FROM python:3.12-slim AS base

# System deps for psycopg2, lxml, scikit-learn
RUN apt-get update && apt-get install -y --no-install-recommends \
    build-essential \
    libpq-dev \
    libxml2-dev \
    libxslt1-dev \
    curl \
    && rm -rf /var/lib/apt/lists/*

WORKDIR /app

# ── Dependencies layer (cached unless requirements.txt changes) ────────
FROM base AS deps
COPY requirements.txt .
RUN pip install --no-cache-dir -r requirements.txt

# ── Development image (used by docker-compose) ─────────────────────────
FROM base AS dev
COPY --from=deps /usr/local/lib/python3.12/site-packages /usr/local/lib/python3.12/site-packages
COPY --from=deps /usr/local/bin /usr/local/bin
COPY . .
EXPOSE 8000
CMD ["uvicorn", "app.main:app", "--host", "0.0.0.0", "--port", "8000", "--reload"]

# ── Production image ───────────────────────────────────────────────────
FROM base AS production
COPY --from=deps /usr/local/lib/python3.12/site-packages /usr/local/lib/python3.12/site-packages
COPY --from=deps /usr/local/bin /usr/local/bin

COPY . .

# Use a unique non-system username to avoid collisions
RUN useradd --no-log-init -m -u 1001 appuser && chown -R appuser:appuser /app
USER appuser

EXPOSE 8000

# Run migrations then start server
CMD ["sh", "-c", "alembic upgrade head && uvicorn app.main:app --host 0.0.0.0 --port 8000 --workers 2"]

HEALTHCHECK --interval=30s --timeout=10s --start-period=15s --retries=3 \
    CMD curl -f http://localhost:8000/health || exit 1
