FROM node:18-alpine

WORKDIR /app

# Install curl for healthcheck
RUN apk add --no-cache curl

# Copy package files first for layer caching
COPY package*.json ./
RUN npm install --production

# Copy app code (changes more often — below the cached layer)
COPY . .

EXPOSE 3000

HEALTHCHECK --interval=10s --timeout=3s --start-period=5s --retries=2 \
  CMD curl -f http://localhost:3000/health || exit 1

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