FROM python:3.9-slim AS builder

# Install system dependencies
RUN apt-get update && apt-get install -y --no-install-recommends \
    build-essential \
    && rm -rf /var/lib/apt/lists/*

# Set working directory
WORKDIR /app

# Copy requirements
COPY requirements.txt .

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

FROM python:3.9-slim

# Set environment variables
ENV TRANSFORMERS_CACHE=/app/cache
ENV PYTHONDONTWRITEBYTECODE=1
ENV PYTHONUNBUFFERED=1

# Install minimal dependencies for runtime
RUN apt-get update && apt-get install -y --no-install-recommends \
    curl \
    && rm -rf /var/lib/apt/lists/*

# Create app directory and cache directory
RUN mkdir -p /app ${TRANSFORMERS_CACHE} && \
    # Create a non-root user to run the application
    useradd -m appuser && \
    chown -R appuser:appuser /app ${TRANSFORMERS_CACHE}

WORKDIR /app

# Copy requirements and install directly in the final stage
COPY requirements.txt .
RUN pip install --no-cache-dir -r requirements.txt

# Copy application code
COPY --chown=appuser:appuser . .

# Switch to non-root user
USER appuser

# Pre-download models to avoid cold starts in production
RUN python -c "from transformers import pipeline; \
    pipeline('summarization', model='facebook/bart-large-cnn'); \
    pipeline('image-to-text', model='nlpconnect/vit-gpt2-image-captioning')"

# Expose the port the app runs on
EXPOSE 8000

# Health check
HEALTHCHECK --interval=30s --timeout=10s --start-period=30s --retries=3 \
  CMD curl -f http://localhost:8000/ || exit 1

# Command to run the application
CMD ["uvicorn", "main:app", "--host", "0.0.0.0", "--port", "8000"]