FROM python:3.10-slim

# Prevent python cache files
ENV PYTHONDONTWRITEBYTECODE=1
ENV PYTHONUNBUFFERED=1

# HuggingFace model cache location
ENV HF_HOME=/tmp/hf
ENV TRANSFORMERS_CACHE=/tmp/hf
ENV HF_HUB_DISABLE_TELEMETRY=1

WORKDIR /app

# Install system dependencies needed for RDKit / scientific stack
RUN apt-get update && apt-get install -y \
    build-essential \
    git \
    && rm -rf /var/lib/apt/lists/*

# Copy requirements first (improves Docker layer caching)
COPY requirements.txt .

# Install Python dependencies
RUN pip install --no-cache-dir --upgrade pip \
    && pip install --no-cache-dir -r requirements.txt

# Copy application files
COPY . .

# HuggingFace Spaces uses port 7860
EXPOSE 7860

# --preload loads models once instead of per worker
CMD ["streamlit", "run", "app.py", "--server.port=7860", "--server.address=0.0.0.0"]