# 1. Stable Python base
FROM python:3.11-slim

# 2. System dependencies (root)
RUN apt-get update && apt-get install -y \
    libgomp1 \
    && rm -rf /var/lib/apt/lists/*

# 3. Create non-root user
RUN useradd -m -u 1000 user
ENV HOME=/home/user \
    PATH=/home/user/.local/bin:$PATH
WORKDIR $HOME/app

# 4. Permissions
RUN chown -R user:user $HOME
USER user

# 5. Environment (FIXED)
ENV PYTHONUNBUFFERED=1 \
    PYTHONDONTWRITEBYTECODE=1 \
    HF_HOME=$HOME/.cache/huggingface

# 6. Copy requirements first (better caching)
COPY --chown=user requirements.txt .

# 7. Install deps (Torch first = correct move)
RUN pip install --upgrade pip && \
    pip install --no-cache-dir torch --index-url https://download.pytorch.org/whl/cpu && \
    pip install --no-cache-dir -r requirements.txt --extra-index-url https://download.pytorch.org/whl/cpu

# 8. Copy app code
COPY --chown=user . .

# 9. Pre-download model (zero cold start)
RUN python -c "from sentence_transformers import CrossEncoder; CrossEncoder('cross-encoder/ms-marco-MiniLM-L6-v2')"

# 10. Expose + run
EXPOSE 7860
CMD ["uvicorn", "main:app", "--host", "0.0.0.0", "--port", "7860"]