import React, { useState, useEffect, useRef, useCallback } from 'react';
import { Link, useNavigate, useParams } from 'react-router-dom';
import apiClient from '../utils/apiClient';
import { ArrowLeft, Users, Calendar, FileText, X, User, Save, Upload, Plus, Image, Tag } from 'lucide-react';
import MDEditor, * as commands from '@uiw/react-md-editor';
import '@uiw/react-md-editor/markdown-editor.css';
import { buildApiUrl, API_ENDPOINTS, API_BASE_URL } from '../config/api';
import DateTimePicker from '../components/DateTimePicker';
import TagEditor from '../components/TagEditor';
import './EditMeeting.css';

const EditMeeting = ({ user }) => {
  const navigate = useNavigate();
  const { meeting_id } = useParams();
  const imageInputRef = useRef(null);
  const [formData, setFormData] = useState({
    title: '',
    meeting_time: '',
    summary: '',
    attendees: [],
    tags: ''
  });
  const [availableUsers, setAvailableUsers] = useState([]);
  const [userSearch, setUserSearch] = useState('');
  const [showUserDropdown, setShowUserDropdown] = useState(false);
  const [audioFile, setAudioFile] = useState(null);
  const [isLoading, setIsLoading] = useState(true);
  const [isSaving, setIsSaving] = useState(false);
  const [isUploading, setIsUploading] = useState(false);
  const [isUploadingImage, setIsUploadingImage] = useState(false);
  const [error, setError] = useState('');
  const [meeting, setMeeting] = useState(null);
  const [showUploadArea, setShowUploadArea] = useState(false);
  const [showUploadConfirm, setShowUploadConfirm] = useState(false);

  const handleSummaryChange = useCallback((value) => {
    setFormData(prev => ({ ...prev, summary: value || '' }));
  }, []);

  useEffect(() => {
    fetchMeetingData();
    fetchUsers();
  }, [meeting_id]);

  const fetchMeetingData = async () => {
    try {
      const response = await apiClient.get(buildApiUrl(API_ENDPOINTS.MEETINGS.EDIT(meeting_id)));
      const meetingData = response.data;
      
      // Check if current user is the creator
      if (meetingData.creator_id !== user.user_id) {
        navigate('/dashboard');
        return;
      }
      
      setMeeting(meetingData);
      setFormData({
        title: meetingData.title,
        meeting_time: meetingData.meeting_time || '',
        summary: meetingData.summary || '',
        attendees: meetingData.attendees || [],
        tags: meetingData.tags ? meetingData.tags.map(t => t.name).join(', ') : ''
      });
    } catch (err) {
      setError('无法加载会议信息');
      console.error('Error fetching meeting:', err);
    } finally {
      setIsLoading(false);
    }
  };

  const fetchUsers = async () => {
    try {
      // 获取所有用户，设置较大的size参数
      const response = await apiClient.get(buildApiUrl(`${API_ENDPOINTS.USERS.LIST}?page=1&size=1000`));
      setAvailableUsers(response.data.users.filter(u => u.user_id !== user.user_id));
    } catch (err) {
      console.error('Error fetching users:', err);
    }
  };

  const handleInputChange = (e) => {
    const { name, value } = e.target;
    setFormData(prev => ({
      ...prev,
      [name]: value
    }));
  };

  const handleAddAttendee = (selectedUser) => {
    if (!formData.attendees.find(a => a.user_id === selectedUser.user_id)) {
      setFormData(prev => ({
        ...prev,
        attendees: [...prev.attendees, selectedUser]
      }));
    }
    setUserSearch('');
    setShowUserDropdown(false);
  };

  const handleRemoveAttendee = (userId) => {
    setFormData(prev => ({
      ...prev,
      attendees: prev.attendees.filter(a => a.user_id !== userId)
    }));
  };

  const handleFileChange = (e) => {
    const file = e.target.files[0];
    if (file) {
      // Check file type - include both MIME types and extensions
      const allowedMimeTypes = ['audio/mp3', 'audio/wav', 'audio/m4a', 'audio/mpeg', 'audio/mp4', 'audio/x-m4a'];
      const fileExtension = file.name.toLowerCase().split('.').pop();
      const allowedExtensions = ['mp3', 'wav', 'm4a', 'mpeg'];
      
      if (!allowedMimeTypes.includes(file.type) && !allowedExtensions.includes(fileExtension)) {
        setError('请上传支持的音频格式 (MP3, WAV, M4A)');
        return;
      }
      // Check file size (max 100MB)
      if (file.size > 100 * 1024 * 1024) {
        setError('音频文件大小不能超过100MB');
        return;
      }
      setAudioFile(file);
      setError('');
    }
  };

  const handleSubmit = async (e) => {
    e.preventDefault();
    if (!formData.title.trim()) {
      setError('请输入会议标题');
      return;
    }

    setIsSaving(true);
    setError('');

    try {
      const updateData = {
        title: formData.title,
        meeting_time: formData.meeting_time || null,
        summary: formData.summary,
        attendee_ids: formData.attendees.map(a => a.user_id),
        tags: formData.tags
      };

      await apiClient.put(buildApiUrl(API_ENDPOINTS.MEETINGS.UPDATE(meeting_id)), updateData);
      navigate(`/meetings/${meeting_id}`);
    } catch (err) {
      setError(err.response?.data?.detail || '更新会议失败，请重试');
    } finally {
      setIsSaving(false);
    }
  };

  const handleUploadAudio = async () => {
    if (!audioFile) {
      setError('请先选择音频文件');
      return;
    }

    setIsUploading(true);
    setError('');

    try {
      const formDataUpload = new FormData();
      formDataUpload.append('audio_file', audioFile);
      formDataUpload.append('meeting_id', meeting_id);
      formDataUpload.append('force_replace', 'true'); // Always force replace in edit mode

      const response = await apiClient.post(buildApiUrl(API_ENDPOINTS.MEETINGS.UPLOAD_AUDIO), formDataUpload, {
        headers: {
          'Content-Type': 'multipart/form-data',
        },
      });

      setAudioFile(null);
      setShowUploadArea(false);
      setShowUploadConfirm(false);
      // Reset file input
      const fileInput = document.getElementById('audio-file');
      if (fileInput) fileInput.value = '';
      
    } catch (err) {
      console.error('Upload error:', err);
      setError(err.response?.data?.detail || '上传音频文件失败，请重试');
    } finally {
      setIsUploading(false);
    }
  };

  const handleImageUpload = async (file) => {
    if (!file) return null;

    // Validate file type
    const allowedTypes = ['image/jpeg', 'image/jpg', 'image/png', 'image/gif', 'image/webp'];
    if (!allowedTypes.includes(file.type)) {
      setError('请上传支持的图片格式 (JPG, PNG, GIF, WebP)');
      return null;
    }

    // Validate file size (10MB)
    if (file.size > 10 * 1024 * 1024) {
      setError('图片大小不能超过10MB');
      return null;
    }

    setIsUploadingImage(true);
    setError('');

    try {
      const formData = new FormData();
      formData.append('image_file', file);

      const response = await apiClient.post(
        buildApiUrl(API_ENDPOINTS.MEETINGS.UPLOAD_IMAGE(meeting_id)), 
        formData,
        {
          headers: {
            'Content-Type': 'multipart/form-data',
          },
        }
      );

      return `${API_BASE_URL}${response.data.file_path}`;
    } catch (err) {
      setError('上传图片失败，请重试');
      return null;
    } finally {
      setIsUploadingImage(false);
    }
  };

  const insertImageMarkdown = (imageUrl, altText = '图片') => {
    const imageMarkdown = `![${altText}](${imageUrl})`;
    setFormData(prev => ({
      ...prev,
      summary: prev.summary + '\n\n' + imageMarkdown
    }));
  };

  const handleImageSelect = async (event) => {
    const file = event.target.files[0];
    if (file) {
      const imageUrl = await handleImageUpload(file);
      if (imageUrl) {
        insertImageMarkdown(imageUrl, file.name);
      }
    }
    // Reset file input
    if (imageInputRef.current) {
      imageInputRef.current.value = '';
    }
  };

  // 创建自定义上传图片命令（只显示文字，不显示图标）
  const uploadImageCommand = {
    name: 'upload-image',
    keyCommand: 'upload-image',
    buttonProps: { 'aria-label': '上传本地图片', title: '上传本地图片' },
    icon: <span style={{fontSize:12}}>UploadImage</span>,
    execute: () => {
      imageInputRef.current?.click();
    }
  };

  // 创建修改后的图片URL命令
  const imageUrlCommand = {
    ...commands.image,
    name: 'image-url',
    icon: <span style={{fontSize:12}}>AddImageURL</span>,
  };

  // 自定义工具栏命令配置
  const customCommands = [
    commands.bold,
    commands.italic,
    commands.strikethrough,
    commands.hr,
    commands.group([
      commands.title1,
      commands.title2,
      commands.title3,
      commands.title4,
      commands.title5,
      commands.title6,
    ], {
      name: 'title',
      groupName: 'title',
      buttonProps: { 'aria-label': '插入标题', title: '插入标题' }
    }),
    commands.divider,
    commands.link,
    commands.quote,
    commands.code,
    commands.codeBlock,
    // 创建图片功能组，使用系统自带的image命令和自定义上传命令
    commands.group([
      imageUrlCommand,
      uploadImageCommand
    ], {
      name: 'image-group',
      groupName: 'image',
      buttonProps: { 'aria-label': '添加图片', title: '添加图片' },
      icon: (
        <svg width="12" height="12" viewBox="0 0 24 24" fill="currentColor">
          <path d="M21 19V5c0-1.1-.9-2-2-2H5c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h14c1.1 0 2-.9 2-2zM8.5 13.5l2.5 3.01L14.5 12l4.5 6H5l3.5-4.5z"/>
        </svg>
      )
    }),
    commands.divider,
    commands.unorderedListCommand,
    commands.orderedListCommand,
    commands.checkedListCommand,
  ];

  // 右侧额外命令（预览、全屏等）
  const customExtraCommands = [
    commands.codeEdit,
    commands.codeLive,
    commands.codePreview,
    commands.divider,
    commands.fullscreen,
  ];

  const filteredUsers = availableUsers.filter(user => {
    // Exclude users already selected as attendees
    const isAlreadySelected = formData.attendees.some(attendee => attendee.user_id === user.user_id);
    if (isAlreadySelected) return false;
    
    // Filter by search text
    return user.caption.toLowerCase().includes(userSearch.toLowerCase()) ||
           user.username.toLowerCase().includes(userSearch.toLowerCase());
  });

  if (isLoading) {
    return (
      <div className="edit-meeting-page">
        <div className="loading-container">
          <div className="loading-spinner"></div>
          <p>加载中...</p>
        </div>
      </div>
    );
  }

  return (
    <div className="edit-meeting-page">
      <div className="edit-header">
        <Link to="/dashboard">
          <span className="back-link">
            <ArrowLeft size={20} />
            <span>返回首页</span>
          </span>
        </Link>
      </div>

      <div className="edit-content">
        <div className="edit-card">
          <header className="edit-card-header">
            <h1>编辑会议纪要</h1>
            <p>修改会议信息、参会人员和摘要内容</p>
          </header>

          <form onSubmit={handleSubmit} className="edit-form">
            <div className="form-group">
              <label htmlFor="title">
                <FileText size={18} />
                会议标题 *
              </label>
              <input
                type="text"
                id="title"
                name="title"
                value={formData.title}
                onChange={handleInputChange}
                placeholder="请输入会议标题"
                required
              />
            </div>

            <div className="form-group">
              <label>
                <Calendar size={18} />
                会议时间
              </label>
              <DateTimePicker
                value={formData.meeting_time}
                onChange={(value) => setFormData(prev => ({ ...prev, meeting_time: value }))}
                placeholder="选择会议时间（可选）"
              />
            </div>

            <div className="form-group">
              <label htmlFor="tags">
                <Tag size={18} />
                会议标签
              </label>
              <TagEditor
                value={formData.tags}
                onChange={(value) => setFormData(prev => ({ ...prev, tags: value }))}
                placeholder="输入标签，按回车或逗号分隔"
              />
            </div>

            <div className="form-group">
              <label>
                <Users size={18} />
                参会人员
              </label>
              <div className="attendees-container">
                <div className="selected-attendees">
                  {formData.attendees.map(attendee => (
                    <div key={attendee.user_id} className="attendee-chip">
                      <User size={16} />
                      <span>{attendee.caption}</span>
                      <button
                        type="button"
                        onClick={() => handleRemoveAttendee(attendee.user_id)}
                        className="remove-attendee"
                        title="移除参会人"
                      >
                        <X size={14} />
                      </button>
                    </div>
                  ))}
                </div>
                <div className="user-search-container">
                  <input
                    type="text"
                    value={userSearch}
                    onChange={(e) => {
                      setUserSearch(e.target.value);
                      setShowUserDropdown(true);
                    }}
                    onFocus={() => setShowUserDropdown(true)}
                    onBlur={() => {
                      // Delay hiding dropdown to allow click events
                      setTimeout(() => setShowUserDropdown(false), 200);
                    }}
                    placeholder="搜索用户名或姓名添加参会人..."
                    className="user-search-input"
                  />
                  {showUserDropdown && userSearch && (
                    <div className="user-dropdown">
                      {filteredUsers.length > 0 ? (
                        filteredUsers.map(user => (
                          <div
                            key={user.user_id}
                            className="user-option"
                            onClick={() => handleAddAttendee(user)}
                          >
                            <User size={16} />
                            <div className="user-info">
                              <span className="user-name">{user.caption}</span>
                              <span className="user-username">@{user.username}</span>
                            </div>
                          </div>
                        ))
                      ) : (
                        <div className="no-users">未找到匹配的用户</div>
                      )}
                    </div>
                  )}
                </div>
              </div>
            </div>

            <div className="form-group">
              <div className="audio-upload-section">
                {!showUploadArea ? (
                  <button
                    type="button"
                    onClick={() => setShowUploadArea(true)}
                    className="show-upload-btn"
                  >
                    <Upload size={16} />
                    <span>重新上传录音文件</span>
                  </button>
                ) : (
                  <div className="file-upload-container">
                    <div className="upload-header">
                      <button
                        type="button"
                        onClick={() => {
                          setShowUploadArea(false);
                          setAudioFile(null);
                          // Reset file input
                          const fileInput = document.getElementById('audio-file');
                          if (fileInput) fileInput.value = '';
                        }}
                        className="close-upload-btn"
                      >
                        <X size={16} />
                      </button>
                    </div>
                    <input
                      type="file"
                      id="audio-file"
                      accept="audio/*"
                      onChange={handleFileChange}
                      className="file-input"
                    />
                    <label htmlFor="audio-file" className="file-upload-label">
                      <Plus size={20} />
                      <span>选择新的音频文件</span>
                      <small>支持 MP3, WAV, M4A 格式，最大100MB</small>
                    </label>
                    {audioFile && (
                      <div className="selected-file">
                        <span>已选择: {audioFile.name}</span>
                        <button
                          type="button"
                          onClick={() => setAudioFile(null)}
                          className="remove-file"
                        >
                          <X size={16} />
                        </button>
                      </div>
                    )}
                    {audioFile && (
                      <button
                        type="button"
                        onClick={() => setShowUploadConfirm(true)}
                        className="upload-btn"
                        disabled={isUploading}
                      >
                        <Upload size={16} />
                        {isUploading ? '上传并分析中...' : '上传并重新分析'}
                      </button>
                    )}
                  </div>
                )}
              </div>
            </div>

            <div className="form-group">
              <div className="summary-header">
                <label htmlFor="summary">
                  <FileText size={18} />
                  会议摘要
                </label>
              </div>
              <div className="markdown-editor-container">
                <MDEditor
                  key="summary-editor"
                  value={formData.summary}
                  onChange={handleSummaryChange}
                  data-color-mode="light"
                  height={400}
                  preview="edit"
                  hideToolbar={false}
                  toolbarBottom={false}
                  commands={customCommands}
                  extraCommands={customExtraCommands}
                  autoFocus={false}
                  textareaProps={{
                    placeholder: '在这里编写会议摘要...',
                    style: {
                      fontSize: '14px',
                      lineHeight: '1.5',
                      fontFamily: 'inherit'
                    },
                    spellCheck: false,
                    autoComplete: 'off',
                    autoCapitalize: 'off',
                    autoCorrect: 'off'
                  }}
                />
                <input
                  ref={imageInputRef}
                  type="file"
                  accept="image/*"
                  onChange={handleImageSelect}
                  style={{ display: 'none' }}
                />
              </div>
              <div className="markdown-hint">
                <small>使用Markdown格式编写会议摘要，支持**粗体**、*斜体*、# 标题、- 列表等格式。工具栏中可以上传图片或插入图片URL。</small>
              </div>
              {isUploadingImage && (
                <div className="uploading-indicator">
                  <span>正在上传图片...</span>
                </div>
              )}
            </div>

            {error && (
              <div className="error-message">{error}</div>
            )}

            <div className="form-actions">
              <Link to={`/meetings/${meeting_id}`}>
                <span className="btn-cancel">取消</span>
              </Link>
              <button
                type="submit"
                className="btn-submit"
                disabled={isSaving}
              >
                <Save size={16} />
                {isSaving ? '保存中...' : '保存更改'}
              </button>
            </div>
          </form>
        </div>
      </div>

      {/* Upload Confirmation Modal */}
      {showUploadConfirm && (
        <div className="delete-modal-overlay" onClick={() => setShowUploadConfirm(false)}>
          <div className="delete-modal" onClick={(e) => e.stopPropagation()}>
            <h3>确认重新上传</h3>
            <p>重传音频文件将清空已有的会话转录，是否继续？</p>
            <div className="modal-actions">
              <button 
                className="btn-cancel"
                onClick={() => setShowUploadConfirm(false)}
              >
                取消
              </button>
              <button 
                className="btn-submit"
                onClick={handleUploadAudio}
                disabled={isUploading}
              >
                确定重传
              </button>
            </div>
          </div>
        </div>
      )}
    </div>
  );
};

export default EditMeeting;