import { useEffect, useMemo, useRef, useState } from 'react';
import { Trans, useTranslation } from 'react-i18next';
import { Link, useLocation, useNavigationType, useParams } from 'react-router-dom';
import { Virtuoso, VirtuosoHandle, StateSnapshot } from 'react-virtuoso';
import { Comment, useAuthorAvatar, useEditedComment, useReplies } from '@plebbit/plebbit-react-hooks';
import Plebbit from '@plebbit/plebbit-js';
import styles from '../../views/post/post.module.css';
import { CommentMediaInfo, getDisplayMediaInfoType, getHasThumbnail, getMediaDimensions } from '../../lib/utils/media-utils';
import { hashStringToColor, getTextColorForBackground } from '../../lib/utils/post-utils';
import { getFormattedDate, getFormattedTimeAgo } from '../../lib/utils/time-utils';
import { isValidURL } from '../../lib/utils/url-utils';
import { isAllView, isPendingPostView, isPostPageView, isSubscriptionsView } from '../../lib/utils/view-utils';
import { useDefaultSubplebbits } from '../../hooks/use-default-subplebbits';
import { getBoardPath } from '../../lib/utils/route-utils';
import useAvatarVisibilityStore from '../../stores/use-avatar-visibility-store';
import useAuthorAddressClick from '../../hooks/use-author-address-click';
import { useCommentMediaInfo } from '../../hooks/use-comment-media-info';
import useCountLinksInReplies from '../../hooks/use-count-links-in-replies';
import useFetchGifFirstFrame from '../../hooks/use-fetch-gif-first-frame';
import useHide from '../../hooks/use-hide';
import useStateString from '../../hooks/use-state-string';
import CommentContent from '../comment-content';
import CommentMedia from '../comment-media';
import EditMenu from '../edit-menu/edit-menu';
import { canEmbed } from '../embed';
import LoadingEllipsis from '../loading-ellipsis';
import PostMenuDesktop from './post-menu-desktop';
import ReplyQuotePreview from '../reply-quote-preview';
import Tooltip from '../tooltip';
import { PostProps } from '../../views/post/post';
import { create } from 'zustand';
import _ from 'lodash';
import { shouldShowSnow } from '../../lib/snow';
import useReplyModalStore from '../../stores/use-reply-modal-store';
import { selectPostMenuProps } from '../../lib/utils/post-menu-props';

// Store scroll position for replies virtuoso across navigations
const lastVirtuosoStates: { [key: string]: StateSnapshot } = {};

interface ShowOmittedRepliesState {
  showOmittedReplies: Record<string, boolean>;
  setShowOmittedReplies: (cid: string, showOmittedReplies: boolean) => void;
}

const useShowOmittedReplies = create<ShowOmittedRepliesState>((set) => ({
  showOmittedReplies: {},
  setShowOmittedReplies: (cid, showOmittedReplies) =>
    set((state) => ({
      showOmittedReplies: {
        ...state.showOmittedReplies,
        [cid]: showOmittedReplies,
      },
    })),
}));

const PostInfo = ({ post, postReplyCount = 0, roles, isHidden, threadNumber }: PostProps) => {
  const { t } = useTranslation();
  const { author, cid, deleted, locked, pinned, parentCid, postCid, reason, removed, state, subplebbitAddress, timestamp } = post || {};
  const title = post?.title?.trim();
  const { replies } = useReplies({ comment: post });
  const { address, shortAddress } = author || {};
  const displayName = author?.displayName?.trim();
  const authorRole = roles?.[address]?.role?.replace('moderator', 'mod');
  const stateString = useStateString(post);
  const isReply = parentCid;
  const { showOmittedReplies } = useShowOmittedReplies();
  const { imageUrl: avatarImageUrl } = useAuthorAvatar({ author });
  const { hideAvatars } = useAvatarVisibilityStore();
  const defaultSubplebbits = useDefaultSubplebbits();
  const boardPath = subplebbitAddress ? getBoardPath(subplebbitAddress, defaultSubplebbits) : undefined;
  const postMenuProps = useMemo(() => selectPostMenuProps(post), [post]);

  const params = useParams();
  const location = useLocation();
  const isInPostPageView = isPostPageView(location.pathname, params);

  const userID = address && Plebbit.getShortAddress({ address }); // should not be shortened to less than 12 characters, because users can create unlimited addresses/IDs before authenticating or passing challenges, so if the ID is short enough they can spoof it to troll users with the same ID
  const userIDBackgroundColor = hashStringToColor(userID);
  const userIDTextColor = getTextColorForBackground(userIDBackgroundColor);

  const handleUserAddressClick = useAuthorAddressClick();
  const numberOfPostsByAuthor = document.querySelectorAll(`[data-author-address="${shortAddress}"][data-post-cid="${postCid}"]`).length;

  const { hidden } = useHide(post);

  const { openReplyModal } = useReplyModalStore();

  const onReplyModalClick = () => {
    deleted
      ? isReply
        ? alert(t('this_reply_was_deleted'))
        : alert(t('this_thread_was_deleted'))
      : removed
        ? isReply
          ? alert(t('this_reply_was_removed'))
          : alert(t('this_thread_was_removed'))
        : openReplyModal && openReplyModal(cid, post?.number, postCid, threadNumber, subplebbitAddress);
  };

  return (
    <div className={styles.postInfo}>
      {isHidden ? parentCid && <span className={styles.hiddenReplyEditMenuSpacer} /> : <EditMenu post={post} />}
      <span className={(hidden || ((removed || deleted) && !reason)) && parentCid ? styles.postDesktopHidden : ''}>
        {title &&
          (title.length <= 75 ? (
            <span className={styles.subject}>{title} </span>
          ) : (
            <Tooltip
              children={<span className={styles.subject}>{title.slice(0, 75) + '(...)'} </span>}
              content={title.length < 1000 ? title : title.slice(0, 1000) + `... ${t('title_too_long')}`}
            />
          ))}
        <span className={styles.nameBlock}>
          <span className={`${styles.name} ${authorRole && !(deleted || removed) && (authorRole === 'mod' ? styles.capcodeMod : styles.capcodeAdmin)}`}>
            {deleted ? (
              _.capitalize(t('deleted'))
            ) : removed ? (
              _.capitalize(t('removed'))
            ) : displayName ? (
              displayName.length <= 20 ? (
                displayName
              ) : (
                <Tooltip
                  children={displayName.slice(0, 20) + '(...)'}
                  content={displayName.length < 1000 ? displayName : displayName.slice(0, 1000) + `... ${t('display_name_too_long')}`}
                />
              )
            ) : (
              _.capitalize(t('anonymous'))
            )}
            {!(deleted || removed) && authorRole && (
              <span className='capitalize'>
                {' '}
                ## Board {authorRole}{' '}
                <span
                  className={`${styles.capcodeIcon} ${authorRole === 'mod' ? styles.capcodeModIcon : styles.capcodeAdminIcon}`}
                  title={authorRole === 'mod' ? t('moderator_of_this_board') : t('administrator_of_this_board')}
                />
              </span>
            )}{' '}
          </span>
          {author?.avatar && !(deleted || removed) && !hideAvatars && avatarImageUrl ? (
            <span className={styles.authorAvatar}>
              <img src={avatarImageUrl} alt='' />
            </span>
          ) : null}
          (ID:{' '}
          {deleted ? (
            t('deleted')
          ) : removed ? (
            t('removed')
          ) : (
            <Tooltip
              children={
                <span
                  title={t('highlight_posts')}
                  className={styles.userAddress}
                  onClick={() => handleUserAddressClick(userID, postCid)}
                  style={{ backgroundColor: userIDBackgroundColor, color: userIDTextColor }}
                >
                  {userID}
                </span>
              }
              content={`${numberOfPostsByAuthor === 1 ? t('1_post_by_this_id') : t('x_posts_by_this_id', { number: numberOfPostsByAuthor })}`}
              showTooltip={isInPostPageView || showOmittedReplies[postCid] || (postReplyCount < 6 && !pinned)}
            />
          )}
          ){' '}
        </span>
        <span className={styles.dateTime}>
          <Tooltip children={<span>{getFormattedDate(timestamp)}</span>} content={getFormattedTimeAgo(timestamp)} />{' '}
        </span>
        <span className={styles.postNum}>
          {cid ? (
            <span className={styles.postNumLink}>
              <Link
                to={boardPath ? `/${boardPath}/thread/${cid}` : `/thread/${cid}`}
                className={styles.linkToPost}
                title={t('link_to_post')}
                onClick={(e) => !cid && e.preventDefault()}
              >
                No.
              </Link>
              <span className={styles.replyToPost} title={t('reply_to_post')} onMouseDown={onReplyModalClick}>
                {post?.number || '?'}
              </span>
            </span>
          ) : (
            <>
              <span>CID:</span>
              <span className={styles.pendingCid}>
                {state === 'failed' || stateString === 'Failed' ? _.capitalize(t('failed')) : state === 'pending' ? _.capitalize(t('pending')) : ''}
              </span>
            </>
          )}
          {pinned && (
            <span className={`${styles.stickyIconWrapper} ${!locked && styles.addPaddingBeforeReply}`}>
              <img src='assets/icons/sticky.gif' alt='' className={styles.stickyIcon} title={t('sticky')} />
            </span>
          )}
          {locked && (
            <span className={`${styles.closedIconWrapper} ${styles.addPaddingBeforeReply} ${pinned && styles.addPaddingInBetween}`}>
              <img src='assets/icons/closed.gif' alt='' className={styles.closedIcon} title={t('closed')} />
            </span>
          )}
          {!isInPostPageView && !isReply && !isHidden && (
            <span className={styles.replyButton}>
              [
              <Link to={boardPath ? `/${boardPath}/thread/${postCid}` : `/thread/${postCid}`} onClick={(e) => !cid && e.preventDefault()}>
                {_.capitalize(t('reply'))}
              </Link>
              ]
            </span>
          )}
        </span>
        {!(removed || deleted) && <PostMenuDesktop postMenu={postMenuProps} />}
        {cid &&
          parentCid &&
          replies &&
          replies.map(
            (reply: Comment, index: number) =>
              reply?.parentCid === cid &&
              reply?.cid &&
              !(reply?.deleted || reply?.removed) && <ReplyQuotePreview key={index} isBacklinkReply={true} backlinkReply={reply} />,
          )}
      </span>
    </div>
  );
};

interface PostMediaProps {
  commentMediaInfo: CommentMediaInfo | undefined;
  hasThumbnail: boolean;
  spoiler: boolean;
  deleted: boolean;
  removed: boolean;
  linkHeight: number;
  linkWidth: number;
  parentCid: string;
  subplebbitAddress: string;
  isInAllView: boolean;
  isInSubscriptionsView: boolean;
}

const PostMedia = ({
  commentMediaInfo,
  hasThumbnail,
  spoiler,
  deleted,
  removed,
  linkHeight,
  linkWidth,
  parentCid,
  subplebbitAddress,
  isInAllView,
  isInSubscriptionsView,
}: PostMediaProps) => {
  const { t } = useTranslation();
  const { url } = commentMediaInfo || {};
  let type = commentMediaInfo?.type;
  const gifFrameUrl = useFetchGifFirstFrame(url);
  const defaultSubplebbits = useDefaultSubplebbits();

  if (type === 'gif' && gifFrameUrl !== null) {
    type = 'animated gif';
  } else if (type === 'gif' && gifFrameUrl === null) {
    type = 'static gif';
  }

  const embedUrl = url && new URL(url);
  const [showThumbnail, setShowThumbnail] = useState(true);

  const mediaDimensions = getMediaDimensions(commentMediaInfo);
  const boardPath = getBoardPath(subplebbitAddress, defaultSubplebbits);

  return (
    <div className={styles.file}>
      <div className={styles.fileText}>
        {subplebbitAddress && (isInAllView || isInSubscriptionsView) && boardPath && !parentCid && (
          <>
            {t('board')}: <Link to={`/${boardPath}`}>{boardPath}</Link>{' '}
          </>
        )}
        {t('link')}:{' '}
        <a href={url} target='_blank' rel='noopener noreferrer'>
          {spoiler ? _.capitalize(t('spoiler')) : url && url.length > 30 ? url.slice(0, 30) + '...' : url}
        </a>{' '}
        ({type && _.lowerCase(getDisplayMediaInfoType(type, t))}
        {mediaDimensions && `, ${mediaDimensions}`})
        {!showThumbnail && (type === 'iframe' || type === 'video' || type === 'audio') && (
          <span>
            -[
            <span className={styles.closeMedia} onClick={() => setShowThumbnail(true)}>
              {t('close')}
            </span>
            ]
          </span>
        )}
        {showThumbnail && !hasThumbnail && embedUrl && canEmbed(embedUrl) && (
          <span>
            -[
            <span className={styles.closeMedia} onClick={() => setShowThumbnail(false)}>
              {t('open')}
            </span>
            ]
          </span>
        )}
      </div>
      {(hasThumbnail || (!hasThumbnail && !showThumbnail) || spoiler) && (
        <div className={styles.fileThumbnail}>
          <CommentMedia
            commentMediaInfo={commentMediaInfo}
            deleted={deleted}
            removed={removed}
            linkHeight={linkHeight}
            linkWidth={linkWidth}
            showThumbnail={showThumbnail}
            setShowThumbnail={setShowThumbnail}
            parentCid={parentCid}
            spoiler={spoiler}
          />
        </div>
      )}
    </div>
  );
};

const Reply = ({ postReplyCount, reply, roles, threadNumber }: PostProps) => {
  let post = reply;
  // handle pending mod or author edit
  const { editedComment } = useEditedComment({ comment: reply });
  if (editedComment) {
    post = editedComment;
  }

  const { author, cid, deleted, link, linkHeight, linkWidth, postCid, reason, removed, spoiler, subplebbitAddress, thumbnailUrl, parentCid } = post || {};
  const defaultSubplebbits = useDefaultSubplebbits();
  const boardPath = subplebbitAddress ? getBoardPath(subplebbitAddress, defaultSubplebbits) : undefined;

  const location = useLocation();
  const route = boardPath ? `/${boardPath}/thread/${cid}` : `/thread/${cid}`;
  const isRouteLinkToReply = cid ? location.pathname.startsWith(route) : false;
  const { hidden } = useHide({ cid });

  const isInAllView = isAllView(location.pathname);
  const params = useParams();
  const isInSubscriptionsView = isSubscriptionsView(location.pathname, params);

  const commentMediaInfo = useCommentMediaInfo(link, thumbnailUrl, linkWidth, linkHeight);
  const hasThumbnail = getHasThumbnail(commentMediaInfo, link);

  return (
    <div className={styles.replyDesktop}>
      <div className={styles.sideArrows}>{'>>'}</div>
      <div className={`${styles.reply} ${isRouteLinkToReply && styles.highlight}`} data-cid={cid} data-author-address={author?.shortAddress} data-post-cid={postCid}>
        <PostInfo post={post} postReplyCount={postReplyCount} roles={roles} isHidden={hidden} threadNumber={threadNumber} />
        {link && !hidden && !(deleted || removed) && isValidURL(link) && (
          <PostMedia
            commentMediaInfo={commentMediaInfo}
            hasThumbnail={hasThumbnail}
            spoiler={spoiler}
            deleted={deleted}
            removed={removed}
            linkHeight={linkHeight}
            linkWidth={linkWidth}
            parentCid={parentCid}
            subplebbitAddress={subplebbitAddress}
            isInAllView={isInAllView}
            isInSubscriptionsView={isInSubscriptionsView}
          />
        )}
        {!hidden && (!(removed || deleted) || ((removed || deleted) && reason)) && <CommentContent comment={post} />}
      </div>
    </div>
  );
};

const PostDesktop = ({ post, roles, showAllReplies, showReplies = true }: PostProps) => {
  const { t } = useTranslation();
  const { author, cid, content, deleted, link, linkHeight, linkWidth, pinned, postCid, removed, spoiler, state, subplebbitAddress, thumbnailUrl, parentCid } = post || {};
  const params = useParams();
  const location = useLocation();
  const navigationType = useNavigationType();
  const isInPendingPostView = isPendingPostView(location.pathname, params);
  const isInPostPageView = isPostPageView(location.pathname, params);
  const isInAllView = isAllView(location.pathname);
  const isInSubscriptionsView = isSubscriptionsView(location.pathname, params);
  const defaultSubplebbits = useDefaultSubplebbits();
  const boardPath = subplebbitAddress ? getBoardPath(subplebbitAddress, defaultSubplebbits) : undefined;

  const { hidden, unhide, hide } = useHide({ cid });
  const isHidden = hidden && !isInPostPageView;

  const { replies, hasMore, loadMore } = useReplies({ comment: post, flat: true });
  const visiblelinksCount = useCountLinksInReplies(post, 5);
  const totalLinksCount = useCountLinksInReplies(post);
  const replyCount = replies?.length;

  const repliesCount = pinned ? replyCount : replyCount - 5;
  const linksCount = pinned ? totalLinksCount : totalLinksCount - visiblelinksCount;
  const { showOmittedReplies, setShowOmittedReplies } = useShowOmittedReplies();

  const stateString = useStateString(post) || t('downloading_board');

  const commentMediaInfo = useCommentMediaInfo(link, thumbnailUrl, linkWidth, linkHeight);
  const hasThumbnail = getHasThumbnail(commentMediaInfo, link);

  // Filter out deleted replies with no children for both virtuoso and non-virtuoso rendering
  const filteredReplies = useMemo(() => (replies || []).filter((reply) => !(reply.deleted && (reply.replyCount === 0 || !reply.replyCount))), [replies]);

  // Virtuoso scroll position management for infinite replies
  const virtuosoRef = useRef<VirtuosoHandle | null>(null);
  const virtuosoStateKey = `replies-desktop-${cid}`;

  useEffect(() => {
    if (!showAllReplies || !isInPostPageView) return;

    const currentKey = virtuosoStateKey;
    const setLastVirtuosoState = () => {
      virtuosoRef.current?.getState((snapshot: StateSnapshot) => {
        if (snapshot?.ranges?.length) {
          lastVirtuosoStates[currentKey] = snapshot;
        }
      });
    };
    window.addEventListener('scroll', setLastVirtuosoState);
    return () => window.removeEventListener('scroll', setLastVirtuosoState);
  }, [virtuosoStateKey, showAllReplies, isInPostPageView]);

  const lastVirtuosoState = navigationType === 'POP' ? lastVirtuosoStates?.[virtuosoStateKey] : undefined;

  // Footer component for Virtuoso showing loading state
  const RepliesFooter = () =>
    hasMore ? (
      <div className={styles.stateString}>
        <LoadingEllipsis string={t('loading')} />
      </div>
    ) : null;

  return (
    <div className={styles.postDesktop}>
      {showReplies ? (
        <div className={styles.hrWrapper}>
          <hr />
        </div>
      ) : (
        <div className={styles.replyQuotePreviewSpacer} />
      )}
      <div className={isHidden ? styles.postDesktopHidden : ''}>
        {!isInPostPageView && showReplies && (
          <span className={`${styles.hideButtonWrapper} ${!hasThumbnail ? styles.hideButtonWrapperNoImage : ''}`}>
            <span className={`${styles.hideButton} ${hidden ? styles.unhideThread : styles.hideThread}`} onClick={hidden ? unhide : hide} />
          </span>
        )}
        <div data-cid={cid} data-author-address={author?.shortAddress} data-post-cid={postCid} className={shouldShowSnow() && hasThumbnail ? styles.xmasHatWrapper : ''}>
          {shouldShowSnow() && hasThumbnail && <img src='assets/xmashat.gif' className={styles.xmasHat} alt='' />}
          {link && !isHidden && !(deleted || removed) && isValidURL(link) && (
            <PostMedia
              commentMediaInfo={commentMediaInfo}
              hasThumbnail={hasThumbnail}
              spoiler={spoiler}
              deleted={deleted}
              removed={removed}
              linkHeight={linkHeight}
              linkWidth={linkWidth}
              parentCid={parentCid}
              subplebbitAddress={subplebbitAddress}
              isInAllView={isInAllView}
              isInSubscriptionsView={isInSubscriptionsView}
            />
          )}
          <PostInfo isHidden={hidden} post={post} postReplyCount={replyCount} roles={roles} threadNumber={post?.number} />
          {!isHidden && !content && !(deleted || removed) && <div className={styles.spacer} />}
          {!isHidden && <CommentContent comment={post} />}
        </div>
        {!isHidden && !isInPendingPostView && (replyCount > 5 || (pinned && repliesCount > 0)) && !isInPostPageView && (
          <span className={styles.summary}>
            <span
              className={`${showOmittedReplies[cid] ? styles.hideOmittedReplies : styles.showOmittedReplies} ${styles.omittedRepliesButtonWrapper}`}
              onClick={() => setShowOmittedReplies(cid, !showOmittedReplies[cid])}
            />
            {showOmittedReplies[cid] ? (
              t('showing_all_replies')
            ) : linksCount > 0 ? (
              <Trans
                i18nKey={'replies_and_links_omitted'}
                shouldUnescape={true}
                components={{ 1: <Link key={cid} to={boardPath ? `/${boardPath}/thread/${cid}` : `/thread/${cid}`} /> }}
                values={{ repliesCount, linksCount }}
              />
            ) : (
              <Trans
                i18nKey={'replies_omitted'}
                shouldUnescape={true}
                components={{ 1: <Link key={cid} to={boardPath ? `/${boardPath}/thread/${cid}` : `/thread/${cid}`} /> }}
                values={{ repliesCount }}
              />
            )}
          </span>
        )}
        {/* Virtuoso infinite scroll for post page view with more than 25 replies */}
        {!isHidden && showAllReplies && !isInPendingPostView && showReplies && replyCount > 25 && (
          <Virtuoso
            increaseViewportBy={{ bottom: 1200, top: 1200 }}
            totalCount={filteredReplies.length}
            data={filteredReplies}
            itemContent={(index, reply) => (
              <div className={styles.replyContainer}>
                <Reply reply={reply} roles={roles} postReplyCount={replyCount} threadNumber={post?.number} />
              </div>
            )}
            useWindowScroll={true}
            components={{ Footer: RepliesFooter }}
            endReached={loadMore}
            ref={virtuosoRef}
            restoreStateFrom={lastVirtuosoState}
            initialScrollTop={lastVirtuosoState?.scrollTop}
          />
        )}
        {/* Non-virtualized rendering for post page view with 25 or fewer replies */}
        {!isHidden &&
          showAllReplies &&
          !isInPendingPostView &&
          showReplies &&
          replyCount <= 25 &&
          filteredReplies.map((reply, index) => (
            <div key={index} className={styles.replyContainer}>
              <Reply reply={reply} roles={roles} postReplyCount={replyCount} threadNumber={post?.number} />
            </div>
          ))}
        {/* Non-virtualized rendering for board view (last 5 replies or show omitted) */}
        {!isHidden &&
          !showAllReplies &&
          !(pinned && !isInPostPageView && !showOmittedReplies[cid]) &&
          !isInPendingPostView &&
          replies &&
          showReplies &&
          (showOmittedReplies[cid] ? filteredReplies : filteredReplies.slice(-5)).map((reply, index) => (
            <div key={index} className={styles.replyContainer}>
              <Reply reply={reply} roles={roles} postReplyCount={replyCount} threadNumber={post?.number} />
            </div>
          ))}
      </div>
      {!isInPendingPostView && stateString && stateString !== 'Failed' && state !== 'succeeded' && isInPostPageView && !(!showReplies && !showAllReplies) ? (
        <div className={styles.stateString}>
          <br />
          <LoadingEllipsis string={stateString} />
        </div>
      ) : (
        state === 'failed' && <span className={styles.error}>{t('failed')}</span>
      )}
    </div>
  );
};

export default PostDesktop;
