"""Fixtures for the AutoCal tests.

Everything here runs offscreen with no controller and no hardware. Two
environment facts are set before Qt is imported:

* ``QT_QPA_PLATFORM=offscreen`` so a window can be built without a display;
* ``QT_QPA_FONTDIR`` because the offscreen platform finds no fonts on Windows
  otherwise, and every label would measure as zero-width.

The suite requires PySide6 — the app's only Qt binding. Where it is missing
(an older interpreter, or a machine with no way to install it) the tests are
reported as skipped rather than failing, so a broken environment cannot look
like a broken application.
"""

from __future__ import annotations

import os
import sys
from pathlib import Path

import pytest

os.environ.setdefault("ORISYS_APP_ID", "autocal")
os.environ.setdefault("QT_QPA_PLATFORM", "offscreen")
if sys.platform == "win32" and "QT_QPA_FONTDIR" not in os.environ:
    _fonts = Path(os.environ.get("WINDIR", r"C:\Windows")) / "Fonts"
    if _fonts.is_dir():
        os.environ["QT_QPA_FONTDIR"] = str(_fonts)


def _have_pyside6() -> tuple[bool, str]:
    try:
        import PySide6
    except ImportError as exc:
        return False, str(exc)
    return True, getattr(PySide6, "__version__", "unknown")


HAVE_PYSIDE6, PYSIDE6_VERSION = _have_pyside6()

if not HAVE_PYSIDE6:  # pragma: no cover - depends on the machine
    collect_ignore_glob = ["test_*.py"]


@pytest.fixture(scope="session")
def qt_app():
    """One ``QApplication`` per session (Qt forbids more than one)."""
    if not HAVE_PYSIDE6:  # pragma: no cover
        pytest.skip("PySide6 is not installed")
    from PySide6.QtWidgets import QApplication

    app = QApplication.instance() or QApplication([])
    yield app


SCRATCH_ROOT = Path(__file__).resolve().parents[1] / "outputs" / "_test_scratch"


def _scratch_dir() -> Path:
    """A fresh scratch directory under the app's own (gitignored) outputs."""
    import time

    path = SCRATCH_ROOT / f"{os.getpid()}-{int(time.time() * 1000) % 1_000_000}"
    path.mkdir(parents=True, exist_ok=True)
    return path


@pytest.fixture
def make_window(qt_app, monkeypatch):
    """Build a window whose preference writes stay inside a scratch directory.

    Deliberately not ``tmp_path``: this suite has to run inside a sandboxed
    shell, and ``tmp_path`` depends on a writable process temp root that such an
    environment may not provide. Using the app's own ``outputs/`` (already
    gitignored) removes that dependency entirely.
    """
    import shutil

    from orisys_app_shared import paths as paths_mod
    from orisys_app_shared import prefs as prefs_pkg

    from orisys_autocal import preferences as prefs_mod
    from orisys_autocal.motion import DemoTransport
    from orisys_autocal.ui.window import AutoCalMainWindow

    scratch = _scratch_dir()
    prefs_file = scratch / "preference.json"
    monkeypatch.setattr(paths_mod, "preference_path", lambda: prefs_file)
    monkeypatch.setattr(prefs_pkg.store, "preference_path", lambda: prefs_file)
    monkeypatch.setattr(prefs_mod, "preference_path", lambda: prefs_file)

    created = []

    def _make(**overrides):
        prefs = prefs_mod.default_preferences()
        prefs.update(overrides)
        # The translator is process-global, so a window built after another test
        # switched language would otherwise keep that language and then be
        # labelled with the wrong locale.
        from orisys_app_shared.i18n import set_locale

        set_locale(str(prefs.get("language") or "zh_CN"))
        window = AutoCalMainWindow(prefs=prefs)
        # Swap in the simulated platform: no test in this suite touches a DLL.
        window.poller.service._transport = DemoTransport()  # noqa: SLF001
        created.append(window)
        return window

    yield _make

    for window in created:
        try:
            window.poller.shutdown()
            window.close()
        except Exception:  # noqa: BLE001 - teardown must not mask a failure
            pass
    shutil.rmtree(scratch, ignore_errors=True)


def pump(app, seconds: float = 0.2) -> None:
    """Run the event loop for a short, bounded time."""
    import time

    deadline = time.monotonic() + seconds
    while time.monotonic() < deadline:
        app.processEvents()
        time.sleep(0.005)


def visible_descendants(widget):
    """Yield every visible descendant of ``widget``."""
    for child in widget.findChildren(object):
        if not hasattr(child, "isVisible") or not hasattr(child, "geometry"):
            continue
        if child.isVisible():
            yield child