FROM python:3.11-slim

ENV PYTHONDONTWRITEBYTECODE=1 \
    PYTHONUNBUFFERED=1 \
    PIP_NO_CACHE_DIR=1

WORKDIR /app

# Minimal system packages for common Python builds.
RUN apt-get update && apt-get install -y --no-install-recommends \
    build-essential \
    curl \
    && rm -rf /var/lib/apt/lists/*

COPY requirements.txt ./
RUN pip install --upgrade pip && pip install -r requirements.txt

COPY . .

# Fail fast during build if critical runtime modules are missing from context.
RUN test -d /app/backend && test -d /app/retriever && test -d /app/models && test -f /app/config.yaml

# Hugging Face Spaces exposes apps on port 7860 by default.
EXPOSE 7860

CMD ["uvicorn", "backend.api:app", "--host", "0.0.0.0", "--port", "7860"]