import React, { useState, useEffect } from 'react';
import {
  Modal,
  ModalOverlay,
  ModalContent,
  ModalHeader,
  ModalBody,
  ModalCloseButton,
  Box,
  Text,
  VStack,
  HStack,
  Avatar,
  Textarea,
  Button,
  Divider,
  useToast,
  Badge,
  Flex,
  IconButton,
  Menu,
  MenuButton,
  MenuList,
  MenuItem,
  useColorModeValue,
  Spinner,
  Center,
  Collapse,
  Input,
} from '@chakra-ui/react';
import {
  ChatIcon,
  TimeIcon,
  DeleteIcon,
  EditIcon,
  ChevronDownIcon,
  TriangleDownIcon,
  TriangleUpIcon,
} from '@chakra-ui/icons';
import { FaHeart, FaRegHeart, FaComment } from 'react-icons/fa';
import { format } from 'date-fns';
import { zhCN } from 'date-fns/locale';
import { eventService } from '../../../services/eventService';

// 获取 API 基础地址
const API_BASE_URL = process.env.NODE_ENV === 'production' ? '' : (process.env.REACT_APP_API_URL || 'http://49.232.185.254:5001');

const EventDiscussionModal = ({ isOpen, onClose, eventId, eventTitle, discussionType = '事件讨论' }) => {
  const [posts, setPosts] = useState([]);
  const [newPostContent, setNewPostContent] = useState('');
  const [newPostTitle, setNewPostTitle] = useState('');
  const [loading, setLoading] = useState(false);
  const [submitting, setSubmitting] = useState(false);
  const [expandedPosts, setExpandedPosts] = useState({});
  const [postComments, setPostComments] = useState({});
  const [replyContents, setReplyContents] = useState({});
  const [loadingComments, setLoadingComments] = useState({});
  
  const toast = useToast();
  const bgColor = useColorModeValue('white', 'gray.800');
  const borderColor = useColorModeValue('gray.200', 'gray.600');
  const hoverBg = useColorModeValue('gray.50', 'gray.700');

  // 加载帖子列表
  const loadPosts = async () => {
    if (!eventId) return;
    
    setLoading(true);
    try {
      const response = await fetch(`${API_BASE_URL}/api/events/${eventId}/posts?sort=latest&page=1&per_page=20`, {
        method: 'GET',
        headers: { 'Content-Type': 'application/json' },
        credentials: 'include'
      });
      const result = await response.json();
      
      if (response.ok && result.success) {
        setPosts(result.data || []);
      } else {
        toast({
          title: '加载帖子失败',
          status: 'error',
          duration: 3000,
          isClosable: true,
        });
      }
    } catch (error) {
      console.error('Failed to load posts:', error);
      toast({
        title: '加载帖子失败',
        status: 'error',
        duration: 3000,
        isClosable: true,
      });
    } finally {
      setLoading(false);
    }
  };

  // 加载帖子的评论
  const loadPostComments = async (postId) => {
    setLoadingComments(prev => ({ ...prev, [postId]: true }));
    try {
      const response = await fetch(`${API_BASE_URL}/api/posts/${postId}/comments?sort=latest`, {
        method: 'GET',
        headers: { 'Content-Type': 'application/json' },
        credentials: 'include'
      });
      const result = await response.json();
      
      if (response.ok && result.success) {
        setPostComments(prev => ({ ...prev, [postId]: result.data || [] }));
      }
    } catch (error) {
      console.error('Failed to load comments:', error);
    } finally {
      setLoadingComments(prev => ({ ...prev, [postId]: false }));
    }
  };

  // 切换展开/收起评论
  const togglePostComments = async (postId) => {
    const isExpanded = expandedPosts[postId];
    if (!isExpanded) {
      // 展开时加载评论
      await loadPostComments(postId);
    }
    setExpandedPosts(prev => ({ ...prev, [postId]: !isExpanded }));
  };

  // 提交新帖子
  const handleSubmitPost = async () => {
    if (!newPostContent.trim()) return;
    
    setSubmitting(true);
    try {
      const response = await fetch(`${API_BASE_URL}/api/events/${eventId}/posts`, {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        credentials: 'include',
        body: JSON.stringify({
          title: newPostTitle.trim(),
          content: newPostContent.trim(),
          content_type: 'text',
        })
      });
      const result = await response.json();
      
      if (response.ok && result.success) {
        setNewPostContent('');
        setNewPostTitle('');
        loadPosts();
        toast({
          title: '帖子发布成功',
          status: 'success',
          duration: 2000,
          isClosable: true,
        });
      } else {
        toast({
          title: result.message || '帖子发布失败',
          status: 'error',
          duration: 3000,
          isClosable: true,
        });
      }
    } catch (error) {
      console.error('Failed to submit post:', error);
      toast({
        title: '帖子发布失败',
        status: 'error',
        duration: 3000,
        isClosable: true,
      });
    } finally {
      setSubmitting(false);
    }
  };

  // 删除帖子
  const handleDeletePost = async (postId) => {
    if (!window.confirm('确定要删除这个帖子吗？')) return;
    
    try {
      const response = await fetch(`${API_BASE_URL}/api/posts/${postId}`, {
        method: 'DELETE',
        headers: { 'Content-Type': 'application/json' },
        credentials: 'include'
      });
      const result = await response.json();
      
      if (response.ok && result.success) {
        loadPosts();
        toast({
          title: '帖子已删除',
          status: 'success',
          duration: 2000,
          isClosable: true,
        });
      } else {
        toast({
          title: result.message || '删除失败',
          status: 'error',
          duration: 3000,
          isClosable: true,
        });
      }
    } catch (error) {
      console.error('Failed to delete post:', error);
      toast({
        title: '删除失败',
        status: 'error',
        duration: 3000,
        isClosable: true,
      });
    }
  };

  // 点赞帖子
  const handleLikePost = async (postId) => {
    try {
      const response = await fetch(`${API_BASE_URL}/api/posts/${postId}/like`, {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        credentials: 'include'
      });
      const result = await response.json();
      
      if (response.ok && result.success) {
        // 更新帖子列表中的点赞状态
        setPosts(prev => prev.map(post => 
          post.id === postId 
            ? { ...post, likes_count: result.likes_count, liked: result.liked }
            : post
        ));
      }
    } catch (error) {
      console.error('Failed to like post:', error);
      toast({
        title: '操作失败',
        status: 'error',
        duration: 2000,
        isClosable: true,
      });
    }
  };

  // 提交评论
  const handleSubmitComment = async (postId) => {
    const content = replyContents[postId];
    if (!content?.trim()) return;
    
    try {
      const response = await fetch(`${API_BASE_URL}/api/posts/${postId}/comments`, {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        credentials: 'include',
        body: JSON.stringify({
          content: content.trim(),
        })
      });
      const result = await response.json();
      
      if (response.ok && result.success) {
        setReplyContents(prev => ({ ...prev, [postId]: '' }));
        // 重新加载该帖子的评论
        await loadPostComments(postId);
        // 更新帖子的评论数
        setPosts(prev => prev.map(post => 
          post.id === postId 
            ? { ...post, comments_count: (post.comments_count || 0) + 1 }
            : post
        ));
        toast({
          title: '评论发布成功',
          status: 'success',
          duration: 2000,
          isClosable: true,
        });
      }
    } catch (error) {
      console.error('Failed to submit comment:', error);
      toast({
        title: '评论发布失败',
        status: 'error',
        duration: 3000,
        isClosable: true,
      });
    }
  };

  // 删除评论
  const handleDeleteComment = async (commentId, postId) => {
    if (!window.confirm('确定要删除这条评论吗？')) return;
    
    try {
      const response = await fetch(`${API_BASE_URL}/api/comments/${commentId}`, {
        method: 'DELETE',
        headers: { 'Content-Type': 'application/json' },
        credentials: 'include'
      });
      const result = await response.json();
      
      if (response.ok && result.success) {
        // 重新加载该帖子的评论
        await loadPostComments(postId);
        // 更新帖子的评论数
        setPosts(prev => prev.map(post => 
          post.id === postId 
            ? { ...post, comments_count: Math.max(0, (post.comments_count || 0) - 1) }
            : post
        ));
        toast({
          title: '评论已删除',
          status: 'success',
          duration: 2000,
          isClosable: true,
        });
      }
    } catch (error) {
      console.error('Failed to delete comment:', error);
      toast({
        title: '删除失败',
        status: 'error',
        duration: 3000,
        isClosable: true,
      });
    }
  };

  useEffect(() => {
    if (isOpen) {
      loadPosts();
    }
  }, [isOpen, eventId]);

  return (
    <Modal isOpen={isOpen} onClose={onClose} size="xl">
      <ModalOverlay />
      <ModalContent maxH="80vh">
        <ModalHeader>
          <VStack align="start" spacing={1}>
            <HStack>
              <ChatIcon />
              <Text>{discussionType}</Text>
            </HStack>
            {eventTitle && (
              <Text fontSize="sm" color="gray.500" fontWeight="normal">
                {eventTitle}
              </Text>
            )}
          </VStack>
        </ModalHeader>
        <ModalCloseButton />
        
        <ModalBody overflowY="auto">
          {/* 发布新帖子 */}
          <Box mb={4}>
            <Input
              value={newPostTitle}
              onChange={(e) => setNewPostTitle(e.target.value)}
              placeholder="帖子标题（可选）"
              size="sm"
              mb={2}
            />
            <Textarea
              value={newPostContent}
              onChange={(e) => setNewPostContent(e.target.value)}
              placeholder="分享您的观点..."
              size="sm"
              resize="vertical"
              minH="80px"
            />
            <Flex justify="flex-end" mt={2}>
              <Button
                colorScheme="blue"
                size="sm"
                onClick={handleSubmitPost}
                isLoading={submitting}
                isDisabled={!newPostContent.trim()}
              >
                发布帖子
              </Button>
            </Flex>
          </Box>

          <Divider mb={4} />

          {/* 帖子列表 */}
          {loading ? (
            <Center py={8}>
              <Spinner size="lg" />
            </Center>
          ) : posts.length > 0 ? (
            <VStack spacing={4} align="stretch">
              {posts.map((post) => (
                <Box
                  key={post.id}
                  p={4}
                  borderWidth="1px"
                  borderColor={borderColor}
                  borderRadius="md"
                  transition="background 0.2s"
                >
                  {/* 帖子头部 */}
                  <Flex justify="space-between" align="start" mb={3}>
                    <HStack align="start" spacing={3}>
                      <Avatar
                        size="sm"
                        name={post.user?.username || '匿名用户'}
                        src={post.user?.avatar_url}
                      />
                      <VStack align="start" spacing={1} flex={1}>
                        <HStack>
                          <Text fontWeight="semibold" fontSize="sm">
                            {post.user?.username || '匿名用户'}
                          </Text>
                        </HStack>
                        <HStack fontSize="xs" color="gray.500">
                          <TimeIcon />
                          <Text>
                            {format(new Date(post.created_at), 'MM月dd日 HH:mm', {
                              locale: zhCN,
                            })}
                          </Text>
                        </HStack>
                      </VStack>
                    </HStack>
                    
                    {/* 操作菜单 */}
                    <Menu>
                      <MenuButton
                        as={IconButton}
                        icon={<ChevronDownIcon />}
                        variant="ghost"
                        size="sm"
                      />
                      <MenuList>
                        <MenuItem
                          icon={<DeleteIcon />}
                          color="red.500"
                          onClick={() => handleDeletePost(post.id)}
                        >
                          删除帖子
                        </MenuItem>
                      </MenuList>
                    </Menu>
                  </Flex>

                  {/* 帖子标题 */}
                  {post.title && (
                    <Text fontSize="md" fontWeight="bold" mb={2}>
                      {post.title}
                    </Text>
                  )}

                  {/* 帖子内容 */}
                  <Text fontSize="sm" whiteSpace="pre-wrap" mb={3}>
                    {post.content}
                  </Text>

                  {/* 帖子操作栏 */}
                  <HStack spacing={4} mb={3}>
                    <Button
                      size="sm"
                      variant="ghost"
                      leftIcon={post.liked ? <FaHeart /> : <FaRegHeart />}
                      color={post.liked ? 'red.500' : 'gray.600'}
                      onClick={() => handleLikePost(post.id)}
                    >
                      {post.likes_count || 0}
                    </Button>
                    <Button
                      size="sm"
                      variant="ghost"
                      leftIcon={<FaComment />}
                      onClick={() => togglePostComments(post.id)}
                      rightIcon={expandedPosts[post.id] ? <TriangleUpIcon /> : <TriangleDownIcon />}
                    >
                      {post.comments_count || 0} 评论
                    </Button>
                  </HStack>

                  {/* 评论区 */}
                  <Collapse in={expandedPosts[post.id]} animateOpacity>
                    <Box borderTopWidth="1px" borderColor={borderColor} pt={3}>
                      {/* 评论输入框 */}
                      <HStack mb={3}>
                        <Textarea
                          size="sm"
                          placeholder="写下你的评论..."
                          value={replyContents[post.id] || ''}
                          onChange={(e) => setReplyContents(prev => ({ ...prev, [post.id]: e.target.value }))}
                          rows={2}
                          flex={1}
                        />
                        <Button
                          size="sm"
                          colorScheme="blue"
                          onClick={() => handleSubmitComment(post.id)}
                          isDisabled={!replyContents[post.id]?.trim()}
                        >
                          评论
                        </Button>
                      </HStack>

                      {/* 评论列表 */}
                      {loadingComments[post.id] ? (
                        <Center py={4}>
                          <Spinner size="sm" />
                        </Center>
                      ) : (
                        <VStack align="stretch" spacing={2}>
                          {postComments[post.id]?.map((comment) => (
                            <Box key={comment.id} pl={4} borderLeftWidth="2px" borderColor="gray.200">
                              <HStack justify="space-between" mb={1}>
                                <HStack spacing={2}>
                                  <Avatar size="xs" name={comment.user?.username} src={comment.user?.avatar_url} />
                                  <Text fontSize="sm" fontWeight="medium">
                                    {comment.user?.username || '匿名用户'}
                                  </Text>
                                  <Text fontSize="xs" color="gray.500">
                                    {format(new Date(comment.created_at), 'MM-dd HH:mm')}
                                  </Text>
                                </HStack>
                                <IconButton
                                  size="xs"
                                  icon={<DeleteIcon />}
                                  variant="ghost"
                                  onClick={() => handleDeleteComment(comment.id, post.id)}
                                />
                              </HStack>
                              <Text fontSize="sm" pl={7}>
                                {comment.content}
                              </Text>
                              
                              {/* 显示回复 */}
                              {comment.replies && comment.replies.length > 0 && (
                                <VStack align="stretch" mt={2} spacing={1} pl={4}>
                                  {comment.replies.map((reply) => (
                                    <Box key={reply.id}>
                                      <HStack spacing={1}>
                                        <Text fontSize="xs" fontWeight="medium">
                                          {reply.user?.username}:
                                        </Text>
                                        <Text fontSize="xs">{reply.content}</Text>
                                      </HStack>
                                    </Box>
                                  ))}
                                </VStack>
                              )}
                            </Box>
                          ))}
                          {(!postComments[post.id] || postComments[post.id].length === 0) && (
                            <Text fontSize="sm" color="gray.500" textAlign="center" py={2}>
                              暂无评论
                            </Text>
                          )}
                        </VStack>
                      )}
                    </Box>
                  </Collapse>
                </Box>
              ))}
            </VStack>
          ) : (
            <Center py={8}>
              <VStack>
                <ChatIcon boxSize={8} color="gray.400" />
                <Text color="gray.500">暂无帖子，快来发表您的观点吧！</Text>
              </VStack>
            </Center>
          )}
        </ModalBody>
      </ModalContent>
    </Modal>
  );
};

export default EventDiscussionModal;