"""Shared fixtures and helpers: plain-text screen reading, and pinned path rendering.

:func:`plain` is THE way a test reads a rendered screen — every screen test needs the
same move (strip the ANSI colour escapes, join the rendered lines) before it can assert
on content, and each file re-deriving it is how the copies drift.

The powerline verdict is environmental — the suite may run inside VS Code or Windows
Terminal (both chip-capable) or a bare CI shell (not) — and screen assertions must
not change with the developer's glass. ``MESHTERM_POWERLINE=0`` is the supported pin;
the cached verdict is cleared around each test so no ordering leaks it. Powerline-
specific tests pass explicit modes or monkeypatch the widget's own switch.
"""

from __future__ import annotations

import re
from typing import Iterable, Iterator, Union

import pytest

from meshterm.platforms import REGULAR, set_platform
from meshterm.ui.termfont import powerline_support

#: ANSI SGR escapes — the colour runs a rendered line carries between its characters.
_ANSI = re.compile(r"\x1b\[[0-9;]*m")


def plain(rendered: Union[str, Iterable[str]]) -> str:
    """The plain-text form of rendered screen output, for content assertions.

    Takes what a render handed back — a list of ANSI lines (joined with newlines) or a
    single already-joined string — and strips the colour escapes, so assertions read
    the screen the way a viewer does.
    """
    if not isinstance(rendered, str):
        rendered = "\n".join(rendered)
    return _ANSI.sub("", rendered)


@pytest.fixture(autouse=True)
def _plain_path_rendering(monkeypatch: pytest.MonkeyPatch) -> Iterator[None]:
    monkeypatch.setenv("MESHTERM_POWERLINE", "0")
    powerline_support.cache_clear()
    yield
    powerline_support.cache_clear()


@pytest.fixture(autouse=True)
def _reset_platform() -> Iterator[None]:
    """Every test starts and ends on :data:`~meshterm.platforms.REGULAR`.

    A test that calls ``set_platform(PICOCALC)`` (directly, or via the gallery harness)
    can't leak that choice into whatever runs next — regular is the suite's baseline, the
    same way it is the default for a process that never passes ``--platform``/
    ``MESHTERM_PLATFORM`` (see :mod:`meshterm.platforms`).
    """
    set_platform(REGULAR)
    yield
    set_platform(REGULAR)