"use client";

import { commentRequest } from "./client";
import { createContext, useCallback, useContext, useEffect, useRef, useState, type ReactNode } from "react";
import Link from "next/link";
import { Badge } from "@/components/ui/badge";
import { useCommentEvents } from "./use-comment-events";

type Counts = { counts: Record<string, number>; total: number };
const UnreadContext = createContext<Counts & { markRead: (target: string) => Promise<void> }>({ counts: {}, total: 0, markRead: async () => {} });
export function AdminUnreadCommentsProvider({ children }: { children: ReactNode }) {
  const [counts, setCounts] = useState<Counts>({ counts: {}, total: 0 });
  const generation = useRef(0);
  const refresh = useCallback(async () => {
    try { const sequence = ++generation.current; const result = await commentRequest<Counts>("/api/admin/comments/unread"); if (sequence === generation.current) setCounts(result); } catch { /* Protected routes handle expired admin sessions. */ }
  }, []);
  const markRead = useCallback(async (target: string) => {
    try {
      await commentRequest("/api/admin/comments/unread", { method: "POST", headers: { "Content-Type": "application/json" }, body: JSON.stringify({ target }) });
      await refresh();
    } catch { /* Reading stays available when the counter cannot be saved. */ }
  }, [refresh]);
  useEffect(() => { void Promise.resolve().then(refresh); }, [refresh]);
  useCommentEvents({ admin: true }, refresh);
  return <UnreadContext value={{ ...counts, markRead }}>{children}</UnreadContext>;
}
export function useMarkCommentsRead() { return useContext(UnreadContext).markRead; }
export function AdminUnreadCount({ target }: { target?: string }) {
  const state = useContext(UnreadContext);
  const count = target ? state.counts[target] ?? 0 : state.total;
  return count > 0 ? <Badge variant="destructive" className="min-w-5 justify-center rounded-full bg-destructive px-1.5 text-background dark:bg-destructive" aria-label={`ความคิดเห็นใหม่ ${count} รายการ`}>{count > 99 ? "99+" : count}</Badge> : null;
}
export function AdminUnreadBadge({ target }: { target: string }) {
  const state = useContext(UnreadContext);
  if (!(state.counts[target] > 0)) return null;
  return <Link href={`/admin/comments?target=${encodeURIComponent(target)}`} prefetch={false} className="relative z-20 self-end" aria-label={"ดูความคิดเห็นใหม่"}><AdminUnreadCount target={target} /></Link>;
}