# Multi-stage Dockerfile for React + Express application
# See SAAC_DEPLOYMENT.md for deployment rules and common mistakes.
#
# Stage 1 (builder): Installs client deps and builds the React app with Vite.
# Stage 2 (production): Installs server deps only, copies built React output.
#
# The .dockerignore excludes client/dist from the build context — this is
# intentional. The builder stage creates a fresh dist/ inside the container,
# and COPY --from=builder copies it between stages (bypasses .dockerignore).

# --- Stage 1: Build React frontend ---
FROM node:20-alpine AS builder

WORKDIR /app/client

# Install client dependencies first (layer caching — only re-runs if package*.json change)
COPY client/package*.json ./
RUN npm install

# Copy client source and build
COPY client/ ./
RUN npm run build

# --- Stage 2: Production server ---
FROM node:20-alpine

ARG SOURCE_COMMIT=unknown
ARG APP_VERSION=1.0.0

WORKDIR /app

# curl is required for the Docker healthcheck below
RUN apk add --no-cache curl

# Install server dependencies only (not devDependencies — they're not needed in production).
# If your app needs devDependencies for a build step (e.g. TypeScript), install ALL deps
# first, run the build, then prune: RUN npm install && npm run build && npm prune --production
COPY package*.json ./
RUN npm install --production

# Copy server code
COPY server.js ./

# Copy built React app from the builder stage (not from host — .dockerignore doesn't apply)
COPY --from=builder /app/client/dist ./client/dist

ENV GIT_COMMIT=${SOURCE_COMMIT} \
    APP_VERSION=${APP_VERSION}

# Use "expose" in docker-compose.yml, not "ports". This EXPOSE is just documentation.
EXPOSE 3000

# Healthcheck — must match the healthcheck in docker-compose.yml
HEALTHCHECK --interval=10s --timeout=3s --start-period=5s --retries=2 \
  CMD curl -f http://localhost:3000/health || exit 1

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