import 'package:cached_network_image/cached_network_image.dart';
import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:go_router/go_router.dart';
import 'package:provider/provider.dart';

import '../constants/app_colors.dart';
import '../models/post.dart';
import '../services/streamable_service.dart';
import '../utils/community_handle_utils.dart';
import '../utils/date_time_utils.dart';
import 'external_link_bar.dart';
import 'fullscreen_video_player.dart';
import 'post_card_actions.dart';

/// Post card widget for displaying feed posts
///
/// Displays a post with:
/// - Community and author information
/// - Post title and text content
/// - External embed (link preview with image)
/// - Action buttons (share, comment, like)
///
/// The [currentTime] parameter allows passing the current time for
/// time-ago calculations, enabling:
/// - Periodic updates of time strings
/// - Deterministic testing without DateTime.now()
class PostCard extends StatelessWidget {
  const PostCard({
    required this.post,
    this.currentTime,
    this.showCommentButton = true,
    this.disableNavigation = false,
    this.showActions = true,
    this.showHeader = true,
    this.showBorder = true,
    this.showFullText = false,
    this.showAuthorFooter = false,
    this.textFontSize = 13,
    this.textLineHeight = 1.4,
    this.embedHeight = 180,
    this.titleFontSize = 16,
    this.titleFontWeight = FontWeight.w400,
    super.key,
  });

  final FeedViewPost post;
  final DateTime? currentTime;
  final bool showCommentButton;
  final bool disableNavigation;
  final bool showActions;
  final bool showHeader;
  final bool showBorder;
  final bool showFullText;
  final bool showAuthorFooter;
  final double textFontSize;
  final double textLineHeight;
  final double embedHeight;
  final double titleFontSize;
  final FontWeight titleFontWeight;

  void _navigateToDetail(BuildContext context) {
    // Navigate to post detail screen
    // Use URI-encoded version of the post URI for the URL path
    // Pass the full post object via extras
    final encodedUri = Uri.encodeComponent(post.post.uri);
    context.push('/post/$encodedUri', extra: post);
  }

  @override
  Widget build(BuildContext context) {
    return Container(
      margin: EdgeInsets.only(bottom: showHeader ? 8 : 0),
      decoration: BoxDecoration(
        color: AppColors.background,
        border:
            showBorder
                ? const Border(bottom: BorderSide(color: AppColors.border))
                : null,
      ),
      child: Padding(
        padding: EdgeInsets.fromLTRB(16, showHeader ? 4 : 12, 16, 1),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            // Community and author info
            if (showHeader) ...[
              Row(
                children: [
                  // Community avatar
                  _buildCommunityAvatar(post.post.community),
                  const SizedBox(width: 8),
                  Expanded(
                    child: Column(
                      crossAxisAlignment: CrossAxisAlignment.start,
                      children: [
                        // Community handle with styled parts
                        _buildCommunityHandle(post.post.community),
                        // Author handle
                        Text(
                          '@${post.post.author.handle}',
                          style: const TextStyle(
                            color: AppColors.textSecondary,
                            fontSize: 12,
                          ),
                        ),
                      ],
                    ),
                  ),
                  // Time ago
                  Text(
                    DateTimeUtils.formatTimeAgo(
                      post.post.createdAt,
                      currentTime: currentTime,
                    ),
                    style: TextStyle(
                      color: AppColors.textPrimary.withValues(alpha: 0.5),
                      fontSize: 14,
                    ),
                  ),
                ],
              ),
              const SizedBox(height: 8),
            ],

            // Post content - title and text are clickable, embed handles
            // its own taps
            Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                // Author info (shown in detail view, above title)
                if (showAuthorFooter) _buildAuthorFooter(),

                // Title and text wrapped in InkWell for navigation
                if (!disableNavigation &&
                    (post.post.title != null || post.post.text.isNotEmpty))
                  InkWell(
                    onTap: () => _navigateToDetail(context),
                    child: Column(
                      crossAxisAlignment: CrossAxisAlignment.start,
                      children: [
                        // Post title
                        if (post.post.title != null) ...[
                          Text(
                            post.post.title!,
                            style: TextStyle(
                              color: AppColors.textPrimary,
                              fontSize: titleFontSize,
                              fontWeight: titleFontWeight,
                              height: 1.3,
                            ),
                          ),
                        ],

                        // Spacing after title
                        if (post.post.title != null &&
                            (post.post.embed?.external != null ||
                                post.post.text.isNotEmpty))
                          const SizedBox(height: 8),
                      ],
                    ),
                  )
                else
                // Title when navigation is disabled
                if (post.post.title != null) ...[
                  Text(
                    post.post.title!,
                    style: TextStyle(
                      color: AppColors.textPrimary,
                      fontSize: titleFontSize,
                      fontWeight: titleFontWeight,
                      height: 1.3,
                    ),
                  ),
                  if (post.post.embed?.external != null ||
                      post.post.text.isNotEmpty)
                    const SizedBox(height: 8),
                ],

                // Embed (handles its own taps - not wrapped in InkWell)
                if (post.post.embed?.external != null) ...[
                  _EmbedCard(
                    embed: post.post.embed!.external!,
                    streamableService: context.read<StreamableService>(),
                    height: embedHeight,
                    onImageTap:
                        disableNavigation
                            ? null
                            : () => _navigateToDetail(context),
                  ),
                  const SizedBox(height: 8),
                ],

                // Post text (clickable for navigation)
                if (post.post.text.isNotEmpty) ...[
                  if (!disableNavigation)
                    InkWell(
                      onTap: () => _navigateToDetail(context),
                      child: _buildTextContent(),
                    )
                  else
                    _buildTextContent(),
                ],
              ],
            ),

            // External link (if present)
            if (post.post.embed?.external != null) ...[
              const SizedBox(height: 8),
              ExternalLinkBar(embed: post.post.embed!.external!),
            ],

            // Reduced spacing before action buttons
            if (showActions) const SizedBox(height: 4),

            // Action buttons row
            if (showActions)
              PostCardActions(post: post, showCommentButton: showCommentButton),
          ],
        ),
      ),
    );
  }

  /// Builds the text content with appropriate styling
  Widget _buildTextContent() {
    if (showFullText) {
      // Detail view: no container, better readability
      return Padding(
        padding: const EdgeInsets.symmetric(horizontal: 4),
        child: Text(
          post.post.text,
          style: TextStyle(
            color: AppColors.textPrimary,
            fontSize: textFontSize,
            height: textLineHeight,
          ),
        ),
      );
    } else {
      // Feed view: compact preview with container
      return Container(
        padding: const EdgeInsets.all(10),
        decoration: BoxDecoration(
          color: AppColors.backgroundSecondary,
          borderRadius: BorderRadius.circular(8),
        ),
        child: Text(
          post.post.text,
          style: TextStyle(
            color: AppColors.textPrimary.withValues(alpha: 0.85),
            fontSize: textFontSize,
            height: textLineHeight,
          ),
          maxLines: 5,
          overflow: TextOverflow.ellipsis,
        ),
      );
    }
  }

  /// Builds the community handle with styled parts (name + instance)
  Widget _buildCommunityHandle(CommunityRef community) {
    final displayHandle =
        CommunityHandleUtils.formatHandleForDisplay(community.handle)!;

    // Split the handle into community name and instance
    // Format: !gaming@coves.social
    final atIndex = displayHandle.indexOf('@');
    final communityPart = displayHandle.substring(0, atIndex);
    final instancePart = displayHandle.substring(atIndex);

    return Text.rich(
      TextSpan(
        children: [
          TextSpan(
            text: communityPart,
            style: const TextStyle(
              color: AppColors.communityName,
              fontSize: 14,
            ),
          ),
          TextSpan(
            text: instancePart,
            style: TextStyle(
              color: AppColors.textSecondary.withValues(alpha: 0.6),
              fontSize: 14,
            ),
          ),
        ],
      ),
    );
  }

  /// Builds the community avatar widget
  Widget _buildCommunityAvatar(CommunityRef community) {
    if (community.avatar != null && community.avatar!.isNotEmpty) {
      // Show real community avatar
      return ClipRRect(
        borderRadius: BorderRadius.circular(4),
        child: CachedNetworkImage(
          imageUrl: community.avatar!,
          width: 24,
          height: 24,
          fit: BoxFit.cover,
          placeholder: (context, url) => _buildFallbackAvatar(community),
          errorWidget: (context, url, error) => _buildFallbackAvatar(community),
        ),
      );
    }

    // Fallback to letter placeholder
    return _buildFallbackAvatar(community);
  }

  /// Builds a fallback avatar with the first letter of community name
  Widget _buildFallbackAvatar(CommunityRef community) {
    return Container(
      width: 24,
      height: 24,
      decoration: BoxDecoration(
        color: AppColors.primary,
        borderRadius: BorderRadius.circular(4),
      ),
      child: Center(
        child: Text(
          community.name[0].toUpperCase(),
          style: const TextStyle(
            color: AppColors.textPrimary,
            fontSize: 12,
            fontWeight: FontWeight.bold,
          ),
        ),
      ),
    );
  }

  /// Builds author footer with avatar, handle, and timestamp
  Widget _buildAuthorFooter() {
    final author = post.post.author;

    return Padding(
      padding: const EdgeInsets.symmetric(horizontal: 4, vertical: 8),
      child: Row(
        children: [
          // Author avatar (circular, small)
          if (author.avatar != null && author.avatar!.isNotEmpty)
            ClipRRect(
              borderRadius: BorderRadius.circular(12),
              child: CachedNetworkImage(
                imageUrl: author.avatar!,
                width: 24,
                height: 24,
                fit: BoxFit.cover,
                placeholder:
                    (context, url) => _buildAuthorFallbackAvatar(author),
                errorWidget:
                    (context, url, error) => _buildAuthorFallbackAvatar(author),
              ),
            )
          else
            _buildAuthorFallbackAvatar(author),
          const SizedBox(width: 8),

          // Author handle
          Text(
            '@${author.handle}',
            style: const TextStyle(
              color: AppColors.textPrimary,
              fontSize: 14,
              fontWeight: FontWeight.w500,
            ),
            overflow: TextOverflow.ellipsis,
          ),

          const SizedBox(width: 8),

          // Timestamp
          Text(
            DateTimeUtils.formatTimeAgo(
              post.post.createdAt,
              currentTime: currentTime,
            ),
            style: TextStyle(
              color: AppColors.textSecondary.withValues(alpha: 0.7),
              fontSize: 13,
            ),
          ),
        ],
      ),
    );
  }

  /// Builds a fallback avatar for the author
  Widget _buildAuthorFallbackAvatar(AuthorView author) {
    final firstLetter =
        (author.displayName ?? author.handle).isNotEmpty
            ? (author.displayName ?? author.handle)[0]
            : '?';
    return Container(
      width: 24,
      height: 24,
      decoration: BoxDecoration(
        color: AppColors.primary,
        borderRadius: BorderRadius.circular(12),
      ),
      child: Center(
        child: Text(
          firstLetter.toUpperCase(),
          style: const TextStyle(
            color: AppColors.textPrimary,
            fontSize: 12,
            fontWeight: FontWeight.bold,
          ),
        ),
      ),
    );
  }
}

/// Embed card widget for displaying link previews
///
/// Shows a thumbnail image for external embeds with loading and error states.
/// For video embeds (Streamable), displays a play button overlay and opens
/// a video player dialog when tapped.
class _EmbedCard extends StatefulWidget {
  const _EmbedCard({
    required this.embed,
    required this.streamableService,
    this.height = 180,
    this.onImageTap,
  });

  final ExternalEmbed embed;
  final StreamableService streamableService;
  final double height;
  final VoidCallback? onImageTap;

  @override
  State<_EmbedCard> createState() => _EmbedCardState();
}

class _EmbedCardState extends State<_EmbedCard> {
  bool _isLoadingVideo = false;

  /// Checks if this embed is a video
  bool get _isVideo {
    final embedType = widget.embed.embedType;
    return embedType == 'video' || embedType == 'video-stream';
  }

  /// Checks if this is a Streamable video
  bool get _isStreamableVideo {
    return _isVideo && widget.embed.provider?.toLowerCase() == 'streamable';
  }

  /// Shows the video player in fullscreen with swipe-to-dismiss
  Future<void> _showVideoPlayer(BuildContext context) async {
    // Capture context-dependent objects before async gap
    final messenger = ScaffoldMessenger.of(context);
    final navigator = Navigator.of(context);

    setState(() {
      _isLoadingVideo = true;
    });

    try {
      // Fetch the MP4 URL from Streamable using the injected service
      final videoUrl = await widget.streamableService.getVideoUrl(
        widget.embed.uri,
      );

      if (!mounted) {
        return;
      }

      if (videoUrl == null) {
        // Show error if we couldn't get the video URL
        messenger.showSnackBar(
          SnackBar(
            content: Text(
              'Failed to load video',
              style: TextStyle(
                color: AppColors.textPrimary.withValues(alpha: 0.9),
              ),
            ),
            backgroundColor: AppColors.backgroundSecondary,
          ),
        );
        return;
      }

      // Navigate to fullscreen video player
      await navigator.push<void>(
        MaterialPageRoute(
          builder: (context) => FullscreenVideoPlayer(videoUrl: videoUrl),
          fullscreenDialog: true,
        ),
      );
    } finally {
      if (mounted) {
        setState(() {
          _isLoadingVideo = false;
        });
      }
    }
  }

  @override
  Widget build(BuildContext context) {
    // Only show image if thumbnail exists
    if (widget.embed.thumb == null) {
      return const SizedBox.shrink();
    }

    // Build the thumbnail image
    final thumbnailWidget = Container(
      decoration: BoxDecoration(
        borderRadius: BorderRadius.circular(8),
        border: Border.all(color: AppColors.border),
      ),
      clipBehavior: Clip.antiAlias,
      child: CachedNetworkImage(
        imageUrl: widget.embed.thumb!,
        width: double.infinity,
        height: widget.height,
        fit: BoxFit.cover,
        placeholder:
            (context, url) => Container(
              width: double.infinity,
              height: widget.height,
              color: AppColors.background,
              child: const Center(
                child: CircularProgressIndicator(
                  color: AppColors.loadingIndicator,
                ),
              ),
            ),
        errorWidget: (context, url, error) {
          if (kDebugMode) {
            debugPrint('❌ Image load error: $error');
            debugPrint('URL: $url');
          }
          return Container(
            width: double.infinity,
            height: widget.height,
            color: AppColors.background,
            child: const Icon(
              Icons.broken_image,
              color: AppColors.loadingIndicator,
              size: 48,
            ),
          );
        },
      ),
    );

    // If this is a Streamable video, add play button overlay and tap handler
    if (_isStreamableVideo) {
      return GestureDetector(
        onTap: _isLoadingVideo ? null : () => _showVideoPlayer(context),
        child: Stack(
          alignment: Alignment.center,
          children: [
            thumbnailWidget,
            // Semi-transparent play button or loading indicator overlay
            Container(
              width: 64,
              height: 64,
              decoration: BoxDecoration(
                color: AppColors.background.withValues(alpha: 0.7),
                shape: BoxShape.circle,
              ),
              child:
                  _isLoadingVideo
                      ? const CircularProgressIndicator(
                        color: AppColors.loadingIndicator,
                      )
                      : const Icon(
                        Icons.play_arrow,
                        color: AppColors.textPrimary,
                        size: 48,
                      ),
            ),
          ],
        ),
      );
    }

    // For non-video embeds (images, link previews), make them tappable
    // to navigate to post detail
    if (widget.onImageTap != null) {
      return GestureDetector(onTap: widget.onImageTap, child: thumbnailWidget);
    }

    // No tap handler provided, just return the thumbnail
    return thumbnailWidget;
  }
}