREE text states (``makeDescCell``):
  stored → the stored text (NEVER the marker); no stored +
  ``summary_pending`` → the ``kb-summary-pending`` class on the
  existing text span + the exact ``Summary pending`` copy + the exact
  D4 title (textContent/title only — the house rule); neither → the
  empty cell (the ls rule, unchanged) — with the Edit button
  UNCONDITIONAL in all three (a manual save creates the row);
* the in-place clear: the editor's success path sets
  ``node.summary_pending = false`` immediately after
  ``node.summary = data.summary`` (no re-fetch — the marker clears in
  the surface where the edit happened);
* the level block's OR condition (a stored description OR
  ``summary_pending``) + the EXACT pending note — neither stored nor
  pending stays hidden (the ls rule, unchanged) — and the level's
  pending text takes the muted ``kb-summary-pending`` class on render
  (the block is REUSED across levels — a stored level clears it);
* the editor's close re-derives the display state from the node (task
  05 defect fix): the pending marker's muted class + D4 tooltip
  CANNOT survive a save (the flag is cleared first — the in-place
  clear, with the stale "next sync" tooltip gone), and a cancel
  restores the surface's pending display (each surface passes its
  pending copy via ``pendingText`` — the row's ``Summary pending``
  marker, the level's D4 note — and its tooltip via ``pendingTitle``,
  the row only);

* ``.kb-summary-pending`` in styles.css (the ink-soft muted AA pair —
  text + color, never color alone; no font/white-space/italic
  overrides, so the row height is unchanged; no new hue in the
  phase-97 block).
"""
from __future__ import annotations

import re
from pathlib import Path

FRONTEND = Path(__file__).resolve().parents[2] / "frontend"
ASSETS = FRONTEND / "assets"
SOURCES_JS = ASSETS / "sources.js"
STYLES_CSS = ASSETS / "styles.css"
SHELL_HTML = FRONTEND / "index.html"


def _text(path: Path) -> str:
    assert path.is_file(), f"missing frontend file: {path}"
    return path.read_text(encoding="utf-8")


def _js() -> str:
    return _text(SOURCES_JS)


def _rag_view(html: str) -> str:
    """The RAG view section of the shell (view-scoped scope — the shell
    carries many views, so whole-file matches hit the wrong view)."""
    i = html.find('<section class="view" id="view-rag"')
    assert i != -1, "the RAG view section must be in the shell"
    j = html.find('<section class="view" id="view-git-sources"', i)
    assert j != -1, "the Sources view section must follow the RAG view"
    return html[i:j]


def _css_block(css_text: str, start_marker: str, end_marker: str) -> str:
    """The CSS between two phase markers (comments included — the no-new
    hue check wants to see that none was added in prose either)."""
    i = css_text.find(start_marker)
    assert i != -1, f"missing CSS marker: {start_marker!r}"
    j = css_text.find(end_marker, i)
    assert j != -1, f"missing CSS end marker: {end_marker!r}"
    return css_text[i:j]


def _fn(js: str, name: str) -> str:
    """The source of a (possibly async, possibly nested) function via
    balanced-brace counting (module-level and mount-scoped alike). The
    brace count starts AFTER the parameter list — a destructured
    parameter (wireDescriptionEdit's target object) may carry braces of
    its own."""
    for prefix in ("async function ", "function "):
        start = js.find(f"{prefix}{name}(")
        if start != -1:
            # Skip the parameter list (balanced parens).
            depth = 0
            i = js.find("(", start)
            close = i
            while i < len(js):
                if js[i] == "(":
                    depth += 1
                elif js[i] == ")":
                    depth -= 1
                    if depth == 0:
                        close = i
                        break
                i += 1
            # Then brace-count the body.
            brace = js.find("{", close)
            depth = 0
            for j in range(brace, len(js)):
                if js[j] == "{":
                    depth += 1
                elif js[j] == "}":
                    depth -= 1
                    if depth == 0:
                        return js[start : j + 1]
            raise AssertionError(f"unbalanced braces in {name}()")
    raise AssertionError(f"{name}() must exist in sources.js")


# ---------- the shell's RAG view: the static tree skeleton ----------


def test_rag_view_ships_the_tree_skeleton_in_order() -> None:
    """The house no-JS-safe skeleton convention: the tree surfaces ship
    in the static HTML (after the stat cards, before the file table)
    and ship HIDDEN — assets/sources.js fills them with createElement.
    ``#kb-crumb`` is the location nav; ``#kb-level`` is the level block
    (title + description); ``#folders-wrap`` hosts the ONE
    folders/sources table (``.table-wrap`` card, Folder | Documents |
    Updated | Description — phase 106 (task 08, D8), visually-hidden
    caption, the ``.docs-table`` language + ``.kb-folders-table``).
    The file table's head is the 6-column contract (Source | Path |
    Title | Chunks | Created | Indexed — phase 106 (task 08, D8))."""
    view = _rag_view(_text(SHELL_HTML))
    for fragment in (
        '<nav id="kb-crumb" class="kb-crumb" aria-label="Catalog location" hidden></nav>',
        '<section id="kb-level" class="kb-level" aria-labelledby="kb-level-title" hidden>',
        '<h2 id="kb-level-title"></h2>',
        '<p id="kb-level-summary"></p>',
        '<div id="folders-wrap" class="table-wrap" role="region" '
        'aria-label="Folders" tabindex="0" hidden>',
        '<table class="docs-table kb-folders-table" id="folders-table">',
        '<caption class="visually-hidden">Catalog sources and folders</caption>',
        '<tbody id="folders-tbody"></tbody>',
    ):
        assert fragment in view, f"the RAG view must ship {fragment!r}"
    head = re.search(r"<thead>(.*?)</thead>", view[view.find('id="folders-table"'):], re.S)
    assert head, "#folders-table must keep a static thead"
    for column in (
        "<th scope=\"col\">Folder</th>",
        "<th scope=\"col\">Documents</th>",
        "<th scope=\"col\">Updated</th>",  # phase 106 (task 08, D8)
        "<th scope=\"col\">Description</th>",
    ):
        assert column in head.group(1), f"#folders-table head must carry {column!r}"
    # The deliberate placement: after the stat cards, before the file
    # table (the file table keeps its own wrap + head, unchanged).
    assert (
        view.find('id="stat-cards"')
        < view.find('id="kb-crumb"')
        < view.find('id="kb-level"')
        < view.find('id="folders-wrap"')
        < view.find('id="docs-table"')
    ), "the skeleton must sit between the stat cards and the file table"
    # The file table's head (the 6-column contract — phase 106 (task
    # 08, D8) added Created BEFORE Indexed; makeRow's home).
    doc_head = re.search(
        r'<table class="docs-table" id="docs-table">.*?<thead>(.*?)</thead>', view, re.S
    )
    assert doc_head, "the file table must keep its static thead"
    for column in ("Source", "Path", "Title", "Chunks", "Created", "Indexed"):
        assert f">{column}</th>" in doc_head.group(1), f"#docs-table head must keep {column!r}"


# ---------- the tree load: the ONE fetch + the race token ----------


def test_sources_js_fetches_the_tree_endpoint_only() -> None:
    """The catalog load is `loadTree()`: ONE fetch of the tree endpoint.
    The flat `GET /api/docs` fetch is GONE from the view module (the
    endpoint itself stays — the API surface is untouched, task 02)."""
    js = _js()
    assert 'fetch("/api/docs/tree")' in js, "the load must fetch /api/docs/tree"
    assert js.count('fetch("/api/docs/tree")') == 1, (
        "the tree is the view's SINGLE catalog fetch (zero per-level fetches)"
    )
    assert 'fetch("/api/docs")' not in js, "the flat /api/docs fetch must be gone"


def test_load_tree_is_race_tokened_and_resets_before_rendering() -> None:
    """Phase 79 carries over: the monotonic loadSeq token — only the
    newest load may touch the DOM after its await. On success the load
    stores the tree in the module-scoped `kbTree`, runs the never-stale
    reset, and renders (in that order — the reset must see the NEW
    tree and happen BEFORE the render)."""
    js = _js()
    assert "async function loadTree()" in js, "loadTree must exist"
    body = js[js.find("async function loadTree()") :]
    body = body[: body.find("\n  }")]
    assert "const my = ++loadSeq;" in body, "the race token stays (phase 79)"
    assert "if (my !== loadSeq) return;" in body, "stale loads must not touch the DOM"
    store_i = body.find("kbTree = tree && Array.isArray(tree.sources) ? tree : { sources: [] };")
    reset_i = body.find("resetVanishedLocation();")
    render_i = body.find("renderLevel();")
    assert -1 < store_i < reset_i < render_i, (
        "store the tree → reset a vanished location → render (in order)"
    )


# ---------- the drill state + the navigation transitions ----------


def test_drill_state_and_module_tree_are_scoped_to_the_mount() -> None:
    """`current` ({ source, folder } — null/null = the top level,
    folder "" = the source root) and `kbTree` are mount-scoped module
    state (the router mounts a view ONCE — the state survives every
    switch, as the sync state machine does)."""
    js = _js()
    assert "let kbTree = { sources: [] };" in js
    assert "let current = { source: null, folder: null };" in js, (
        "the drill state starts at the top level"
    )


def test_source_row_click_drills_into_the_source_root() -> None:
    """Top-level row = a SOURCE (the ls() equivalence): the name cell
    is a `.folder-link` whose click sets `{ source, "" }` (the source
    ROOT) and re-renders — client-side only (no fetch, no URL change).
    The row carries the recursive count and the stored (source, "")
    description — textContent only."""
    js = _js()
    # Slice to the next function (the row builders grew with phase 106's
    # Updated cell — a fixed window would drift out of the function).
    body = js[js.find("function makeSourceRow(") : js.find("function makeFolderRow(")]
    assert 'link.className = "folder-link"' in body, "the source row uses the row drill link"
    assert "link.textContent = s.name" in body
    assert "goTo({ source: s.name, folder: \"\" })" in body, (
        "a source row drills to the source ROOT (folder \"\")"
    )
    assert "countTd.textContent = String(s.documents)" in body, "the recursive count"
    assert 'makeDescCell(s, s.name, "", s.name)' in body, (
        "the Description cell (task 05): the stored (source, \"\") "
        "description + the ALWAYS-present Edit button — folder_path \"\" "
        "for the source root"
    )
    assert "link.href = \"#\"" in body, "client-side drill — no URL change"


def test_folder_row_click_drills_into_the_folder() -> None:
    """A level's subfolder row: the folder's LAST path segment as the
    label (the full source-relative path rides the title), the
    recursive count, the stored description — and the click sets
    `{ source, folder: f.path }` (the source-relative folder path)."""
    js = _js()
    start = js.find("function makeFolderRow(")
    body = js[start : js.find("function renderLevel(")]
    assert 'link.className = "folder-link"' in body
    assert "link.textContent = f.path.split(\"/\").pop()" in body, (
        "the label is the last segment (the breadcrumb language)"
    )
    assert "link.title = current.source + \"/\" + f.path" in body, "full path on hover"
    assert "goTo({ source: current.source, folder: f.path })" in body, (
        "a folder row drills to that folder"
    )
    assert "countTd.textContent = String(f.documents)" in body
    assert (
        'makeDescCell(f, current.source, f.path, current.source + "/" + f.path)'
        in body
    ), "the Description cell (task 05): the stored row + the ALWAYS-present Edit"


def test_breadcrumb_links_go_up_and_the_top_reset() -> None:
    """The breadcrumb: hidden at the top level; when drilled in, one
    link per ancestor — the TOP level (→ `{ null, null }` — the reset),
    the source (→ `{ source, "" }`), then the folder chain (→ each
    ancestor folder) — the LAST segment a span with
    aria-current=\"page\" (not a link)."""
    js = _js()
    start = js.find("function renderCrumb(")
    body = js[start : js.find("function crumbSegment(")]
    assert "if (current.source === null) {" in body
    assert "crumbEl.hidden = true" in body, "the breadcrumb is hidden at the top level"
    assert "crumbSegment(\"Knowledge base\", { source: null, folder: null })" in body, (
        "the top-level segment goes back to the sources list (the reset)"
    )
    assert "crumbSegment(current.source, { source: current.source, folder: \"\" })" in body, (
        "the source segment goes up to the source root"
    )
    assert "crumbSegment(part, { source: current.source, folder: acc })" in body, (
        "each folder-ancestor segment goes up to that folder"
    )
    assert "crumbCurrent(part)" in body, "the last segment is the current span"
    seg = js[js.find("function crumbSegment(") : js.find("function crumbCurrent(")]
    assert 'a.className = "kb-crumb-link"' in seg
    assert "a.textContent = label" in seg, "segment labels are textContent"
    cur = js[js.find("function crumbCurrent(") : js.find("function goTo(")]
    assert 'span.className = "kb-crumb-current"' in cur
    assert 'span.setAttribute("aria-current", "page")' in cur, (
        "the last segment is aria-current (a span, never a link)"
    )
    assert "span.textContent = label" in cur


def test_drill_navigation_pushes_state_only_entries() -> None:
    """Phase 99 (task 02, D2): every user-initiated drill is a history
    entry — ``goTo`` is the push variant of ``applyTarget``: when the
    target DIFFERS from the current level (a re-click of the current
    row/segment pushes NO duplicate entry), it FIRST records a
    STATE-ONLY entry — ``history.pushState({ view: "rag", kb: target },
    "")`` — the second arg is ``""`` and there is no third (the URL
    stays the shell's pathname: no new route, the phase-76 deep-link
    surface is untouched) — then sets ``current`` + re-renders. The
    drill still never fetches (the tree is in memory) and the module
    never ``replaceState``s."""
    js = _js()
    start = js.find("function applyTarget(")
    assert start != -1, "applyTarget must exist (the two-step drill)"
    body = js[start : js.find("function makeSourceRow(")]
    gate_i = body.find(
        "if (push && (target.source !== current.source || target.folder !== current.folder)) {"
    )
    push_i = body.find('history.pushState({ view: "rag", kb: target }, "")')
    set_i = body.find("current = { source: target.source, folder: target.folder };")
    render_i = body.find("renderLevel();")
    assert -1 < gate_i < push_i < set_i < render_i, (
        "push gate (target differs from current) → pushState → set current → render"
    )
    # STATE-ONLY: exactly ONE pushState call site — the "" second arg,
    # no third (no URL change).
    assert _code(body).count("pushState") == 1, (
        "ONE pushState call site — the state-only drill entry"
    )
    assert "replaceState" not in _code(js), "no replaceState anywhere in the module"
    # goTo is the push variant — every drill call site keeps calling it.
    go = body[body.find("function goTo(") :]
    assert "applyTarget(target, true)" in go, "goTo pushes (the user-initiated drill)"
    assert "fetch(" not in body, "the drill never fetches (client-side only)"


# ---------- the level rendering ----------


def test_top_level_lists_sources_and_hides_the_file_table() -> None:
    """Top level: the breadcrumb + level block are hidden; the folders
    table lists the SOURCES themselves (makeSourceRow for every source)
    and the file table is ALWAYS hidden (files are seen per source —
    `ls()` shows none at the top)."""
    js = _js()
    start = js.find("function renderLevel(")
    body = js[start : js.find("function renderEmpty(")]
    top = body[body.find("if (current.source === null) {") :]
    assert "levelEl.hidden = true;" in top, "the level block is hidden at the top level"
    assert "for (const s of kbTree.sources) foldersTbody.appendChild(makeSourceRow(s));" in top, (
        "ONE table for every level: at the top the rows are the sources"
    )
    assert "foldersWrap.hidden = false;" in top
    assert "if (tableWrap) tableWrap.hidden = true;" in top, (
        "the file table is always hidden at the top level"
    )


def test_level_block_shows_the_stored_description_or_the_pending_note() -> None:
    """Inside a source/folder: the level block shows the CURRENT
    level's stored description — the title is the full source-relative
    path (e.g. `alpha/two`; the source root shows the source name) —
    or, since Phase 98 (task 04, D4), the PENDING note when the level
    is summary_pending (no stored description yet — the next sync's
    gap-fill will generate it, or the owner writes one via the block's
    Edit button). HIDDEN only when NEITHER is stored nor pending (the
    ls rule: count only, no placeholder — unchanged)."""
    js = _js()
    start = js.find("function renderLevel(")
    body = js[start : js.find("function renderEmpty(")]
    cond = "if (node.summary || node.summary_pending) {"
    assert cond in body, "the block shows for a stored OR a pending level"
    shown = body[body.find(cond) : body.find("} else {", body.find(cond))]
    assert "levelTitleEl.textContent = current.folder" in shown
    assert "current.source + \"/\" + current.folder" in shown, (
        "the folder title is the full source-relative path"
    )
    assert ": current.source;" in shown, "the source root title is the source name"
    assert "levelSummaryEl.textContent = node.summary ||" in shown, (
        "the stored text first, the pending note as the fall-through"
    )
    assert (
        "No description stored yet — the next sync will generate one. (You can write one yourself.)"
        in shown
    ), "the EXACT D4 pending note"
    assert (
        'levelSummaryEl.className = node.summary ? "" : "kb-summary-pending";'
        in shown
    ), (
        "the pending text is the muted marker style — and a stored level CLEARS a "
        "previous pending level's class (the block is reused, task-05 defect fix)"
    )
    assert "levelEl.hidden = false;" in shown
    hidden = body[body.find("} else {", body.find(cond)) :]
    assert "levelEl.hidden = true;" in hidden[:200], (
        "neither stored nor pending → the block is hidden (the ls rule)"
    )


def test_level_lists_subfolders_and_direct_files_only() -> None:
    """A level's folders table = its DIRECT subfolders (hidden when
    none); its file table = its DIRECT files (hidden when none) —
    makeRow UNCHANGED (the file node carries no source: the row object
    restores the flat /api/docs shape makeRow reads, so the phase-10/26
    pins on makeRow stay green)."""
    js = _js()
    start = js.find("function renderLevel(")
    body = js[start : js.find("function renderEmpty(")]
    assert 'children.filter((c) => c.kind === "folder")' in body
    assert 'children.filter((c) => c.kind === "file")' in body
    assert "for (const f of subfolders) foldersTbody.appendChild(makeFolderRow(f));" in body
    assert "foldersWrap.hidden = subfolders.length === 0;" in body, (
        "#folders-wrap hidden when the level has no subfolders"
    )
    assert "for (const f of files) {" in body
    assert "source: current.source," in body, "the row object restores the source"
    assert "makeRow({" in body, "makeRow is unchanged (the phase-10/26 pins)"
    assert "if (tableWrap) tableWrap.hidden = files.length === 0;" in body, (
        "the file table hides when the level has no direct files"
    )
    # makeRow itself is untouched — the standing pins on its body.
    assert "link.href = documentUrl(d.source, d.path)" in js
    assert "openDocumentModal(d.source, d.path, link)" in js


def test_render_clears_both_row_containers_before_filling() -> None:
    """Re-entrancy (the phase-77 pattern, extended to the second
    container): the render clears BOTH tbodies at the top — a refresh
    from a populated level into a sparser one leaves no ghost rows."""
    js = _js()
    start = js.find("function renderLevel(")
    body = js[start : js.find("\n  }", start)]
    clear_folders = body.find("if (foldersTbody) foldersTbody.replaceChildren();")
    clear_docs = body.find("if (tbody) tbody.replaceChildren();")
    assert 0 <= clear_folders < clear_docs, "both containers clear at the top"
    for append in ("foldersTbody.appendChild", "tbody.appendChild"):
        assert clear_docs < body.find(append), f"{append} must come after the clears"


# ---------- the stat cards: the whole-tree walk ----------


def test_stat_cards_walk_the_whole_tree() -> None:
    """The KB-wide stat cards walk the WHOLE tree (every file node at
    any depth): document count, chunks sum, max indexed_at (fmtDate
    reuse) — the values identical to the former flat walk. A
    0-document registered source contributes nothing (and still lists
    its row — the ls invariant)."""
    js = _js()
    body = js[js.find("function treeStats()") : js.find("function renderCrumb(")]
    assert "docs += 1;" in body
    assert "totalChunks += child.chunks;" in body
    assert "if (child.indexed_at > last) last = child.indexed_at;" in body
    assert "walk(child);" in body, "the walk recurses into subfolders"
    assert "for (const s of kbTree.sources) walk(s);" in body, "every source is walked"
    render = js[js.find("function renderLevel(") : js.find("function renderEmpty(")]
    assert "const st = treeStats();" in render
    assert "statDocs.textContent = String(st.docs);" in render
    assert "statChunks.textContent = String(st.totalChunks);" in render
    assert 'st.last ? fmtDate(st.last) : "–"' in render, "the fmtDate reuse"


# ---------- the empty state: the zero-sources semantic ----------


def test_empty_state_is_zero_sources_only() -> None:
    """The deliberate phase-97 semantic change (module docstring):
    #sources-empty shows ONLY when the tree has zero sources — a
    registered 0-document source renders its row instead (the ls
    invariant). A failed tree fetch renders the same no-data state
    (the former loadDocs failure behavior, unchanged in kind)."""
    js = _js()
    render = js[js.find("function renderLevel(") : js.find("function renderEmpty(")]
    assert "if (!kbTree.sources.length) {" in render, (
        "the empty state fires on ZERO SOURCES (not zero documents)"
    )
    assert "renderEmpty();" in render[render.find("if (!kbTree.sources.length) {"):]
    empty_start = js.find("function renderEmpty(")
    empty = js[empty_start : js.find("\n  }", empty_start)]
    assert 'statDocs.textContent = "0";' in empty
    assert 'statChunks.textContent = "0";' in empty
    assert 'statLast.textContent = "–";' in empty
    assert "if (foldersWrap) foldersWrap.hidden = true;" in empty, "both wraps hidden"
    assert "if (tableWrap) tableWrap.hidden = true;" in empty
    assert "emptyEl.hidden = false;" in empty, "#sources-empty shows"
    # The failure paths of the load land in the same no-data state.
    load = js[js.find("async function loadTree()") : js.find("async function loadTree()") + 900]
    assert load.count("renderEmpty();") >= 2, "a failed fetch renders the no-data state"


def test_module_docstring_documents_the_semantic_change() -> None:
    """The house module-docstring convention: the phase-97 section
    records the tree load, the drill state, and the deliberate
    0-document-source semantic change."""
    js = _js()
    header = js[: js.find("import { fetchIsAdmin }")]
    assert "Phase 97 (task 04)" in header
    assert "zero SOURCES" in header, "the empty-state semantic change is documented"
    assert "0-document source renders its row" in header, (
        "the registered 0-document source exception is documented"
    )
    assert "loadTree()" in header


# ---------- the never-stale reset-to-top fallback ----------


def test_reset_to_top_when_the_location_vanished() -> None:
    """PLAN §7.4: after a re-fetch, if the current source is no longer
    in the tree (unregistered/pruned) OR the current folder no longer
    exists under it, `current` RESETS to the top level BEFORE rendering
    — no stale breadcrumb, no stale block. The folder existence check
    mirrors the phase-94 rule: some indexed path starts with
    `folder + "/"` (the source root — \"\" — always exists)."""
    js = _js()
    body = js[js.find("function resetVanishedLocation()") : js.find("function folderExistsIn(")]
    assert "if (current.source === null) return;" in body, "the top level never vanishes"
    assert "kbTree.sources.find((s) => s.name === current.source)" in body
    assert body.count("current = { source: null, folder: null };") == 2, (
        "both vanishing arms reset to the top level"
    )
    exists = js[js.find("function folderExistsIn(") : js.find("function currentLevelNode(")]
    assert 'if (folderPath === "") return true;' in exists, "the source root always exists"
    assert "p.startsWith(folderPath + \"/\")" in exists, "the phase-94 existence rule"
    # The reset runs on the success path of the load, before the render
    # (pinned in the load-order test — here: it is defined and called).
    assert "resetVanishedLocation();" in js[js.find("async function loadTree()"):]


# ---------- the refresh wirings: loadTree at the three points ----------


def test_load_tree_wired_at_exactly_the_three_refresh_points_plus_boot() -> None:
    """loadDocs's call sites become loadTree's (same points, same
    semantics): the boot load, the bor:view-refresh listener (admin
    branch), applySyncSuccess (the KB just changed), and the
    upload-success branch of startSyncPolling — and the old name is
    gone. Exactly 5 occurrences of `loadTree()`: the definition +
    those 4 calls (no other call site exists)."""
    js = _js()
    assert "loadDocs" not in js, "the old load name is gone from the module"
    assert _code(js).count("loadTree()") == 5, (
        "the definition + the 4 call sites, no others (code, not comments)"
    )
    # 1. the view-refresh listener, armed in the admin branch — since
    #    Phase 99 (task 02, D2) its body is the ALIGNMENT step (a
    #    kb-carrying history.state entry keeps the drill — the
    #    active-link re-click; a kb-less entry starts at the top — a
    #    fresh nav visit) BEFORE the re-fetch.
    listener = js.find('addEventListener("bor:view-refresh"')
    assert listener != -1
    gate = js.find("const admin = await fetchIsAdmin();")
    assert -1 < gate < listener, "armed after the whoami gate (the phase-77 pin)"
    listener_body = js[listener : js.find('window.addEventListener("popstate"')]
    state_i = listener_body.find("history.state && history.state.kb")
    adopt_i = listener_body.find("applyTarget(kb, false)")
    reset_i = listener_body.find("applyTarget({ source: null, folder: null }, false)")
    load_i = listener_body.find("loadTree();")
    assert -1 < state_i < adopt_i < reset_i < load_i, (
        "align with history.state (adopt kb / reset to top) BEFORE the re-fetch"
    )
    assert "pushState" not in _code(listener_body), ("the alignment adopts only — no push")
    # 2. the boot load — the last statement of mount, right after the
    #    listeners are armed (the mount's own load is the first fetch).
    pop = js.find('window.addEventListener("popstate"')
    boot = js[js.find("});", pop) + 3 :]  # past the popstate listener's close
    assert boot.strip().startswith("loadTree();"), (
        "the boot load follows the listeners (no pushState on boot)"
    )
    # 3. applySyncSuccess (the sync's terminal — the KB just changed).
    success = js[js.find("function applySyncSuccess(") : js.find("function applySyncFailure(")]
    assert "loadTree();" in success
    # 4. the upload-success branch of the tick (settle + refresh).
    tick = js[js.find("function startSyncPolling(") : js.find("function startSync()")]
    up_ok = tick.find('uploadStatus && uploadStatus.state === "success"')
    up_fail = tick.find('uploadStatus && uploadStatus.state === "failed"')
    assert -1 < up_ok < up_fail
    assert "loadTree();" in tick[up_ok:up_fail], "the upload success refreshes the tree"


def test_anonymous_branch_never_fetches_the_tree() -> None:
    """The phase-16 soft rule (unchanged in kind): the anonymous branch
    gates the catalog in / out with NO catalog fetch — no /api/docs/
    tree request at all, and the tree surfaces stay hidden (they ship
    hidden and never fill)."""
    js = _js()
    start = js.find("if (!admin) {")
    end = js.find("if (gateEl) gateEl.hidden = true;")
    assert -1 < start < end, "the anonymous branch must exist"
    branch = js[start:end]
    assert "fetch(" not in branch, "anonymous never fetches the catalog"
    assert "loadTree" not in branch, "anonymous never starts a tree load"
    assert "if (foldersWrap) foldersWrap.hidden = true;" in branch, (
        "the folders wrap is part of the anonymous hide"
    )
    assert "if (tableWrap) tableWrap.hidden = true;" in branch
    assert "if (gateEl) gateEl.hidden = false;" in branch


# ---------- the textContent contract ----------


def _code(js: str) -> str:
    """sources.js with comments stripped (a comment may legally carry
    any string — the count pins below must only see code)."""
    no_block = re.sub(r"/\*.*?\*/", "", js, flags=re.S)
    return re.sub(r"//.*", "", no_block)


def test_tree_cells_never_use_innerhtml_with_derived_data() -> None:
    """The module's standing rule: document-derived text goes through
    textContent only. The ONE innerHTML left in the module CODE is the
    static (non-derived) sync-error modal skeleton — unchanged since
    phase 41."""
    js = _js()
    code = _code(js)
    assert code.count("innerHTML") == 1, (
        "only the static sync-modal skeleton may use innerHTML (code, not comments)"
    )
    modal = code.find("function createSyncModal()")
    assert modal != -1
    assert code.find("innerHTML") > modal, "the single innerHTML is the sync-modal creation"
    # The tree's derived-text sinks are all textContent (spot the
    # contract across the builders + the level block).
    for sink in (
        "link.textContent = s.name",
        "link.textContent = f.path.split(\"/\").pop()",
        "text.textContent = node.summary",
        'text.textContent = "Summary pending"',
        "levelSummaryEl.textContent = node.summary ||",
        "a.textContent = label",
        "span.textContent = label",
        "countTd.textContent = String(s.documents)",
        "countTd.textContent = String(f.documents)",
    ):
        assert sink in js, f"the derived-text contract: {sink!r}"


# ---------- the file-table wrap lookup (the new class collision) ----------


def test_file_wrap_lookup_avoids_the_new_folders_wrap() -> None:
    """#folders-wrap ALSO carries the shared .table-wrap class (the
    card language) — the FILE table's wrap is looked up through its
    own table, not the class (a class lookup would hit #folders-wrap
    first in document order and hide/show the wrong card)."""
    js = _js()
    assert 'root.querySelector("#docs-table").parentElement' in js
    assert 'root.querySelector(".table-wrap")' not in js, (
        "the bare class lookup must not survive (it would hit #folders-wrap)"
    )


# ---------- the styles: the tree's classes, no new hue ----------


def test_styles_carry_the_tree_classes_with_no_new_hue() -> None:
    """The new classes exist (.kb-crumb + link/current/separator,
    .kb-level, .kb-folders-table, .folder-link) and the phase-97 block
    introduces NO new hue (the phase-92 monochrome invariant — every
    color via a var(); no hex/rgb literal)."""
    css = _text(STYLES_CSS)
    for selector in (
        ".kb-crumb",
        ".kb-crumb-link",
        ".kb-crumb-current",
        ".kb-crumb-sep",
        ".kb-level",
        ".kb-folders-table",
        ".folder-link",
    ):
        assert re.search(r"(?<![\w-])" + re.escape(selector) + r"\s*\{", css), (
            f"styles.css must define {selector}"
        )
    block = _css_block(css, "KB drill-down tree (phase 97", "Git sources page (phase 35)")
    assert not re.search(r"#[0-9a-fA-F]{3,8}\b", block), "no new hue (phase-92 invariant)"
    assert not re.search(r"rgba?\(", block), "no new hue (phase-92 invariant)"
    # The drill link keeps the AA brand-ink pair + the hover/focus
    # affordance (text + color, never color alone).
    link = block[block.find(".folder-link {") : block.find(".folder-link:hover")]
    assert "var(--brand-ink)" in link
    assert ".folder-link:hover, .folder-link:focus-visible" in block, (
        "the drill affordance covers hover AND focus"
    )


# ---------- the folder-description editor (phase 97, task 05) ----------
#
# The phase-57 edit affordance, mirrored: Edit → inline textarea
# (prefilled) → Save/Cancel → live-region status, wired to
# PATCH /api/folders/summary (task 03). The browser behavior is
# E2E-covered by the phase's dedicated suite (task 06); this module
# pins the source-level contract (the house pattern of
# tests/unit/test_summary_edit_ui.py for the phase-57 analog).


def test_level_block_ships_the_static_edit_button() -> None:
    """The level block ships the phase-57 Edit button in the static
    HTML: a real type=button with the .kb-summary-edit class and the
    "Edit" label, INSIDE #kb-level after p#kb-level-summary — in the
    .kb-level-body (the editor swaps inside it, the <h2> stays put)."""
    view = _rag_view(_text(SHELL_HTML))
    assert '<div class="kb-level-body">' in view, (
        "the level's description UI ships in the .kb-level-body"
    )
    assert (
        '<button type="button" class="kb-summary-edit" id="kb-level-edit">Edit</button>'
        in view
    ), "the static level Edit button (phase-57 label, real button)"
    body = view[view.find('id="kb-level"') : view.find('id="folders-wrap"')]
    assert (
        body.find('<h2 id="kb-level-title"></h2>')
        < body.find('<p id="kb-level-summary"></p>')
        < body.find('id="kb-level-edit"')
    ), "title → description → Edit button, in order"


def test_row_description_cell_builds_text_and_always_present_edit() -> None:
    """makeDescCell (the shared Description-cell builder, called from
    BOTH row builders): the description text as a text node
    (textContent — never innerHTML) + the Edit button built
    UNCONDITIONALLY — a description can be CREATED where none is
    stored (a < 2-document folder, the generator's fail-soft miss), so
    the button sits OUTSIDE the three-state text branch (Phase 98:
    the text gates on the node state, the button never does). The
    button is a real type=button with a human aria-label, and the
    shared editor is wired with a CONSTANT target { node, source,
    folder }. Phase 99 (task 01, D1): text + button live in ONE
    `div.kb-desc-cell` flex wrapper (the <td> holds only the wrapper),
    and the editor's container IS the wrapper (the open/close swaps
    fill it — the cell layout survives the editor swap)."""
    body = _fn(_js(), "makeDescCell")
    # The Edit button is built unconditionally — the whole button
    # block (from its creation to the append) carries no `if` gate on
    # the stored description or the pending flag.
    btn_block = body[
        body.find("const btn = document.createElement") : body.find("wrap.append(text, btn)")
    ]
    assert "if (" not in btn_block, (
        "always present: no gate on the stored description"
    )
    assert 'btn.type = "button"' in body
    assert 'btn.className = "kb-summary-edit"' in body
    assert 'btn.textContent = "Edit"' in body
    assert 'btn.setAttribute("aria-label", `Edit description: ${label}`)' in body
    assert 'wrap.className = "kb-desc-cell"' in body, "the ONE flex wrapper"
    assert "wrap.append(text, btn)" in body, "text + button, in order, in the wrapper"
    assert "td.append(wrap)" in body, "the <td> holds the wrapper (no new td class)"
    assert "container: wrap" in body, (
        "the editor's container is the WRAPPER (Phase 99 — the swap fills it)"
    )
    assert "getTarget: () => ({ node, source, folder })" in body, (
        "a row's target is a constant (its own node)"
    )
    # The level block's editor is UNTOUCHED — its container is still
    # .kb-level-body (the D1 escape hatch keeps its full text).
    js = _js()
    wire = js[js.find("levelEditor = wireDescriptionEdit({") : js.find("/* ---------- view boot")]
    assert "container: levelBody" in wire


def test_desc_cell_pending_marker_branch() -> None:
    """Phase 98 (task 04, D4): makeDescCell's THREE text states, in
    order — (1) a stored summary → the stored text, NEVER the
    marker; (2) no stored summary AND node.summary_pending → the
    marker: the kb-summary-pending class on the EXISTING text span +
    the exact "Summary pending" copy + the exact D4 title
    (textContent/title only — the house rule, no innerHTML); (3)
    neither stored nor pending → the empty cell (the ls rule,
    unchanged)."""
    body = _fn(_js(), "makeDescCell")
    stored_i = body.find("if (node && node.summary) {")
    pending_i = body.find("else if (node && node.summary_pending) {")
    empty_i = body.find("} else {")
    assert -1 < stored_i < pending_i < empty_i, ("stored → pending → empty, in order")
    stored = body[stored_i:pending_i]
    assert "text.textContent = node.summary;" in stored, "stored → the stored text"
    assert "kb-summary-pending" not in stored, "a stored summary is NEVER the marker"
    assert "Summary pending" not in stored
    pending = body[pending_i:empty_i]
    assert 'text.classList.add("kb-summary-pending")' in pending, (
        "Phase 99: the marker TOGGLES onto the .kb-desc-text base class"
    )
    assert 'text.className = "kb-summary-pending"' not in body, (
        "a bare className re-assignment would drop the clamp's base class"
    )
    assert 'text.textContent = "Summary pending"' in pending, "the D4 marker copy"
    assert (
        'text.title = "No stored description yet — the next sync will generate one."'
        in pending
    ), "the D4 title"
    empty = body[empty_i : empty_i + 160]
    assert 'text.textContent = ""' in empty, "neither stored nor pending → the empty cell"
    # The marker is textContent/title only — the house rule (no
    # innerHTML anywhere in the cell builder).
    code = re.sub(r"//.*?$|/\*.*?\*/", "", body, flags=re.S | re.M)
    assert "innerHTML" not in code


def test_save_success_clears_the_pending_flag_in_place() -> None:
    """Phase 98 (task 04, D4): a successful save syncs the in-memory
    node IN PLACE — node.summary = data.summary AND, immediately
    after, node.summary_pending = false (a created/updated description
    is no longer pending: the marker clears in the surface where the
    edit happened, NO re-fetch). The flag clear sits between the
    summary sync and the announcement, and nothing after it re-fetches
    the tree (the re-fetch stays the safety net, not the in-place
    clear)."""
    body = _fn(_js(), "wireDescriptionEdit")
    save = body[body.find("async function saveDescription()") :]
    sync_i = save.find("node.summary = data.summary")
    clear_i = save.find("node.summary_pending = false")
    announce_i = save.find(
        'closeEditor(data.summary === null ? "Description cleared." : "Description updated.")'
    )
    assert -1 < sync_i < clear_i < announce_i, (
        "summary sync → pending-flag clear → announce (in place)"
    )
    tail = save[clear_i:]
    assert "loadTree()" not in tail and 'fetch("' not in tail, (
        "the in-place clear is the whole of it — no re-fetch"
    )


def test_close_editor_rederives_the_pending_display() -> None:
    """Phase 98 (task 05 defect fix, D4): closeEditor re-renders the
    display state from the node with the SAME three-state rule the
    surfaces use — the pending marker's muted class + D4 tooltip
    CANNOT survive a save (the success path cleared
    ``node.summary_pending`` first, so a stale "next sync" tooltip
    under a just-created description is impossible), and a cancel
    RESTORES the surface's pending display. Each surface passes its
    pending copy via ``pendingText`` (the row's ``Summary pending``
    marker, the level's D4 note) and its tooltip via ``pendingTitle``
    (the row only — D4's title is the row cell's, the level's <p>
    carries none). textContent/class/title only — the house rule."""
    body = _fn(_js(), "wireDescriptionEdit")
    close = body[body.find("function closeEditor(") : body.find("function openEditor()")]
    flag_i = close.find('const pending = node !== null && stored === "" && node.summary_pending;')
    value_i = close.find("const value = pending && pendingText ? pendingText : stored;")
    class_i = close.find('textEl.classList.toggle("kb-summary-pending", pending);')
    title_i = close.find("if (pendingTitle) textEl.title = pendingTitle;")
    hover_i = close.find('} else if (stored && textEl.classList.contains("kb-desc-text")) {')
    full_i = close.find("textEl.title = stored;")
    clear_title_i = close.find('textEl.removeAttribute("title")')
    render_i = close.find("textEl.textContent = value")
    assert -1 < flag_i < value_i < class_i < title_i < hover_i < full_i, (
        "flag → value → class toggle → title (pending / hover-full), in order"
    )
    assert full_i < clear_title_i < render_i, "title-set → title-clear → text, in order"
    # Phase 99 (task 01): the class line is a TOGGLE (the base classes
    # survive — the row's span keeps .kb-desc-text, the clamp; the
    # level's <p> keeps none), and the CLAMPED row span's title is
    # re-derived from the stored text (the D1 hover escape hatch — a
    # stale pre-edit title cannot survive a save; the unclamped
    # level's <p> is gated out by the kb-desc-text check).
    assert 'textEl.className' not in close, "no bare className re-assignment"
    # The row passes its marker copy + the EXACT D4 tooltip…
    cell = _fn(_js(), "makeDescCell")
    assert 'pendingText: "Summary pending"' in cell
    assert (
        'pendingTitle: "No stored description yet — the next sync will generate one."'
        in cell
    ), "the D4 tooltip is the row's"
    # …and the level passes the D4 note WITHOUT a tooltip.
    js = _js()
    wire = js[js.find("levelEditor = wireDescriptionEdit({") : js.find("/* ---------- view boot")]
    assert 'pendingText:' in wire and "pendingTitle" not in wire, (
        "the level's <p> carries the note, never a tooltip (D4)"
    )
    assert (
        "No description stored yet — the next sync will generate one. (You can write one yourself.)"
        in wire
    ), "the level's pending copy is the D4 note"


def test_editor_swap_builds_textarea_save_cancel_and_live_region() -> None:
    """Edit swaps the description UI for the inline editor: a
    <textarea class="kb-summary-editor"> prefilled via .value (NEVER
    innerHTML — the XSS contract), the Save / Cancel real type=buttons,
    and the <p class="kb-summary-status" role="status"
    aria-live="polite"> live region (the shared parts are built once).
    The Edit button hides while the editor is open; hide → swap →
    focus the textarea, in order."""
    body = _fn(_js(), "wireDescriptionEdit")
    open_body = body[
        body.find("function openEditor()") : body.find("async function saveDescription()")
    ]
    assert 'editor.className = "kb-summary-editor"' in open_body
    assert (
        'editor.value = typeof target.node.summary === "string" ? target.node.summary : ""'
        in open_body
    ), "prefill via .value — value, not innerHTML"
    assert "container.replaceChildren(editor, actions, status)" in open_body
    hide = open_body.find("editBtn.hidden = true")
    swap = open_body.find("container.replaceChildren(editor, actions, status)")
    focus = open_body.find("editor.focus()")
    assert -1 < hide < swap < focus, "hide Edit → swap → focus the textarea"
    # The shared parts (built once at wiring).
    assert 'actions.className = "kb-summary-actions"' in body
    assert 'mkBtn("kb-summary-save", "Save")' in body
    assert 'mkBtn("kb-summary-cancel", "Cancel")' in body
    assert 'status.className = "kb-summary-status"' in body
    assert 'status.setAttribute("role", "status")' in body
    assert 'status.setAttribute("aria-live", "polite")' in body
    # The bindings.
    assert 'editBtn.addEventListener("click", openEditor)' in body
    assert 'cancelBtn.addEventListener("click", () => closeEditor(""))' in body
    # The textarea is rebuilt on every open (fresh prefill each time).
    assert "editor = document.createElement(\"textarea\")" in open_body
    assert "let editor = null;" in body
    # XSS contract: the whole affordance is textContent/.value only.
    code = re.sub(r"//.*?$|/\*.*?\*/", "", body, flags=re.S | re.M)
    assert "innerHTML" not in code, "XSS contract: no innerHTML in the wiring"


def test_save_patches_the_exact_endpoint_with_the_folder_body() -> None:
    """Save → PATCH /api/folders/summary (the task-03 endpoint) with
    the EXACT body { source, folder_path, summary } — folder_path ""
    for the source root (makeSourceRow passes ""), the
    source-relative folder path otherwise (f.path), JSON content
    type. Exactly ONE call site in the module (the shared editor)."""
    js = _js()
    assert js.count('fetch("/api/folders/summary"') == 1, (
        "exactly one PATCH call site (the shared editor)"
    )
    body = _fn(js, "wireDescriptionEdit")
    save = body[body.find("async function saveDescription()") :]
    assert 'method: "PATCH"' in save
    assert '"Content-Type": "application/json"' in save
    assert "JSON.stringify({ source, folder_path: folder, summary: value })" in save, (
        "the exact body shape: { source, folder_path, summary }"
    )
    # folder_path "" for the source root; the source-relative path for
    # folder rows.
    src_row = _fn(js, "makeSourceRow")
    assert 'makeDescCell(s, s.name, "", s.name)' in src_row, "root: folder_path \"\""
    f_row = _fn(js, "makeFolderRow")
    assert (
        "makeDescCell(f, current.source, f.path, current.source + \"/\" + f.path)" in f_row
    ), "folder rows: the source-relative folder path"


def test_save_success_updates_kbtree_in_place_and_announces() -> None:
    """A 200 syncs the in-memory kbTree node IN PLACE (node.summary =
    data.summary — no re-fetch: the tree state stays coherent, the
    re-fetch is the safety net), then re-renders the text node via
    textContent only, with the EXACT status copies: "Description
    updated." for a saved text, "Description cleared." for the null
    (cleared) echo the server returns."""
    body = _fn(_js(), "wireDescriptionEdit")
    save = body[body.find("async function saveDescription()") :]
    ok_i = save.find("if (!res.ok)")
    json_i = save.find("await res.json()")
    sync_i = save.find("node.summary = data.summary")
    announce_i = save.find(
        'closeEditor(data.summary === null ? "Description cleared." : "Description updated.")'
    )
    assert -1 < ok_i < json_i < sync_i < announce_i, (
        "non-ok checked first → JSON → in-place node sync → announce"
    )
    close = body[body.find("function closeEditor(") : body.find("function openEditor()")]
    assert "textEl.textContent = value" in close, (
        "the display state re-renders the text node (textContent only)"
    )
    assert 'status.textContent = message' in close


def test_empty_save_clears_hides_the_level_or_empties_the_cell() -> None:
    """An empty save (the server echoes summary null) empties the text
    (row cell) and, for the level block, hides the WHOLE block (the ls
    rule) via onCleared — with the phase-57 announcement beat first
    (setTimeout) so the role=status "Description cleared." is still
    readable, GUARDED so a navigate-away first (or a re-create within
    the beat) can't get the block yanked out from under a newer level.
    A row cell passes NO onCleared: it just goes empty, its
    always-present Edit button stays (a description can be
    re-created)."""
    js = _js()
    body = _fn(js, "wireDescriptionEdit")
    close = body[body.find("function closeEditor(") : body.find("function openEditor()")]
    clear_i = close.find('if (value.trim() === "" && onCleared) onCleared();')
    focus_i = close.find("editBtn.focus()")
    assert -1 < clear_i < focus_i, "cleared → onCleared; otherwise focus the opener"
    # The level wiring passes the guarded delayed hide.
    wire = js[
        js.find("levelEditor = wireDescriptionEdit({") : js.find("/* ---------- view boot")
    ]
    assert "onCleared" in wire
    assert "setTimeout" in wire, "the phase-57 announcement beat before the hide"
    assert "levelEl.hidden = true" in wire
    guard = wire[wire.find("setTimeout") :]
    assert "currentLevelNode()" in guard and "!n.summary" in guard, (
        "the hide is guarded: only if the current node still has none"
    )
    # The row cells pass NO onCleared (makeDescCell's call omits it).
    cell = _fn(js, "makeDescCell")
    assert "onCleared" not in cell, "a row cell never hides — the button stays"


def test_cancel_restores_the_text_node() -> None:
    """Cancel → closeEditor(""): the display state restored (the text
    element re-rendered from the node — the stored text was NEVER
    mutated: only the editor held the draft), the (empty) live region
    kept, the Edit button un-hidden + re-focused. Cancel never
    fetches (no PATCH was sent)."""
    body = _fn(_js(), "wireDescriptionEdit")
    assert 'cancelBtn.addEventListener("click", () => closeEditor(""))' in body
    close = body[body.find("function closeEditor(") : body.find("function openEditor()")]
    render_i = close.find("textEl.textContent = value")
    unhide_i = close.find("editBtn.hidden = false")
    restore_i = close.find("container.replaceChildren(textEl, editBtn, status)")
    assert -1 < render_i < unhide_i < restore_i, (
        "re-render → unhide → restore (focus follows for a non-clear)"
    )
    assert "fetch(" not in close, "cancel never fetches"


def test_failure_keeps_the_editor_with_neutral_copy() -> None:
    """A failed Save (non-ok HTTP OR network) keeps the editor open
    with the user's text (no swap back, no node mutation) and shows
    neutral retry copy (phase-55 convention — no sign-in wording):
    "…try again." for a non-ok response, "…is the app reachable?" for
    the network path (the phase-55 pin style: the failure slices carry
    neither a close nor a stored-text touch)."""
    body = _fn(_js(), "wireDescriptionEdit")
    save = body[body.find("async function saveDescription()") :]
    nonok = save.find("if (!res.ok)")
    neutral = save.find("Couldn't save the description — try again.")
    assert -1 < nonok < neutral, "the non-ok branch lands on the neutral copy"
    catch_i = save.find("} catch {")
    reachable = save.find("Couldn't save the description — is the app reachable?")
    assert -1 < catch_i < reachable, "the network path carries the reachable? copy"
    assert "signed in" not in body, "no sign-in wording (neutral retry copy)"
    # The two FAILURE branches never close the editor or touch the node
    # — the editor stays open with the user's text.
    nonok_slice = save[nonok : save.find("await res.json()")]
    assert "closeEditor" not in nonok_slice
    assert "node.summary" not in nonok_slice
    catch_slice = save[catch_i : save.find("finally")]
    assert "closeEditor" not in catch_slice
    assert "node.summary" not in catch_slice


def test_save_double_click_guard_releases_in_finally() -> None:
    """One PATCH at a time: Save disables itself BEFORE the fetch and
    re-enables in the ``finally`` (every outcome — success, clear,
    non-ok, network — never leaves a stale disabled button, PLAN
    §7.4). The reset() teardown re-enables too (a torn-down editor's
    Save must be usable again after the row is rebuilt… the button
    ships disabled-ready for the next open)."""
    body = _fn(_js(), "wireDescriptionEdit")
    save = body[body.find("async function saveDescription()") :]
    disable_i = save.find("saveBtn.disabled = true")
    fetch_i = save.find('fetch("/api/folders/summary"')
    finally_i = save.find("finally")
    enable_i = save.find("saveBtn.disabled = false")
    assert -1 < disable_i < fetch_i < finally_i < enable_i, (
        "disable before the fetch; re-enable in the finally"
    )
    assert body.count("saveBtn.disabled = true") == 1
    assert body.count("saveBtn.disabled = false") == 2, (
        "the save finally + the reset() teardown"
    )


def test_level_editor_uses_a_target_getter_and_resets_on_every_rerender() -> None:
    """The level block is PERSISTENT (reused across levels as you
    drill) — its target is a GETTER reading `current` +
    currentLevelNode() at open/save time (a row's is a constant),
    with the PATCH pair from the drill state (folder "" at the source
    root). The handle's reset() is called on EVERY re-render
    (renderLevel + renderEmpty) so a navigate-away / refresh never
    leaves a stale open editor (PLAN §7.4); reset tears down only an
    OPEN editor, with no message, and the display state it restores
    is text + button (a stale status line must not survive)."""
    js = _js()
    wire = js[
        js.find("levelEditor = wireDescriptionEdit({") : js.find("/* ---------- view boot")
    ]
    assert "getTarget: () => {" in wire, "the level's target is a getter"
    assert "currentLevelNode()" in wire
    assert "{ node, source: current.source, folder: current.folder }" in wire, (
        "the PATCH pair from the drill state (folder \"\" at the source root)"
    )
    # reset() runs on both re-render paths.
    rl = js.find("function renderLevel(")
    render = js[rl : js.find("\n  }", rl)]
    assert "if (levelEditor) levelEditor.reset();" in render
    re_ = js.find("function renderEmpty(")
    empty = js[re_ : js.find("\n  }", re_)]
    assert "if (levelEditor) levelEditor.reset();" in empty
    # The handle: reset is a no-op for a closed editor, and the display
    # state is text + button (the status line is dropped).
    body = _fn(js, "wireDescriptionEdit")
    reset = body[body.find("reset() {") :]
    assert "if (!isOpen) return;" in reset
    assert "container.replaceChildren(textEl, editBtn);" in reset, (
        "the display state is text + button (the status line is dropped)"
    )


def test_editor_wiring_never_uses_innerhtml() -> None:
    """The whole task-05 wiring (mkBtn, wireDescriptionEdit,
    makeDescCell) is createElement + textContent/.value only — the
    module's single innerHTML stays the static sync-modal skeleton
    (the phase-41 shape, unchanged)."""
    js = _js()
    code = _code(js)
    assert code.count("innerHTML") == 1, (
        "only the static sync-modal skeleton may use innerHTML (code, not comments)"
    )
    for name in ("mkBtn", "wireDescriptionEdit", "makeDescCell"):
        fn_code = re.sub(r"//.*?$|/\*.*?\*/", "", _fn(js, name), flags=re.S | re.M)
        assert "innerHTML" not in fn_code, f"{name} must be textContent/.value only"


def test_module_docstring_documents_the_edit_section() -> None:
    """The house per-phase module-note convention: the phase-97
    task-05 section records the shared editor, the PATCH body
    (folder_path "" for the root), the exact status copies, the
    in-place kbTree update, and the reset contract."""
    js = _js()
    header = js[: js.find("import { fetchIsAdmin }")]
    assert "Phase 97 (task 05)" in header
    assert "wireDescriptionEdit()" in header
    assert "PATCH /api/folders/summary" in header
    assert '"Description updated."' in header
    assert '"Description cleared."' in header
    assert "IN PLACE" in header


def test_styles_carry_the_folder_editor_classes() -> None:
    """styles.css carries the five task-named .kb-summary-* classes on
    the house dark-tech palette: the 24px+ edit target with the
    [hidden] override, the 8rem-min editor (the phase-57 spec), the
    solid brand Save pill (--bg on --brand, borderless), the ink-soft
    Cancel + status (AA), :focus-visible via the global rule, and NO
    new hue in the phase-97 block (the phase-92 invariant — the
    task-05 block sits inside it)."""
    css = _text(STYLES_CSS)
    for cls in (
        ".kb-summary-edit",
        ".kb-summary-editor",
        ".kb-summary-save",
        ".kb-summary-cancel",
        ".kb-summary-status",
    ):
        assert re.search(r"(?<![\w-])" + re.escape(cls) + r"\s*\{", css), (
            f"styles.css must define {cls}"
        )
    block = _css_block(css, "KB drill-down tree (phase 97", "Git sources page (phase 35)")
    assert "kb-summary-editor" in block, "the task-05 block lives in the phase-97 region"
    assert not re.search(r"#[0-9a-fA-F]{3,8}\b", block), "no new hue (phase-92 invariant)"
    assert not re.search(r"rgba?\(", block), "no new hue (phase-92 invariant)"
    edit = css[css.find(".kb-summary-edit {") :]
    edit = edit[: edit.find("\n}")]
    assert "min-height: 24px" in edit, "the 24px+ edit target"
    assert "var(--line)" in edit and "var(--ink-soft)" in edit
    hidden = css.find(".kb-summary-edit[hidden]")
    assert hidden != -1 and "display: none" in css[hidden : hidden + 80], (
        "the hidden attr must beat the base display rule"
    )
    editor = css[css.find(".kb-summary-editor {") :]
    editor = editor[: editor.find("\n}")]
    for prop in ("display: block", "width: 100%", "min-height: 8rem", "resize: vertical"):
        assert prop in editor, f".kb-summary-editor must keep {prop}"
    save = css[css.find(".kb-summary-save {") :]
    save = save[: save.find("\n}")]
    assert "background: var(--brand)" in save and "color: var(--bg)" in save
    assert "border: 0" in save, "the solid brand pill family (Save/Share)"
    status = css[css.find(".kb-summary-status {") :]
    status = status[: status.find("\n}")]
    assert "var(--ink-soft)" in status, "AA status copy (5.1:1)"
    # :focus-visible via the GLOBAL 3px outline rule (no local
    # suppression for these controls).
    assert ":focus-visible {" in css
    assert "outline: 3px solid var(--brand)" in css


# ---------- the "Summary pending" markers (phase 98, task 04) ----------


def test_styles_carry_the_pending_marker_class() -> None:
    """Phase 98 (task 04, D4): .kb-summary-pending mutes the row-cell
    marker via the ink-soft token (5.1:1 on --surface — AA; text +
    color, never color alone — B5). The class sits on the EXISTING
    description text span, so the row cell's font-size/line-height
    apply — no font/white-space/italic overrides (the marker must not
    change row height), and the phase-97 block carries no new hue
    (the phase-92 monochrome invariant)."""
    css = _text(STYLES_CSS)
    m = re.search(r"(?<![\w-])\.kb-summary-pending\s*\{([^}]*)\}", css)
    assert m, "styles.css must define .kb-summary-pending"
    rule = m.group(1)
    assert "color: var(--ink-soft)" in rule, "the muted AA pair (5.1:1 on --surface)"
    for prop in ("font-style", "font-size", "line-height", "white-space"):
        assert prop not in rule, f"the marker keeps the row's {prop} (row height unchanged)"
    block = _css_block(css, "KB drill-down tree (phase 97", "Git sources page (phase 35)")
    assert ".kb-summary-pending" in block, "the marker class lives in the phase-97 region"
    assert not re.search(r"#[0-9a-fA-F]{3,8}\b", block), "no new hue (phase-92 invariant)"
    assert not re.search(r"rgba?\(", block), "no new hue (phase-92 invariant)"


def test_module_docstring_documents_the_pending_markers() -> None:
    """The house per-phase module-note convention: the phase-98
    task-04 section records the marker's surfaces — the row cell's
    D4 copy + title, the level block's pending note — and the
    in-place clear on the editor's success path."""
    js = _js()
    header = js[: js.find("import { fetchIsAdmin }")]
    assert "Phase 98 (task 04)" in header
    assert '"Summary pending"' in header, "the D4 marker copy"
    assert "No stored description yet — the next sync will generate one." in header, (
        "the D4 row-cell title"
    )
    assert (
        "No description stored yet — the next sync will generate one. (You can write one yourself.)"
        in header
    ), "the level block's pending note"
    assert "node.summary_pending = false" in header, "the in-place clear"


# ---------- the one-line Description clamp (phase 99, task 01) ----------
# D1: the clamp is VISUAL only — the row's Description cell is ONE flex
# row (text flexes + ellipsizes, the Edit button stays fixed), the full
# text stays in the DOM + on the span's hover title, and the level
# block keeps the full unclamped description. The measured-height proof
# lands in the phase's E2E (task 03); this module pins the structure
# and the CSS.


def _css_rule(css_text: str, selector: str) -> str:
    """The declarations of the rule with exactly this selector (the
    task-named classes own their base rule — no compound matches)."""
    m = re.search(r"(?<![\w-])" + re.escape(selector) + r"\s*\{([^}]*)\}", css_text)
    assert m, f"styles.css must define {selector}"
    return m.group(1)


def test_desc_cell_hover_title_covers_real_description_text_only() -> None:
    """Phase 99 (task 01, D1): the text span (`.kb-desc-text` — the
    base class, set UNCONDITIONALLY before the three-state branch) AL-
    WAYS carries `title` = the FULL description text for real
    (non-empty) stored text — the hover escape hatch of the visual
    clamp; the phase-98 marker keeps its OWN D4 title (never over-
    ridden by the hover rule); the empty cell carries no title at all.
    textContent/title only — the house rule (no innerHTML)."""
    body = _fn(_js(), "makeDescCell")
    base_i = body.find('text.className = "kb-desc-text"')
    stored_i = body.find("if (node && node.summary) {")
    pending_i = body.find("else if (node && node.summary_pending) {")
    empty_i = body.find("} else {")
    assert -1 < base_i < stored_i, "the base clamp class is set before the state branch"
    stored = body[stored_i:pending_i]
    assert "text.title = node.summary;" in stored, "stored → title = the full text (hover)"
    assert "Summary pending" not in stored, "the stored branch never touches the marker"
    pending = body[pending_i:empty_i]
    assert (
        'text.title = "No stored description yet — the next sync will generate one."'
        in pending
    ), "the marker keeps its OWN D4 title"
    empty = body[empty_i : empty_i + 200]
    assert "text.title" not in empty, "the empty cell carries no title"
    code = re.sub(r"//.*?$|/\*.*?\*/", "", body, flags=re.S | re.M)
    assert "innerHTML" not in code, "the house rule: no innerHTML in the cell builder"


def test_close_editor_rederives_the_hover_title_from_the_stored_text() -> None:
    """Phase 99 (task 01, D1): the hover title is the escape hatch for
    the CLAMPED text, so a Save/Cancel must re-derive it — a stale
    pre-edit title cannot survive a save (the span is re-inserted
    into the wrapper by the swap, attributes included). The re-
    derivation is gated on the kb-desc-text class: only the clamped
    row span gets the full-text title; the unclamped level's <p>
    (full text visible) keeps its no-title behavior, and an emptied
    (cleared) cell loses its title."""
    body = _fn(_js(), "wireDescriptionEdit")
    close = body[body.find("function closeEditor(") : body.find("function openEditor()")]
    gate_i = close.find('} else if (stored && textEl.classList.contains("kb-desc-text")) {')
    set_i = close.find("textEl.title = stored;")
    clear_i = close.find('textEl.removeAttribute("title")')
    assert -1 < gate_i < set_i < clear_i, "gated set (stored + clamped span) → clear, in order"
    assert close.count("textEl.title =") == 2, (
        "exactly: pendingTitle (the marker's own) + stored (the hover full text) — nothing else"
    )


def test_styles_carry_the_one_line_clamp() -> None:
    """Phase 99 (task 01, D1): the Description cell is one flex row —
    .kb-desc-cell (flex + center + the 0.4rem gap that replaces the
    button's old margin-left + min-width: 0) and .kb-desc-text (flex:
    1 1 auto + min-width: 0 — the flex item may shrink — + the
    ellipsis triad). The column itself is white-space: nowrap (was
    normal — the column width is the clamp's budget; the min/max width
    + font-size stay). The button's margin-left rule is GONE, the
    level block's margin-top rule is untouched, and the open editor
    fills the flex wrapper (flex: 1 1 auto + min-width: 0). .kb-level
    p is UNTOUCHED (the full unclamped description — D1), and the
    phase-97 block carries no new hue (the phase-92 invariant)."""
    css = _text(STYLES_CSS)
    cell = _css_rule(css, ".kb-desc-cell")
    for prop in ("display: flex", "align-items: center", "gap: 0.4rem", "min-width: 0"):
        assert prop in cell, f".kb-desc-cell must carry {prop!r}"
    text = _css_rule(css, ".kb-desc-text")
    for prop in (
        "flex: 1 1 auto",
        "min-width: 0",
        "overflow: hidden",
        "text-overflow: ellipsis",
        "white-space: nowrap",
    ):
        assert prop in text, f".kb-desc-text must carry {prop!r}"
    # Phase 106 (task 08): the clamp follows the Description cell, which
    # moved to the 4th column (Updated took 3rd).
    col_i = css.find(".kb-folders-table td:nth-child(4) {")
    assert col_i != -1
    col = css[col_i : col_i + 400]
    col = col[: col.find("\n}")]
    assert "white-space: nowrap" in col, "the column is one line (was: normal)"
    assert "white-space: normal" not in col
    for prop in ("min-width: 18rem", "max-width: 44rem", "font-size: 0.88rem"):
        assert prop in col, f"the column keeps {prop!r} (the clamp's budget)"
    assert ".kb-folders-table .kb-summary-edit" not in css, (
        "the button's margin-left is gone — the wrapper's gap replaces it"
    )
    lvl_i = css.find(".kb-level-body .kb-summary-edit")
    assert lvl_i != -1
    assert "margin-top: 0.5rem" in css[lvl_i : lvl_i + 80], (
        "the level block's spacing rule is untouched"
    )
    fill_i = css.find(".kb-desc-cell .kb-summary-editor")
    assert fill_i != -1
    fill = css[fill_i : fill_i + 80]
    assert "flex: 1 1 auto" in fill and "min-width: 0" in fill, (
        "the open editor fills the flex wrapper"
    )
    # The level block keeps the FULL unclamped description (D1) — its
    # rule is unchanged (no white-space/ellipsis additions).
    m = re.search(r"(?<![\w-])\.kb-level p\s*\{([^}]*)\}", css)
    assert m, "the level block's <p> rule must exist"
    assert "white-space" not in m.group(1) and "text-overflow" not in m.group(1)
    block = _css_block(css, "KB drill-down tree (phase 97", "Git sources page (phase 35)")
    assert ".kb-desc-cell" in block and ".kb-desc-text" in block, (
        "the clamp lives in the phase-97 tree region"
    )
    assert not re.search(r"#[0-9a-fA-F]{3,8}\b", block), "no new hue (phase-92 invariant)"
    assert not re.search(r"rgba?\(", block), "no new hue (phase-92 invariant)"


def test_module_docstring_documents_the_one_line_clamp() -> None:
    """The house per-phase module-note convention: the phase-99
    task-01 section records the flex wrapper structure (text flexes +
    ellipsizes, button fixed), the VISUAL-only clamp (full text in the
    DOM + on the hover title), the marker's own title, and the wrapper
    as the editor's container (the level block's container stays
    .kb-level-body)."""
    js = _js()
    header = js[: js.find("import { fetchIsAdmin }")]
    assert "Phase 99 (task 01, D1)" in header
    assert "kb-desc-cell" in header and "kb-desc-text" in header
    assert "VISUAL only" in header, "the clamp is documented as visual only"
    assert "title" in header, "the hover escape hatch is documented"
    assert "kb-level-body" in header, "the level block's container is documented as kept"


# ---------- the history integration (phase 99, task 02, D2) ----------
# The drill state IS the history state: every drill pushes a state-
# only entry (no URL change), Back/Forward adopt the entry's kb (or
# reset to the top), the re-show aligns before the re-fetch, and the
# anonymous gate installs no listeners. The browser proof lands in
# the phase's E2E (task 03); this module pins the wiring.


def test_popstate_adopts_the_entry_kb_or_resets_to_top() -> None:
    """Phase 99 (task 02, D2): the window popstate — armed exactly
    ONCE, in the ADMIN branch (after the whoami gate, next to the
    refresh listener) — ADOPTS the popped entry's ``event.state.kb``
    via the no-push variant (the browser owns its entries —
    adopt/reset never push), and an entry WITHOUT a kb (the boot
    entry, the router's view entries, any foreign state) RESETS the
    drill to the TOP level. Rendering a currently-hidden view is
    harmless: the router's own popstate (registered earlier, at shell
    boot) owns the view switch for foreign entries; rag-internal
    entries never change the pathname, so this listener's render is
    the visible one."""
    js = _js()
    assert js.count('window.addEventListener("popstate"') == 1, (
        "armed exactly once (mount-once — the router mounts a view ONCE)"
    )
    pop = js.find('window.addEventListener("popstate"')
    gate = js.find("const admin = await fetchIsAdmin();")
    refresh = js.find('root.addEventListener("bor:view-refresh"')
    assert -1 < gate < refresh < pop, (
        "armed in the admin branch, after the gate, next to the refresh listener"
    )
    body = js[pop : js.find("});", pop)]
    kb_i = body.find("event.state && event.state.kb")
    adopt_i = body.find("applyTarget(kb, false)")
    reset_i = body.find("applyTarget({ source: null, folder: null }, false)")
    assert -1 < kb_i < adopt_i < reset_i, (
        "read event.state.kb → adopt (no push) / reset to the top"
    )
    assert "pushState" not in _code(body), ("adopt/reset never push (the browser owns its entries)")


def test_refresh_alignment_adopts_history_state_before_the_refetch() -> None:
    """Phase 99 (task 02, D2): the bor:view-refresh listener (the
    phase-77 re-show) aligns ``current`` with ``history.state``
    BEFORE ``loadTree()`` — a kb-carrying top entry (the active-link
    re-click pushed NOTHING — the drilled entry is still on top)
    KEEPS the drill (``applyTarget(kb, false)``); a kb-less entry (a
    fresh nav visit) RESETS to the top level. The alignment adopts —
    it never pushes."""
    js = _js()
    listener = js.find('root.addEventListener("bor:view-refresh"')
    assert listener != -1
    body = js[listener : js.find("});", listener)]
    state_i = body.find("history.state && history.state.kb")
    adopt_i = body.find("applyTarget(kb, false)")
    reset_i = body.find("applyTarget({ source: null, folder: null }, false)")
    load_i = body.find("loadTree();")
    assert -1 < state_i < adopt_i < reset_i < load_i, (
        "align (adopt kb / reset to top) BEFORE the re-fetch"
    )
    assert "pushState" not in _code(body), "the alignment never pushes"


def test_anonymous_branch_installs_no_navigation_listeners() -> None:
    """Phase 99 (task 02): the anonymous gate installs NO listeners at
    all — no popstate, no refresh (the phase-16 rule: anonymous shows
    the gate, fetches nothing, and owns no drill state — both
    listeners are armed only in the admin branch)."""
    js = _js()
    start = js.find("if (!admin) {")
    end = js.find("if (gateEl) gateEl.hidden = true;")
    assert -1 < start < end, "the anonymous branch must exist"
    branch = js[start:end]
    assert "addEventListener" not in branch, (
        "the anonymous branch arms no listeners (no popstate, no refresh)"
    )


def test_module_docstring_documents_the_history_integration() -> None:
    """The house per-phase module-note convention: the phase-99
    task-02 section records the push/adopt/reset rules — the
    STATE-ONLY push (the URL STAYS PUT, no new route — the phase-76
    deep-link surface untouched), the duplicate-push skip, the
    popstate adopt/reset, the refresh alignment before the re-fetch,
    the no-boot-push contract, the UNCHANGED (no-push)
    resetVanishedLocation, and the UNTOUCHED router module."""
    js = _js()
    header = js[: js.find("import { fetchIsAdmin }")]
    assert "Phase 99 (task 02, D2)" in header
    assert "STATE-ONLY" in header, "the state-only push is documented"
    assert "STAYS PUT" in header, "the URL-stays-put note"
    assert "no duplicate history" in header, "the duplicate-push skip"
    assert "ADOPTS" in header and "popstate" in header, "the popstate adopt"
    assert "RESETS the drill to the TOP level" in header, "the reset branch"
    assert "BEFORE the re-fetch" in header, "the refresh alignment"
    assert "Boot pushes NOTHING" in header, "no pushState on boot"
    assert "resetVanishedLocation is UNCHANGED" in header
    assert "module is UNTOUCHED" in header, "the router module is untouched"