# ─────────────────────────────────────────────────────────────────────────────
#  SAMPLE GENERATOR  —  Dockerfile
#  Flask + Meta MusicGen (audiocraft)
#  Compatible with: HuggingFace Spaces (Docker SDK), Render, local Docker
# ────────────────────────────────────────────── ───────────────────────────────

FROM python:3.11-slim

# ── System deps ───────────────────────────────────────────────────────────────
# ffmpeg   → audio encoding/decoding used by torchaudio & audiocraft
# libsndfile1 → soundfile I/O backend
# git      → audiocraft may pull sub-packages from git at install time
RUN apt-get update && apt-get install -y --no-install-recommends \
        ffmpeg \
        libavformat-dev \
        libavcodec-dev \
        libavdevice-dev \
        libavutil-dev \
        libavfilter-dev \
        libswscale-dev \
        libswresample-dev \
        libsndfile1 \
        git \
        pkg-config \
    && rm -rf /var/lib/apt/lists/*

# ── Create a non-root user (required by HuggingFace Spaces) ──────────────────
RUN useradd -m -u 1000 appuser

WORKDIR /app

# ── Install PyTorch (CPU-only) first, before audiocraft pulls its own copy ───
# Using the official CPU wheel index keeps the image ~2 GB smaller than CUDA.
RUN pip install --no-cache-dir \
        torch==2.1.0 \
        torchaudio==2.1.0 \
        --index-url https://download.pytorch.org/whl/cpu

# ── Stub out xformers ─────────────────────────────────────────────────────────
# xformers has no CPU-only pre-built wheel and fails to compile from source
# (it needs CUDA). audiocraft lists it as a dependency but MusicGen inference
# works fine without it on CPU. We install a minimal stub so pip's resolver
# sees the requirement as satisfied and skips the source build entirely.
RUN mkdir -p /tmp/xformers-stub && \
    echo "from setuptools import setup; setup(name='xformers', version='0.0.28.post1')" \
        > /tmp/xformers-stub/setup.py && \
    pip install --no-cache-dir /tmp/xformers-stub

# ── Install remaining Python deps ─────────────────────────────────────────────
# --extra-index-url ensures pip can still find CPU wheels for any torch-related
# packages pulled in transitively by audiocraft, preventing it from silently
# upgrading torch to a CUDA build from the default PyPI index.
COPY requirements.txt .
RUN pip install --no-cache-dir \
        --extra-index-url https://download.pytorch.org/whl/cpu \
        -r requirements.txt

# ── Copy application source ───────────────────────────────────────────────────
COPY app.py index.html ./

# ── Runtime environment ───────────────────────────────────────────────────────
# HF_HOME: store downloaded model weights in a predictable location.
# On Render, mount a persistent disk at /data to avoid re-downloading on restart.
ENV HF_HOME=/data/huggingface \
    PORT=7860

# Ensure the cache dir is writable by the non-root user even when /data is
# not mounted (e.g. plain `docker run` without a volume).
RUN mkdir -p /data/huggingface && chown -R appuser:appuser /data /app

USER appuser

EXPOSE 7860

CMD ["python", "app.py"]