feed_controller.dart

import 'package:flutter_riverpod/flutter_riverpod.dart';
import '../models/post_model.dart';
import '../models/pet_model.dart';
import '../repositories/feed_repository.dart';

// ---------------------------------------------------------------------------
// State wrapper
// ---------------------------------------------------------------------------
class FeedState {
  final List<PostModel> posts;
  final bool isLoading;
  final String? error;

  FeedState({
    this.posts = const [],
    this.isLoading = false,
    this.error,
  });

  FeedState copyWith({
    List<PostModel>? posts,
    bool? isLoading,
    String? error,
    bool clearError = false,
  }) {
    return FeedState(
      posts: posts ?? this.posts,
      isLoading: isLoading ?? this.isLoading,
      error: clearError ? null : (error ?? this.error),
    );
  }
}

// ---------------------------------------------------------------------------
// Notifier
// ---------------------------------------------------------------------------
class FeedNotifier extends Notifier<FeedState> {
  FeedRepository get _repository => ref.read(feedRepositoryProvider);

  @override
  FeedState build() {
    _fetchPosts();
    return FeedState(isLoading: true);
  }

  Future<void> _fetchPosts() async {
    try {
      final posts = await _repository.fetchPosts();
      state = state.copyWith(posts: posts, isLoading: false, clearError: true);
    } catch (e) {
      state = state.copyWith(isLoading: false, error: e.toString());
    }
  }

  Future<void> refresh() => _fetchPosts();

  // -------------------------------------------------------------------------
  // Toggle Like (optimistic update then sync with real IDs from server)
  // -------------------------------------------------------------------------
  Future<void> toggleLike(String postId, String currentPetId) async {
    // Optimistic update
    state = state.copyWith(
      posts: state.posts.map((post) {
        if (post.id != postId) return post;
        final newLikes = List<String>.from(post.likedByPetIds);
        if (newLikes.contains(currentPetId)) {
          newLikes.remove(currentPetId);
        } else {
          newLikes.add(currentPetId);
        }
        return post.copyWith(likedByPetIds: newLikes);
      }).toList(),
    );

    try {
      final updatedLikes =
          await _repository.toggleLike(postId, currentPetId);
      state = state.copyWith(
        posts: state.posts.map((post) {
          if (post.id != postId) return post;
          return post.copyWith(likedByPetIds: updatedLikes);
        }).toList(),
      );
    } catch (_) {
      // Revert optimistic update on failure
      state = state.copyWith(
        posts: state.posts.map((post) {
          if (post.id != postId) return post;
          final revertedLikes = List<String>.from(post.likedByPetIds);
          if (revertedLikes.contains(currentPetId)) {
            revertedLikes.remove(currentPetId);
          } else {
            revertedLikes.add(currentPetId);
          }
          return post.copyWith(likedByPetIds: revertedLikes);
        }).toList(),
      );
    }
  }

  // -------------------------------------------------------------------------
  // Add Post (media URL already uploaded by caller)
  // -------------------------------------------------------------------------
  Future<void> addPost(PetModel pet, String mediaUrl, String caption) async {
    try {
      final newPost = await _repository.createPost(
        petId: pet.id,
        mediaUrl: mediaUrl,
        caption: caption,
      );
      state = state.copyWith(posts: [newPost, ...state.posts]);
    } catch (e) {
      state = state.copyWith(error: 'Failed to create post: $e');
    }
  }

  // -------------------------------------------------------------------------
  // Add Comment
  // -------------------------------------------------------------------------
  Future<void> addComment(
      String postId, String petId, String petName, String text) async {
    try {
      final newComment = await _repository.addComment(
        postId: postId,
        petId: petId,
        text: text,
      );
      state = state.copyWith(
        posts: state.posts.map((post) {
          if (post.id != postId) return post;
          return post.copyWith(
              comments: [...post.comments, newComment]);
        }).toList(),
      );
    } catch (e) {
      state = state.copyWith(error: 'Failed to add comment: $e');
    }
  }
}

// ---------------------------------------------------------------------------
// Provider
// ---------------------------------------------------------------------------
final feedProvider = NotifierProvider<FeedNotifier, FeedState>(FeedNotifier.new);