# Base on official Node.js Alpine image
FROM node:18-alpine AS builder

# Set working directory
WORKDIR /app

# Copy package.json and package-lock.json before other files
# Utilize Docker cache to save re-installing dependencies if unchanged
COPY package*.json ./

# Install dependencies
RUN npm ci

# Copy all files
COPY . .

# Define build arguments with defaults
ARG NEXT_PUBLIC_SUPABASE_URL
ARG NEXT_PUBLIC_SUPABASE_ANON_KEY

# Set environment variables from build arguments
ENV NEXT_PUBLIC_SUPABASE_URL=$NEXT_PUBLIC_SUPABASE_URL
ENV NEXT_PUBLIC_SUPABASE_ANON_KEY=$NEXT_PUBLIC_SUPABASE_ANON_KEY


# Build app
RUN npm run build

# Production image, copy all the files and run next
FROM node:18-alpine AS runner

WORKDIR /app

# Set to production environment
ENV NODE_ENV=production

# Add user so we don't run as root
RUN addgroup --system --gid 1001 nodejs \
    && adduser --system --uid 1001 nextjs

# Copy built app
COPY --from=builder --chown=nextjs:nodejs /app/.next ./.next
COPY --from=builder --chown=nextjs:nodejs /app/node_modules ./node_modules
COPY --from=builder --chown=nextjs:nodejs /app/package.json ./package.json
COPY --from=builder --chown=nextjs:nodejs /app/public ./public

# Switch to non-root user
USER nextjs

# Expose port
EXPOSE 3000

# Start the app
CMD ["npm", "start"]

# Note: When running the container, override environment variables with:
# docker run -p 3000:3000 -e NEXT_PUBLIC_SUPABASE_URL=your_url -e NEXT_PUBLIC_SUPABASE_ANON_KEY=your_key nextjs-slack-clone
# Note: These lines correctly declare and set up build arguments.
# To load values for these arguments from a file, you would use
# external mechanisms (like a shell script parsing an .env file and passing
# --build-arg flags, or Docker Compose with its .env file handling)
# when invoking `docker build`. The Dockerfile itself does not need changes
# for this purpose.