"""Unit tests: ``app.api.docs.build_kb_tree`` (phase 97, task 02).

The PURE tree builder behind ``GET /api/docs/tree`` — the RAG view's
drill-down tree, the same tree the agent's ``ls`` walks plus file
metadata. Driven without a database (module-level function, plain
inputs): multi-source ordering (the superset rule), the 0-document
registered source, the nested recursive counts, the phase-94 existence
rule, the file/folder name collision, ordering, summaries, verbatim
file metadata, and the ``group_folder_listing`` cross-check property
("the UI shows what the agent sees") at the root and one nested level.
"""
from __future__ import annotations

import pytest
from pydantic import ValidationError

from app.api.docs import (
    TreeDocRow,
    _folder_counts,
    _kb_totals,
    _subtree_max,
    build_kb_tree,
)
from app.rag.agent import group_folder_listing
from app.schemas import KbTree, KbTreeFile, KbTreeTotals

T0 = "2026-09-01T08:00:00+00:00"
T1 = "2026-09-02T08:00:00+00:00"
T2 = "2026-09-03T08:00:00+00:00"

# Phase 106 (task 05): the 6th catalogue element — the document's
# creation date (``created_at``, ISO-8601). Deliberately DISTINCT from
# the ``indexed_at`` stamps so a test that confuses the two columns
# fails loudly.
C0 = "2020-01-01T00:00:00+00:00"
C1 = "2021-06-15T12:00:00+00:00"
C2 = "2022-03-01T06:00:00+00:00"
C3 = "2023-11-30T23:59:59+00:00"


def _folder_nodes(node) -> list:
    """The folder-kind children of a source/folder node, in order."""
    return [child for child in node.children if child.kind == "folder"]


def _file_nodes(node) -> list:
    """The file-kind children of a source/folder node, in order."""
    return [child for child in node.children if child.kind == "file"]


def test_multi_source_registry_order_leads_and_indexed_only_appended() -> None:
    """Sources = the registry names in order, then the distinct
    indexed-only sources in alphabetical order (the superset rule)."""
    names = ["beta", "alpha", "empty"]  # registry order — NOT alphabetical
    doc_rows: list[TreeDocRow] = [
        ("beta", "b.md", "B", 1, T0, C0),
        ("alpha", "a.md", "A", 1, T0, C0),
        ("gamma", "g.md", "G", 1, T0, C0),  # indexed-only → appended
        ("delta", "d.md", "D", 1, T0, C0),  # indexed-only → appended
    ]
    tree = build_kb_tree(names, doc_rows, {})
    assert [s.name for s in tree] == ["beta", "alpha", "empty", "delta", "gamma"]
    # The registry sources keep their registry order even though it is
    # not alphabetical; the indexed-only ones trail, sorted.
    assert tree[0].name == "beta"
    assert tree[1].name == "alpha"
    assert tree[3].name == "delta"
    assert tree[4].name == "gamma"


def test_registered_zero_document_source_lists_empty() -> None:
    """A registered source with no indexed documents lists (the
    phase-70/72 invariant): ``documents: 0``, no children, summary null
    when nothing is stored."""
    tree = build_kb_tree(["solo"], [], {})
    assert len(tree) == 1
    assert tree[0].name == "solo"
    assert tree[0].documents == 0
    assert tree[0].children == []
    assert tree[0].summary is None
    # Phase 106 (D9): a 0-document source has no dates at all.
    assert tree[0].updated_at is None


def test_nested_document_counts_into_source_ancestors_and_own_folder() -> None:
    """A document under ``a/b/c/`` contributes to the source, to ``a``,
    to ``a/b``, and to ``a/b/c`` (the recursive subtree, the phase-94
    ``ls`` count rule)."""
    rows = [
        ("S", "a/b/c/deep.md", "Deep", 1, T0, C0),
        ("S", "a/b/shallow.md", "Shallow", 1, T0, C0),
        ("S", "a/top.md", "Top", 1, T0, C0),
        ("S", "root.md", "Root", 1, T0, C0),
    ]
    (source,) = build_kb_tree(["S"], rows, {})
    assert source.documents == 4
    a = _folder_nodes(source)[0]
    assert a.path == "a"
    assert a.documents == 3  # deep + shallow + top
    a_b = _folder_nodes(a)[0]
    assert a_b.path == "a/b"
    assert a_b.documents == 2  # deep + shallow
    a_b_c = _folder_nodes(a_b)[0]
    assert a_b_c.path == "a/b/c"
    assert a_b_c.documents == 1  # deep only
    assert [f.path for f in _file_nodes(a_b_c)] == ["a/b/c/deep.md"]
    assert [f.path for f in _file_nodes(a)] == ["a/top.md"]


def test_existence_rule_a_file_path_is_never_a_folder() -> None:
    """A folder node appears only with a true descendant (some path
    starts with ``folder + "/"``); a document's own path — even one
    with dots — never creates a folder."""
    rows = [
        ("S", "x.md", "X", 1, T0, C0),
        ("S", "x.y/z.md", "Z", 1, T0, C1),
    ]
    (source,) = build_kb_tree(["S"], rows, {})
    folders = _folder_nodes(source)
    # Only ``x.y`` exists (``x.y/z.md`` starts with ``x.y/``); ``x`` and
    # ``x.md`` are file names, not folders.
    assert [f.path for f in folders] == ["x.y"]
    assert [f.path for f in _file_nodes(source)] == ["x.md"]
    assert [f.path for f in _file_nodes(folders[0])] == ["x.y/z.md"]


def test_file_folder_name_collision_both_appear() -> None:
    """A document sharing a directory's name: BOTH appear — the folder
    node (via its descendants) and the file node (its own row); the
    colliding file counts into the folder's subtree (the ``ls`` count
    rule's ``path == folder`` arm)."""
    rows = [
        ("S", "a", "File A", 1, T0, C0),  # a file wearing the folder's name
        ("S", "a/b.md", "B", 1, T0, C1),  # makes ``a`` a folder
    ]
    (source,) = build_kb_tree(["S"], rows, {})
    folders = _folder_nodes(source)
    files = _file_nodes(source)
    assert [f.path for f in folders] == ["a"]
    assert folders[0].documents == 2  # "a" itself + "a/b.md"
    assert [f.path for f in files] == ["a"]
    assert files[0].title == "File A"
    assert [f.path for f in _file_nodes(folders[0])] == ["a/b.md"]


def test_subfolder_path_order_and_file_catalog_order() -> None:
    """Direct subfolders list in path (sorted) order; direct files keep
    the input (catalog — ``GET /api/docs``) order, independent of the
    subfolder ordering."""
    rows = [
        ("S", "zeta/z1.md", "Z1", 1, T0, C0),
        ("S", "alpha/a1.md", "A1", 1, T0, C0),
        ("S", "mike/m1.md", "M1", 1, T0, C0),
        ("S", "beta/b1.md", "B1", 1, T0, C0),
        ("S", "z-file.md", "Z", 1, T0, C0),  # file AFTER the folders in input
        ("S", "a-file.md", "A", 1, T0, C0),  # file before it in input
    ]
    (source,) = build_kb_tree(["S"], rows, {})
    assert [f.path for f in _folder_nodes(source)] == ["alpha", "beta", "mike", "zeta"]
    # Input order is preserved for the files (z-file.md precedes
    # a-file.md in the input, so it does too here — catalog order is
    # the INPUT order, not a re-sort).
    assert [f.path for f in _file_nodes(source)] == ["z-file.md", "a-file.md"]


def test_summaries_present_and_absent() -> None:
    """``summary`` is the stored row (source root ``""`` or folder
    path) or null when absent — any row (AI or manual is indistinguishable
    here; the builder carries whatever is stored)."""
    rows = [
        ("S", "one/a.md", "A", 1, T0, C0),
        ("S", "one/b.md", "B", 1, T0, C0),
        ("S", "two/c.md", "C", 1, T0, C0),
    ]
    summaries = {("S", ""): "Source desc.", ("S", "one"): "One desc."}
    # ("S", "two") is NOT stored → null.
    (source,) = build_kb_tree(["S"], rows, summaries)
    assert source.summary == "Source desc."
    one, two = _folder_nodes(source)
    assert one.summary == "One desc."
    assert two.summary is None
    # File nodes carry no summary key at all on the WIRE (the
    # 00_phase.md shape — the model_dump set check below is the wire
    # pin); since phase 106 they DO carry the creation date
    # (``created_at`` — the RAG view's ``Created`` column).
    file = _file_nodes(one)[0]
    assert set(file.model_dump()) == {
        "kind", "path", "title", "chunks", "created_at", "indexed_at"
    }
    # Phase 122 (task 04): the image-affordance fields DO exist on the
    # class now (image file nodes set them — the wire omission for text
    # nodes is the ``KbTreeFile`` serializer, pinned by the model_dump
    # set check above: a text node never leaks the three keys).
    from app.schemas import KbTreeFile

    assert {"is_image", "image_url", "summary"} <= set(KbTreeFile.model_fields)


def test_file_metadata_unchanged_in_tree() -> None:
    """File ``title`` / ``chunks`` / ``created_at`` (phase 106) /
    ``indexed_at`` ride into the tree verbatim from the catalogue row
    (no reformatting) — and the two stamps stay distinct (the
    ``created_at`` date is not confused with the ``indexed_at`` stamp)."""
    rows = [("S", "deep/x/y.md", "The Title", 7, T2, C2)]
    (source,) = build_kb_tree(["S"], rows, {})
    file = _file_nodes(_folder_nodes(_folder_nodes(source)[0])[0])[0]
    assert file.path == "deep/x/y.md"
    assert file.title == "The Title"
    assert file.chunks == 7
    assert file.created_at == C2  # phase 106: verbatim from the catalogue row
    assert file.indexed_at == T2


def test_empty_inputs_empty_tree() -> None:
    """No registry sources and no indexed documents → an empty tree
    (the RAG view's ``{"sources": []}`` case)."""
    assert build_kb_tree([], [], {}) == []


def test_indexed_document_under_unlisted_source_is_impossible() -> None:
    """By construction (the superset rule) every doc source is listed —
    the registry names lead and every other doc source follows; there
    is no input where a document is dropped."""
    names = ["reg-b", "reg-a"]
    rows: list[TreeDocRow] = [
        ("reg-b", "b.md", "B", 1, T0, C0),
        ("zzz", "z.md", "Z", 1, T0, C1),
        ("aaa", "a.md", "A", 1, T0, C2),
        ("reg-a", "a.md", "A2", 1, T0, C3),
    ]
    tree = build_kb_tree(names, rows, {})
    listed = [s.name for s in tree]
    assert listed == ["reg-b", "reg-a", "aaa", "zzz"]
    doc_paths = {
        f.path for s in tree for f in s.children if f.kind == "file"
    }
    # Every document from the input is present exactly once.
    assert doc_paths == {"b.md", "z.md", "a.md"}
    assert sum(s.documents for s in tree) == len(rows)


# --------------------------------------------------------------------
# The cross-check property — "the UI shows what the agent sees":
# for a single-source dataset the builder's level equals
# ``app.rag.agent.group_folder_listing``'s output.
# --------------------------------------------------------------------

#: The shared single-source dataset: nested folders, root files, a
#: summary-stored folder and an unstored one. Paths are in (source,
#: path) catalog order; titles map 1:1 to paths.
CROSS_ROWS: list[TreeDocRow] = [
    ("S", "note", "Note", 1, T0, C0),
    ("S", "one/a.md", "A", 2, T1, C1),
    ("S", "one/b.md", "B", 0, T1, C1),
    ("S", "one/two/c.md", "C", 3, T1, C2),
    ("S", "one/two/d.md", "D", 1, T1, C2),
    ("S", "root.md", "Root", 4, T0, C3),
    ("S", "zz/e.md", "E", 2, T2, C0),
    ("S", "zz/f.md", "F", 2, T2, C0),
]

CROSS_SUMMARIES = {
    ("S", ""): "Source desc.",
    ("S", "one"): "One desc.",
    ("S", "zz"): "Zz desc.",
    # ("S", "one/two") deliberately unstored → null at that level.
}


def _cross_check(folder: str, builder_node) -> None:
    """Assert the builder's level *folder* equals
    ``group_folder_listing("S", folder, ...)`` — same subfolder
    ``(path, count, summary)`` triples in order AND same file
    ``(source, path, title, date)`` 4-tuples in order (uncapped — the
    dataset is well under the ``ls`` 50-line cap, so the cap is inert).
    Phase 106 (task 06, D5): the cross-check compares the builder's
    OUTPUT node projections against the agent's extended file shape —
    the node's ``created_at`` DATE PART (the same ``YYYY-MM-DD`` the
    agent's ``ls`` line renders) joins the comparison.
    """
    rows = [
        (path, title, created[:10])
        for _source, path, title, _chunks, _stamp, created in CROSS_ROWS
    ]
    source_summaries = {
        folder_path: summary
        for (source, folder_path), summary in CROSS_SUMMARIES.items()
        if source == "S"
    }
    subs, files, _total = group_folder_listing("S", folder, rows, source_summaries)
    assert [(f.path, f.documents, f.summary) for f in _folder_nodes(builder_node)] == subs
    assert [(f.path, f.title, f.created_at[:10]) for f in _file_nodes(builder_node)] == [
        (path, title, date) for _source, path, title, date in files
    ]


def test_cross_check_root_level_matches_group_folder_listing() -> None:
    """At the source root the builder's direct subfolders / direct
    files equal the agent's root level, element for element."""
    (source,) = build_kb_tree(["S"], CROSS_ROWS, CROSS_SUMMARIES)
    _cross_check("", source)
    # And the explicit expectations (the test is readable without the
    # helper): one → 4 docs (its whole subtree), zz → 2.
    assert source.documents == 8
    assert [(f.path, f.documents, f.summary) for f in _folder_nodes(source)] == [
        ("one", 4, "One desc."),
        ("zz", 2, "Zz desc."),
    ]
    assert [(f.path, f.title) for f in _file_nodes(source)] == [
        ("note", "Note"),
        ("root.md", "Root"),
    ]


def test_cross_check_nested_level_matches_group_folder_listing() -> None:
    """One nested level (``one``): subfolder ``one/two`` (2 docs, no
    stored summary) + the direct files ``one/a.md`` / ``one/b.md`` —
    equal to the agent's drill into the same folder."""
    (source,) = build_kb_tree(["S"], CROSS_ROWS, CROSS_SUMMARIES)
    one = next(f for f in _folder_nodes(source) if f.path == "one")
    _cross_check("one", one)
    assert [(f.path, f.documents, f.summary) for f in _folder_nodes(one)] == [
        ("one/two", 2, None),
    ]
    assert [(f.path, f.title) for f in _file_nodes(one)] == [
        ("one/a.md", "A"),
        ("one/b.md", "B"),
    ]


# --------------------------------------------------------------------
# summary_pending (phase 98, task 03) — the D3 rule (ONE concept):
# a SOURCE or FOLDER node is pending iff its recursive document count
# ≥ MIN_DOCS_PER_FOLDER (1) AND it has NO stored folder_summaries row
# (AI or manual — any row). That is exactly
# ``app.rag.folder_summaries.missing_folder_summaries``'s candidate
# set — the marker never drifts from the gap-fill (the integration
# cross-check in ``tests/integration/test_docs_api.py`` pins it
# end to end). FILE nodes carry no flag.
# --------------------------------------------------------------------


def test_folder_two_docs_no_stored_row_is_pending() -> None:
    """A ≥ 2-doc folder with NO stored row → ``summary_pending`` true
    (the marker's "waiting to generate" semantics); file nodes carry
    no flag at all (the file table has no description column)."""
    rows = [
        ("S", "one/a.md", "A", 1, T0, C0),
        ("S", "one/b.md", "B", 1, T0, C0),
    ]
    (source,) = build_kb_tree(["S"], rows, {})
    (one,) = _folder_nodes(source)
    assert one.documents == 2
    assert one.summary is None
    assert one.summary_pending is True
    file = _file_nodes(one)[0]
    assert "summary_pending" not in file.__class__.model_fields
    assert "summary_pending" not in file.model_dump()


def test_folder_with_stored_row_is_not_pending() -> None:
    """The same ≥ 2-doc folder WITH a stored row — ANY row, the builder
    cannot tell AI from manual — is NOT pending (a description exists).
    A row on the folder does not cover the source root: with no
    ``(source, "")`` row the SOURCE node stays pending."""
    rows = [
        ("S", "one/a.md", "A", 1, T0, C0),
        ("S", "one/b.md", "B", 1, T0, C0),
    ]
    (source,) = build_kb_tree(["S"], rows, {("S", "one"): "Manual."})
    (one,) = _folder_nodes(source)
    assert one.summary == "Manual."
    assert one.summary_pending is False
    # The source root (2 docs) has no (source, "") row of its own.
    assert source.summary is None
    assert source.summary_pending is True


def test_single_document_folder_is_pending() -> None:
    """The ≥ 1 rule: a 1-document folder with NO stored row IS pending
    (its one file line no longer exempts it — the next sync
    summarizes it), as is its source root (2 docs, no root row).
    A registered 0-document source is the only never-pending case."""
    rows = [
        ("S", "solo/only.md", "Only", 1, T0, C0),  # 1-doc folder
        ("S", "top.md", "Top", 1, T0, C1),  # source total = 2
    ]
    (source,) = build_kb_tree(["S"], rows, {})
    (solo,) = _folder_nodes(source)
    assert solo.documents == 1
    assert solo.summary_pending is True
    assert source.summary_pending is True


def test_name_collision_pending_follows_recursive_count() -> None:
    """The phase-94 count-rule edge: documents ``one/a`` AND ``one/a/b``
    → folder ``one/a`` exists and its recursive count is 2 (the document
    whose path EQUALS the folder name counts — the ``path == folder``
    arm) → pending true with no stored row, even though the folder has
    only ONE direct file — pending follows the RECURSIVE count, not
    the number of direct children. A stored row on the NESTED folder
    alone clears only that marker (the rule is per node)."""
    rows = [
        ("S", "one/a", "File A", 1, T0, C0),  # a file wearing the folder's name
        ("S", "one/a/b.md", "B", 1, T0, C1),  # makes ``one/a`` a folder
    ]
    (source,) = build_kb_tree(["S"], rows, {})
    one = _folder_nodes(source)[0]
    assert one.path == "one"
    assert one.documents == 2
    assert one.summary_pending is True
    a = _folder_nodes(one)[0]
    assert a.path == "one/a"
    assert a.documents == 2  # "one/a" itself + "one/a/b.md"
    assert len(_file_nodes(a)) == 1  # ONE direct file — the count is not that
    assert a.summary_pending is True
    # Stored row on the nested folder only: it clears that node, and
    # only that node.
    (nested,) = build_kb_tree(["S"], rows, {("S", "one/a"): "Nested."})
    one2 = _folder_nodes(nested)[0]
    a2 = _folder_nodes(one2)[0]
    assert a2.summary == "Nested."
    assert a2.summary_pending is False
    assert one2.summary_pending is True


def test_source_root_pending_and_zero_document_source_never() -> None:
    """The source root: a source with ≥ 1 docs and NO ``(source, "")``
    row → the SOURCE node is pending; the stored root row clears it.
    A registered 0-document source is NEVER pending (0 < the minimum —
    there is nothing to summarize), with or without a manual row."""
    rows = [
        ("Full", "x/1.md", "1", 1, T0, C0),
        ("Full", "y.md", "Y", 1, T0, C1),
    ]
    full, empty = build_kb_tree(["Full", "Empty"], rows, {})
    assert full.documents == 2
    assert full.summary_pending is True
    assert empty.documents == 0
    assert empty.summary_pending is False
    full2, empty2 = build_kb_tree(
        ["Full", "Empty"], rows, {("Full", ""): "Root desc."}
    )
    assert full2.summary == "Root desc."
    assert full2.summary_pending is False
    assert empty2.summary_pending is False


def test_two_sources_pending_independently() -> None:
    """Pending is computed per source: with one source holding a root
    row and the other not, only the rowless source's node is pending —
    the markers never leak across sources."""
    rows = [
        ("A", "a1.md", "A1", 1, T0, C0),
        ("A", "a2.md", "A2", 1, T0, C1),
        ("B", "b1.md", "B1", 1, T0, C2),
        ("B", "b2.md", "B2", 1, T0, C3),
    ]
    a, b = build_kb_tree(["A", "B"], rows, {("A", ""): "A root."})
    assert (a.summary, a.summary_pending) == ("A root.", False)
    assert (b.summary, b.summary_pending) == (None, True)


# --------------------------------------------------------------------
# Document dates (phase 106, task 05, D8/D9) — the pure builder's date
# threading: file ``created_at`` verbatim; folder/source ``updated_at``
# = the subtree's MAX document ``created_at`` (derived as the builder
# recurses, never stored; ``None`` for a node with no documents).
# --------------------------------------------------------------------


def test_updated_at_deep_file_beats_shallow_sibling() -> None:
    """D9: a folder's ``updated_at`` is the MAX over its WHOLE subtree —
    a deeper file's date wins over a shallower sibling's (the max
    recurses through every level, not just the direct files)."""
    rows = [
        ("S", "root.md", "Root", 1, T0, C0),
        ("S", "a/top.md", "Top", 1, T0, C1),
        ("S", "a/b/shallow.md", "Shallow", 1, T0, C2),
        ("S", "a/b/c/deep.md", "Deep", 1, T0, C3),  # the overall max
    ]
    (source,) = build_kb_tree(["S"], rows, {})
    a = _folder_nodes(source)[0]
    a_b = _folder_nodes(a)[0]
    a_b_c = _folder_nodes(a_b)[0]
    # The deepest folder: its one file's date.
    assert a_b_c.updated_at == C3
    # a/b: its own file (C2) vs its child's subtree max (C3) → C3.
    assert a_b.updated_at == C3
    # a: its direct file (C1) vs the deeper subtree (C3) → the DEEPER
    # file's date wins over the shallow sibling's.
    assert a.updated_at == C3
    # The source root: max over root.md (C0) + a's subtree (C3).
    assert source.updated_at == C3
    # File nodes carry their own date verbatim — no ``updated_at`` key.
    deep = _file_nodes(a_b_c)[0]
    assert deep.created_at == C3
    assert "updated_at" not in deep.model_dump()


def test_updated_at_direct_file_wins_when_it_is_the_max() -> None:
    """The inverse: when a folder's OWN direct file holds the newest
    date, the max stays at the direct level (the recursion takes the
    max, it does not prefer depth)."""
    rows = [
        ("S", "root.md", "Root", 1, T0, C0),
        ("S", "a/top.md", "Top", 1, T0, C3),  # the overall max, DIRECT
        ("S", "a/b/shallow.md", "Shallow", 1, T0, C1),
        ("S", "a/b/c/deep.md", "Deep", 1, T0, C2),
    ]
    (source,) = build_kb_tree(["S"], rows, {})
    a = _folder_nodes(source)[0]
    a_b = _folder_nodes(a)[0]
    a_b_c = _folder_nodes(a_b)[0]
    assert a_b_c.updated_at == C2  # its own file
    assert a_b.updated_at == C2  # max(C1, child C2)
    assert a.updated_at == C3  # the direct file (C3) beats the subtree (C2)
    assert source.updated_at == C3  # max(C0, a's C3)


def test_updated_at_threads_through_folder_only_subtree() -> None:
    """A folder with NO direct files (only subfolders) still carries the
    date threaded up from its child subfolders — the max is over the
    children (files AND folders), so a pure directory chain never loses
    the dates below it."""
    rows = [("S", "a/b/c/x.md", "X", 1, T0, C2)]
    (source,) = build_kb_tree(["S"], rows, {})
    a = _folder_nodes(source)[0]  # no direct files — only subfolder a/b
    a_b = _folder_nodes(a)[0]  # no direct files — only subfolder a/b/c
    a_b_c = _folder_nodes(a_b)[0]
    assert a_b_c.updated_at == C2
    assert a_b.updated_at == C2
    assert a.updated_at == C2
    assert source.updated_at == C2


def test_updated_at_is_none_only_for_nodes_without_documents() -> None:
    """``None`` is reserved for nodes with NO documents at all — a
    registered 0-document source; every node that has ≥ 1 document in
    its subtree carries a date (the 6th catalogue element is always
    present — ``created_at`` is NOT NULL, D1)."""
    full, empty = build_kb_tree(
        ["Full", "Empty"],
        [("Full", "only.md", "Only", 1, T0, C1)],
        {},
    )
    assert full.documents == 1
    assert full.updated_at == C1
    assert empty.documents == 0
    assert empty.updated_at is None
    assert empty.children == []


def test_updated_at_does_not_leak_across_sources() -> None:
    """The max is per source subtree: one source's newest document never
    lifts another source's ``updated_at`` (the dates are computed
    inside :func:`build_kb_tree`'s per-source node, like ``documents``
    and ``summary_pending``)."""
    rows = [
        ("A", "a1.md", "A1", 1, T0, C0),
        ("B", "b1.md", "B1", 1, T0, C3),  # B's date is the global max
    ]
    a, b = build_kb_tree(["A", "B"], rows, {})
    assert a.updated_at == C0
    assert b.updated_at == C3


# ---------------------------------------------------------------------------
# Phase 122 (task 04) — the image-docs affordance on tree file nodes
# ---------------------------------------------------------------------------

DOC_ID = "11111111-2222-3333-4444-555555555555"


def test_image_file_node_carries_the_affordance_and_text_node_unchanged() -> None:
    """The ``images`` map (``{(source, path): (doc_id, summary)}``) turns
    a file node into the image-docs node: ``is_image`` true,
    ``image_url`` = the bytes route's path built from the mapped id,
    ``summary`` verbatim (the RAG view's thumbnail ``alt``). A file
    node NOT in the map keeps the pre-phase wire shape byte-identically
    (the three image keys are OMITTED, not false/null)."""
    rows = [
        ("S", "one/a.md", "A", 1, T0, C0),
        ("S", "one/pic.png", "pic", 2, T0, C0),
    ]
    images = {("S", "one/pic.png"): (DOC_ID, "A red square on a white background.")}
    (source,) = build_kb_tree(["S"], rows, {}, images)
    one = _folder_nodes(source)[0]
    # File nodes keep the FULL source-relative path (the phase-97
    # shape — the folder prefix rides the node).
    files = {f.path: f for f in _file_nodes(one)}

    # Text node: the pre-phase wire shape, byte-identical (no image keys).
    assert set(files["one/a.md"].model_dump()) == {
        "kind", "path", "title", "chunks", "created_at", "indexed_at"
    }

    # Image node: the affordance rides the node.
    dumped = files["one/pic.png"].model_dump()
    assert dumped["kind"] == "file"
    assert dumped["is_image"] is True
    assert dumped["image_url"] == f"/api/documents/{DOC_ID}/image"
    assert dumped["summary"] == "A red square on a white background."
    # The catalogue fields still ride verbatim.
    assert (dumped["title"], dumped["chunks"]) == ("pic", 2)
    assert (dumped["created_at"], dumped["indexed_at"]) == (C0, T0)


def test_image_file_node_null_summary_and_missing_map_entry() -> None:
    """A mapped image node with a NULL summary (the fail-soft backfill
    corner) keeps ``summary: null`` on the wire (meaningful — the alt
    falls back client-side). A map entry that points at a NON-existent
    (source, path) affects nothing (the builder only reads mapped keys
    it meets in the catalogue rows)."""
    rows = [
        ("S", "one/ghost.png", "ghost", 1, T0, C0),
        ("S", "one/other.md", "Other", 1, T0, C0),
    ]
    images = {
        ("S", "one/ghost.png"): (DOC_ID, None),
        ("S", "one/absent.png"): (DOC_ID, "never matched"),
    }
    (source,) = build_kb_tree(["S"], rows, {}, images)
    one = _folder_nodes(source)[0]
    files = {f.path: f for f in _file_nodes(one)}
    ghost = files["one/ghost.png"].model_dump()
    assert ghost["is_image"] is True
    assert ghost["summary"] is None  # null stays (the alt fallback corner)
    assert ghost["image_url"] == f"/api/documents/{DOC_ID}/image"
    assert set(files["one/other.md"].model_dump()) == {
        "kind", "path", "title", "chunks", "created_at", "indexed_at"
    }


def test_image_affordance_absent_without_the_map() -> None:
    """No map (the default) → every file node is the pre-phase shape,
    even for ``.png`` paths: the fields are map-driven (the endpoint
    composes the map from the ``is_image`` rows), never path-guessed —
    a pre-phase KB serializes byte-identically."""
    rows = [("S", "pic.png", "pic", 1, T0, C0)]
    (source,) = build_kb_tree(["S"], rows, {})
    (file,) = _file_nodes(source)
    assert set(file.model_dump()) == {
        "kind", "path", "title", "chunks", "created_at", "indexed_at"
    }


# ---------------------------------------------------------------------------
# Phase 167 (task 02, D2/A2) — the depth budget: a node whose children were
# NOT built says so (``truncated``) while keeping every field the Sources
# view renders (recursive count, recursive updated_at — the D9 max via the
# _folder_counts max-date map, summary, summary_pending), the untruncated
# wire shape stays byte-identical, and the catalogue totals ride the
# response (``_kb_totals`` — the stat cards cannot be summed client-side
# off a truncated tree).
# ---------------------------------------------------------------------------

#: The depth fixture: one chain four levels deep, distinct created dates
#: (C0 < C1 < C2 < C3 — the DEEPEST file holds the max, the D9 trap) and
#: distinct indexed stamps.
DEPTH_ROWS: list[TreeDocRow] = [
    ("S", "root.md", "Root", 1, T0, C0),
    ("S", "a/top.md", "Top", 2, T1, C1),
    ("S", "a/b/mid.md", "Mid", 3, T1, C2),
    ("S", "a/b/c/deep.md", "Deep", 4, T2, C3),
]

DEPTH_SUMMARIES = {("S", "a"): "A desc."}  # a/b and a/b/c stay un-stored


def _all_nodes(node):
    """The node plus every descendant node (folders and files)."""
    yield node
    for child in getattr(node, "children", []):
        if child.kind == "folder":
            yield from _all_nodes(child)
        else:
            yield child


def _all_folder_nodes(node):
    """Every FOLDER descendant (the SOURCE node itself is excluded — it
    carries ``name``, not ``path``, and has no ``kind``)."""
    return [n for n in _all_nodes(node) if getattr(n, "kind", None) == "folder"]


def _paths_under(node) -> set[str]:
    """Paths of every descendant (folders and files); the source node
    has no path of its own."""
    out: set[str] = set()
    for child in getattr(node, "children", []):
        out.add(child.path)
        if child.kind == "folder":
            out |= _paths_under(child)
    return out


def test_depth_none_is_byte_identical_to_the_unlimited_build() -> None:
    """``depth=None`` (the builder default) reproduces today's tree
    byte-for-byte: the default call, the explicit None, and an
    over-deep budget all serialize identically, and NO node carries the
    truncated key (the omission rule)."""
    default = [s.model_dump() for s in build_kb_tree(["S"], DEPTH_ROWS, DEPTH_SUMMARIES)]
    explicit = [
        s.model_dump() for s in build_kb_tree(["S"], DEPTH_ROWS, DEPTH_SUMMARIES, depth=None)
    ]
    over_deep = [
        s.model_dump() for s in build_kb_tree(["S"], DEPTH_ROWS, DEPTH_SUMMARIES, depth=8)
    ]
    assert default == explicit == over_deep
    (source,) = build_kb_tree(["S"], DEPTH_ROWS, DEPTH_SUMMARIES)
    assert all("truncated" not in n.model_dump() for n in _all_nodes(source))
    # The full chain IS built: every level of the fixture is present.
    assert _paths_under(source) == {
        "root.md",
        "a",
        "a/top.md",
        "a/b",
        "a/b/mid.md",
        "a/b/c",
        "a/b/c/deep.md",
    }


def test_depth_one_ships_sources_plus_one_level_with_truncated_flags() -> None:
    """``depth=1``: the source's direct children are built (direct file
    ``root.md`` included) and the subfolder with unloaded contents
    carries the FULL truncation field set — ``truncated is True``,
    ``children == []``, the RECURSIVE count, the RECURSIVE max date
    (the deep C3 — D9 survives without the children), the stored
    ``summary`` and the ``summary_pending`` flag (rule unchanged)."""
    (source,) = build_kb_tree(["S"], DEPTH_ROWS, DEPTH_SUMMARIES, depth=1)
    assert [f.path for f in _file_nodes(source)] == ["root.md"]
    (a,) = _folder_nodes(source)
    assert a.path == "a"
    assert a.truncated is True
    assert a.model_dump()["truncated"] is True
    assert a.children == []
    assert a.documents == 3  # recursive — the count rule is depth-proof
    assert a.updated_at == C3  # the DEEP max, no built children to derive from
    assert a.summary == "A desc."  # the level row shows a subfolder's description
    assert a.summary_pending is False  # the stored row covers it (phase 98)
    # Nothing deeper is built anywhere.
    assert _paths_under(source) == {"root.md", "a"}


def test_depth_two_builds_two_levels_and_truncates_the_deeper_one() -> None:
    """``depth=2``: level 1 (``a``) is expanded UNTRUNCATED (its direct
    file ``a/top.md`` ships), level 2 (``a/b``) is the truncated node —
    the pending rule applies to it (2 docs, no stored row →
    ``summary_pending`` true with ``summary None``), and neither its
    own file (``a/b/mid.md``) nor the third level appear: the budget
    removes the LEVELS below it, level by level."""
    (source,) = build_kb_tree(["S"], DEPTH_ROWS, DEPTH_SUMMARIES, depth=2)
    (a,) = _folder_nodes(source)
    assert "truncated" not in a.model_dump()  # untruncated: key absent
    assert [f.path for f in _file_nodes(a)] == ["a/top.md"]
    (a_b,) = _folder_nodes(a)
    assert a_b.truncated is True
    assert a_b.children == []
    assert (a_b.documents, a_b.updated_at) == (2, C3)  # mid + deep, max C3
    assert a_b.summary is None
    assert a_b.summary_pending is True  # the phase-98 rule rides truncated nodes
    assert _paths_under(source) == {
        "root.md",
        "a",
        "a/top.md",
        "a/b",
    }


def test_source_node_is_never_truncated_at_any_depth() -> None:
    """The view's top level is source → level 1, so the budget never
    marks the SOURCE node truncated (at any depth, empty sources
    included) — its wire shape never carries the key."""
    (ref,) = build_kb_tree(["S"], DEPTH_ROWS, DEPTH_SUMMARIES)
    for depth in (1, 2, 3, 8):
        full, empty = build_kb_tree(
            ["S", "Empty"], DEPTH_ROWS, DEPTH_SUMMARIES, depth=depth
        )
        assert full.truncated is False
        assert "truncated" not in full.model_dump()
        assert empty.truncated is False
        assert "truncated" not in empty.model_dump()
        assert empty.children == []
        # Direct children always built: the source's level is complete.
        assert [c.path for c in full.children] == [c.path for c in ref.children]


def test_truncated_key_never_touches_the_file_node_shape() -> None:
    """A FILE node has no children to truncate: the field does not even
    exist on the class, and no dump ever carries it (the phase-122 text
    wire shape stays byte-identical at every depth)."""
    assert "truncated" not in KbTreeFile.model_fields
    for depth in (1, 2, 8):
        (source,) = build_kb_tree(["S"], DEPTH_ROWS, {}, depth=depth)
        file_nodes = [n for n in _all_nodes(source) if getattr(n, "kind", None) == "file"]
        assert file_nodes  # the fixture has files at every shipped level
        for node in file_nodes:
            assert "truncated" not in node.model_dump()


def test_max_dates_map_agrees_with_subtree_max_at_every_depth() -> None:
    """One concept, two derivations, cross-pinned: the
    ``_folder_counts`` max-date map equals ``_subtree_max`` over the
    FULLY expanded children for every folder (the expanded builder path
    stays ``_subtree_max``, so a divergence fails loudly) — and every
    node present in a depth-limited tree carries the SAME
    ``updated_at`` as the full build, truncated or not (the phase-106
    D9 column survives the payload diet)."""
    file_rows = [
        (path, title, chunks, indexed, created)
        for _source, path, title, chunks, indexed, created in DEPTH_ROWS
    ]
    _folders, _counts, max_dates = _folder_counts(file_rows)
    (full,) = build_kb_tree(["S"], DEPTH_ROWS, DEPTH_SUMMARIES)
    full_dates = {n.path: n.updated_at for n in _all_folder_nodes(full)}
    assert full_dates == max_dates  # the cross-pin at full expansion
    for node in _all_folder_nodes(full):
        # The expanded node's derivation equals the aggregate map.
        assert _subtree_max(node.children) == max_dates[node.path]
    for depth in (1, 2, 3):
        (limited,) = build_kb_tree(["S"], DEPTH_ROWS, DEPTH_SUMMARIES, depth=depth)
        for node in _all_folder_nodes(limited):
            assert node.updated_at == max_dates[node.path] == full_dates[node.path]
        # The source max also spans the UNSENT levels.
        assert limited.updated_at == C3


def test_truncation_keeps_the_phase_94_and_98_invariants_at_every_depth() -> None:
    """Existence rule, ordering, counts, summaries, pending markers and
    dates: every node a limited tree DOES send is field-for-field the
    node the full tree sends (the depth budget removes depth only — it
    never changes what a shipped level says), and the top level is
    identical at every depth."""
    (full,) = build_kb_tree(["S"], CROSS_ROWS, CROSS_SUMMARIES)
    full_map = {
        n.path: (n.documents, n.summary_pending, n.updated_at, n.summary)
        for n in _all_folder_nodes(full)
    }
    for depth in (1, 2, 3):
        (limited,) = build_kb_tree(["S"], CROSS_ROWS, CROSS_SUMMARIES, depth=depth)
        # Same level-1 rows, same order, at every depth.
        assert [c.path for c in limited.children] == [c.path for c in full.children]
        for node in _all_folder_nodes(limited):
            assert (
                node.documents,
                node.summary_pending,
                node.updated_at,
                node.summary,
            ) == full_map[node.path]
            # Existence rule: a node is present ⟺ a catalogue prefix.
            assert node.path in full_map
        # Every truncated node is exactly the truncation contract.
        for node in _all_folder_nodes(limited):
            if node.truncated:
                assert node.children == []
            else:
                assert node.model_dump().get("truncated") is None


def test_truncated_nodes_keep_the_image_affordance_at_their_level() -> None:
    """Phase 122's affordance is row-driven, not depth-driven: a DIRECT
    image file of the source root still carries the thumbnail keys at
    ``depth=1``; the truncated folder below simply does not list its
    own rows (they arrive with the drill)."""
    rows = [
        ("S", "pic.png", "pic", 1, T0, C0),
        ("S", "d/x.png", "x", 1, T0, C0),
    ]
    images = {
        ("S", "pic.png"): (DOC_ID, "A red square."),
        ("S", "d/x.png"): (DOC_ID, "A blue circle."),
    }
    (source,) = build_kb_tree(["S"], rows, {}, images, depth=1)
    (pic,) = _file_nodes(source)
    assert pic.is_image is True
    assert pic.model_dump()["image_url"] == f"/api/documents/{DOC_ID}/image"
    assert pic.model_dump()["summary"] == "A red square."
    (d,) = _folder_nodes(source)
    assert d.truncated is True
    assert d.children == []


# ---------------------------------------------------------------------------
# _kb_totals (phase 167, task 02) — the stat-card totals the endpoint ships
# beside any depth of tree (no extra query, empty-KB honest).
# ---------------------------------------------------------------------------


def test_kb_totals_math_over_the_catalogue_rows() -> None:
    """documents = the row count, chunks = the sum, last_indexed = the
    MAX indexed stamp (lexicographic over one ISO shape = chronological
    — the same rule as the D9 max)."""
    totals = _kb_totals(DEPTH_ROWS)
    assert totals.documents == 4
    assert totals.chunks == 10  # 1 + 2 + 3 + 4
    assert totals.last_indexed == T2  # the newest indexed_at


def test_kb_totals_empty_kb_is_zero_and_none() -> None:
    """The empty KB: 0 documents, 0 chunks, ``last_indexed is None`` —
    the stat cards render the designed empty state, never a crash."""
    totals = _kb_totals([])
    assert totals == KbTreeTotals(documents=0, chunks=0, last_indexed=None)
    assert totals.model_dump() == {
        "documents": 0,
        "chunks": 0,
        "last_indexed": None,
    }


def test_kb_tree_totals_default_and_floor_validation() -> None:
    """``KbTree.totals`` is an additive top-level key with an honest
    empty default (an older call shape still serializes), and the
    ge=0 bounds refuse negative totals loudly (the endpoint computes
    them — a negative is a bug, never data)."""
    assert KbTree(sources=[]).model_dump()["totals"] == {
        "documents": 0,
        "chunks": 0,
        "last_indexed": None,
    }
    with pytest.raises(ValidationError):
        KbTreeTotals(documents=-1, chunks=0)
    with pytest.raises(ValidationError):
        KbTreeTotals(documents=0, chunks=-1)