"""Minimal `rembg` runner, invoked as its own subprocess.

We deliberately don't shell out to the official `rembg` CLI: that needs
the `rembg[cli]` extra (aiohttp, gradio, watchdog, ...) just to run a
single background removal. Calling the `remove()` API directly from a
tiny script keeps the image smaller while still giving pipeline.py a
subprocess boundary to apply `nice` and a hard timeout to.

Defaults target the event box (≈8GB RAM): u2net + alpha matting.
`birefnet-general` (~928MB weights) OOMs here; override via REMBG_MODEL
/ REMBG_ALPHA if the host has more headroom.
"""

from __future__ import annotations

import os
import sys
import traceback
from pathlib import Path


def _env_bool(name: str, default: bool) -> bool:
    raw = os.environ.get(name)
    if raw is None:
        return default
    return raw.strip().lower() in {"1", "true", "yes", "on"}


def main() -> int:
    if len(sys.argv) != 3:
        print("usage: python -m app.rembg_cli <input> <output>", file=sys.stderr)
        return 2

    # Keep model-download progress bars from polluting error parsing upstream.
    os.environ.setdefault("TQDM_DISABLE", "1")

    try:
        from rembg import new_session, remove

        input_path = Path(sys.argv[1])
        output_path = Path(sys.argv[2])
        output_path.parent.mkdir(parents=True, exist_ok=True)

        model = os.environ.get("REMBG_MODEL", "u2net")
        alpha = _env_bool("REMBG_ALPHA", True)
        session = new_session(model)
        output_path.write_bytes(
            remove(
                input_path.read_bytes(),
                session=session,
                alpha_matting=alpha,
            )
        )
        return 0
    except Exception as exc:  # noqa: BLE001 - surface real cause to parent process
        print(f"{type(exc).__name__}: {exc}", file=sys.stderr)
        traceback.print_exc(file=sys.stderr)
        return 1


if __name__ == "__main__":
    raise SystemExit(main())