# Use a lightweight Node.js 20 Alpine image (digest-pinned for reproducibility)
FROM node:20-alpine@sha256:9bef0ef1e268f60627da9ba7d7605e8831d5b56ad07487d24d1aa386336d1944

# Accept a build argument for the working directory
ARG WORKDIR_PATH

ENV NODE_ENV=production

# Set the working directory inside the container
WORKDIR /app

# Copy only the production-ready files built in CI
# These files must be passed as GitLab artifacts:
# - .next/         → built Next.js app
# - public/        → static assets
# - package.json   → app manifest
# - package-lock.json → to lock dependencies for reproducibility
COPY ${WORKDIR_PATH}/.next .next
COPY ${WORKDIR_PATH}/public public
COPY ${WORKDIR_PATH}/package.json package.json
COPY ${WORKDIR_PATH}/package-lock.json package-lock.json

# Install only production dependencies to reduce image size
RUN npm ci --omit=dev

# Expose the port that Next.js serves on (default is 3000)
EXPOSE 3000

# Start the Next.js app in production mode
CMD ["npm", "run", "start"]