# syntax=docker/dockerfile:1

# ---------------------------------------------------------------------------
# Stage 1 — builder: install production deps, compiling native addons (bcrypt)
# ---------------------------------------------------------------------------
FROM node:20-bookworm-slim AS builder
WORKDIR /app

# Toolchain required to compile native modules (bcrypt) when no prebuilt
# binary matches the platform. Lives only in this stage.
RUN apt-get update && apt-get install -y --no-install-recommends \
      python3 make g++ \
    && rm -rf /var/lib/apt/lists/*

# Install against the lockfile for reproducible builds. Copy manifests first
# so this layer caches until deps actually change.
COPY package.json package-lock.json ./
RUN npm ci --omit=dev

# ---------------------------------------------------------------------------
# Stage 2 — runtime: slim image with only prod node_modules + app source
# ---------------------------------------------------------------------------
FROM node:20-bookworm-slim AS runtime
ENV NODE_ENV=production
WORKDIR /app

# Compiled node_modules (same base image → ABI-compatible bcrypt .node binary).
COPY --from=builder /app/node_modules ./node_modules
COPY package.json ./
COPY src ./src

# Drop privileges — node:* images ship a non-root `node` user.
USER node

# Public listener only. INTERNAL_PORT (3001) binds to 127.0.0.1 inside the
# container by default and is intentionally NOT published.
EXPOSE 3000

# No HTTP health route exists — probe the TCP port directly so the check is
# route-agnostic. Orchestrators (k8s) can override with their own probes.
HEALTHCHECK --interval=30s --timeout=3s --start-period=20s --retries=3 \
  CMD node -e "require('net').connect({port: process.env.PUBLIC_PORT||3000, host:'127.0.0.1'}).on('connect',()=>process.exit(0)).on('error',()=>process.exit(1))"

CMD ["node", "src/server.js"]