# ============================================================================
# Multi-stage build for optimized production Docker image
# ============================================================================

# Stage 1: Dependencies
FROM node:20-alpine AS dependencies

WORKDIR /app

# Copy only package files
COPY package*.json ./

# Install dependencies (using npm ci for production)
RUN npm ci --prefer-offline --no-audit

# ============================================================================
# Stage 2: Production
FROM node:20-alpine AS production

# Install curl for healthcheck and dumb-init for signal handling
RUN apk add --no-cache curl dumb-init

# Set working directory
WORKDIR /app

# Set Node.js environment to production
ENV NODE_ENV=production

# Copy node_modules from dependencies stage
COPY --from=dependencies /app/node_modules ./node_modules

# Copy package files
COPY package*.json ./

# Copy application code
COPY . .

# Create non-root user for security
RUN addgroup -g 1001 -S nodejs && adduser -S nodejs -u 1001

USER nodejs

# Expose port
EXPOSE 3000

# Health check
HEALTHCHECK --interval=30s --timeout=10s --start-period=40s --retries=3 \
  CMD curl -f http://localhost:3000 || exit 1

# Use dumb-init to handle signals properly (graceful shutdown)
ENTRYPOINT ["/usr/bin/dumb-init", "--"]

# Start application
CMD ["node", "server.js"]