FROM node:20-alpine AS builder
WORKDIR /app
COPY backend/package*.json backend/
# Install all dependencies (including dev) in builder so tools like tsc are available for build
RUN sh -c 'if [ -f backend/package-lock.json ] || [ -f backend/npm-shrinkwrap.json ]; then npm ci --prefix backend --no-audit --no-fund --prefer-offline --no-progress; else npm install --prefix backend --no-audit --no-fund --prefer-offline --no-progress; fi'
COPY backend/ backend/
RUN sh -c 'NODE_OPTIONS="--max_old_space_size=512" npm run build --prefix backend'
## Prune dev dependencies to shrink runtime layer
RUN npm prune --omit=dev --prefix backend && rm -rf /root/.npm /tmp/*

FROM node:20-alpine
WORKDIR /app
ENV NODE_ENV=production
COPY --from=builder /app/backend/dist ./dist
COPY --from=builder /app/backend/node_modules ./node_modules
COPY backend/package*.json ./
EXPOSE 4000
CMD ["node", "./dist/index.js"]