# syntax=docker/dockerfile:1.7
#
# Python Multi-Stage Dockerfile with UV Package Manager
# Features: Fast builds, minimal image, non-root, security hardened
#
# Build args:
#   PYTHON_VERSION - Python version (default: 3.12)
#   UV_VERSION     - UV package manager version (default: 0.5)
#
# Usage:
#   docker build -t myapp:latest .
#   docker run --rm -p 8000:8000 myapp:latest

# =============================================================================
# Stage 1: Build environment with UV
# =============================================================================
ARG PYTHON_VERSION=3.12
ARG UV_VERSION=0.5

FROM ghcr.io/astral-sh/uv:${UV_VERSION} AS uv
FROM python:${PYTHON_VERSION}-slim AS builder

# Install UV from official image
COPY --from=uv /uv /usr/local/bin/uv

# Set UV environment variables for reproducible builds
ENV UV_COMPILE_BYTECODE=1 \
    UV_LINK_MODE=copy \
    UV_PYTHON_DOWNLOADS=never

WORKDIR /app

# Install dependencies first (layer caching)
# Copy only dependency files to maximize cache hits
COPY pyproject.toml uv.lock* ./

# Install dependencies into the virtual environment
RUN --mount=type=cache,target=/root/.cache/uv \
    uv sync --frozen --no-install-project --no-dev

# Copy application source
COPY . .

# Install the project itself
RUN --mount=type=cache,target=/root/.cache/uv \
    uv sync --frozen --no-dev

# =============================================================================
# Stage 2: Production runtime (minimal)
# =============================================================================
FROM python:${PYTHON_VERSION}-slim AS runtime

# Security: Create non-root user
RUN groupadd --gid 1000 appgroup && \
    useradd --uid 1000 --gid 1000 --shell /bin/false --create-home appuser

# Security: Install only essential runtime packages, remove caches
RUN apt-get update && \
    apt-get install -y --no-install-recommends \
        ca-certificates \
        tini && \
    apt-get clean && \
    rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*

WORKDIR /app

# Copy virtual environment from builder
COPY --from=builder --chown=appuser:appgroup /app/.venv /app/.venv

# Copy application code
COPY --from=builder --chown=appuser:appgroup /app /app

# Set environment
ENV PATH="/app/.venv/bin:$PATH" \
    PYTHONDONTWRITEBYTECODE=1 \
    PYTHONUNBUFFERED=1 \
    PYTHONFAULTHANDLER=1

# Security: Switch to non-root user
USER appuser

# Health check (customize endpoint as needed)
HEALTHCHECK --interval=30s --timeout=10s --start-period=5s --retries=3 \
    CMD python -c "import urllib.request; urllib.request.urlopen('http://localhost:8000/health')" || exit 1

# Expose port (documentation)
EXPOSE 8000

# Use tini as init system for proper signal handling
ENTRYPOINT ["tini", "--"]

# Default command (override in docker-compose or at runtime)
CMD ["python", "-m", "app.main"]

# =============================================================================
# OCI Labels (customize these)
# =============================================================================
LABEL org.opencontainers.image.title="My Python App" \
      org.opencontainers.image.description="Python application with UV" \
      org.opencontainers.image.version="1.0.0" \
      org.opencontainers.image.vendor="Your Organization" \
      org.opencontainers.image.licenses="MIT" \
      org.opencontainers.image.source="https://github.com/your-org/your-repo"