"""Regression tests for the Plotly hover/snap-marker contract.

``plotly_hover``/``plotly_unhover`` fire continuously while the mouse moves.
Touching the plot on each one made it redraw per mouse move, re-firing hover
until the stack blew (``RangeError: Maximum call stack size exceeded``) and the
canvas froze. The marker is therefore coalesced and only touched when its
shown/hidden state actually changes.
"""

from __future__ import annotations

from pathlib import Path

import pytest

pytest.importorskip("PySide6")
pytest.importorskip("plotly")

from otko.services import load_project

EXAMPLES = Path(__file__).resolve().parents[2] / "examples"

#: 200 mouse-move events over a *non-snap* point with snapping armed.
_CHURN_PROBE = """(function(){
  var gd = document.getElementById('plot');
  var n = 0; var original = Plotly.restyle;
  Plotly.restyle = function () { n++; return original.apply(Plotly, arguments); };
  var point = { data: gd.data[0], customdata: [0, 0, 0] };
  try {
    for (var i = 0; i < 200; i++) {
      gd.emit('plotly_hover', { points: [point] });
      gd.emit('plotly_unhover', {});
    }
    return n;
  } finally { Plotly.restyle = original; }
})()"""

_HOVER_MARKER_X = (
    "JSON.stringify((document.getElementById('plot').data"
    ".find(function(d){return d.meta && d.meta.kind === 'hover';}) || {}).x)"
)

_EMIT_SNAP_HOVER = """(function(){
  var gd = document.getElementById('plot');
  var snap = gd.data.filter(function(d){return d.meta && d.meta.kind === 'snap';})[0];
  var point = { data: snap, customdata: [snap.x[0], snap.y[0], snap.z[0]] };
  gd.emit('plotly_hover', { points: [point] });
  return true;
})()"""


def _open_canvas(qtbot, name: str):  # type: ignore[no-untyped-def]
    from otko.views.canvas_plotly import PlotlyCanvas

    canvas = PlotlyCanvas()
    qtbot.addWidget(canvas)
    canvas.show_project(load_project(EXAMPLES / name))
    qtbot.waitUntil(lambda: canvas._ready, timeout=30000)
    qtbot.wait(1500)  # let the first Plotly.react settle
    return canvas


def _run_js(canvas, qtbot, script: str, timeout: int = 15000):  # type: ignore[no-untyped-def]
    box: dict[str, object] = {}
    canvas._web.page().runJavaScript(script, lambda value: box.update(value=value))
    qtbot.waitUntil(lambda: "value" in box, timeout=timeout)
    return box["value"]


@pytest.mark.gui
def test_ordinary_mouse_movement_does_not_redraw(qtbot) -> None:  # type: ignore[no-untyped-def]
    """The unfixed version restyled once per hover/unhover event."""
    canvas = _open_canvas(qtbot, "space_frame_3d.osmodel")

    restyles = _run_js(canvas, qtbot, _CHURN_PROBE)

    assert restyles == 0, f"mouse movement caused {restyles} plot restyles"


@pytest.mark.gui
def test_snap_marker_shows_and_clears(qtbot) -> None:  # type: ignore[no-untyped-def]
    canvas = _open_canvas(qtbot, "basic_truss.osmodel")
    assert _run_js(canvas, qtbot, _HOVER_MARKER_X) == "[]"

    canvas.set_snap_preview_enabled(True)
    qtbot.wait(100)
    _run_js(canvas, qtbot, _EMIT_SNAP_HOVER)
    qtbot.wait(250)
    assert _run_js(canvas, qtbot, _HOVER_MARKER_X) != "[]", "snap target not shown"

    _run_js(canvas, qtbot, "document.getElementById('plot').emit('plotly_unhover',{})")
    qtbot.wait(250)
    assert _run_js(canvas, qtbot, _HOVER_MARKER_X) == "[]", "snap target not cleared"