# SPDX-License-Identifier: Apache-2.0
# Copyright 2026 Lucasgitguy-co
from pathlib import Path

import numpy as np

from .data import cache_sample
from .splats import Splats, preview


def create_demo(root, count=12, grid=8):
    """Procedural ellipsoids only. Never presented as outputs of any real teacher."""
    if count < 4:
        raise ValueError("Use at least four fixtures")
    root = Path(root)
    root.mkdir(parents=True, exist_ok=True)
    rng = np.random.default_rng(17)
    phi, theta = np.meshgrid(np.linspace(.06, np.pi-.06, 14), np.linspace(0, 2*np.pi, 28, endpoint=False))
    unit = np.stack([np.sin(phi)*np.cos(theta), np.cos(phi), np.sin(phi)*np.sin(theta)], axis=-1).reshape(-1, 3)
    for i in range(count):
        radii = rng.uniform(.17, .36, 3)
        xyz = (unit * radii).astype(np.float32)
        colour = rng.uniform(.2, .95, 3)
        rgb = np.clip(colour[None] * (.8 + .2 * unit[:, 1:2]), 0, 1)
        splats = Splats(xyz, rgb, np.full_like(xyz, .035), np.tile([1,0,0,0], (len(xyz),1)), np.full((len(xyz),1), .9))
        image_path = root / f"fixture-{i:03}.png"
        preview(splats, size=128).save(image_path)
        cache_sample(root, f"fixture-{i:03}", image_path, splats, grid, source="synthetic",
                     extra={"purpose": "code verification only", "object_id": f"fixture-{i:03}"})
        image_path.unlink()
    return root / "manifest.jsonl"