LLeMbas/tests/test_ui_js.py

"""Dialogs and toasts, checked without a runtime.

There is no JavaScript test runner here and hard rule 1 keeps Node out of the
project, so the behaviour is driven by hand under a DOM stub before committing.
What can be pinned in the suite are the invariants the file states about itself
-- and in particular the one that would look like an improvement to somebody
tidying up later.
"""

from __future__ import annotations

import re
from pathlib import Path

import lembas

ROOT = Path(lembas.__file__).parent
SOURCE = (ROOT / "web/static/js/ui.js").read_text(encoding="utf-8")
TEMPLATES = ROOT / "web/templates"


def test_the_dialogs_never_fall_back_to_the_browsers_own():
    """`window.confirm` and `window.prompt` cannot be styled, ignore the theme
    and block the tab. Putting one back is the thing this module exists to
    prevent."""
    assert "window.confirm(" not in SOURCE
    assert "window.prompt(" not in SOURCE


def test_no_template_uses_htmx_s_own_prompt():
    """htmx's hx-prompt calls the browser's prompt() *synchronously* and only
    then fires htmx:prompt with the answer already in hand -- so intercepting
    the event cannot supply a different one, and the native box appears
    regardless. `data-prompt` exists because of that, and an hx-prompt slipped
    in later would summon the grey box back with nothing to catch it.

    hx-confirm is fine and is used widely: that one fires *before*, and ui.js
    intercepts it.
    """
    # The attribute, not the word: the comment beside `data-prompt` names
    # hx-prompt in order to say why it is not being used.
    offenders = [
        path.relative_to(TEMPLATES)
        for path in TEMPLATES.rglob("*.html")
        if 'hx-prompt="' in path.read_text(encoding="utf-8")
    ]
    assert not offenders, f"hx-prompt summons window.prompt: {offenders}"


def test_the_prompt_answer_is_json_encoded_rather_than_concatenated():
    """A folder called `"` would otherwise produce hx-vals that does not parse,
    and htmx would send the request with the field missing rather than with the
    name -- a rename that silently does nothing."""
    start = SOURCE.index("[data-prompt]")
    block = SOURCE[start : SOURCE.index("data-confirm", start)]
    assert "JSON.stringify" in block


def test_every_prompt_button_names_a_field_or_takes_the_default():
    """The field name is what the route reads. A button with a field the route
    does not look at posts nothing and looks exactly like one that works."""
    for path in TEMPLATES.rglob("*.html"):
        text = path.read_text(encoding="utf-8")
        if "data-prompt=" not in text:
            continue
        # Either an explicit field, or the "name" default the handler applies.
        assert "data-prompt-field" in text or "/api/folders" in text, path


# --- The transcript's open blocks, and the scroll that used to chase them ------
STEPS = (ROOT / "web/static/js/steps.js").read_text(encoding="utf-8")
APP = (ROOT / "web/static/js/app.js").read_text(encoding="utf-8")


def test_the_toggle_listener_is_registered_in_the_capture_phase():
    """`toggle` does not bubble. Registered without the third argument the
    listener is never called, in every browser, with nothing anywhere to say so
    -- the same shape as a trigger bound where the event does not go, which cost
    two selects an entire release.

    Asserted as the property rather than as the markup, for that reason.
    """
    found = re.search(r'"toggle",[\s\S]{0,600}?\n\s*(true|false)\n\s*\);', APP)
    assert found, "the toggle listener is gone"
    assert found.group(1) == "true"


def test_the_scroll_listener_is_too():
    """A scroll event does not bubble either, and this one is on the thread
    rather than on the document it is registered against."""
    found = re.search(r'"scroll",[\s\S]{0,600}?\n\s*(true|false)\n\s*\);', APP)
    assert found, "the scroll listener is gone"
    assert found.group(1) == "true"


def test_the_stream_no_longer_scrolls_for_every_frame():
    """`metrics`, `status`, `ask` and `canvas` all arrive on htmx:sseMessage,
    and none of them changes the height of the thread. Scrolling for all of them
    is what made an opened block impossible to keep on screen."""
    found = re.search(r'htmx:sseMessage", function \(event\) \{([\s\S]{0,400}?)\n  \}\);', APP)
    assert found, "the handler is gone"
    assert "thread-scroll" in found.group(1)


def test_the_open_state_is_recorded_before_the_swap_and_restored_after():
    """Both halves, or it is a module that does nothing. The container is
    replaced with innerHTML twelve times a second, so anything not written down
    first is gone by the time there is somewhere to put it back."""
    assert "htmx:sseBeforeMessage" in STEPS
    assert "htmx:sseMessage" in STEPS
    assert "htmx:afterSwap" in STEPS


def test_it_never_cancels_the_frame_it_is_listening_to():
    """htmx:sseBeforeMessage is cancellable -- the extension reads what handlers
    return to decide whether to swap at all. Cancelling here would freeze the
    transcript with no error anywhere."""
    assert "preventDefault" not in STEPS


def test_an_id_is_escaped_rather_than_concatenated_into_a_selector():
    """The same rule `data-prompt` follows for hx-vals. An id is a message id
    and two integers today; a selector assembled by hand is how that stops being
    true safely."""
    assert "CSS.escape" in STEPS


def test_the_finished_bubble_repeats_the_live_container_s_id():
    """That is the whole mechanism for carrying an opened block across the
    `done` frame, which replaces the entire article: same id on the container,
    same ids inside it, because both come from the mark index."""
    message = (TEMPLATES / "chat/_message.html").read_text(encoding="utf-8")

    assert message.count('id="steps-{{ message.id }}" data-steps') == 2