# ── Base image ────────────────────────────────────────────────────────────────
FROM python:3.11-slim

ENV PYTHONUNBUFFERED=1

# ── Non-root user (required by Hugging Face Spaces) ───────────────────────────
RUN useradd -m -u 1000 user
ENV HOME=/home/user \
    PATH=/home/user/.local/bin:$PATH

# Fix: point HF cache to the user's writable home so the pre-downloaded model
# is found at runtime (same path used in app.py via os.environ.setdefault).
ENV HF_HOME=/home/user/.cache/huggingface \
    TRANSFORMERS_CACHE=/home/user/.cache/huggingface

WORKDIR $HOME/app

# ── System dependencies ───────────────────────────────────────────────────────
USER root
RUN apt-get update && apt-get install -y --no-install-recommends \
        build-essential \
    && rm -rf /var/lib/apt/lists/*
USER user

# ── Python dependencies ───────────────────────────────────────────────────────
COPY --chown=user requirements.txt .

# Step 1 — Install PyTorch CPU wheel from its dedicated index
RUN pip install --no-cache-dir --upgrade pip && \
    pip install --no-cache-dir \
        torch==2.3.1 \
        --index-url https://download.pytorch.org/whl/cpu

# Step 2 — Install the remaining packages from PyPI
RUN pip install --no-cache-dir \
        streamlit==1.35.0 \
        chronos-forecasting==1.3.0 \
        pandas==2.2.2 \
        numpy==1.26.4 \
        plotly==5.22.0

# ── Pre-download model weights at build time ──────────────────────────────────
# Runs as `user` with HF_HOME set above — weights land in the correct cache dir
RUN python -c "\
import os; \
os.environ['HF_HOME'] = '/home/user/.cache/huggingface'; \
from chronos import BaseChronosPipeline; \
BaseChronosPipeline.from_pretrained('amazon/chronos-bolt-base', device_map='cpu')"

# ── Application code ──────────────────────────────────────────────────────────
COPY --chown=user app.py .
COPY --chown=user interface.py .

# ── Network ───────────────────────────────────────────────────────────────────
EXPOSE 7860

# ── Entrypoint ────────────────────────────────────────────────────────────────
CMD ["streamlit", "run", "interface.py", \
     "--server.port=7860", \
     "--server.address=0.0.0.0", \
     "--browser.gatherUsageStats=false", \
     "--server.headless=true"]