"use client";

import {
  createContext,
  useContext,
  useEffect,
  useRef,
  useState,
  type ReactNode,
} from "react";
import { useRouter } from "next/navigation";
import { realtime, RT_SETTINGS_CHANGED, type RtSettingsData } from "@/lib/realtime";

type CommentsPolicy = {
  open: boolean;
  requireLogin: boolean;
};

const CommentsPolicyContext = createContext<CommentsPolicy>({
  open: true,
  requireLogin: false,
});

/** 前台是否开放评论（SSR 初值 + 后台开关热更新） */
export function useAllowComments(): boolean {
  return useContext(CommentsPolicyContext).open;
}

/** 评论是否仅登录可见 */
export function useCommentsRequireLogin(): boolean {
  return useContext(CommentsPolicyContext).requireLogin;
}

/**
 * 根布局注入：关闭评论后前台立即隐藏评论区/数量；
 * 「登录可见」切换时刷新以重拉/清空评论树。
 */
export default function CommentsPolicyProvider({
  allowComments,
  requireLogin = false,
  children,
}: {
  allowComments: boolean;
  requireLogin?: boolean;
  children: ReactNode;
}) {
  const router = useRouter();
  const [policy, setPolicy] = useState<CommentsPolicy>({
    open: allowComments,
    requireLogin,
  });
  const policyRef = useRef(policy);
  policyRef.current = policy;

  useEffect(() => {
    setPolicy({ open: allowComments, requireLogin });
  }, [allowComments, requireLogin]);

  useEffect(() => {
    return realtime.on<RtSettingsData>(RT_SETTINGS_CHANGED, (data) => {
      if (!data) return;
      const prev = policyRef.current;
      const nextOpen =
        typeof data.allow_comments === "boolean" ? data.allow_comments : prev.open;
      const nextRequire =
        typeof data.comments_require_login === "boolean"
          ? data.comments_require_login
          : prev.requireLogin;
      if (nextOpen === prev.open && nextRequire === prev.requireLogin) return;
      setPolicy({ open: nextOpen, requireLogin: nextRequire });
      router.refresh();
    });
  }, [router]);

  return (
    <CommentsPolicyContext.Provider value={policy}>{children}</CommentsPolicyContext.Provider>
  );
}