import React, { useState, useEffect, useCallback, useRef } from 'react';
import { useTranslation } from 'react-i18next';
import {
  getVideoById,
  getVideoComments,
  postVideoComment,
  deleteComment,
  toggleVideoLike,
  isLoggedIn,
  getUserMe,
  API_URL,
} from '../utils/api';
import { VideoDetailItem, CommentItem, UserMeResponse } from '../types/api';
import { buildVideoShareUrl, tryNativeShare } from '../utils/nativeShare';
import LoginPromptModal from './LoginPromptModal';

interface VideoDetailContentProps {
  videoId: string;
  isModal?: boolean;
  onClose?: () => void;
}

const VideoDetailContent: React.FC<VideoDetailContentProps> = ({ videoId, isModal = false, onClose }) => {
  const { t } = useTranslation();
  const authed = isLoggedIn();

  const [video, setVideo] = useState<VideoDetailItem | null>(null);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState<string | null>(null);

  const [likeCount, setLikeCount] = useState(0);
  const [isLiked, setIsLiked] = useState(false);

  const [copied, setCopied] = useState(false);
  const [isLandscape, setIsLandscape] = useState(false);
  const [showLoginModal, setShowLoginModal] = useState(false);

  const [comments, setComments] = useState<CommentItem[]>([]);
  const [commentsTotal, setCommentsTotal] = useState(0);
  const [commentsPage, setCommentsPage] = useState(1);
  const [commentsHasNext, setCommentsHasNext] = useState(false);
  const [commentsLoading, setCommentsLoading] = useState(false);
  const [commentInput, setCommentInput] = useState('');
  const [commentSubmitting, setCommentSubmitting] = useState(false);
  const commentTextareaRef = useRef<HTMLTextAreaElement>(null);

  const [currentUser, setCurrentUser] = useState<UserMeResponse | null>(null);

  const fetchComments = useCallback(async (page: number, append = false) => {
    setCommentsLoading(true);
    try {
      const res = await getVideoComments(videoId, page, 20);
      const sorted = [...res.items].sort(
        (a, b) => new Date(a.created_at).getTime() - new Date(b.created_at).getTime()
      );
      setComments(prev => append ? [...prev, ...sorted] : sorted);
      setCommentsTotal(res.total);
      setCommentsHasNext(res.has_next);
      setCommentsPage(page);
    } catch (err) {
      console.error('Failed to fetch comments:', err);
    } finally {
      setCommentsLoading(false);
    }
  }, [videoId]);

  useEffect(() => {
    const fetchVideo = async () => {
      setLoading(true);
      setError(null);
      try {
        const data = await getVideoById(videoId);
        setVideo(data);
        setLikeCount(data.like_count);
        setIsLiked(data.is_liked_by_me);
      } catch (err) {
        console.error('Failed to fetch video:', err);
        setError(t('ado2Contents.loadFailed'));
      } finally {
        setLoading(false);
      }
    };

    fetchVideo();
    fetchComments(1);
  }, [videoId, fetchComments]);

  useEffect(() => {
    if (!authed) return;
    getUserMe().then(setCurrentUser).catch((err) => {
      console.error('Failed to fetch current user:', err);
    });
  }, [authed]);

  const formatDate = (dateString: string) => {
    const date = new Date(dateString);
    return t('videoDetail.dateFormat', { year: date.getFullYear(), month: date.getMonth() + 1, day: date.getDate() });
  };

  const formatCommentDate = (dateString: string) => {
    const date = new Date(dateString);
    return `${date.getFullYear()}.${String(date.getMonth() + 1).padStart(2, '0')}.${String(date.getDate()).padStart(2, '0')}`;
  };

  const shareUrl = buildVideoShareUrl(API_URL, videoId);
  const shareTitle = video?.title || video?.store_name || t('videoDetail.kakaoDefaultTitle');

  const handleCopyLink = async () => {
    try {
      await navigator.clipboard.writeText(shareUrl);
    } catch {
      // clipboard API 미지원 환경에서는 무시
    }
    setCopied(true);
    setTimeout(() => setCopied(false), 2000);
  };

  const handleShareButtonClick = async () => {
    const handled = await tryNativeShare({
      title: shareTitle,
      url: shareUrl,
    });
    if (handled) {
      return;
    }
    await handleCopyLink();
  };

  const likeDebounceRef = React.useRef<ReturnType<typeof setTimeout> | null>(null);

  const handleLike = () => {
    if (!authed) { setShowLoginModal(true); return; }

    // 1. UI 즉시 업데이트 (Optimistic)
    setIsLiked(prev => !prev);
    setLikeCount(prev => isLiked ? prev - 1 : prev + 1);

    // 2. 기존 debounce 타이머 취소 후 재설정
    if (likeDebounceRef.current) clearTimeout(likeDebounceRef.current);
    likeDebounceRef.current = setTimeout(async () => {
      const prevLiked = isLiked;
      const prevCount = likeCount;
      try {
        await toggleVideoLike(videoId);
      } catch (err) {
        // 3. 실패 시 롤백
        console.error('Failed to toggle like:', err);
        setIsLiked(prevLiked);
        setLikeCount(prevCount);
      }
    }, 500);
  };

  const handleHeaderAction = () => {
    if (!isModal && !authed) { setShowLoginModal(true); return; }
    onClose?.();
  };

  const handleCommentFocus = () => {
    if (!authed) setShowLoginModal(true);
  };

  const handleCommentSubmit = async () => {
    if (!authed) { setShowLoginModal(true); return; }
    if (!commentInput.trim() || commentSubmitting) return;
    setCommentSubmitting(true);
    try {
      await postVideoComment(videoId, commentInput.trim());
      setCommentInput('');
      if (commentTextareaRef.current) {
        commentTextareaRef.current.style.height = 'auto';
      }
      await fetchComments(1);
    } catch (err) {
      console.error('Failed to post comment:', err);
    } finally {
      setCommentSubmitting(false);
    }
  };

  const handleDeleteComment = async (commentId: number) => {
    try {
      await deleteComment(commentId);
      await fetchComments(commentsPage);
    } catch (err) {
      console.error('Failed to delete comment:', err);
    }
  };

  const renderCommentContent = (content: string | null, isDeleted: boolean) => {
    if (isDeleted) return <span style={{ color: '#6B9EA0', fontStyle: 'italic' }}>{t('videoDetail.deletedComment')}</span>;
    return content;
  };

  return (
    <div className={isModal ? 'video-detail-modal-content' : 'video-detail-page-content'}>
      {/* 헤더 */}
      <div className="video-detail-header">
        {isModal ? (
          <button className="video-detail-close-btn" onClick={handleHeaderAction} aria-label={t('videoDetail.closeAriaLabel')}>
            <svg width="22" height="22" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2">
              <line x1="18" y1="6" x2="6" y2="18"/><line x1="6" y1="6" x2="18" y2="18"/>
            </svg>
          </button>
        ) : (
          <button className="video-detail-back-btn" onClick={handleHeaderAction}>
            <svg width="20" height="20" viewBox="0 0 20 20" fill="none" stroke="currentColor" strokeWidth="1.5">
              <path d="M13 4l-6 6 6 6"/>
            </svg>
            {t('sidebar.ado2Contents')}
          </button>
        )}
      </div>

      {loading ? (
        <div className="ado2-contents-loading">
          <div className="loading-spinner"></div>
          <p>{t('ado2Contents.loading')}</p>
        </div>
      ) : error ? (
        <div className="ado2-contents-error"><p>{error}</p></div>
      ) : video ? (
        <div className={`video-detail-content ${isLandscape ? 'landscape' : ''}`}>
          <video
            src={video.result_movie_url}
            controls
            autoPlay
            controlsList="nodownload"
            onContextMenu={(e) => e.preventDefault()}
            className="video-detail-player"
            onLoadedMetadata={(e) => {
              const v = e.currentTarget;
              setIsLandscape(v.videoWidth > v.videoHeight);
            }}
          />

          <div className="video-detail-info">
            <h2 className="video-detail-store">{video.store_name}</h2>
            <p className="video-detail-date">{formatDate(video.created_at)}</p>

            {/* 좋아요 + 링크 복사 */}
            <div style={{ display: 'flex', gap: '8px', flexWrap: 'wrap' }}>
              <button
                className={`video-detail-like-btn ${isLiked ? 'liked' : ''}`}
                onClick={handleLike}
                disabled={false}
              >
                <svg width="16" height="16" viewBox="0 0 24 24" fill={isLiked ? 'currentColor' : 'none'} stroke="currentColor" strokeWidth="2">
                  <path d="M20.84 4.61a5.5 5.5 0 0 0-7.78 0L12 5.67l-1.06-1.06a5.5 5.5 0 0 0-7.78 7.78l1.06 1.06L12 21.23l7.78-7.78 1.06-1.06a5.5 5.5 0 0 0 0-7.78z"/>
                </svg>
                {likeCount}
              </button>
              <button
                className="video-detail-copy-btn"
                onClick={handleShareButtonClick}
                title={t('videoDetail.share')}
              >
                <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2">
                  <circle cx="18" cy="5" r="3"/><circle cx="6" cy="12" r="3"/><circle cx="18" cy="19" r="3"/>
                  <line x1="8.59" y1="13.51" x2="15.42" y2="17.49"/><line x1="15.41" y1="6.51" x2="8.59" y2="10.49"/>
                </svg>
                {copied ? t('videoDetail.copied') : t('videoDetail.share')}
              </button>
            </div>

            {/* 댓글 섹션 */}
            <div className="video-detail-comments">
              <div className="video-detail-comments-header">
                <h3 className="video-detail-comments-title">{t('videoDetail.commentsTitle')}</h3>
                <span className="video-detail-comments-count">{commentsTotal}</span>
              </div>

              {/* 댓글 작성자 프로필 (카카오 로그인 정보) */}
              {authed && currentUser && (
                <div className="video-detail-comment-profile">
                  {currentUser.profile_image_url && (
                    <img
                      src={currentUser.profile_image_url}
                      alt={currentUser.nickname}
                      className="video-detail-comment-avatar"
                    />
                  )}
                  <span className="video-detail-comment-nickname">{currentUser.nickname}</span>
                </div>
              )}

              <div className="video-detail-comment-input-wrap">
                <textarea
                  ref={commentTextareaRef}
                  className="video-detail-comment-input"
                  placeholder={authed ? t('videoDetail.commentPlaceholder') : t('videoDetail.commentLoginRequired')}
                  maxLength={500}
                  rows={1}
                  value={commentInput}
                  onChange={(e) => {
                    setCommentInput(e.target.value);
                    e.target.style.height = 'auto';
                    e.target.style.height = `${e.target.scrollHeight}px`;
                  }}
                  onFocus={handleCommentFocus}
                  onKeyDown={(e) => {
                    if (e.key === 'Enter' && !e.shiftKey) {
                      e.preventDefault();
                      handleCommentSubmit();
                    }
                  }}
                  disabled={!authed}
                />
                <button
                  className="video-detail-comment-submit"
                  onClick={handleCommentSubmit}
                  disabled={!authed || !commentInput.trim() || commentSubmitting}
                >
                  {commentSubmitting ? t('videoDetail.commentSubmitting') : t('videoDetail.commentSubmit')}
                </button>
              </div>

              {comments.length === 0 && !commentsLoading ? (
                <p className="video-detail-comments-empty">{t('videoDetail.noComments')}</p>
              ) : (
                <ul className="video-detail-comment-list">
                  {comments.map((c) => (
                    <li key={c.id} className="video-detail-comment-item">
                      {c.profile_image_url && (
                        <img
                          src={c.profile_image_url}
                          alt={c.nickname || t('videoDetail.anonymous')}
                          className="video-detail-comment-avatar"
                        />
                      )}
                      <div className="video-detail-comment-body">
                        <span className="video-detail-comment-nickname">
                          {c.nickname || t('videoDetail.anonymous')}
                        </span>
                        <p className="video-detail-comment-text">
                          {renderCommentContent(c.content, c.is_deleted)}
                        </p>
                        <div className="video-detail-comment-bottom">
                          <span className="video-detail-comment-date">{formatCommentDate(c.created_at)}</span>
                          {c.is_mine && !c.is_deleted && (
                            <button
                              className="video-detail-comment-delete"
                              onClick={() => handleDeleteComment(c.id)}
                            >
                              {t('videoDetail.deleteComment')}
                            </button>
                          )}
                        </div>

                        {/* 대댓글 (읽기 전용) */}
                        {c.replies && c.replies.length > 0 && (
                          <ul className="video-detail-reply-list">
                            {c.replies.map((r) => (
                              <li key={r.id} className="video-detail-reply-item">
                                {r.profile_image_url && (
                                  <img
                                    src={r.profile_image_url}
                                    alt={r.nickname || t('videoDetail.anonymous')}
                                    className="video-detail-comment-avatar small"
                                  />
                                )}
                                <div className="video-detail-comment-body">
                                  <span className="video-detail-comment-nickname">
                                    {r.nickname || t('videoDetail.anonymous')}
                                  </span>
                                  <p className="video-detail-comment-text">
                                    {renderCommentContent(r.content, r.is_deleted)}
                                  </p>
                                  <div className="video-detail-comment-bottom">
                                    <span className="video-detail-comment-date">{formatCommentDate(r.created_at)}</span>
                                    {r.is_mine && !r.is_deleted && (
                                      <button
                                        className="video-detail-comment-delete"
                                        onClick={() => handleDeleteComment(r.id)}
                                      >
                                        {t('videoDetail.deleteComment')}
                                      </button>
                                    )}
                                  </div>
                                </div>
                              </li>
                            ))}
                          </ul>
                        )}
                      </div>
                    </li>
                  ))}
                </ul>
              )}

              {commentsHasNext && (
                <button
                  className="video-detail-comments-more"
                  onClick={() => fetchComments(commentsPage + 1, true)}
                  disabled={commentsLoading}
                >
                  {commentsLoading ? t('videoDetail.loadingComments') : t('videoDetail.loadMoreComments')}
                </button>
              )}
            </div>
          </div>
        </div>
      ) : null}

      {showLoginModal && (
        <LoginPromptModal onClose={() => setShowLoginModal(false)} />
      )}
    </div>
  );
};

export default VideoDetailContent;