# Multi-stage build for optimized image
FROM python:3.9-slim as builder

# Install build dependencies
RUN apt-get update && apt-get install -y \
    build-essential \
    curl \
    && rm -rf /var/lib/apt/lists/*

# Copy requirements and install Python dependencies
COPY requirements.txt .
RUN pip install --no-cache-dir -r requirements.txt

# Final stage
FROM python:3.9-slim

# Install runtime dependencies
RUN apt-get update && apt-get install -y \
    curl \
    && rm -rf /var/lib/apt/lists/* \
    && apt-get clean

# Set working directory
WORKDIR /app

# Set environment variables
ENV PYTHONDONTWRITEBYTECODE=1 \
    PYTHONUNBUFFERED=1 \
    TRANSFORMERS_CACHE=/app/model_cache \
    HF_HOME=/app/model_cache \
    HUGGINGFACE_HUB_CACHE=/app/model_cache \
    MODEL_NAME=microsoft/DialoGPT-medium

# Create cache directories with proper permissions
RUN mkdir -p /app/model_cache && chmod 777 /app/model_cache

# Copy installed packages from builder stage
COPY --from=builder /usr/local/lib/python3.9/site-packages /usr/local/lib/python3.9/site-packages
COPY --from=builder /usr/local/bin /usr/local/bin

# Copy application code
COPY . .

# Create non-root user and set permissions
RUN useradd -m -u 1000 user && \
    chown -R user:user /app && \
    chmod 777 /app/model_cache

USER user

# Expose HuggingFace Spaces port (7860)
EXPOSE 7860

# Health check
HEALTHCHECK --interval=30s --timeout=30s --start-period=300s --retries=3 \
    CMD curl -f https://cronjob-python-chatbot.hf.space/health || exit 1

# Run FastAPI application
CMD ["python", "main.py"]