# ============================================================
# Stage 1: Builder — 构建 Next.js 生产产物
# ============================================================
FROM node:20-alpine AS builder

WORKDIR /app

# 安装依赖（利用缓存层）
COPY package.json package-lock.json ./
RUN npm ci

# 复制源码并构建
COPY . .
RUN npm run build

# ============================================================
# Stage 2: Runner — 只保留运行时必要文件
# ============================================================
FROM node:20-alpine AS runner

WORKDIR /app

ENV NODE_ENV=production

# 创建非 root 用户运行应用
RUN addgroup --system --gid 1001 nodejs \
 && adduser  --system --uid 1001 nextjs

# 复制 standalone 构建产物
COPY --from=builder --chown=nextjs:nodejs /app/.next/standalone ./
COPY --from=builder --chown=nextjs:nodejs /app/.next/static ./.next/static
COPY --from=builder --chown=nextjs:nodejs /app/public ./public

USER nextjs

EXPOSE 3000

ENV PORT=3000
ENV HOSTNAME="0.0.0.0"

# 健康检查
HEALTHCHECK --interval=30s --timeout=10s --start-period=20s --retries=3 \
    CMD wget -qO- http://localhost:3000/ || exit 1

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