"""Offscreen tests for the BOM window's drag/drop path (no display needed —
QGraphicsScene is pure Qt). Guards the placement-id vs cut-item-id crash."""
import os

import pytest

os.environ.setdefault("QT_QPA_PLATFORM", "offscreen")
pytest.importorskip("PySide6")

from PySide6.QtWidgets import QApplication  # noqa: E402

from woodshop.cutplan import find_placement  # noqa: E402
from woodshop.gui.bom_window import BomWindow, _Piece  # noqa: E402
from woodshop.gui.controller import Controller  # noqa: E402

_app = QApplication.instance() or QApplication([])


def _pieces(w):
    return sorted((it for it in w.scene.items() if isinstance(it, _Piece)),
                  key=lambda it: it.pos().x())


def test_drop_overlap_reverts_without_crashing(tmp_path):
    c = Controller(str(tmp_path / "s.json"))
    c.place("2x4", 30)
    c.place("2x4", 30)                       # one stick, two pieces
    w = BomWindow(c)
    first, second = _pieces(w)[:2]
    home = (second.sp_id, second.pos().x(), second.pos().y())
    second.setPos(0, second.pos().y())       # drop on top of the first -> overlap
    w._drop_piece(second, home)              # must not raise (was StopIteration)
    assert "revert" in w._status.text().lower()


def test_drop_onto_incompatible_stock_reverts(tmp_path):
    c = Controller(str(tmp_path / "s.json"))
    c.place("2x4", 24)
    c.place("ply-3/4", 24, width_in=24)
    w = BomWindow(c)
    lumber = next(it for it in _pieces(w)
                  if not find_placement(w._plan, it.pid)[0].is_sheet)
    sheet_y = next(y0 for y0, _y1, sp in w._rows if sp.is_sheet)
    home = (lumber.sp_id, lumber.pos().x(), lumber.pos().y())
    lumber.setPos(10, sheet_y + 5)           # drag the 2x4 onto the plywood sheet
    w._drop_piece(lumber, home)              # must not raise
    assert "can't go" in w._status.text()


def test_best_of_n_button_keeps_valid_plan(tmp_path):
    from woodshop.cutplan import validate_cut_plan
    c = Controller(str(tmp_path / "s.json"))
    for ln in (50, 46, 40, 30):
        c.place("2x4", ln)
    w = BomWindow(c)
    w._best_of_n()                           # no locks -> best of 100
    assert validate_cut_plan(w._plan) == []
    assert "best" in w._status.text().lower()


def test_best_of_n_with_lock_runs_and_validates(tmp_path):
    from woodshop.cutplan import validate_cut_plan
    c = Controller(str(tmp_path / "s.json"))
    for ln in (50, 46, 40, 30):
        c.place("2x4", ln)
    w = BomWindow(c)
    p = next(p for sp in w._plan.stock_pieces for p in sp.placements)
    p.locked = True
    w._best_of_n()                           # locked path: strategies + shuffles
    assert validate_cut_plan(w._plan) == []
    assert "locked" in w._status.text()


def test_valid_move_commits(tmp_path):
    c = Controller(str(tmp_path / "s.json"))
    c.place("2x4", 20)
    c.place("2x4", 20)
    w = BomWindow(c)
    second = _pieces(w)[1]
    home = (second.sp_id, second.pos().x(), second.pos().y())
    second.setPos(50 * w._px, second.pos().y())   # slide it right, still clear
    w._drop_piece(second, home)
    assert "placed" in w._status.text().lower()