import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:firebase_auth/firebase_auth.dart';
import '../constants.dart';
import '../enumerations.dart';
import '../models/language.dart';
import '../models/location.dart';
import '../models/user_profile.dart';

class UserService {
  UserService._(); // Private constructor to prevent instantiation

  static Future<void> saveUserRegistrationData(UserCredential userCredential,
      String email, String firstname, String lastname) async {
    // create full name
    String fullName = (firstname.isNotEmpty && lastname.isNotEmpty)
        ? '$firstname $lastname'
        : (firstname.isNotEmpty
            ? firstname
            : (lastname.isNotEmpty ? lastname : ''));

    // save user info to users document
    await FirebaseFirestore.instance
        .collection(Constants.dbCollectionUsers)
        .doc(userCredential.user!.uid)
        .set(
      {
        Constants.dbFieldUsersID: userCredential.user!.uid,
        Constants.dbFieldUsersEmail: email,
        Constants.dbFieldUsersFirstName: firstname,
        Constants.dbFieldUsersLastName: lastname,
        Constants.dbFieldUsersName: fullName,
      },
    );
  }

  static Future<List<SkillOption>> getSkillsFromFirebase(
      bool skillsSought, String userId) async {
    // Fetch skills from Firestore
    DocumentSnapshot userDoc = await FirebaseFirestore.instance
        .collection(Constants.dbCollectionUsers)
        .doc(userId)
        .get();

    if (userDoc.exists && userDoc.data() != null) {
      Map<String, dynamic> userData = userDoc.data()! as Map<String, dynamic>;

      List<dynamic>? skills;
      if (skillsSought) {
        skills = userData[Constants.dbFieldUsersSkillsSought];
      } else {
        skills = userData[Constants.dbFieldUsersSkills];
      }

      return convertSkillStringToEnum(skills);
    }

    return [];
  }

  static List<SkillOption> convertSkillStringToEnum(List<dynamic>? skills) {
    if (skills != null && skills.isNotEmpty) {
      // Convert skills from strings to enum values
      List<SkillOption> userSkills = skills
          .map((skill) => SkillOption.values
              .firstWhere((x) => x.toString() == 'SkillOption.$skill'))
          .toList();
      return userSkills;
    }
    return [];
  }

  static List<VisionOption> convertVisionStringToEnum(List<dynamic>? visions) {
    if (visions != null && visions.isNotEmpty) {
      List<VisionOption> userVisions = visions
          .map((vision) =>
              VisionOption.values.firstWhere((x) => x.toString() == vision))
          .toList();
      return userVisions;
    }
    return [];
  }

  static List<WorkValueOption> convertWorkValuesStringToEnum(
      List<dynamic>? values) {
    if (values != null && values.isNotEmpty) {
      List<WorkValueOption> userWorkValues = values
          .map((workValue) => WorkValueOption.values
              .firstWhere((x) => x.toString() == workValue))
          .toList();
      return userWorkValues;
    }
    return [];
  }

  static Future<bool> saveSkillsToFirebase(List<SkillOption> selectedOptions,
      bool skillsSought, String userId) async {
    try {
      // Convert enum values to strings, removing leading EnumType with split
      List<String> skills = selectedOptions
          .map((option) => option.toString().split('.').last)
          .toList();

      // Update the corresponding 'skills' field in the user's document
      String keyToUpdate = skillsSought
          ? Constants.dbFieldUsersSkillsSought
          : Constants.dbFieldUsersSkills;

      FirebaseFirestore.instance
          .collection(Constants.dbCollectionUsers)
          .doc(userId)
          .update({keyToUpdate: skills});

      return true;
    } catch (e) {
      return false;
    }
  }

  /// Get UserProfile for given [userId]
  static Future<UserProfile> getUserProfileById(String userId) async {
    FirebaseFirestore firestore = FirebaseFirestore.instance;

    DocumentSnapshot userDoc = await firestore
        .collection(Constants.dbCollectionUsers)
        .doc(userId)
        .get();

    QuerySnapshot languagesSnapshot = await firestore
        .collection(Constants.dbCollectionUsers)
        .doc(userId)
        .collection(Constants.dbCollectionLanguages)
        .get();
    List<Language> languages = languagesSnapshot.docs
        .map((doc) => Language.fromDocument(doc))
        .toList();

    QuerySnapshot locationsSnapshot = await firestore
        .collection(Constants.dbCollectionUsers)
        .doc(userId)
        .collection(Constants.dbCollectionLocations)
        .get();
    Map<String, MyLocation?> locations = {
      for (var doc in locationsSnapshot.docs)
        doc.id: MyLocation.fromDocument(doc)
    };

    // Fill UserProfile including its sub collections
    UserProfile userProfile = UserProfile.fromDocument(userDoc);
    userProfile.languages.addAll(languages);
    userProfile.locations.addAll(locations);

    return userProfile;
  }

  // get users stream
  static Stream<List<Map<String, dynamic>>> getUsersStream() {
    return FirebaseFirestore.instance
        .collection(Constants.dbCollectionUsers)
        .snapshots()
        .map((snapshot) {
      return snapshot.docs.map((doc) {
        // iterate each user
        final user = doc.data();

        //return user
        return user;
      }).toList();
    });
  }

  // Get list of matched user ids for a given user
  static Future<List<String>> getMatchedUserIds(String userId) async {
    List<String> matchedUserIds = [];

    final snapshot = await FirebaseFirestore.instance
        .collection(Constants.dbCollectionUsers)
        .doc(userId)
        .collection(Constants.dbCollectionMatches)
        .get();

    for (var doc in snapshot.docs) {
      final data = doc.data();
      final otherUserId = data['otherUserId'] as String?;
      if (otherUserId != null && otherUserId.isNotEmpty) {
        matchedUserIds.add(otherUserId);
      }
      // assuming the match document ID is the matched user's ID
      // it would just be an one liner:
      // matchedUserIds.add(doc.id);
    }

    return matchedUserIds;
  }

  // Get matched users data for a given user as stream
  static Stream<List<Map<String, dynamic>>> getMatchedUsersStream(
      String userId) {
    return FirebaseFirestore.instance
        .collection(Constants.dbCollectionUsers)
        .doc(userId)
        .collection(Constants.dbCollectionMatches)
        .snapshots()
        .asyncMap((snapshot) async {
      final matchedUserIds = snapshot.docs
          .map((doc) => doc.data()['otherUserId'] as String?)
          .where((otherUserId) => otherUserId != null && otherUserId.isNotEmpty)
          .toList();

      if (matchedUserIds.isEmpty) {
        return [];
      }

      final matchedUsersSnapshot = await FirebaseFirestore.instance
          .collection(Constants.dbCollectionUsers)
          .where(FieldPath.documentId, whereIn: matchedUserIds)
          .get();

      return matchedUsersSnapshot.docs.map((doc) => doc.data()).toList();
    });
  }
}