#!/usr/bin/env bash
set -euo pipefail

ENV_PREFIX="${1:-$PWD/.venv}"
PYTHON_BIN="${PYTHON_BIN:-python3}"
TORCH_INDEX_URL="${TORCH_INDEX_URL:-https://download.pytorch.org/whl/cu128}"

if [[ ! -x "$(command -v "$PYTHON_BIN")" ]]; then
  echo "Python executable not found: $PYTHON_BIN" >&2
  exit 2
fi

"$PYTHON_BIN" -m venv "$ENV_PREFIX"
"$ENV_PREFIX/bin/python" -m pip install --upgrade pip setuptools wheel
"$ENV_PREFIX/bin/python" -m pip install \
  --index-url "$TORCH_INDEX_URL" \
  torch==2.8.0 torchvision==0.23.0
"$ENV_PREFIX/bin/python" -m pip install -r "$(dirname "$0")/requirements.txt"

"$ENV_PREFIX/bin/python" - <<'PY'
import cv2
import torch
import ultralytics

print(f"torch={torch.__version__}")
print(f"torchvision CUDA build={torch.version.cuda}")
print(f"ultralytics={ultralytics.__version__}")
print(f"opencv={cv2.__version__}")
print(f"cuda_available={torch.cuda.is_available()}")
if torch.cuda.is_available():
    for index in range(torch.cuda.device_count()):
        print(f"gpu[{index}]={torch.cuda.get_device_name(index)}")
PY

echo "Environment ready. Activate with: source $ENV_PREFIX/bin/activate"