#!/usr/bin/env python3
import pathlib
import sys

import bpy


def main(output: pathlib.Path) -> None:
    bpy.ops.wm.read_factory_settings(use_empty=True)

    mesh = bpy.data.meshes.new("WebGapArmatureMesh")
    mesh.from_pydata(
        [(-1.0, -1.0, 0.0), (1.0, -1.0, 0.0), (1.0, 1.0, 0.0), (-1.0, 1.0, 0.0)],
        [],
        [(0, 1, 2), (0, 2, 3)],
    )
    mesh.update()
    mesh_object = bpy.data.objects.new("WebGapArmatureMeshObject", mesh)
    bpy.context.collection.objects.link(mesh_object)

    armature = bpy.data.armatures.new("WebGapArmature")
    armature_object = bpy.data.objects.new("WebGapArmatureObject", armature)
    bpy.context.collection.objects.link(armature_object)
    bpy.context.view_layer.objects.active = armature_object
    armature_object.select_set(True)
    bpy.ops.object.mode_set(mode="EDIT")
    root = armature.edit_bones.new("Root")
    root.head = (0.0, 0.0, 0.0)
    root.tail = (0.0, 0.0, 1.0)
    bpy.ops.object.mode_set(mode="OBJECT")
    armature_object.select_set(False)

    vertex_group = mesh_object.vertex_groups.new(name="Root")
    vertex_group.add([0, 1, 2, 3], 1.0, "REPLACE")
    modifier = mesh_object.modifiers.new(name="WebGapArmature", type="ARMATURE")
    modifier.object = armature_object
    modifier.vertex_group = "Root"
    modifier.show_viewport = True
    modifier.show_render = True
    modifier.show_in_editmode = True
    modifier.show_on_cage = False

    bpy.context.view_layer.objects.active = mesh_object
    mesh_object.select_set(True)
    bpy.ops.wm.save_as_mainfile(filepath=str(output.resolve()), check_existing=False, compress=True)


if __name__ == "__main__":
    arguments = sys.argv[sys.argv.index("--") + 1 :]
    if len(arguments) != 1:
        raise SystemExit("usage: blender -b --python M16-GAP-00030.py -- OUTPUT")
    main(pathlib.Path(arguments[0]))