import json
import pathlib
import sys

import bpy


def main(blend_path: str, output_path: str) -> None:
    bpy.ops.wm.open_mainfile(filepath=str(pathlib.Path(blend_path).resolve()), load_ui=False)
    scene = bpy.context.scene
    object_name = "AnimatedObject"
    obj = bpy.data.objects.get(object_name)
    if obj is None:
        raise RuntimeError(f"{object_name} is missing")

    frames = [1, 5, 10]
    samples = []
    for frame in frames:
        scene.frame_set(frame)
        depsgraph = bpy.context.evaluated_depsgraph_get()
        evaluated = obj.evaluated_get(depsgraph)
        mesh = evaluated.to_mesh(preserve_all_data_layers=True, depsgraph=depsgraph)
        try:
            samples.append({
                "frame": frame,
                "worldMatrix": [value for row in evaluated.matrix_world for value in row],
                "positions": [coordinate for vertex in mesh.vertices for coordinate in vertex.co],
            })
        finally:
            evaluated.to_mesh_clear()

    result = {
        "schemaVersion": 1,
        "fixture": pathlib.Path(blend_path).name,
        "evaluator": "Blender Depsgraph",
        "blenderVersion": bpy.app.version_string,
        "object": object_name,
        "mesh": obj.data.name,
        "frames": samples,
        "tolerance": {"maxPositionError": 1e-5, "rmsPositionError": 1e-6, "maxMatrixError": 1e-5},
    }
    pathlib.Path(output_path).write_text(json.dumps(result, indent=2) + "\n", encoding="utf-8")


if __name__ == "__main__":
    if "--" not in sys.argv or len(sys.argv) <= sys.argv.index("--") + 2:
        raise SystemExit("usage: blender -b --python generate-frame-evaluation-golden.py -- input.blend output.json")
    arguments = sys.argv[sys.argv.index("--") + 1:]
    main(arguments[0], arguments[1])