"""
Creating meshes from pyvista surfaces
======================================

For this example we create meshes from pyvista surfaces. See other examples for
different meshing algorithms.
"""

# %%
from itertools import pairwise
from shutil import which

import ogstools as ot
from ogstools.mesh import create

# an optional requirement (needs to be installed on system or via pip)
tetgen_present = which("tetgen") is not None

if tetgen_present:
    bounds = (-200, 210, -200, 210)
    args = {"bound2D": bounds, "amplitude": 100, "spread": 100, "n": 40}
    gaussians = [
        create.Gaussian2D(**args, height_offset=h) for h in [0, -100, -200]
    ]
    surfaces = [create.Surface(g, mat_id) for mat_id, g in enumerate(gaussians)]
    layers = [create.Layer(sf1, sf2) for sf1, sf2 in pairwise(surfaces)]
    ls = create.LayerSet(layers)

    mesh = ls.to_region_tetrahedron(40).mesh
else:
    mesh = None

# %%
# Visualize the prism mesh
if tetgen_present:
    plotter = ot.plot.contourf(mesh, ot.variables.material_id)
    plotter.show()

# %%