"""Regression tests for the GUI window/lifecycle fixes (B1-B10).

These tests need a QApplication but run head-less under
``QT_QPA_PLATFORM=offscreen``.  They check the *behaviour* of the centralized
window helpers and assert that the known bug patterns are gone, without trying
to drive a full Electrum session.

Usage:
    QT_QPA_PLATFORM=offscreen PYTHONPATH=<electrum-src> \
        python3 tests/gui_fixes_test.py <PKG>
where <PKG> is e.g. electrum.plugins.bal
"""

import ast
import importlib
import inspect
import sys


def _active_source_without_strings(module) -> str:
    """Return module source with docstrings/strings removed.

    Lets us assert a token is absent from *executable* code even if it still
    appears inside an explanatory docstring/comment.
    """
    src = inspect.getsource(module)
    tree = ast.parse(src)
    # collect string-constant spans to drop
    class _S(ast.NodeVisitor):
        def __init__(self):
            self.spans = []
        def visit_Constant(self, node):
            if isinstance(node.value, str) and hasattr(node, "end_lineno"):
                self.spans.append((node.lineno, node.end_lineno))
            self.generic_visit(node)
    s = _S(); s.visit(tree)
    drop = set()
    for a, b in s.spans:
        drop.update(range(a, b + 1))
    lines = src.splitlines()
    kept = [ln for i, ln in enumerate(lines, start=1)
            if i not in drop and not ln.lstrip().startswith("#")]
    return "\n".join(kept)


def main(pkg: str) -> int:
    from PyQt6.QtWidgets import QApplication, QDialog, QWidget
    app = QApplication.instance() or QApplication(sys.argv)

    wu = importlib.import_module(pkg + ".gui.qt.window_utils")

    # top_level_of: returns the top-level container of a child widget
    w = QWidget(); child = QWidget(w)
    assert wu.top_level_of(child) is w
    assert wu.top_level_of(None) is None
    print("[OK] top_level_of")

    # bring_to_front / stop_thread must never raise on edge inputs
    wu.bring_to_front(QDialog())
    wu.stop_thread(None)
    print("[OK] bring_to_front / stop_thread(None)")

    # _window_key: stable and unique per window
    plugin_mod = importlib.import_module(pkg + ".gui.qt.plugin")
    a, b = QWidget(), QWidget()
    assert plugin_mod._window_key(a) == plugin_mod._window_key(a)
    assert plugin_mod._window_key(a) != plugin_mod._window_key(b)
    print("[OK] _window_key stable & unique")

    # B3/B4: no winId bound-method key, no 'restart Electrum' surrender in
    # *executable* code (docstrings explaining the old behaviour are allowed).
    active = _active_source_without_strings(plugin_mod)
    assert "winId" not in active, "winId still used in executable code"
    print("[OK] no winId in executable code")

    win_mod = importlib.import_module(pkg + ".gui.qt.window")
    active_win = _active_source_without_strings(win_mod)
    assert "restart Electrum" not in active_win
    print("[OK] no 'restart Electrum' surrender in window.py code")

    # B1: BalDialog must not shadow QWidget.parent() with an attribute
    dialogs_mod = importlib.import_module(pkg + ".gui.qt.dialogs")
    dsrc = inspect.getsource(dialogs_mod)
    assert "self.parent =" not in dsrc, "self.parent assignment still present"
    print("[OK] no self.parent shadowing in dialogs.py")

    # REGRESSION: BalDialog.closeEvent / hideEvent must NOT stop the task
    # thread.  Electrum's TaskThread.on_done calls cb_done (often self.accept,
    # which closes the dialog) BEFORE cb_result (on_success, e.g. updating the
    # will-executor list).  If the base closeEvent stopped/joined the thread,
    # the auto-close from accept() would tear the thread down before
    # on_success ran and the downloaded list would be silently dropped.
    close_src = inspect.getsource(dialogs_mod.BalDialog.closeEvent)
    hide_src = inspect.getsource(dialogs_mod.BalDialog.hideEvent)
    assert "stop_thread" not in close_src, (
        "BalDialog.closeEvent must not stop the thread (drops download result)")
    assert "stop_thread" not in hide_src, (
        "BalDialog.hideEvent must not stop the thread (drops download result)")
    print("[OK] BalDialog.closeEvent/hideEvent do not kill the task thread")

    print(f"\n[OK] all GUI-fix checks passed for package {pkg!r}")
    return 0


if __name__ == "__main__":
    if len(sys.argv) != 2:
        print(__doc__)
        sys.exit(2)
    sys.exit(main(sys.argv[1]))