# -*- coding: utf-8 -*-
"""An opening that all but reaches an edge must not leave a fibre behind.

A real piece had an opening drawn to 11.1041 ft on a panel 11.1042 ft wide.
The 0.001 in of concrete left over was, arithmetically, the outermost material
in the section -- so every in-plane stress was reported at a fibre 110 in from
the centroid instead of 23 in, on a sliver nothing could be cast into. The
piece came back at 432 psi where a commercial check of the same piece said
162, and it was one of only two failures in a 194-piece sweep.

The stress at a fibre that is not really there is a stress nobody has.
"""
import pytest

from panellift import section
from panellift.model import Blockout

from conftest import make_panel


def _panel_with_opening(gap_ft):
    """A panel whose only opening stops `gap_ft` short of the far edge."""
    panel = make_panel()
    panel.blockouts = [Blockout(
        name='O1', x0=10.0, y0=3.0, length=4.0,
        width=panel.width_ft - 3.0 - gap_ft)]
    return panel


@pytest.mark.parametrize('gap_ft', [0.0, 1e-4, 1e-3, 0.004])
def test_a_drafting_sliver_is_not_the_extreme_fibre(gap_ft):
    """Whether the opening lands exactly on the edge or a thousandth short,
    the section has to be the same piece of concrete."""
    exact = section.NetSection(_panel_with_opening(0.0), 12.0)
    nearly = section.NetSection(_panel_with_opening(gap_ft), 12.0)

    assert nearly.width_in == pytest.approx(exact.width_in, abs=0.1)
    assert nearly.y_extremes_in[1] == pytest.approx(exact.y_extremes_in[1],
                                                    abs=0.1)
    assert nearly.iy_in4 == pytest.approx(exact.iy_in4, rel=0.01)


def test_the_extreme_fibre_is_inside_the_concrete():
    """The outermost fibre cannot be further from the centroid than the
    material is. This is what the sliver broke: 110 in of lever arm on a
    section only 46 in wide."""
    net = section.NetSection(_panel_with_opening(1e-3), 12.0)
    reach = max(abs(v) for v in net.y_extremes_in)
    assert reach <= net.width_in, (
        'extreme fibre %.1f in from the centroid, but the section is only '
        '%.1f in wide' % (reach, net.width_in))


def test_an_opening_well_short_of_the_edge_keeps_its_strip():
    """The snap is a noise floor, not a licence to delete real concrete. A
    strip an inch and a half wide is still a strip."""
    panel = _panel_with_opening(0.125)          # 1.5 in of concrete left
    net = section.NetSection(panel, 12.0)
    strips = section.strips_at(panel, 12.0)
    assert len(strips) == 2
    assert net.y_extremes_in[1] > 0.5 * panel.width_ft * 12.0