"""Der Graph, aus dem die Straßen entstehen. Gegenstück zum Entwurf, Abschnitt "Das Netz"."""
from __future__ import annotations

import numpy as np

from leonida.coords import SLICE
from leonida.roads import JUNCTION_RADIUS, graph_from_skeleton


def skeleton(pixels: list[tuple[int, int]], shape=(120, 120)) -> np.ndarray:
    skel = np.zeros(shape, dtype=bool)
    for r, c in pixels:
        skel[r, c] = True
    return skel


def kreuz(arm: int = 40) -> np.ndarray:
    """Ein Pluszeichen: vier Arme von 40 px an einem Mittelpunkt."""
    pixels = [(60, c) for c in range(60 - arm, 60 + arm + 1)]
    pixels += [(r, 60) for r in range(60 - arm, 60 + arm + 1)]
    return skeleton(pixels)


def test_ein_kreuz_gibt_einen_knoten_und_vier_kanten():
    graph = graph_from_skeleton(kreuz())
    junctions = [i for i in range(len(graph.nodes)) if graph.degree(i) >= 3]
    assert len(junctions) == 1
    assert graph.degree(junctions[0]) == 4
    assert len(graph.edges) == 4


def test_kanten_beginnen_und_enden_am_knotenpunkt():
    graph = graph_from_skeleton(kreuz())
    mitte = graph.nodes[next(i for i in range(len(graph.nodes)) if graph.degree(i) >= 3)].point
    for edge in graph.edges:
        enden = {edge.points[0], edge.points[-1]}
        assert mitte in enden, "jede Kante des Kreuzes hängt am Mittelknoten"


def test_zwei_kreuzungen_naeher_als_der_radius_werden_ein_knoten():
    # Zwei Abzweige im Abstand von 4 m — unter JUNCTION_RADIUS, also ein Knoten.
    pixels = [(60, c) for c in range(20, 100)]
    pixels += [(r, 58) for r in range(40, 60)]
    pixels += [(r, 62) for r in range(60, 80)]
    graph = graph_from_skeleton(skeleton(pixels))
    assert 4 < JUNCTION_RADIUS
    assert len([i for i in range(len(graph.nodes)) if graph.degree(i) >= 3]) == 1


def test_gerade_strecke_ohne_abzweig_gibt_eine_kante_mit_zwei_enden():
    graph = graph_from_skeleton(skeleton([(60, c) for c in range(20, 100)]))
    assert len(graph.edges) == 1
    assert [graph.degree(i) for i in range(len(graph.nodes))] == [1, 1]


def test_punkte_liegen_in_weltkoordinaten():
    graph = graph_from_skeleton(skeleton([(60, c) for c in range(20, 100)]))
    xs = [x for x, _ in graph.edges[0].points]
    assert min(xs) == SLICE["x0"] + 20
    assert max(xs) == SLICE["x0"] + 99