"use client";

import { commentRequest } from "./client";
import { useCallback, useEffect, useRef, useState } from "react";
import type { CommentPage } from "@/lib/comments/types";

export function useCommentFeed(endpoint: string, initial?: CommentPage) {
  const [page, setPage] = useState<CommentPage>(initial ?? { items: [], nextCursor: null, viewer: null });
  const [dataEndpoint, setDataEndpoint] = useState(endpoint);
  const [busy, setBusy] = useState(!initial);
  const [error, setError] = useState("");
  const [revision, setRevision] = useState(0);
  const generation = useRef(0);
  const loadedPages = useRef(1);
  const mountedEndpoint = useRef(initial ? endpoint : "");
  const active = useRef<AbortController | null>(null);
  const lastPayload = useRef(JSON.stringify(initial ?? { items: [], nextCursor: null, viewer: null }));
  const refresh = useCallback(async (options: { silent?: boolean; forceRevision?: boolean } = {}) => {
    active.current?.abort();
    const controller = new AbortController();
    active.current = controller;
    const sequence = ++generation.current;
    if (options.silent === false) setBusy(true);
    try {
      let result = await commentRequest<CommentPage>(endpoint, { signal: controller.signal });
      for (let i = 1; i < loadedPages.current && result.nextCursor; i++) {
        const next = await commentRequest<CommentPage>(`${endpoint}&cursor=${encodeURIComponent(result.nextCursor)}`, { signal: controller.signal });
        result = { ...next, items: [...result.items, ...next.items] };
      }
      if (sequence === generation.current) {
        const payload = JSON.stringify(result);
        if (payload !== lastPayload.current) {
          lastPayload.current = payload;
          setPage(result); setRevision((value) => value + 1);
        } else if (options.forceRevision) {
          setRevision((value) => value + 1);
        }
        setDataEndpoint(endpoint); setError("");
      }
    } catch (cause) {
      if (!controller.signal.aborted && sequence === generation.current) setError(cause instanceof Error ? cause.message : "ไม่สามารถโหลดความคิดเห็นได้");
    } finally { if (sequence === generation.current) setBusy(false); }
  }, [endpoint]);
  const more = useCallback(async () => {
    if (!page.nextCursor || busy) return;
    const sequence = ++generation.current;
    setBusy(true);
    try {
      const next = await commentRequest<CommentPage>(`${endpoint}&cursor=${encodeURIComponent(page.nextCursor)}`);
      if (sequence === generation.current) {
        const result = { ...next, items: [...page.items, ...next.items.filter((item) => !page.items.some((old) => old.id === item.id))] };
        lastPayload.current = JSON.stringify(result);
        setPage(result);
        loadedPages.current += 1;
        setError("");
      }
    } catch (cause) { if (sequence === generation.current) setError(cause instanceof Error ? cause.message : "ไม่สามารถโหลดความคิดเห็นได้"); }
    finally { if (sequence === generation.current) setBusy(false); }
  }, [endpoint, page, busy]);
  useEffect(() => {
    if (mountedEndpoint.current !== endpoint) {
      loadedPages.current = 1;
      mountedEndpoint.current = endpoint;
      void refresh({ silent: false });
    }
    return () => { active.current?.abort(); };
  }, [endpoint, refresh]);
  const visiblePage = dataEndpoint === endpoint ? page : { items: [], nextCursor: null, viewer: page.viewer };
  return { page: visiblePage, busy, error, revision, refresh, more };
}