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

import bpy


def triangle(name):
    mesh = bpy.data.meshes.new(name)
    mesh.from_pydata([(-1, 0, 0), (1, 0, 0), (0, 1, 0)], [], [(0, 1, 2)])
    mesh.update()
    return mesh


def main(output):
    bpy.ops.wm.read_factory_settings(use_empty=True)
    scene = bpy.context.scene
    scene.name = "WBV2P2002Scene"
    root = scene.collection
    source = bpy.data.collections.new("WBV2P2002Source")
    target = bpy.data.collections.new("WBV2P2002Target")
    root.children.link(source)
    root.children.link(target)

    parent = bpy.data.objects.new("WBV2P2002Parent", triangle("WBV2P2002ParentMesh"))
    source.objects.link(parent)
    parent.location = (1.0, 0.0, 0.0)

    child = bpy.data.objects.new("WBV2P2002Child", triangle("WBV2P2002ChildMesh"))
    source.objects.link(child)
    child.parent = parent
    child.location = (0.0, 2.0, 0.0)

    bpy.context.view_layer.objects.active = parent
    parent.select_set(True)
    child.select_set(False)
    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 --factory-startup --python WBV2-P2-002.py -- OUTPUT")
    main(pathlib.Path(arguments[0]))