"""Export ground-truth meshes (tooth + canal) for the held-out test cases by
running marching cubes directly on the CLEANED label volume in WORLD coords.
This lets you compare GT vs prediction as two separate assembled scenes.

    python -m toothcanal.export_gt --config configs/default.yaml
"""
import os, argparse
import numpy as np
from .utils import load_config, ensure_dir
from .splits import make_split
from .geometry import sdf_from_mask, marching_cubes_to_mesh


def main():
    ap = argparse.ArgumentParser()
    ap.add_argument("--config", default="configs/default.yaml")
    args = ap.parse_args()
    cfg = load_config(args.config)

    _, test = make_split(cfg["paths"]["proc_dir"], cfg)
    out_dir = ensure_dir(os.path.join(cfg["paths"]["out_dir"], "gt_meshes"))
    for cid in test:
        d = dict(np.load(os.path.join(cfg["paths"]["proc_dir"], f"{cid}.npz")))
        inst = d["inst"]; cinst = d["cinst"]
        sp = d["spacing"].astype(np.float32)
        origin = d.get("origin", np.zeros(3)).astype(np.float32)
        ids = [int(v) for v in np.unique(inst) if v > 0]
        print(f"[gt] {cid}: {len(ids)} teeth")
        for iid in ids:
            tooth_mask = (inst == iid)
            canal_mask = (cinst == iid)
            for name, mask in [("tooth", tooth_mask), ("canal", canal_mask)]:
                if not mask.any():
                    continue
                # crop to bbox + small pad to keep MC fast
                ax = np.argwhere(mask)
                lo = ax.min(0) - 2; hi = ax.max(0) + 3
                lo = np.maximum(lo, 0); hi = np.minimum(hi, mask.shape)
                sl = tuple(slice(int(a), int(b)) for a, b in zip(lo, hi))
                sdf = sdf_from_mask(mask[sl], sp)
                mesh = marching_cubes_to_mesh(sdf, 0.0, sp)
                if mesh is None:
                    continue
                # shift to world coords
                mesh.vertices += (origin + lo * sp)[None, :]
                mesh.export(os.path.join(out_dir, f"{cid}_t{iid:02d}_{name}_GT.stl"))
    print(f"[gt] written GT meshes to {out_dir}")


if __name__ == "__main__":
    main()