# ──────────────────────────────────────────────────────────────
#  BanGUI — Backend image (Python / FastAPI)
#
#  Compatible with Docker and Podman.
#  Build context must be the project root.
#
#  Usage:
#    docker build -t bangui-backend -f Docker/Dockerfile.backend .
#    podman build -t bangui-backend -f Docker/Dockerfile.backend .
#
#  Signal handling:
#    - STOPSIGNAL defaults to SIGTERM (handled by uvicorn → lifespan shutdown)
#    - stop_grace_period in docker-compose.yml controls Docker's kill timeout
#    - Python code allows 25s for in-flight tasks to drain before hard kill
# ──────────────────────────────────────────────────────────────

# ── Stage 1: build dependencies ──────────────────────────────
FROM docker.io/library/python:3.12-slim AS builder

WORKDIR /build

# Install build-time system dependencies
RUN apt-get update \
    && apt-get install -y --no-install-recommends gcc libffi-dev \
    && rm -rf /var/lib/apt/lists/*

COPY backend/pyproject.toml /build/

# Install Python dependencies into a virtual-env so we can copy it cleanly
RUN python -m venv /opt/venv
ENV PATH="/opt/venv/bin:$PATH"
RUN pip install --no-cache-dir --upgrade pip \
    && pip install --no-cache-dir .

# ── Stage 2: runtime image ───────────────────────────────────
FROM docker.io/library/python:3.12-slim AS runtime

LABEL maintainer="BanGUI" \
      description="BanGUI backend — fail2ban web management API"

# Install curl for healthcheck (used by Docker HEALTHCHECK and Compose healthcheck)
RUN apt-get update \
    && apt-get install -y --no-install-recommends curl \
    && rm -rf /var/lib/apt/lists/*

# Non-root user for security
RUN groupadd --gid 1000 bangui \
    && useradd --uid 1000 --gid bangui --shell /bin/bash --create-home bangui

WORKDIR /app

# Copy the pre-built virtual-env
COPY --from=builder /opt/venv /opt/venv
ENV PATH="/opt/venv/bin:$PATH" \
    PYTHONDONTWRITEBYTECODE=1 \
    PYTHONUNBUFFERED=1

# Copy application source
COPY backend/app /app/app
COPY fail2ban-master /app/fail2ban-master

# Data directory for the SQLite database
RUN mkdir -p /data && chown bangui:bangui /data
VOLUME ["/data"]

# Default environment values (override at runtime)
ENV BANGUI_DATABASE_PATH="/data/bangui.db" \
    BANGUI_FAIL2BAN_SOCKET="/var/run/fail2ban/fail2ban.sock" \
    BANGUI_LOG_LEVEL="info" \
    BANGUI_WORKERS="1"

EXPOSE 8000

USER bangui

# Health-check using the built-in health endpoint
# Returns exit 0 (success) for HTTP 200 (fail2ban online)
# Returns exit 1 (failure) for HTTP 503 (fail2ban offline)
HEALTHCHECK --interval=30s --timeout=10s --start-period=40s --retries=3 \
    CMD curl -f http://localhost:8000/api/health || exit 1

# ⚠️  IMPORTANT: Single-Worker Requirement
# BanGUI must always run as a single worker process:
#   - Do NOT pass --workers or --worker-class to uvicorn
#   - Do NOT use gunicorn with -w 4 or similar
#   - Do NOT override BANGUI_WORKERS to > 1
#
# Why? The session cache is process-local. Multiple workers would cause:
#   - Random user logouts (sessions not shared between workers)
#   - Duplicate background jobs (each worker runs the scheduler)
#   - SQLite lock contention and timeouts
#
# For high availability, use container orchestration (Kubernetes, Docker Swarm)
# to run multiple instances, not multiple workers in a single process.
#
# See Docs/Architekture.md § Deployment Constraints for details.
CMD ["uvicorn", "app.main:create_app", "--factory", "--host", "0.0.0.0", "--port", "8000"]
