"""
The page ships before the nodes do.

The SPA is served by the hub, so deploying the hub puts this version of the
client in front of *every* node, including the ones still running MNP 1.0. That
window is not a corner case — it is the normal state for as long as it takes an
operator to update, and for a node someone else runs it may be indefinite.

The failure mode is specific and quiet: a node logs an unknown message type and
sends **nothing back**, so a control that speaks MNP 1.1 to it produces a
thirty-second wait ending in a timeout, with nothing on screen to say the node
simply cannot do this. Three of them were like that before these tests:

* The shared-directories toggles, eject and plug have no older equivalent at
  all.
* The per-app folder pickers spoke `app_directories`, where a 1.0 node
  understands `video_root` / `audio_root` / `photo_roots`.

Source-reading, like the other SPA guards. What it cannot check is that the
degraded path is pleasant; what it does check is that each of the three exists.
"""

import re
from pathlib import Path

import pytest

STATIC = Path(__file__).resolve().parents[1] / "src" / "meshbay_hub" / "static"
TRANSPORT = STATIC / "transport.js"
FILES_APP = STATIC / "files-app.js"
GROUP_PAGE = STATIC / "group-page.js"
GROUP_SETTINGS = STATIC / "group-settings.js"

pytestmark = pytest.mark.skipif(not TRANSPORT.exists(),
                                reason="SPA sources unavailable")


def _component(source: str, name: str) -> str:
    start = source.index(f"\nfunction {name}(")
    end = source.find("\nfunction ", start + 1)
    return source[start:end if end != -1 else len(source)]


# ── Knowing which node you are talking to ───────────────────────────────────

def test_the_client_keeps_the_version_it_checked():
    """
    `_checkNodeVersion` parsed the node's version and threw it away, so nothing
    downstream could ask. Refusing to connect is not the only thing a version
    is good for.
    """
    source = TRANSPORT.read_text(encoding="utf-8")
    assert "this._nodeVersion = String(reply.v" in source
    assert "get supportsAppOps()" in source


def test_the_capability_reads_the_version_rather_than_guessing():
    """
    Inferring it from whether some field happens to be present is how two
    unrelated things end up coupled — the flag would flip because a payload
    changed shape for another reason entirely.
    """
    source = TRANSPORT.read_text(encoding="utf-8")
    getter = source[source.index("get supportsAppOps()"):]
    getter = getter[:getter.index("\n  }") + 4]
    assert "_nodeVersion" in getter
    assert "1" in getter, "no version comparison in the capability check"


# ── The three degraded paths ────────────────────────────────────────────────

def test_app_directories_fall_back_to_the_three_older_messages():
    """
    Videos, Music and Photos each had their own message before the generic op,
    and those still work — so an operator on an un-upgraded node keeps the
    ability they had rather than being handed a control that times out.
    """
    source = TRANSPORT.read_text(encoding="utf-8")
    legacy = source[source.index("async setAppDirectoriesLegacy("):]
    legacy = legacy[:legacy.index("\n  async ", 1)]
    for call in ("setPhotoRoots", "setVideoRoot", "setAudioRoot"):
        assert call in legacy, f"{call} is not reachable on the older path"

    panel = _component(GROUP_SETTINGS.read_text(encoding="utf-8"),
                       "GroupSettingsPanel")
    assert "transport.supportsAppOps" in panel, (
        "the settings page sends the 1.1 message unconditionally")


def test_the_older_path_refuses_what_it_cannot_carry():
    """
    `video_root` and `audio_root` hold one folder. Sending several would store
    the first and drop the rest silently, which is worse than refusing — the
    operator would see a saved setting that is not what they chose.
    """
    source = TRANSPORT.read_text(encoding="utf-8")
    legacy = source[source.index("async setAppDirectoriesLegacy("):]
    legacy = legacy[:legacy.index("\n  async ", 1)]
    assert "clean.length > 1" in legacy
    assert "throw new Error" in legacy


def test_root_management_is_read_only_against_an_older_node():
    """
    Unlike the app directories, `writable`, `removable`, eject and plug have no
    older equivalent to route to. The controls are shown without being
    offered, with the reason, rather than accepting a click that goes nowhere.
    """
    panel = _component(GROUP_SETTINGS.read_text(encoding="utf-8"),
                       "GroupSettingsPanel")
    table_call = panel[panel.index("<${SharedDirectoriesTable}"):]
    table_call = table_call[:table_call.index("/>")]
    assert "readOnly=" in table_call
    assert "nodeSupportsAppOps" in table_call
    assert "settings_node.roots_node_too_old" in panel, (
        "nothing says why the controls are inert")


def test_chat_settings_are_hidden_rather_than_routed():
    """
    Chat's directory and link-preview switch are new in 1.1 with nothing
    before them, so there is no older message to fall back to.
    """
    panel = _component(GROUP_SETTINGS.read_text(encoding="utf-8"),
                       "GroupSettingsPanel")
    assert "settings_node.app_node_too_old" in panel


# ── Reading an older node's handshake ───────────────────────────────────────

def test_the_ack_is_read_in_both_shapes(app=None):
    """
    A 1.0 ack has `video_root` and no `video_directories`, and no
    `chat_link_preview` at all. Reading a missing plural as "nothing
    configured" empties a working Videos tab; reading a missing switch as off
    silently changes what a group's chat does.
    """
    page = GROUP_PAGE.read_text(encoding="utf-8")
    block = page[page.index("setAppDirectories({"):]
    block = block[:block.index("setNodeSupportsAppOps")]
    for legacy in ("ack.video_root", "ack.audio_root", "ack.photo_roots"):
        assert legacy in block, f"{legacy} is not read as a fallback"
    assert "ack.chat_link_preview !== false" in page, (
        "an absent link-preview switch must read as on, not off")