"""Convert the official MIRepNet checkpoint to Braindecode Hub format."""

from __future__ import annotations

import argparse
import hashlib
from pathlib import Path

import torch

from braindecode.models import MIRepNet


SOURCE_SHA256 = "432288958007e344a5a84a9ffe9d0e5e5c0cb616aef86c85522375a3f4da9aaf"


def main() -> None:
    parser = argparse.ArgumentParser()
    parser.add_argument("source", type=Path)
    parser.add_argument("output", type=Path)
    args = parser.parse_args()

    if hashlib.sha256(args.source.read_bytes()).hexdigest() != SOURCE_SHA256:
        raise ValueError("Source checkpoint SHA-256 does not match the official file.")

    source = torch.load(args.source, map_location="cpu", weights_only=True)
    model = MIRepNet(n_chans=45, n_outputs=3, n_times=1000, sfreq=250)
    incompatible = model.load_state_dict(source, strict=False)
    expected_unexpected = {
        "mask_token",
        "embedding.chan_embed.weight",
        *(key for key in source if key.startswith("decoder.")),
    }
    if (
        incompatible.missing_keys
        or set(incompatible.unexpected_keys) != expected_unexpected
    ):
        raise RuntimeError(f"Unexpected conversion result: {incompatible}")
    model.save_pretrained(args.output)


if __name__ == "__main__":
    main()