import 'package:flutter/material.dart';
import 'package:share_plus/share_plus.dart';
import '../models/post_models.dart';
import '../services/post_service.dart';
import '../utils/invitation_utils.dart';

class PostsList extends StatefulWidget {
  final Future<Map<String, dynamic>> Function() fetchPosts;
  final String emptyStateTitle;
  final String emptyStateSubtitle;
  final bool showRefreshIndicator;
  final Widget? floatingActionButton;

  const PostsList({
    Key? key,
    required this.fetchPosts,
    this.emptyStateTitle = 'Nothing here..',
    this.emptyStateSubtitle = 'Create the first post!',
    this.showRefreshIndicator = true,
    this.floatingActionButton,
  }) : super(key: key);

  @override
  PostsListState createState() => PostsListState();
}

class PostsListState extends State<PostsList> {
  bool _isLoading = true;
  List<Post> _posts = [];
  String _errorMessage = '';

  @override
  void initState() {
    super.initState();
    _loadPosts();
  }

  Future<void> _loadPosts() async {
    setState(() {
      _isLoading = true;
      _errorMessage = '';
    });

    try {
      final result = await widget.fetchPosts();
      setState(() {
        if (result['success']) {
          _posts = result['posts'];
        } else {
          _errorMessage = result['message'] ?? 'Failed to load posts';
        }
        _isLoading = false;
      });
    } catch (e) {
      setState(() {
        _errorMessage = 'Network error: $e';
        _isLoading = false;
      });
    }
  }

  Future<void> _refreshPosts() async {
    await _loadPosts();
    
    if (widget.showRefreshIndicator) {
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(
          content: Text('Posts refreshed!'),
          backgroundColor: Color(0xFF6A4C93),
        ),
      );
    }
  }

  @override
  Widget build(BuildContext context) {
    Widget body = _buildBody();
    
    if (widget.showRefreshIndicator) {
      body = RefreshIndicator(
        onRefresh: _refreshPosts,
        child: body,
      );
    }
    
    return body;
  }

  Widget _buildBody() {
    if (_isLoading) {
      return Center(
        child: CircularProgressIndicator(
          valueColor: AlwaysStoppedAnimation<Color>(Color(0xFF6A4C93)),
        ),
      );
    }

    if (_errorMessage.isNotEmpty) {
      return Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Icon(
              Icons.error_outline,
              size: 64,
              color: Colors.grey[400],
            ),
            SizedBox(height: 16),
            Text(
              _errorMessage,
              style: TextStyle(
                fontSize: 16,
                color: Colors.grey[600],
              ),
              textAlign: TextAlign.center,
            ),
            SizedBox(height: 16),
            ElevatedButton(
              onPressed: _loadPosts,
              style: ElevatedButton.styleFrom(
                backgroundColor: Color(0xFF6A4C93),
                foregroundColor: Colors.white,
              ),
              child: Text('Try Again'),
            ),
          ],
        ),
      );
    }

    if (_posts.isEmpty) {
      return Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Icon(
              Icons.post_add,
              size: 64,
              color: Colors.grey[400],
            ),
            SizedBox(height: 16),
            Text(
              widget.emptyStateTitle,
              style: TextStyle(
                fontSize: 18,
                fontWeight: FontWeight.w600,
                color: Colors.grey[600],
              ),
            ),
            SizedBox(height: 8),
            Text(
              widget.emptyStateSubtitle,
              style: TextStyle(
                fontSize: 14,
                color: Colors.grey[500],
              ),
            ),
          ],
        ),
      );
    }

    return ListView.builder(
      padding: EdgeInsets.symmetric(vertical: 8),
      itemCount: _posts.length,
      itemBuilder: (context, index) {
        return PostCard(
          post: _posts[index],
        );
      },
    );
  }

  void refreshPosts() {
    _loadPosts();
  }
}

class PostCard extends StatefulWidget {
  final Post post;

  const PostCard({Key? key, required this.post})
    : super(key: key);

  @override
  _PostCardState createState() => _PostCardState();
}

class _PostCardState extends State<PostCard> {
  late Post _currentPost;
  bool _isLiking = false;

  @override
  void initState() {
    super.initState();
    _currentPost = widget.post;
  }

  @override
  void didUpdateWidget(PostCard oldWidget) {
    super.didUpdateWidget(oldWidget);
    // Update current post if the widget's post changed
    if (oldWidget.post.id != widget.post.id) {
      _currentPost = widget.post;
    }
  }

  Color _getAvatarColor(String displayName) {
    final colors = [
      Color(0xFF32B0A5),
      Color(0xFF4600B9),
      Color(0xFF6A4C93),
      Color(0xFFFF6347),
      Color(0xFF32CD32),
      Color(0xFF9932CC),
    ];
    
    int hash = displayName.hashCode;
    return colors[hash.abs() % colors.length];
  }

  String _getAvatarLetter(String displayName) {
    return displayName.isNotEmpty ? displayName[0].toUpperCase() : '?';
  }

  void _sharePost(Post post) {
    final shareText = '${post.creator.displayName} posted on Wesal.online:\n\n${post.body}';
    Share.share(shareText);
  }

  Future<void> _toggleLike() async {
    if (_isLiking) return; // Prevent multiple simultaneous requests

    setState(() {
      _isLiking = true;
      // Optimistic update - immediately change UI
      _currentPost = _currentPost.copyWith(
        liked: !_currentPost.liked,
        likes: _currentPost.liked ? _currentPost.likes - 1 : _currentPost.likes + 1,
      );
    });

    try {
      Map<String, dynamic> result;
      if (widget.post.liked) {
        result = await PostService.unlikePost(widget.post.id);
      } else {
        result = await PostService.likePost(widget.post.id);
      }

      if (result['success'] && result['post'] != null) {
        // Update with server response
        setState(() {
          _currentPost = result['post'];
          _isLiking = false;
        });
      } else {
        // Revert optimistic update on failure
        setState(() {
          _currentPost = widget.post;
          _isLiking = false;
        });
        
        // Show error message
        if (mounted) {
          ScaffoldMessenger.of(context).showSnackBar(
            SnackBar(
              content: Text(result['message'] ?? 'Failed to update like'),
              backgroundColor: Colors.red,
            ),
          );
        }
      }
    } catch (e) {
      // Revert optimistic update on error
      setState(() {
        _currentPost = widget.post;
        _isLiking = false;
      });
      
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
            content: Text('Network error occurred'),
            backgroundColor: Colors.red,
          ),
        );
      }
    }
  }

  @override
  Widget build(BuildContext context) {
    final creator = _currentPost.creator;
    final avatarColor = _getAvatarColor(creator.displayName);
    final avatarLetter = _getAvatarLetter(creator.displayName);
    final relativeTime = InvitationUtils.getRelativeTime(_currentPost.creationDate);

    return Container(
      margin: EdgeInsets.symmetric(horizontal: 16, vertical: 8),
      decoration: BoxDecoration(
        color: Colors.white,
        borderRadius: BorderRadius.circular(12),
        boxShadow: [
          BoxShadow(
            color: Colors.black.withOpacity(0.05),
            blurRadius: 10,
            offset: Offset(0, 2),
          ),
        ],
      ),
      child: Padding(
        padding: EdgeInsets.all(16),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Row(
              children: [
                CircleAvatar(
                  radius: 20,
                  backgroundColor: avatarColor,
                  child: Text(
                    avatarLetter,
                    style: TextStyle(
                      color: Colors.white,
                      fontWeight: FontWeight.bold,
                      fontSize: 16,
                    ),
                  ),
                ),
                SizedBox(width: 12),
                Expanded(
                  child: Column(
                    crossAxisAlignment: CrossAxisAlignment.start,
                    children: [
                      Text(
                        creator.displayName,
                        style: TextStyle(
                          fontWeight: FontWeight.w600,
                          fontSize: 16,
                          color: Colors.black87,
                        ),
                      ),
                      SizedBox(height: 2),
                      Text(
                        relativeTime,
                        style: TextStyle(color: Colors.grey[600], fontSize: 12),
                      ),
                    ],
                  ),
                ),
                IconButton(
                  onPressed: () {
                    ScaffoldMessenger.of(context).showSnackBar(
                      SnackBar(content: Text('More options pressed')),
                    );
                  },
                  icon: Icon(Icons.more_horiz, color: Colors.grey[600]),
                ),
              ],
            ),
            SizedBox(height: 12),
            Text(
              _currentPost.body,
              style: TextStyle(
                fontSize: 15,
                height: 1.4,
                color: Colors.black87,
              ),
            ),
            SizedBox(height: 16),
            Row(
              children: [
                IconButton(
                  onPressed: _toggleLike,
                  icon: Icon(
                    _currentPost.liked ? Icons.favorite : Icons.favorite_border,
                    color: _currentPost.liked ? Colors.red : Colors.grey[600],
                    size: 24,
                  ),
                ),
                Text(
                  '${_currentPost.likes}',
                  style: TextStyle(
                    color: Colors.grey[700],
                    fontWeight: FontWeight.w500,
                  ),
                ),
                SizedBox(width: 16),
                IconButton(
                  onPressed: () {
                    ScaffoldMessenger.of(context).showSnackBar(
                      SnackBar(content: Text('Comments feature coming soon!')),
                    );
                  },
                  icon: Icon(
                    Icons.chat_bubble_outline,
                    color: Colors.grey[600],
                    size: 24,
                  ),
                ),
                Text(
                  '${_currentPost.comments}',
                  style: TextStyle(
                    color: Colors.grey[700],
                    fontWeight: FontWeight.w500,
                  ),
                ),
                Spacer(),
                IconButton(
                  onPressed: () => _sharePost(_currentPost),
                  icon: Icon(
                    Icons.share_outlined,
                    color: Colors.grey[600],
                    size: 24,
                  ),
                ),
              ],
            ),
          ],
        ),
      ),
    );
  }
}

class ProfilePostsList extends StatefulWidget {
  final Future<Map<String, dynamic>> Function() fetchPosts;
  final Function(int posts, int likes)? onStatsUpdate;

  const ProfilePostsList({
    Key? key,
    required this.fetchPosts,
    this.onStatsUpdate,
  }) : super(key: key);

  @override
  _ProfilePostsListState createState() => _ProfilePostsListState();
}

class _ProfilePostsListState extends State<ProfilePostsList> {
  bool _isLoading = true;
  List<Post> _posts = [];
  String _errorMessage = '';

  @override
  void initState() {
    super.initState();
    _loadPosts();
  }

  Future<void> _loadPosts() async {
    setState(() {
      _isLoading = true;
      _errorMessage = '';
    });

    try {
      final result = await widget.fetchPosts();
      setState(() {
        if (result['success']) {
          _posts = result['posts'];
          // Update parent stats
          if (widget.onStatsUpdate != null) {
            final totalLikes = _posts.fold(0, (sum, post) => sum + post.likes);
            widget.onStatsUpdate!(_posts.length, totalLikes);
          }
        } else {
          _errorMessage = result['message'] ?? 'Failed to load posts';
        }
        _isLoading = false;
      });
    } catch (e) {
      setState(() {
        _errorMessage = 'Network error: $e';
        _isLoading = false;
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    if (_isLoading) {
      return Container(
        padding: EdgeInsets.all(32),
        child: Center(
          child: CircularProgressIndicator(
            valueColor: AlwaysStoppedAnimation<Color>(
              Color(0xFF6A4C93),
            ),
          ),
        ),
      );
    }

    if (_errorMessage.isNotEmpty) {
      return Container(
        padding: EdgeInsets.all(32),
        child: Center(
          child: Column(
            children: [
              Icon(
                Icons.error_outline,
                size: 64,
                color: Colors.grey[400],
              ),
              SizedBox(height: 16),
              Text(
                _errorMessage,
                style: TextStyle(
                  fontSize: 16,
                  color: Colors.grey[600],
                ),
                textAlign: TextAlign.center,
              ),
              SizedBox(height: 16),
              ElevatedButton(
                onPressed: _loadPosts,
                style: ElevatedButton.styleFrom(
                  backgroundColor: Color(0xFF6A4C93),
                  foregroundColor: Colors.white,
                ),
                child: Text('Try Again'),
              ),
            ],
          ),
        ),
      );
    }

    if (_posts.isEmpty) {
      return Container(
        padding: EdgeInsets.all(32),
        child: Center(
          child: Column(
            children: [
              Icon(
                Icons.post_add,
                size: 64,
                color: Colors.grey[400],
              ),
              SizedBox(height: 16),
              Text(
                'No posts yet',
                style: TextStyle(
                  fontSize: 18,
                  color: Colors.grey[600],
                  fontWeight: FontWeight.w500,
                ),
              ),
              SizedBox(height: 8),
              Text(
                'Start sharing your thoughts!',
                style: TextStyle(
                  fontSize: 14,
                  color: Colors.grey[500],
                ),
              ),
            ],
          ),
        ),
      );
    }

    return Column(
      children: [
        ..._posts.map((post) => 
          Container(
            margin: EdgeInsets.only(bottom: 16, left: 16, right: 16),
            child: PostCard(post: post),
          )
        ),
        SizedBox(height: 24),
      ],
    );
  }
}