import { Suspense } from "react"
import type { JSX } from "react"
import { getTranslations } from "next-intl/server"

import { requirePermission } from "@/shared/lib/auth-guard"
import { Permissions } from "@/shared/types/permissions"
import { SectionErrorBoundary } from "@/shared/components/section-error-boundary"
import { getNotifications } from "@/modules/notifications/data-access"
import { NotificationList } from "@/modules/notifications/components/notification-list"
import { MessageListSection } from "@/modules/messaging/components/message-list-section"
import { MessageListSkeleton } from "@/modules/messaging/components/message-list-skeleton"
import { Card, CardContent, CardHeader } from "@/shared/components/ui/card"
import { Skeleton } from "@/shared/components/ui/skeleton"

export const dynamic = "force-dynamic"

export async function generateMetadata() {
  const t = await getTranslations("messages")
  return { title: t("title.list") }
}

/**
 * P2-9: 通知列表区块骨架屏（Suspense fallback）。
 */
function NotificationListSkeleton(): JSX.Element {
  return (
    <div className="space-y-4" role="status" aria-label="Loading notifications">
      <Skeleton className="h-10 w-48" />
      {Array.from({ length: 3 }).map((_, i) => (
        <Card key={i} aria-hidden="true">
          <CardHeader className="space-y-2 pb-3">
            <Skeleton className="h-4 w-3/4" />
            <Skeleton className="h-3 w-1/2" />
          </CardHeader>
          <CardContent className="pt-0">
            <Skeleton className="h-3 w-full" />
          </CardContent>
        </Card>
      ))}
    </div>
  )
}

/**
 * P2-9: 通知列表区块（Server Component，流式加载）。
 */
async function NotificationListSection({ userId }: { userId: string }): Promise<JSX.Element> {
  const result = await getNotifications(userId, { page: 1, pageSize: 20 })
  return <NotificationList notifications={result.items} />
}

export default async function MessagesPage(): Promise<JSX.Element> {
  const t = await getTranslations("messages")
  const ctx = await requirePermission(Permissions.MESSAGE_READ)

  return (
    <div className="flex h-full flex-col space-y-8 p-8">
      <div>
        <h2 className="text-2xl font-bold tracking-tight">{t("title.list")}</h2>
        <p className="text-muted-foreground">
          {t("description.list")}
        </p>
      </div>

      {/* P2-8 + P2-9: 消息列表区块独立 Suspense + ErrorBoundary，局部失败不影响通知区块 */}
      <Suspense fallback={<MessageListSkeleton />}>
        <SectionErrorBoundary namespace="messages">
          <MessageListSection userId={ctx.userId} canGroupSend={ctx.dataScope.type === "class_taught"} />
        </SectionErrorBoundary>
      </Suspense>

      {/* P2-8 + P2-9: 通知列表区块独立 Suspense + ErrorBoundary */}
      <Suspense fallback={<NotificationListSkeleton />}>
        <SectionErrorBoundary namespace="notifications">
          <NotificationListSection userId={ctx.userId} />
        </SectionErrorBoundary>
      </Suspense>
    </div>
  )
}