import { useEffect, useRef, useState } from "react";
import { useLocation } from "react-router";

import { add } from "~/components/ui/notice/utils";
import { useHydrated } from "~/hooks/use-hydrated";
import { clsn } from "~/utils";
import CommentForm, { type CommentFormSubmitValues } from "../comment-form";
import CommentItem from "../comment-item";

const { APP_APIURL } = import.meta.env;

interface CommentsProps {
  className?: string;
  refs: string;
}

export default function Comments({ className, refs }: CommentsProps) {
  const wrapperRef = useRef<HTMLDivElement>(null);
  const location = useLocation();
  const hydrated = useHydrated();
  const [list, setList] = useState<API.Comment.ICommentDetailData[]>([]);
  const [loading, setLoading] = useState(true);
  const prevRefsRef = useRef<string>("");

  const scrollToComment = (hash: string) => {
    const id = hash.replace(/^#/, "");

    if (!id || !id.startsWith("c")) {
      return;
    }

    const commentItem = document.querySelector<HTMLDivElement>(`#${id}`);

    if (!commentItem) {
      console.log("定位评论失败");
      return;
    }

    console.log("定位评论成功");

    commentItem.scrollIntoView();
    commentItem.classList.add("animate-scale");

    const onAnimationEnd = (ev: AnimationEvent) => {
      const el = ev.target as HTMLDivElement;

      if (el) {
        el.classList.remove("animate-scale");
      }

      commentItem.removeEventListener("animationend", onAnimationEnd);
    };

    commentItem.addEventListener("animationend", onAnimationEnd);
  };

  const getCommentRequest = () => {
    fetch(`${APP_APIURL}/api/comment/detail/?ref=${encodeURIComponent(refs)}`)
      .then((res) => res.json())
      .then((res: API.PageResponse<API.Comment.ICommentDetailData[]>) => {
        if (res.status === "Success") {
          setList(res.data);
          setLoading(false);
        }

        if (location.hash.match(/^#c/)) {
          scrollToComment(location.hash);
        }
      });
  };

  useEffect(() => {
    if (!hydrated || !wrapperRef.current) {
      return;
    }

    if (location.hash.match(/^#c/)) {
      wrapperRef.current.scrollIntoView();
    }

    const observer = new IntersectionObserver(
      (entries) => {
        entries.forEach((entry) => {
          if (entry.isIntersecting && prevRefsRef.current !== refs) {
            console.log("获取评论");
            prevRefsRef.current = refs;
            getCommentRequest();
          }
        });
      },
      {
        threshold: 0.1,
      },
    );

    observer.observe(wrapperRef.current);

    return () => {
      observer.disconnect();
    };
  }, [hydrated, refs, location.hash]);

  useEffect(() => {
    if (hydrated && location.hash.match(/^#c/) && wrapperRef.current) {
      scrollToComment(location.hash);
    }
  }, [hydrated, location.hash]);

  const addCommentRequest = (data: CommentFormSubmitValues) => {
    return new Promise<void>((resolve, reject) => {
      fetch(`${APP_APIURL}/api/comment/add`, {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({ ...data, ref: refs }),
      })
        .then((res) => res.json())
        .then((res: API.Response<API.Comment.ICommentDetailData>) => {
          if (res.status === "Success") {
            add({
              title: "评论成功",
              type: "success",
              content: res.msg,
            });

            if (res.data) {
              if (res.data.root) {
                setList((prev) => {
                  const index = prev.findIndex((item) => item.uuid === res.data.root);

                  if (index > -1) {
                    const next = [...prev];
                    next[index] = {
                      ...next[index],
                      children: [res.data, ...next[index].children],
                    };
                    return next;
                  }

                  return prev;
                });
              }
              else {
                setList((prev) => [{ ...res.data, children: [] }, ...prev]);
              }
            }

            resolve();
          }
          else {
            add({
              title: "评论失败",
              type: "error",
              content: res.msg,
            });

            reject();
          }
        })
        .catch(() => {
          reject();
        });
    });
  };

  return (
    <div ref={wrapperRef} className={clsn("bg-white rounded-xl border-b-4 border-b-cyan-200 p-5 md:p-12", className)} id="comments">
      <h3 className="text-pink-400 text-2xl font-bold mb-6">
        评论
      </h3>
      <CommentForm onSubmit={addCommentRequest} />
      {list.length > 0 ? (
        <div>
          {list.map((item) => (
            <CommentItem key={item.uuid} data={item} onSubmit={addCommentRequest} />
          ))}
        </div>
      ) : (
        <div className="text-center opacity-50 py-8">
          {loading
            ? "评论获取中"
            : list.length === 0
              ? "快来成为第一个评论的人吧"
              : null}
        </div>
      )}
    </div>
  );
}