import matplotlib

matplotlib.use("Agg")

import numpy as np
from pathlib import Path
from scipy.spatial import Voronoi, voronoi_plot_2d

np.set_printoptions(precision=1, suppress=True)

points = np.array(
    [
        [0.0, 0.0],
        [0.0, 1.0],
        [0.0, 2.0],
        [1.0, 0.0],
        [1.0, 1.0],
        [1.0, 2.0],
        [2.0, 0.0],
        [2.0, 1.0],
        [2.0, 2.0],
    ]
)

vor = Voronoi(points)

center_point = 4
center_region_index = vor.point_region[center_point]
center_region = vor.regions[center_region_index]
finite_ridges = [ridge for ridge in vor.ridge_vertices if -1 not in ridge]

print("input points:", len(points))
print("Voronoi vertices:")
for vertex in vor.vertices:
    print(f"  [{vertex[0]:.1f}, {vertex[1]:.1f}]")
print("regions total:", len(vor.regions))
print("point 4 region index:", center_region_index)
print("point 4 region vertices:", center_region)
print("finite ridges:", len(finite_ridges))
print("first ridge pairs:")
for point_pair, vertex_pair in zip(vor.ridge_points[:4], vor.ridge_vertices[:4]):
    print(f"  points {point_pair.tolist()} -> vertices {vertex_pair}")

fig = voronoi_plot_2d(
    vor,
    show_vertices=False,
    line_colors="tab:blue",
    line_width=2,
    point_size=35,
)
ax = fig.axes[0]
ax.set_aspect("equal", adjustable="box")
ax.set_xlim(-0.5, 2.5)
ax.set_ylim(-0.5, 2.5)
ax.set_title("Voronoi diagram")
fig.savefig("voronoi-demo.png", dpi=150, bbox_inches="tight")

print("saved plot:", Path("voronoi-demo.png").name)