r"""
.. _ref_example_geo_specimen_1_H00:

Specimen 1
----------
This example demonstrates the procedure for generating a mesh for the compact tension specimen presented in :footcite:t:`example_Wagner2018_phd_thesis`, from which some of the simulation results will be compared. In this case, the mesh refers to the configuration with no additional holes, so the dimensions of the mesh are related to the stress intensity factor presented in :footcite:t:`lefm_Anderson2005` and :footcite:t:`lefm_Tada`.

All dimensions follow the relationship given in the LEFM formula, which refers to the base dimension $b$. In the case of the paper, $b = 40$ mm, but with this script, the geometry can be scaled simply by modifying this value in the .geo file.

.. footbibliography::

Below is the .geo file used for the specimen 1:

Reference
---------

.. include::  ../../../../examples/GmshGeoFiles/Compact_specimen/specimen_1_H00.geo
   :literal:

"""

###############################################################################
# Mesh Visualization
# ------------------
# The purpose of this code is to visualize the mesh. The mesh is generated from
# the .geo file and saved as output_mesh_for_view.vtu. It is then loaded and
# visualized using PyVista.

import os
import gmsh
import pyvista as pv

folder = "Compact_specimen"

###############################################################################
# Reference
# ---------
# Initialize Gmsh
gmsh.initialize()

# %%
# Open the .geo file
geo_file = os.path.join(folder, "specimen_1_H00.geo")
gmsh.open(geo_file)

# %%
# Generate the mesh (2D example, for 3D use generate(3))
gmsh.model.mesh.generate(2)

# %%
# Write the mesh to a .vtk file for visualization
# Note that the input mesh file for the *phasefieldx* simulation should have the .msh extension.
# Use "output_mesh_for_view.msh" to generate the mesh for the simulation input.
# In this case, the mesh is saved in .vtk format to facilitate visualization with PyVista.
vtu_file = os.path.join(folder, "output_mesh_for_view_1.vtk")
gmsh.write(vtu_file)

# %%
# Finalize Gmsh
gmsh.finalize()

print(f"Mesh successfully written to {vtu_file}")

pv.start_xvfb()
file_vtu = pv.read(vtu_file)
file_vtu.plot(cpos='xy', color='white', show_edges=True)

save_image=False
# Create a PyVista plotter
if save_image:
   plotter = pv.Plotter(off_screen=True)

   # Add the mesh with a light gray surface and visible edges
   plotter.add_mesh(file_vtu, color="lightgray", show_edges=True,
                         edge_color="darkblue", line_width=0.5, opacity=0.7)

   # Add the wireframe with darker lines to highlight the mesh structure
   plotter.add_mesh(file_vtu, style="wireframe", color="black",
                         line_width=1.2)

   # Set the view and background
   plotter.view_xy()
   plotter.set_background("white")
   plotter.camera.tight(padding=0.0)
   plotter.camera.clipping_range = (0.1, 1000.0)

   # Save the screenshot
   image_file = os.path.join(folder, "specimen_1_H00.png")
   plotter.screenshot(image_file, transparent_background=False, return_img=False)
   plotter.close()

   print(f"Image saved to {image_file}")