FROM node:20-alpine

WORKDIR /app

# Install dependencies first (better layer caching).
COPY package.json package-lock.json ./
RUN npm ci --omit=dev

# App source.
COPY server ./server
COPY public ./public

ENV NODE_ENV=production
ENV PORT=3000
ENV DATA_DIR=/app/data

EXPOSE 3000
CMD ["node", "server/index.js"]