FabledScribe/tests/test_write_path_design_arm.py

"""The write-path design arm: a UI write is told which design system binds it (#4256).

A design system binds like a rule, and before this it reached a session only
through the session-start block — complete for a session that knows to ask,
silent for one writing a component. These tests pin:

- THE TRIGGER is the file, not a search: a UI path in a project that has a
  design system. No vectors, no score, no slot taken from the ranked menu.
- WHAT IT SAYS is an index — each inherited layer's section headings, with a
  layer short enough to be a line (the leaf's departure) shown whole.
- IT DOES NOT MOVE THE OTHER ARMS. A design-only write returns without
  running the standing-rule arm, which is gated on there being prior art;
  letting the design line into that gate would change the rule arm's call
  distribution under the floor it was tuned against.
- ONCE PER SESSION PER SYSTEM, on the hook's token-keyed channel.
"""
from __future__ import annotations

from unittest.mock import AsyncMock, MagicMock, patch

import pytest

from scribe.services import plugin_context as pc
from tests.helpers import writepath_cfg

HOUSE = (
    "## Aesthetic\n\nModern-mythic with restraint. " + "Long prose. " * 60
    + "\n\n## Where the accent must NOT appear\n\nNot on buttons.\n\n"
    "## Voice and tone\n\nPlain language for anything functional."
)
LEAF = "The accent appears on the wordmark and active navigation."


def _design(ds_id=9):
    return {
        "id": ds_id, "title": "App", "description": "",
        "inherits_from": ["House"],
        "guidance": [
            {"design_system_id": 1, "title": "House", "guidance": HOUSE},
            {"design_system_id": ds_id, "title": "App", "guidance": LEAF},
        ],
        "token_count": 3, "token_groups": ["accent"],
    }


def _project(ds_id=9):
    return MagicMock(id=2, title="App", design_system_id=ds_id)


# ── the trigger ───────────────────────────────────────────────────────────


@pytest.mark.parametrize("path,ui", [
    ("frontend/src/views/NoteView.vue", True),
    ("frontend/src/styles/components.css", True),
    ("web/App.TSX", True),
    ("templates/index.html", True),
    ("src/scribe/services/dedup.py", False),
    ("frontend/src/utils/deadWeight.ts", False),
    ("README.md", False),
    ("", False),
])
def test_ui_paths(path, ui):
    """`.ts` is deliberately not UI: a utility module is logic, and firing on
    it would put the design line in front of writes it says nothing about."""
    assert pc.is_ui_path(path) is ui


@pytest.mark.asyncio
async def test_no_project_asks_nothing():
    get = AsyncMock()
    with patch.object(pc.projects_svc, "get_project", get):
        assert await pc._design_arm(1, 0, "a/B.vue", set()) == ("", "")
    get.assert_not_called()


@pytest.mark.asyncio
async def test_a_non_ui_write_asks_nothing():
    get = AsyncMock()
    with patch.object(pc.projects_svc, "get_project", get):
        assert await pc._design_arm(1, 2, "src/x.py", set()) == ("", "")
    get.assert_not_called()


@pytest.mark.asyncio
async def test_a_project_without_a_design_system_says_nothing():
    ctx = AsyncMock()
    with patch.object(pc.projects_svc, "get_project", AsyncMock(return_value=_project(None))), \
         patch.object(pc.design_systems_svc, "design_context", ctx):
        assert await pc._design_arm(1, 2, "a/B.vue", set()) == ("", "")
    ctx.assert_not_called()


@pytest.mark.asyncio
async def test_already_shown_this_session_is_not_fetched_again():
    ctx = AsyncMock()
    with patch.object(pc.projects_svc, "get_project", AsyncMock(return_value=_project())), \
         patch.object(pc.design_systems_svc, "design_context", ctx):
        out = await pc._design_arm(1, 2, "a/B.vue", {pc.design_key(9)})
    assert out == ("", "")
    ctx.assert_not_called()


@pytest.mark.asyncio
async def test_an_unreadable_design_system_says_nothing():
    with patch.object(pc.projects_svc, "get_project", AsyncMock(return_value=_project())), \
         patch.object(pc.design_systems_svc, "design_context", AsyncMock(return_value=None)):
        assert await pc._design_arm(1, 2, "a/B.vue", set()) == ("", "")


@pytest.mark.asyncio
async def test_a_failure_never_breaks_the_write():
    with patch.object(pc.projects_svc, "get_project", AsyncMock(side_effect=RuntimeError)):
        assert await pc._design_arm(1, 2, "a/B.vue", set()) == ("", "")


# ── what it says ──────────────────────────────────────────────────────────


def test_the_line_indexes_the_house_style_and_inlines_the_departure():
    line = pc._design_line("a/B.vue", _design())
    assert "App (id 9) (inherits House)" in line
    assert "`get_design_system(9)` → `resolved_guidance`" in line
    assert "`resolve_design_system(9)`" in line
    # The long layer is named by its headings, not pasted.
    assert "House covers Aesthetic · Where the accent must NOT appear · Voice and tone" in line
    assert "Long prose." not in line
    # The short layer is the app's own departure, and is shown whole.
    assert f'App: "{LEAF}"' in line


def test_the_line_stays_a_line():
    """The index exists because the prose does not fit: resolved guidance
    runs to thousands of characters. A line that grew back to that size
    would be the prose again under another name."""
    assert len(pc._design_line("a/B.vue", _design())) < 800


def test_a_long_layer_with_no_headings_is_elided_not_pasted():
    design = _design()
    design["guidance"][0]["guidance"] = "Unheaded prose. " * 200
    line = pc._design_line("a/B.vue", design)
    assert len(line) < 1200
    assert "House:" in line


# ── in the hint ───────────────────────────────────────────────────────────


def _quiet():
    """Every other arm silent: nothing recorded, nothing similar."""
    return [
        patch.object(pc, "get_writepath_config", AsyncMock(return_value=writepath_cfg())),
        patch.object(pc.snippets_svc, "list_snippets", AsyncMock(return_value=([], 0))),
        patch.object(pc, "semantic_search_notes", AsyncMock(return_value=[])),
        patch.object(pc, "record_retrieval", MagicMock()),
        patch.object(pc.projects_svc, "get_project", AsyncMock(return_value=_project())),
        patch.object(pc.design_systems_svc, "design_context", AsyncMock(return_value=_design())),
        patch.object(pc, "owner_names_for", AsyncMock(return_value={})),
    ]


async def _hint(patches, **kw):
    import contextlib
    with contextlib.ExitStack() as stack:
        for p in patches:
            stack.enter_context(p)
        rules = stack.enter_context(
            patch.object(pc, "semantic_search_rules", AsyncMock(return_value=[]))
        )
        out = await pc.build_write_path_hint(1, "frontend/src/B.vue", project_id=2, **kw)
    return out, rules


@pytest.mark.asyncio
async def test_a_ui_write_with_no_prior_art_still_hears_the_design_system():
    out, _ = await _hint(_quiet())
    assert out["context"].startswith("> Design system binds `frontend/src/B.vue`")
    assert out["derive_keys"] == [pc.design_key(9)]
    assert out["note_ids"] == [] and out["rule_ids"] == []


@pytest.mark.asyncio
async def test_a_design_only_write_does_not_switch_the_rule_arm_on():
    """The rule arm runs only where there is prior art. A design line that
    joined that gate would start a semantic rule search on every UI write —
    a new population of calls under a floor tuned without them."""
    _, rules = await _hint(_quiet())
    rules.assert_not_called()


@pytest.mark.asyncio
async def test_shown_once_per_session():
    out, _ = await _hint(_quiet(), exclude_derive=[pc.design_key(9)])
    assert out["context"] == ""
    assert out["derive_keys"] == []


@pytest.mark.asyncio
async def test_beside_prior_art_it_leads_and_rides_the_keyed_channel():
    patches = _quiet()
    patches[1] = patch.object(pc.snippets_svc, "list_snippets", AsyncMock(return_value=(
        [{"id": 5, "title": "fs-button", "user_id": 1, "note_type": "snippet"}], 1,
    )))
    out, _ = await _hint(patches)
    lines = out["context"].splitlines()
    assert lines[0].startswith("> Design system binds")
    assert any("fs-button" in ln for ln in lines[1:])
    assert pc.design_key(9) in out["derive_keys"]
    # It takes no menu slot: the snippet is still reported as surfaced.
    assert 5 in out["note_ids"]