"""U7 slice 1 — the rail, the filters, the grid keyboard.

⚠ SCOPE. This covers ONLY the three components ROADMAP's U7 row already
ratifies: a sticky rail, filters, and grid keyboard. The fourth — replacing
directory sections with filename-derived groups — is a scope DEPARTURE proposed
in `docs/contracts/u7_navigation.contract.md` and is deliberately NOT built
here, because it is the operator's call and he has not made it. The rail
therefore carries totals and filter counts and no jump-to-group anchors yet.

`unanswered` is taken to mean HAS AN OPEN PICK — the U4 hold predicate, which
already exists and already has a home. The alternative reading ("has no mark at
all") is a real and different question and is the contract's open question.
"""

from __future__ import annotations

import json
import pathlib
import sys

import pytest
from fastapi.testclient import TestClient

sys.path.insert(0, str(pathlib.Path(__file__).parent.parent))

from booth.app import create_app  # noqa: E402
from booth.marks import declare_pick, set_flag, write_note  # noqa: E402

PNG = b"\x89PNG\r\n\x1a\n"


@pytest.fixture
def gallery(tmp_path):
    """A booth with one of each: flagged, annotated, open pick, and plain."""
    b = tmp_path / "g"
    b.mkdir()
    for n in ("a.png", "b.png", "c.png", "d.png"):
        (b / n).write_bytes(PNG)
    set_flag(b, "a.png", True)
    write_note(b, "b.png", "a remark")
    declare_pick(b, "q", {"prompt": "Which?", "options": ["x", "y"]}, target="c.png")
    app = create_app(tmp_path, ttl_hours=24, start_sweeper=False)
    return TestClient(app), b


def _tiles(body: str) -> list[str]:
    """The rels the grid actually rendered, in render order."""
    import re
    # `data-item` already exists on every tile (both the doc and media
    # variants). Reusing it rather than adding a parallel `data-rel` is the
    # same one-fact-one-place discipline INV-1 states for item facts.
    return re.findall(r'data-item="([^"]+)"', body)


def test_the_rail_counts_every_filter(gallery):
    c, _ = gallery
    body = c.get("/b/g/").text
    assert 'class="rail"' in body
    for token in ("all", "flagged", "annotated", "unanswered"):
        assert f'data-filter="{token}"' in body, token


@pytest.mark.parametrize("flt,expected", [
    ("all", ["a.png", "b.png", "c.png", "d.png"]),
    ("flagged", ["a.png"]),
    ("annotated", ["b.png"]),
    ("unanswered", ["c.png"]),
])
def test_a_filter_narrows_the_grid_server_side(gallery, flt, expected):
    """INV-4: a filter is a LINK, not a script. Fetched directly, with no JS
    executed, the server must return the narrowed grid.

    Defeating change: binding filters to a click handler and returning the full
    grid for every URL — under which this test gets four tiles every time."""
    c, _ = gallery
    assert _tiles(c.get(f"/b/g/?filter={flt}").text) == expected


def test_filtering_never_reorders(gallery):
    """INV-2, the load-bearing one. Grouping and filtering are VIEWS.

    The defeating change is sorting the grid by anything derived from the
    filter — which looks right and silently changes what "the third one" means,
    the misfiled-judgment failure CLAUDE.md invariant 6 exists to prevent.

    Asserted as a SUBSEQUENCE rather than a set: order is the property, so a
    filter that returned the right tiles in the wrong sequence must go red."""
    c, _ = gallery
    # ⚠ THE BASELINE IS COMPUTED INDEPENDENTLY, and that is the whole test.
    # The first version of this compared each filtered view against the
    # UNFILTERED RESPONSE — and a mutation that reversed the order reversed
    # both sides, so it stayed green under the exact change it forbade. Caught
    # by running the mutation rather than trusting the assertion, which is the
    # discipline in persistent-memory.d/2026-09-22-vacuous-falsifiers.md and
    # which this test failed first time out.
    #
    # The independent truth is U1 INV-3: the item order IS `sorted(rel)`. So
    # each filtered view must be sorted, full stop, with no reference to any
    # other response.
    for flt in ("all", "flagged", "annotated", "unanswered"):
        got = _tiles(c.get(f"/b/g/?filter={flt}").text)
        assert got == sorted(got), f"{flt} rendered out of sorted(rel) order: {got}"
    # and every filtered view is a SUBSEQUENCE of the true order, not a reshuffle
    every = sorted(["a.png", "b.png", "c.png", "d.png"])
    for flt in ("all", "flagged", "annotated", "unanswered"):
        got = _tiles(c.get(f"/b/g/?filter={flt}").text)
        assert got == [r for r in every if r in got], flt


def test_an_unknown_filter_falls_back_to_all_and_does_not_500(gallery):
    """A filter arrives from a URL, which is operator-editable and link-shared.
    Defeating change: indexing a dict by the raw parameter."""
    c, _ = gallery
    for junk in ("nonsense", "", "../../etc", "flagged;drop"):
        r = c.get(f"/b/g/?filter={junk}")
        assert r.status_code == 200, junk
        assert len(_tiles(r.text)) == 4, junk


def test_the_zoom_ring_is_identical_under_every_filter(gallery):
    """The ring is the item order filtered to images and must not notice the
    grid's filter — otherwise `next` means something different depending on how
    the operator arrived, and a flag lands on the wrong artifact.

    Defeating change: building the ring from the filtered list."""
    c, _ = gallery
    rings = set()
    for flt in ("all", "flagged", "annotated", "unanswered"):
        c.get(f"/b/g/?filter={flt}")
        body = c.get("/b/g/b.png?view=1").text
        import re
        rings.add(tuple(re.findall(r'href="([^"]*\.png[^"]*)"', body)))
    assert len(rings) == 1, f"the ring changed with the filter: {rings}"


def test_the_rail_is_absent_on_a_booth_with_no_grid(tmp_path):
    """INV-5's sibling: a rail over nothing is chrome. The standing link board
    has no items, so it must not render one."""
    b = tmp_path / "links"
    b.mkdir()
    (b / "links.md").write_text("- [r](https://x.test/) <sub>· a · 2026-09-01 00:00</sub>\n")
    c = TestClient(create_app(tmp_path, ttl_hours=24, start_sweeper=False))
    assert 'class="rail"' not in c.get("/b/links/").text


def test_the_keyboard_is_not_bound_when_there_is_no_grid(tmp_path):
    """INV-5. Defeating change: binding the handler unconditionally, so `f` on
    the standing link board swallows the keystroke and flags nothing."""
    b = tmp_path / "links"
    b.mkdir()
    (b / "links.md").write_text("- [r](https://x.test/) <sub>· a · 2026-09-01 00:00</sub>\n")
    c = TestClient(create_app(tmp_path, ttl_hours=24, start_sweeper=False))
    assert "gridkeys" not in c.get("/b/links/").text


def test_the_keyboard_is_bound_when_there_is_one(gallery):
    c, _ = gallery
    assert "gridkeys" in c.get("/b/g/").text


def test_no_group_rail_is_shipped_yet(gallery):
    """⚠ SCOPE GUARD, and it is deliberate. Replacing directory sections with
    filename-derived groups is a scope DEPARTURE from ROADMAP's U7 row that the
    operator has not ruled on. This test fails the moment somebody builds it
    anyway, so the departure cannot arrive by accident while he is away."""
    c, _ = gallery
    body = c.get("/b/g/").text
    assert "data-group" not in body
    assert 'class="rail-groups"' not in body
    assert 'class="rail"' in body, "the approved rail must still be here"