import 'package:flutter/material.dart';
import 'package:cloud_firestore/cloud_firestore.dart';

import '../components/user_tile_likes.dart';
import '../constants.dart';
import '../services/auth/auth_service.dart';
import '../utils/helper.dart';

enum MenuSort { nameAsc, nameDesc, timestampAsc, timestampDesc }

enum ViewOrder { swipedFirst, matchedFirst }

class LikedUsersPage extends StatefulWidget {
  const LikedUsersPage({super.key});

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

class LikedUsersPageState extends State<LikedUsersPage> {
  final String currentUserId = AuthService().getCurrentUser()!.uid;

  ViewOrder _orderPreference = ViewOrder.swipedFirst;
  MenuSort _sortPreference = MenuSort.nameAsc;

  Future<List<DocumentSnapshot>> _fetchLikedUsers() async {
    QuerySnapshot likedUsersSnapshot = await FirebaseFirestore.instance
        .collection(Constants.dbCollectionUsers)
        .doc(currentUserId)
        .collection(Constants.dbCollectionSwipes)
        .where('liked', isEqualTo: true)
        .get();

    List<String> likedUserIds =
        likedUsersSnapshot.docs.map((doc) => doc.id).toList();

    List<DocumentSnapshot> likedUsers = [];
    for (String userId in likedUserIds) {
      DocumentSnapshot userDoc = await FirebaseFirestore.instance
          .collection(Constants.dbCollectionUsers)
          .doc(userId)
          .get();
      likedUsers.add(userDoc);
    }

    return likedUsers;
  }

  Future<bool> _hasMatch(String userId) async {
    DocumentSnapshot matchDoc = await FirebaseFirestore.instance
        .collection(Constants.dbCollectionUsers)
        .doc(currentUserId)
        .collection(Constants.dbCollectionMatches)
        .doc(userId)
        .get();
    return matchDoc.exists;
  }

  Future<void> _unlikeUser(String userId) async {
    try {
      await FirebaseFirestore.instance
          .collection(Constants.dbCollectionUsers)
          .doc(currentUserId)
          .collection(Constants.dbCollectionSwipes)
          .doc(userId)
          .delete(); //.update({'liked': false});
      setState(() {}); // Refresh the UI
    } catch (e) {
      showMsg(context, 'Error unlike', e.toString());
    }
  }

  void _showMatchMessage() {
    showDialog(
      context: context,
      builder: (BuildContext context) {
        return AlertDialog(
          title: const Text('Match Exists'),
          content: const Text(
            'You cannot unlike a user with whom you have a match.',
          ),
          actions: [
            TextButton(
              onPressed: () => Navigator.of(context).pop(),
              child: const Text('Close'),
            ),
          ],
        );
      },
    );
  }

  Future<void> _showConfirmationDialog(String userId, String userName) async {
    bool? confirm = await showDialog<bool>(
      context: context,
      builder: (BuildContext context) {
        return AlertDialog(
          title: const Text('Confirm Unlike'),
          content: Text('Are you sure you want to unlike $userName?'),
          actions: [
            TextButton(
              onPressed: () => Navigator.of(context).pop(false),
              child: const Text('Cancel'),
            ),
            TextButton(
              onPressed: () => Navigator.of(context).pop(true),
              child: const Text('Confirm'),
            ),
          ],
        );
      },
    );

    if (confirm == true) {
      await _unlikeUser(userId);
    }
  }

  void _showUserInfo(DocumentSnapshot user) {
    Map<String, dynamic> userMap = user.data() as Map<String, dynamic>;
    bool hasName = userMap.containsKey(Constants.dbFieldUsersName);
    bool hasBio = userMap.containsKey(Constants.dbFieldUsersBio);

    showDialog(
      context: context,
      builder: (BuildContext context) {
        return AlertDialog(
          title: hasName
              ? Text(user[Constants.dbFieldUsersName])
              : const Text('Name: n/a'),
          content: hasBio
              ? Text(user[Constants.dbFieldUsersBio])
              : const Text('Bio: n/a'),
          actions: [
            TextButton(
              onPressed: () => Navigator.of(context).pop(),
              child: const Text('Close'),
            ),
          ],
        );
      },
    );
  }

  Future<List<DocumentSnapshot>> _fetchSortedLikedUsers() async {
    List<DocumentSnapshot> likedUsers = await _fetchLikedUsers();
    List<DocumentSnapshot> likedOnlyUsers = [];
    List<DocumentSnapshot> matchedUsers = [];

    for (DocumentSnapshot user in likedUsers) {
      bool hasMatch = await _hasMatch(user.id);
      if (hasMatch) {
        matchedUsers.add(user);
      } else {
        likedOnlyUsers.add(user);
      }
    }

    if (_sortPreference == MenuSort.nameAsc) {
      likedOnlyUsers.sort((a, b) => (a[Constants.dbFieldUsersName] as String)
          .compareTo(b[Constants.dbFieldUsersName] as String));
      matchedUsers.sort((a, b) => (a[Constants.dbFieldUsersName] as String)
          .compareTo(b[Constants.dbFieldUsersName] as String));
    } else if (_sortPreference == MenuSort.nameDesc) {
      likedOnlyUsers.sort((a, b) => (b[Constants.dbFieldUsersName] as String)
          .compareTo(a[Constants.dbFieldUsersName] as String));
      matchedUsers.sort((a, b) => (b[Constants.dbFieldUsersName] as String)
          .compareTo(a[Constants.dbFieldUsersName] as String));
    }

    if (_orderPreference == ViewOrder.swipedFirst) {
      return [...likedOnlyUsers, ...matchedUsers];
    } else {
      return [...matchedUsers, ...likedOnlyUsers];
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Liked Users'),
      ),
      body: Column(
        children: [
          Padding(
            padding: const EdgeInsets.all(8.0),
            child: Row(
              mainAxisAlignment: MainAxisAlignment.spaceBetween,
              children: [
                DropdownButton<ViewOrder>(
                  value: _orderPreference,
                  items: const [
                    DropdownMenuItem(
                        value: ViewOrder.swipedFirst,
                        child: Text('Swiped First')),
                    DropdownMenuItem(
                        value: ViewOrder.matchedFirst,
                        child: Text('Matched First')),
                  ],
                  onChanged: (value) {
                    // update UI on change only
                    if (_orderPreference != value) {
                      setState(() {
                        _orderPreference = value!;
                      });
                    }
                  },
                ),
                Align(
                  alignment: Alignment.centerRight,
                  child: PopupMenuButton<MenuSort>(
                    icon: const Icon(Icons.sort),
                    onSelected: (MenuSort item) {
                      // update UI on change only
                      if (_sortPreference != item) {
                        setState(() {
                          _sortPreference = item;
                        });
                      }
                    },
                    itemBuilder: (BuildContext context) =>
                        <PopupMenuEntry<MenuSort>>[
                      PopupMenuItem<MenuSort>(
                        value: MenuSort.nameAsc,
                        child: ListTile(
                          leading: _sortPreference == MenuSort.nameAsc
                              ? const Icon(Icons.check)
                              : const Icon(null),
                          title: const Text('Name Ascending'),
                        ),
                      ),
                      PopupMenuItem<MenuSort>(
                        value: MenuSort.nameDesc,
                        child: ListTile(
                          leading: _sortPreference == MenuSort.nameDesc
                              ? const Icon(Icons.check)
                              : const Icon(null),
                          title: const Text('Name Descending'),
                        ),
                      ),
                    ],
                  ),
                ),
              ],
            ),
          ),
          buildLikedUserList(),
        ],
      ),
    );
  }

  Widget buildLikedUserList() {
    return Expanded(
      child: FutureBuilder<List<DocumentSnapshot>>(
        future: _fetchSortedLikedUsers(),
        builder: (BuildContext context,
            AsyncSnapshot<List<DocumentSnapshot>> snapshot) {
          if (snapshot.connectionState == ConnectionState.waiting) {
            return const Center(child: CircularProgressIndicator());
          } else if (snapshot.hasError) {
            return Center(child: Text('Error: ${snapshot.error}'));
          } else if (!snapshot.hasData || snapshot.data!.isEmpty) {
            return const Center(child: Text('No liked users found.'));
          } else {
            return ListView.builder(
              itemCount: snapshot.data!.length,
              itemBuilder: (BuildContext context, int index) {
                DocumentSnapshot user = snapshot.data![index];
                return FutureBuilder<bool>(
                  future: _hasMatch(user.id),
                  builder: (context, snapshot) {
                    if (snapshot.connectionState == ConnectionState.waiting) {
                      return const CircularProgressIndicator();
                    }
                    bool hasMatch = snapshot.data ?? false;
                    return UserTileLikes(
                      user: user,
                      hasMatch: hasMatch,
                      onUnlike: () {
                        Map<String, dynamic> userMap =
                            user.data() as Map<String, dynamic>;
                        bool hasName =
                            userMap.containsKey(Constants.dbFieldUsersName);

                        _showConfirmationDialog(
                          user.id,
                          (hasName
                              ? user[Constants.dbFieldUsersName]
                              : 'Name: n/a'),
                        );
                      }, //_unlikeUser(user.id),
                      onShowMatchMessage: _showMatchMessage,
                      onViewInfo: () => _showUserInfo(user),
                    );
                  },
                );
              },
            );
          }
        },
      ),
    );
  }
}