# ════════════════════════════════════════════════════════════
#  Qwen AI Chatbot — Docker Image for HuggingFace Spaces CPU
#  Base: Python 3.11 slim | Port: 7860
# ════════════════════════════════════════════════════════════

FROM python:3.11-slim

# System dependencies
RUN apt-get update && apt-get install -y --no-install-recommends \
    git \
    ffmpeg \
    libsm6 \
    libxext6 \
    libgl1-mesa-glx \
    build-essential \
    curl \
    && apt-get clean \
    && rm -rf /var/lib/apt/lists/*

# Create non-root user (required by HF Spaces)
RUN useradd -m -u 1000 user
USER user
ENV HOME=/home/user \
    PATH=/home/user/.local/bin:$PATH

WORKDIR /home/user/app

# Install PyTorch CPU first (avoids downloading CUDA version)
RUN pip install --no-cache-dir --upgrade pip && \
    pip install --no-cache-dir \
    torch==2.4.1+cpu \
    torchvision==0.19.1+cpu \
    torchaudio==2.4.1+cpu \
    --extra-index-url https://download.pytorch.org/whl/cpu

# Install other Python dependencies
COPY --chown=user requirements.txt .
RUN pip install --no-cache-dir -r requirements.txt

# Copy application code
COPY --chown=user . .

# Create necessary directories
RUN mkdir -p uploads static

# Pre-download the model during build (optional — comment out to download at runtime)
# This adds ~2GB to image size but avoids cold-start download time
# RUN python -c "from transformers import AutoModelForCausalLM, AutoTokenizer; \
#     AutoTokenizer.from_pretrained('Qwen/Qwen3.5-0.8B', trust_remote_code=True); \
#     AutoModelForCausalLM.from_pretrained('Qwen/Qwen3.5-0.8B', torch_dtype='float16', trust_remote_code=True)"

# Set environment variables
ENV PYTHONUNBUFFERED=1 \
    TRANSFORMERS_CACHE=/home/user/.cache/huggingface \
    HF_HOME=/home/user/.cache/huggingface \
    TOKENIZERS_PARALLELISM=false \
    OMP_NUM_THREADS=4 \
    MKL_NUM_THREADS=4

# Expose port (HF Spaces requires 7860)
EXPOSE 7860

# Health check
HEALTHCHECK --interval=30s --timeout=30s --start-period=120s --retries=3 \
    CMD curl -f http://localhost:7860/api/info || exit 1

# Launch server
CMD ["python", "app.py"]