# --- STAGE 1: Build the application ---
FROM node:20-alpine AS builder
WORKDIR /app

# Copy dependency configurations
COPY package*.json ./

# Install all dependencies (including devDependencies needed for building)
RUN npm ci

# Copy the rest of the application source code
COPY . .

# Build the production application
RUN npm run build

# Prune node_modules down to only production requirements
RUN npm prune --production


# --- STAGE 2: Run the application ---
FROM node:20-alpine AS runner
WORKDIR /app

# Set production configurations
ENV NODE_ENV=production
ENV PORT=3000

# Create a secure non-root system user for security hardening
RUN addgroup -g 1001 -S nodejs && \
    adduser -u 1001 -S svelteuser -G nodejs

# Copy essential production files from the builder stage
COPY --from=builder /app/package.json ./package.json
COPY --from=builder /app/node_modules ./node_modules
COPY --from=builder /app/build ./build

# Switch execution contexts to the non-root user
USER svelteuser

# Expose target internal application port
EXPOSE 3000

# Fire up the SvelteKit Node cluster server
CMD ["node", "build/index.js"]