"""Geometric predicates and constants."""

import math

from herding.world.geometry import (
    FIELD_X, FIELD_Y, GATE_X, GATE_Y, MAX_SHEEP, PEN_ENTRY, PEN_X, PEN_Y,
    distance_to_pen_entry, in_field, in_gate_corridor, in_pen,
    is_penned_position,
)


def test_field_dimensions():
    assert FIELD_X == (-15.0, 15.0)
    assert FIELD_Y == (-15.0, 15.0)


def test_pen_geometry():
    assert PEN_X == (10.0, 13.0)
    assert PEN_Y == (-22.0, -15.0)
    assert PEN_ENTRY == (11.5, -15.0)
    assert GATE_X == PEN_X
    assert GATE_Y == -15.0


def test_in_pen_strict_interior():
    assert in_pen(11.5, -18.0)
    assert not in_pen(10.0, -18.0)        # boundary excluded
    assert not in_pen(11.5, -15.0)        # gate plane excluded
    assert not in_pen(0.0, 0.0)


def test_in_field_with_margin():
    assert in_field(0.0, 0.0)
    assert in_field(14.0, 14.0)
    assert not in_field(15.5, 0.0)
    assert in_field(14.4, 0.0, margin=0.5)
    assert not in_field(14.6, 0.0, margin=0.5)


def test_in_gate_corridor():
    assert in_gate_corridor(11.5, -18.0)
    assert in_gate_corridor(10.0, -15.0)
    assert not in_gate_corridor(11.5, -10.0)
    assert not in_gate_corridor(5.0, -18.0)


def test_is_penned_position_latches_below_gate():
    # In the gate column and south of the gate plane → penned.
    assert is_penned_position(11.5, -15.0)
    assert is_penned_position(10.5, -18.0)
    assert is_penned_position(12.5, -22.0)
    # Above the gate plane → not yet.
    assert not is_penned_position(11.5, -14.9)
    # Outside the gate column → not penned even if south.
    assert not is_penned_position(0.0, -16.0)
    assert not is_penned_position(14.0, -16.0)


def test_is_penned_position_latch_margin():
    # Slight tolerance on the gate column.
    assert is_penned_position(9.9, -15.5)
    assert is_penned_position(13.1, -15.5)
    assert not is_penned_position(9.7, -15.5)


def test_distance_to_pen_entry():
    assert distance_to_pen_entry(*PEN_ENTRY) == 0.0
    assert math.isclose(distance_to_pen_entry(11.5, -10.0), 5.0)
    assert math.isclose(distance_to_pen_entry(0.0, 0.0),
                        math.hypot(11.5, 15.0))


def test_max_sheep_positive_int():
    assert isinstance(MAX_SHEEP, int)
    assert MAX_SHEEP >= 1