FROM python:3.9-slim

# Prevent Python from writing pyc files & enable unbuffered logs
ENV PYTHONDONTWRITEBYTECODE=1 \
    PYTHONUNBUFFERED=1

WORKDIR /app

# System dependencies (minimal)
RUN apt-get update && apt-get install -y --no-install-recommends \
    gcc \
    g++ \
    curl \
    && rm -rf /var/lib/apt/lists/*

# Upgrade pip first
RUN pip install --upgrade pip

# Copy requirements first (better caching)
COPY requirements.txt .

# ---- FORCE CPU-ONLY TORCH ----
RUN pip install --no-cache-dir \
    torch --index-url https://download.pytorch.org/whl/cpu \
    && pip install --no-cache-dir -r requirements.txt

# Copy app code
COPY . .

# Create chroma directory
RUN mkdir -p /app/chroma_db

# Create non-root user
RUN useradd -m appuser && chown -R appuser:appuser /app
USER appuser

# Hugging Face Spaces / FastAPI default
EXPOSE 7860

# Healthcheck (no extra Python deps needed)
HEALTHCHECK --interval=30s --timeout=3s --start-period=10s --retries=3 \
    CMD curl -f http://localhost:7860/health || exit 1

# Run app
CMD ["uvicorn", "main:app", "--host", "0.0.0.0", "--port", "7860"]